Colorectal cancer remains a leading cause of mortality worldwide, and early detection is essential for improving outcomes. CT colonography (CTC) has emerged as a promising alternative to optical colonoscopy for colorectal cancer screening. This article explores the potential of CTC in Japan, focusing on quality control, patient acceptability, complications, and its role in screening programs. CTC has demonstrated high sensitivity and specificity for detecting colorectal polyps, with its diagnostic performance comparable to colonoscopy for lesions ≥ 10 mm. Techniques such as fecal tagging and dual-position imaging significantly enhance diagnostic accuracy. However, the variability in diagnostic outcomes underscores the need for rigorous interpretation training and quality control. The American College of Radiology recommends training with at least 50 cases verified by colonoscopy. Despite its advantages, the adoption of CTC in Japan remains limited due to low awareness among medical professionals, a shortage of trained radiologists, and the absence of specific guidelines endorsing its use. Patient acceptability for CTC is high due to its non-invasive nature, shorter examination time, and reduced bowel preparation requirements compared to colonoscopy. Nonetheless, complications such as bowel perforation, albeit rare, necessitate careful risk assessment. While CTC has been recognized in the U.S. and Europe for screening and diagnostic follow-up, its integration into Japan's colorectal cancer screening guidelines is crucial to expand its utilization. To maximize the benefits of CTC, efforts must focus on standardizing methodologies, establishing quality indicators, and generating robust evidence on mortality reduction and cost-effectiveness.

This document serves to update the 2018 ACR Appropriateness Criteria® colorectal screening guidance document. In light of new recommendations from the US Preventative Services Task Force (USPSTF), an updated literature review of the imaging procedures for the screening of colorectal cancer was performed. Average-risk, elevated-risk, and high-risk individuals as well as those individuals who had an incomplete colonoscopy or were unable to tolerate colonoscopy were included. CT colonography without contrast was found to be usually appropriate for individuals at average and elevated risk between 45 to 75 years of age at initial screening. Additionally, CT colonography without contrast was found to be usually appropriate in individuals at average risk, elevated risk, and at high risk after incomplete colonoscopy or unable to tolerate colonoscopy. Other imaging procedures such as barium fluoroscopy and CT of the abdomen and pelvis were usually not appropriate. CT colonography without contrast, barium fluoroscopy, and CT of the abdomen and pelvis were usually not appropriate in high-risk individuals who can undergo a complete colonoscopy. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Early detection of colorectal cancer (CRC) through screening is the most effective method to reduce morbidity as well as mortality from this disease. Fecal immunochemical test (FIT)-based screening has shown to be effective, especially in multi-round population-based screening. However, its sensitivity and specificity are suboptimal, leaving room for improvement. In this perspective, the development journey of a new screening test, the multitargetFIT (mtFIT), which outperforms FIT, is described from discovery down to large-scale clinical utility testing and health technology assessment.

BackgroundChanging colorectal cancer (CRC) incidence rates, including recent increases for people younger than 50 y, need to be considered in planning for future cancer control and screening initiatives. Reliable estimates of the impact of changing CRC trends on the National Bowel Cancer Screening Program (NBCSP) are essential for programmatic planning in Australia. An existing microsimulation model of CRC, Policy1-Bowel, was updated to reproduce Australian CRC trends data and provide updated projections of CRC- and screening-related outcomes to inform clinical practice guidelines for the prevention of CRC.MethodsPolicy1-Bowel was recalibrated to reproduce statistical age-period-cohort model trends and projections of CRC incidence for 1995-2045 in the absence of the NBCSP as well as published data on CRC incidence trends, stage distribution, and survival in 1995-2020 in Australia. The recalibrated Policy1-Bowel predictions were validated by comparison with published Australian CRC mortality trends for 1995-2015 and statistical projections to 2040. Metamodels were developed to aid the calibration process and significantly reduce the computational burden.ResultsPolicy1-Bowel was recalibrated, and best-fit parameter sets were identified for lesion incidence, CRC stage progression rates, detection rates, and survival rates by age, sex, bowel location, cancer stage, and birth year. The recalibrated model was validated and successfully reproduced observed CRC mortality rates for 1995-2015 and statistical projections for 2016-2030.ConclusionThe recalibrated Policy1-Bowel model captures significant additional detail on the future incidence and mortality burden of CRC in Australia. This is particularly relevant as younger cohorts with higher CRC incidence rates approach screening ages to inform decision making for these groups. The metamodeling approach allows fast recalibration and makes regular updates to incorporate new evidence feasible.HighlightsIn Australia, colorectal cancer incidence rates are increasing for people younger than 50 y but decreasing for people older than 50 y, and colorectal cancer survival is improving as new treatment technologies emerge.To evaluate the future health and economic impact of screening and inform policy, modeling must include detailed trends and projections of colorectal cancer incidence, mortality, and diagnosis stage.We used novel techniques including integrative age-period cohort projections and metamodel calibration to update Policy1-Bowel, a detailed microsimulation of colorectal cancer and screening in Australia.

The incidence of colorectal cancer (CRC) has been increasing in recent decades. Current methods for CRC screening have their own drawbacks, thus there is an urgent need to identify the key microbes that drive the development of CRC for wider application in the early detection and prevention of CRC. To address this issue, we performed fecal microbiome analysis by high-throughput sequencing of 16S rRNA gene combined with blood biochemical indicators in patients with CRC stages I, II, III, and IV, healthy people, and patients with polyps. Fecal microbiota of patients with CRC was disturbed, as evidenced by significantly reduced α-diversity in patients with CRC stage IV and markedly different β-diversity. The random forest model identified the top 25 genera from 174 training data, resulting in a diagnostic accuracy of 87.95%. Further, by combining with differential genera analysis, we screened out 11 biomarkers that significantly changed in different groups. Peptostreptococcus, Parvimonas, Shewanella, Oscillibacter, Eggerthella, and Gemella associated with the development of CRC were significantly enriched, while Fenollaria, Staphylococcus, Ezakiella, Finegoldia, and Neisseria associated with the remission of CRC were significantly suppressed in patients with CRC. Importantly, carcinoembryonic antigen (CEA) was significantly correlated with these 11 microbial biomarkers, and carbohydrate antigen 19-9 (CA 19-9) was markedly correlated with Oscillibacter. Notably, co-occurrence network analysis at the genus level exhibited that the microbial co-occurrence network of CRC IV was the most complex and stable. These results suggested that CEA, CA 19-9 and 11 microbial biomarkers may be co-biomarkers for the disease occurrence and development, and non-invasive diagnosis of CRC.

Identifying the key microbes that drive the development of colorectal cancer (CRC) has been important in this field. We delved into the research on the association between CRC and fecal microbiota in this study, providing a detailed analysis of the characteristics of fecal microbiota during the transition from normal intestine to polyps to cancer. Fecal bacterial biomarkers and blood biochemical indicators may be co-biomarkers in the development of CRC.

CT colonography (CTC) is a CT examination, performed with low dose and typically without IV contrast media, optimized to detect colorectal polyps and cancer. Despite extensive supporting data, CTC has had variable acceptance and use over the past two decades, particularly for a main indication of colorectal cancer screening. CTC is now at an inflection point after the approval in 2025 by CMS for reimbursement of CTC performed for colorectal cancer screening. Widespread use of CTC for CRC screening could help increase screening adherence rates and prevent cancer incidence. Nonetheless, radiologists must incorporate emerging knowledge regarding polyps' natural history and recognition of sessile serrated lesions, to leverage the screening efficiencies of CTC-based screening. The purposes of this article are to describe the current status of CRC in the United States and United Kingdom with consideration of historical reasons that have limited the test's use along with recent events that may portend a marked change in the test's acceptance; to highlight the challenges and potential solutions toward successful widespread CTC implementation; and to present new concepts in CTC and CRC screening relevant to radiologists.

Colorectal cancer (CRC) ranks as the third most prevalent cancer globally, both in terms of diagnoses and cancer-related mortality. Increasing evidence suggests that an imbalance in intestinal flora can contribute to the progression of CRC, and fecal microbiota may serve as potential biomarkers for its screening and diagnosis. Notably, Porphyromonas gingivalis has been identified in the malignant tissues and feces of CRC patients, establishing it as a significant biomarker for early screening, diagnosis, and prognostic assessment of CRC. Current methods for detecting P. gingivalis face numerous challenges, including high costs, complex procedures, and lengthy implementation times. Therefore, developing rapid, highly specific, and sensitive detection methods for P. gingivalis is of great importance. In this study, we utilized the whole-bacterium systematic evolution of ligands by exponential enrichment method to identify highly specific and high-affinity aptamers targeting P. gingivalis through 15 selection cycles. Subsequently, we developed an aptasensor driven by MoS2 nanoflowers, which integrates strand displacement amplification and CRISPR/Cas12a double amplification for sensitive detection of P. gingivalis, achieving a limit of detection of 10 CFU/mL. Using this aptasensor, we evaluated the abundance of P. gingivalis in clinical fecal samples and observed significantly higher levels in the feces of CRC patients compared to healthy individuals, corroborating the results obtained from quantitative polymerase chain reaction. In summary, we developed a highly specific and sensitive aptasensor for the first time, representing a promising new approach for the identification of P. gingivalis, with significant potential for CRC screening and diagnosis.

Demonstrating mortality reduction in new colorectal cancer (CRC) screening programs through randomized clinical trials (RCTs) is challenging. We systematically reviewed single-round program performance outcomes using a stepwise approach proposed by the World Endoscopy Organization CRC Screening Committee framework.

The MEDLINE, EMBASE, Central, and Ichushi Web databases were searched until October 28, 2024, to find RCTs comparing guaiac-based and immunochemical fecal occult blood testing (gFOBT and FIT), flexible sigmoidoscopy (FS), computed tomographic colonography (CTC), and total colonoscopy (TCS). Paired reviewers screened studies, extracted data, and assessed bias risk. A Bayesian random-effects network meta-analysis was conducted, and the certainty of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation approach. The primary outcome was advanced neoplasia (AN) detection, and the secondary outcomes were participation and colorectal cancer (CRC) detection, all during the first screening round.

Eighteen RCTs (437,072 invitees) were included. The risk of bias was low or raised some concerns for screening participation, but it was high for detection outcomes. In the network meta-analysis of 15 RCTs not allowing crossover, the FIT-based program had a higher AN detection rate than the gFOBT-based program (relative risk [RR] 2.48; 95% credible interval [CrI] 1.52-4.21; moderate certainty). AN detection rates were not different in the CTC- (RR 1.01; CrI 0.43-2.23; very low certainty) and TCS-based (RR 1.03; CrI 0.54-1.78; low certainty) programs compared with the FS-based program. All the visualization modality programs had higher AN detection rates than the FIT-based program (FS: RR 2.13 [CrI 1.38-3.77]; CTC 2.16 [1.11-4.51]; and TCS 2.19 [1.43-3.48]; all with low certainty). Low event rates precluded definitive conclusions regarding CRC detection (very low to low certainty). The TCS-based program had the worst participation rate (very low to low certainty). Comparative data allowing crossover were limited.

This is the first network meta-analysis that evaluates program-level initial performance indicators. FIT-based programs likely detect more AN cases than gFOBT-based programs, while FS-, CTC-, and TCS-based programs may outperform FIT. Due to limitations in first-round results, long-term outcomes should be assessed after 10-15 years.

Adenomatous colorectal polyps require endoscopic resection, as opposed to non-adenomatous hyperplastic colorectal polyps. This study aims to evaluate the effect of artificial intelligence (AI)-assisted differentiation of adenomatous and non-adenomatous colorectal polyps at CT colonography on radiologists' therapy management.

Five board-certified radiologists evaluated CT colonography images with colorectal polyps of all sizes and morphologies retrospectively and decided whether the depicted polyps required endoscopic resection. After a primary unassisted reading based on current guidelines, a second reading with access to the classification of a radiomics-based random-forest AI-model labelling each polyp as "non-adenomatous" or "adenomatous" was performed. Performance was evaluated using polyp histopathology as the reference standard.

77 polyps in 59 patients comprising 118 polyp image series (47% supine position, 53% prone position) were evaluated unassisted and AI-assisted by five independent board-certified radiologists, resulting in a total of 1180 readings (subsequent polypectomy: yes or no). AI-assisted readings had higher accuracy (76% +/- 1% vs. 84% +/- 1%), sensitivity (78% +/- 6% vs. 85% +/- 1%), and specificity (73% +/- 8% vs. 82% +/- 2%) in selecting polyps eligible for polypectomy (p < 0.001). Inter-reader agreement was improved in the AI-assisted readings (Fleiss' kappa 0.69 vs. 0.92).

AI-based characterisation of colorectal polyps at CT colonography as a second reader might enable a more precise selection of polyps eligible for subsequent endoscopic resection. However, further studies are needed to confirm this finding and histopathologic polyp evaluation is still mandatory.

Question This is the first study evaluating the impact of AI-based polyp classification in CT colonography on radiologists' therapy management. Findings Compared with unassisted reading, AI-assisted reading had higher accuracy, sensitivity, and specificity in selecting polyps eligible for polypectomy. Clinical relevance Integrating an AI tool for colorectal polyp classification in CT colonography could further improve radiologists' therapy recommendations.

Colonoscopy-based surveillance to prevent colorectal cancer (CRC) causes substantial burden for patients and health care. Stool tests may help to reduce surveillance colonoscopies by limiting colonoscopies to individuals at increased risk of advanced neoplasia.

This cross-sectional observational study included individuals aged 50-75 years with surveillance indication. Before bowel preparation, participants collected samples for a multitarget stool DNA test and 2 fecal immunochemical tests (FITs). Test accuracy was calculated for all surveillance indications. For the post-polypectomy indication only, which is the most common and is associated with a relatively low CRC risk, long-term impact of stool-based surveillance was evaluated with the Adenoma and Serrated Pathway to Colorectal Cancer (ASCCA) model. Stool-based strategies were simulated to tune each test's positivity threshold to obtain strategies at least as effective as colonoscopy surveillance.

There were 3453 individuals with results for all stool tests and colonoscopy; 2226 had previous polypectomy, 1003 had previous CRC, and 224 had a familial risk. Areas under the receiver operating characteristic curve for advanced neoplasia were 0.72 (95% CI, 0.69-0.75) for the multitarget stool DNA test, 0.61 (95% CI, 0.58-0.64) for the FIT OC-SENSOR (Eiken Chemical Co, Tokyo, Japan) and 0.59 (95% CI, 0.56-0.61) for the FIT FOB-Gold (Sentinel, Milan, Italy). Stool-based post-polypectomy surveillance strategies at least as effective as colonoscopy surveillance reduced the number of colonoscopies by 15%-41% and required 5.6-9.5 stool tests over a person's lifetime. Multitarget stool DNA-based surveillance was more costly than colonoscopy surveillance, whereas FIT-based surveillance saved costs.

This study found that stool-based post-polypectomy surveillance strategies can be safe and cost-effective, with potential to reduce the number of colonoscopies by up to 41%.

gov, Number: NCT02715141.

The purpose of this study was to analyze the effectiveness of the Cancer Screening Program in Urban China (CanSPUC) in Hebei Province, 2016-2023.

A questionnaire for risk factors of lung, breast, upper gastrointestinal, liver, and colorectal cancers was administered to urban residents aged 40-74 years in five cities to assess their cancer risk. High-risk participants were invited for screening and classified into five groups on the basis of the number of cancer types that were assessed to be high risk. The participation and positive outcome rates were analyzed. The incidence and the mortality of five types of cancer and all-cause mortality of the screened and nonscreened participants were calculated via inverse probability weighting.

A total of 237,975 eligible participants were enrolled in our study and 118,339 participants (49.94%) were assessed to be at high risk for one or more of the five cancer types. The number of screenings performed was 103,824, with a screening participation rate of 40.49%. Among the 57,315 screening participants, 9077 (15.84%) had positive cancer diagnoses and 871 (1.52%) were diagnosed with suspected cancer. Compared with the participants at high risk for a single cancer type, the participation and positive outcome rate increased by 45% and 71.5% in the participants at high risk for multiple cancer types. Compared with the non-screened participants, the screened participants had a 27.0% decrease in mortality due to the five types of cancer and a 45.8% decrease in all-cause mortality.

A combined screening program for multiple cancers could increase participation and positive outcome rates. It could also decrease the five types of cancer mortality and all-cause mortality. Our findings highlight the effectiveness of combined screening for multiple cancers with limited health care resources, and may provide foundational evidence for the feasibility of conducting combined screening programs.

As the impact of unmanaged bias (i.e. systematic source of inaccuracy) in fecal immunochemical test (FIT) analytical performance on long-term colorectal cancer (CRC) outcomes is unknown, we assessed the impact bias in FIT performance in an ongoing FIT-based CRC screening program.

This study consisted of two parts: cross-sectional observational data analysis to estimate change in short-term outcomes and microsimulation modelling to estimate change in long-term outcomes assuming different levels of bias by assuming 15 % lower up to 15 % higher Hemoglobin detected in the stool compared to observed. Two scenarios were considered: bias occurring 1) one-time only, due to the occasional bias associated with the FIT kits used in 2020 and 2) consistently due to a constant bias associated with the FIT kits used from 2020 onwards.

With a hypothetical bias of -15 % to +15 %, we observed a positivity rate ranging from 6.7 % to 7.8 %, and a detection rate for CRC between 0.65 % and 0.68 %. Single biases in FIT performance resulted in less than 0.1 % change in long-term CRC screening outcomes, while consistent biases resulted in a much larger change (up to 1.4 % in CRC cases and CRC-related deaths and up to 2.07 % in total costs). Detecting lower Hemoglobin concentrations resulted in a relatively larger change on long-term CRC outcomes in comparison to positive bias.

Because of the substantial impact of consistent FIT bias, it is important to set evidence-based acceptance criteria of bias on long-term CRC screening outcomes and in particular, the introduction of an asymmetrical or upward shifted tolerance interval for FIT bias.

Environmental factors like the pathogenicity island polyketide synthase positive (pks+) Escherichia coli (E. coli) could have potential for risk stratification in colorectal cancer (CRC) screening. The association between pks+ E. coli measured in fecal immunochemical test (FIT) samples and the detection of advanced neoplasia (AN) at colonoscopy was investigated. Biobanked FIT samples were analyzed for both presence of E. coli and pks+ E. coli and correlated with colonoscopy findings; 5020 CRC screening participants were included. Controls were participants in which no relevant lesion was detected because of FIT-negative results (cut-off ≥15 μg Hb/g feces), a negative colonoscopy, or a colonoscopy during which only a nonadvanced polyp was detected. Cases were participants with AN [CRC, advanced adenoma (AA), or advanced serrated polyp (ASP)]. Existing DNA isolation and quantitative polymerase chain reaction (qPCR) procedures were used for the detection of E. coli and pks+ E. coli in stool. A total of 4542 (90.2%) individuals were E. coli positive, and 1322 (26.2%) were pks+ E. coli positive. The prevalence of E. coli in FIT samples from individuals with AN was 92.9% compared to 89.7% in FIT samples of controls (p = 0.010). The prevalence of pks+ E. coli in FIT samples from individuals with AN (28.6%) and controls (25.9%) was not significantly different (p = 0.13). The prevalences of pks+ E. coli in FIT samples from individuals with CRC, AA, or ASP were 29.6%, 28.3%, and 32.1%, respectively. In conclusion, the prevalence of pks+ E. coli in a screening population was 26.2% and did not differ significantly between individuals with AN and controls. These findings disqualify the straightforward option of using a snapshot measurement of pks+ E. coli in FIT samples as a stratification biomarker for CRC risk. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Although there is no debate around the effectiveness of colorectal cancer screening in reducing disease burden, there remains a question regarding the most effective and cost-effective screening modality. Current United States guidelines present a panel of options that include the 2 most commonly used modalities, colonoscopy and stool testing with the fecal immunochemical test (FIT). Large-scale comparative effectiveness trials comparing colonoscopy and FIT for colorectal cancer outcomes are underway, but results are not yet available. This review will separately state the "best case" for FIT and colonoscopy as the screening tool of first choice. In addition, the review will examine these modalities from a health economics perspective to provide the reader further context about the relative advantages of these commonly used tests.

Socioeconomic inequalities in the uptake of colorectal cancer screening are well documented, but the implications on inequities in health gain remain unclear.

Sixty-year-olds were randomly recruited from the Swedish population between March 2014 and March 2020 and invited to undergo either 2 rounds of fecal immunochemical testing (FIT) 2 years apart (n = 60 137) or primary colonoscopy just once (n = 30 400). By linkage to Statistics Sweden's registries, we obtained socioeconomic data. In each defined socioeconomic group, we estimated the cumulative yield of advanced neoplasia in each screening arm (intention-to-screen analysis). In the biennial FIT arm, we predicted the probability of exceeding the yield in the primary colonoscopy arm by linear extrapolation of the cumulative yield to (hypothetical) additional rounds of FIT.

In the lowest income group, the yield of advanced neoplasia was 1.63% (95% confidence interval [CI] = 1.35% to 1.93%) after 2 rounds of FIT vs 1.93% (95% CI = 1.49% to 2.40%) in the primary colonoscopy arm. Extrapolation to a third round of FIT implied a 86% probability of exceeding the yield in the primary colonoscopy arm. In the highest income group, we found a more pronounced yield gap between the 2 screening strategies-2.32% (95% CI = 2.15% to 2.49%) vs 3.71% (95% CI = 3.41% to 4.02%)- implying a low (2%) predicted probability of exceeding yield after a third round of FIT.

Yield of advanced neoplasia from 2 rounds of FIT 2 years apart was poorer as compared with primary colonoscopy, but the difference was less in lower socioeconomic groups.

ClinicalTrials.gov identifier NCT02078804.

To facilitate informed decision making on participating in colorectal cancer (CRC) screening, we assessed the benefit-harm balance of CRC screening for a wide range of subgroups over different time horizons.

The study combined incidence proportions of benefits and harms of (not) participating in CRC screening estimated by the Adenoma and Serrated pathway to CAncer microsimulation model, a preference eliciting survey, and benefit-harm balance modeling combining all outcomes to determine the net health benefit of CRC screening over 10, 20, and 30 years. Probability of net health benefit was estimated for 210 different subgroups based on age, sex, previous participation in CRC screening, and lifestyle.

CRC screening was net beneficial in 183 of 210 subgroups over 30 years (median probability [MP] of 0.79, interquartile range [IQR] of 0.69-0.85) across subgroups. Net health benefit was greater for men (MP 0.82; IQR 0.69-0.89) than women (MP 0.76; IQR 0.67-0.83) and for those without history of participation in previous screenings (MP 0.84; IQR 0.80-0.89) compared with those with (MP 0.69; IQR 0.59-0.75). Net health benefit decreased with increasing age, from MP of 0.84 (IQR 0.80-0.86) at age 55 to 0.61 (IQR 0.56-0.71) at age 75. Shorter time horizons led to lower benefit, with MP of 0.70 (IQR 0.62-0.80) over 20 years and 0.54 (IQR 0.48-0.67) over 10 years.

Our benefit-harm analysis provides information about net health benefit of screening participation, based on important characteristics and preferences of individuals, which could assist screening invitees in making informed decisions on screening participation.

Genetic changes in repetitive sequences are a hallmark of cancer and other diseases, but characterizing these has been challenging using standard sequencing approaches. We developed a de novo kmer finding approach, called ARTEMIS (Analysis of RepeaT EleMents in dISease), to identify repeat elements from whole-genome sequencing. Using this method, we analyzed 1.2 billion kmers in 2837 tissue and plasma samples from 1975 patients, including those with lung, breast, colorectal, ovarian, liver, gastric, head and neck, bladder, cervical, thyroid, or prostate cancer. We identified tumor-specific changes in these patients in 1280 repeat element types from the LINE, SINE, LTR, transposable element, and human satellite families. These included changes to known repeats and 820 elements that were not previously known to be altered in human cancer. Repeat elements were enriched in regions of driver genes, and their representation was altered by structural changes and epigenetic states. Machine learning analyses of genome-wide repeat landscapes and fragmentation profiles in cfDNA detected patients with early-stage lung or liver cancer in cross-validated and externally validated cohorts. In addition, these repeat landscapes could be used to noninvasively identify the tissue of origin of tumors. These analyses reveal widespread changes in repeat landscapes of human cancers and provide an approach for their detection and characterization that could benefit early detection and disease monitoring of patients with cancer.

The faecal immunochemical test (FIT) is widely employed for colorectal cancer screening. However, its sensitivity for advanced precursor lesions remains suboptimal. The multitarget FIT (mtFIT), measuring haemoglobin, calprotectin, and serpin family F member 2, has demonstrated enhanced sensitivity for advanced neoplasia, especially advanced adenomas, at equal specificity to FIT. This study aimed to prospectively validate and investigate the clinical utlitity of mtFIT versus FIT in a setting of population-based colorectal cancer screening.

Individuals aged 55-75 years and who were eligible for the Dutch national FIT-based colorectal cancer screening programme were invited to submit both a FIT and mtFIT sample collected from the same bowel movement. Positive FIT (47 μg/g haemoglobin cutoff) or mtFIT (based on decision-tree algorithm) led to a colonoscopy referral. The primary outcome was the relative detection rate of mtFIT versus FIT for all advanced neoplasia. Secondary outcomes were the relative detection rates of colorectal cancer, advanced adenoma, and advanced serrated polyps individually and the long-term effect of mtFIT-based versus FIT-based programmatic screening on colorectal cancer incidence, mortality, and cost, determined with microsimulation modelling. The study has been registered in ClinicalTrials.gov, NCT05314309, and is complete.

Between March 25 and Dec 7, 2022, 35 786 individuals were invited to participate in the study, of whom 15 283 (42·7%) consented, and 13 187 (86·3%) of 15 283 provided both mtFIT and FIT samples with valid results. Of the 13 187 participants, 6637 (50·3%) were male and 6550 (49·7%) were female. mtFIT showed a 9·11% (95% CI 8·62-9·61) positivity rate and 2·27% (95% CI 2·02-2·54) detection rate for advanced neoplasia, compared with a positivity rate of 4·08% (3·75-4·43) and a detection rate of 1·21% (1·03-1·41) for FIT. Detection rates of mtFIT versus FIT were 0·20% (95% CI 0·13-0·29) versus 0·17% (0·11-0·27) for colorectal cancer; 1·64% (1·43-1·87) versus 0·86% (0·72-1·04) for advanced adenoma, and 0·43% (0·33-0·56) versus 0·17% (0·11-0·26) for advanced serrated polyps. Modelling demonstrated that mtFIT-based screening could reduce colorectal cancer incidence by 21% and associated mortality by 18% compared with the current Dutch colorectal cancer screening programme, at feasible costs. Furthermore, at equal positivity rates, mtFIT outperformed FIT in terms of diagnostic yield. At an equally low positivity rate, mtFIT-based screening was predicted to further decrease colorectal cancer incidence by 5% and associated mortality by 4% compared with FIT-based screening.

The higher detection rate of mtFIT for advanced adenoma compared with FIT holds the potential to translate into additional and clinically meaningful long-term colorectal cancer incidence and associated mortality reductions in programmatic colorectal cancer screening.

Stand Up to Cancer, Dutch Cancer Society, Dutch Digestive Foundation, and Health~Holland.

The risk that a large polyp (≥10 mm) evolves into high-grade dysplasia (HGD) is relatively high compared with that of a small/diminutive polyp (<10 mm). Recently, the detection of small and diminutive polyps has been substantially improved with the advancement of endoscopy. However, further research is needed on the role of the incidence of HGD caused by the co-occurrence of small and diminutive polyps in the progression of HGD. In this study, we aim to investigate whether and how the small and diminutive polyps correlate with the incidence of HGD in the population.

The pooled data were deeply analyzed from four published randomized controlled trials (RCTs) regarding colon polyp detection. All polyps detected were examined and confirmed by pathologists. The primary outcome was the composition ratio of the HGD polyps in each polyp size category.

Among a total of 3,179 patients with 2,730 polyps identified, there were 83 HGD polyps confirmed, and 68 patients had at least one polyp with HGD. The risk of development of HGD was lower for a single small and diminutive polyp than for one large polyp (2.18% vs. 22.22%, P < 0.0001). On the contrary, the composition ratio for HGD from small and diminutive polyps was significantly higher than that from the large ones (68.67% vs. 31.33%, P < 0.0001). The combined number of HGD presented a trend negatively correlated to size.

Our data demonstrated that the absolute number of HGD significantly derives more from small and diminutive polyps than from the large ones, and the collective number of small and diminutive polyps per patient is indicative of his/her HGD exposure. These findings positively provide novel perspectives on the management of polyps and may further optimize the prevention of colorectal cancer.

http://www.chictr.org.cn, identifier ChiCTR1900025235, ChiCTR1800017675, ChiCTR1800018058, and ChiCTR1900023086.

Colon cancer is the third most common malignancy in Canada. Computed tomography colonography (CTC) provides a creditable and validated option for colon screening and assessment of known pathology in patients for whom conventional colonoscopy is contraindicated or where patients self-select to use imaging as their primary modality for initial colonic assessment. This updated guideline aims to provide a toolkit for both experienced imagers (and technologists) and for those considering launching this examination in their practice. There is guidance for reporting, optimal exam preparation, tips for problem solving to attain high quality examinations in challenging scenarios as well as suggestions for ongoing maintenance of competence. We also provide insight into the role of artificial intelligence and the utility of CTC in tumour staging of colorectal cancer. The appendices provide more detailed guidance into bowel preparation and reporting templates as well as useful information on polyp stratification and management strategies. Reading this guideline should equip the reader with the knowledge base to perform colonography but also provide an unbiased overview of its role in colon screening compared with other screening options.

To inform guidance for cancer detection in patients with idiopathic inflammatory myopathy (IIM), we evaluated the diagnostic yield of computed tomography (CT) imaging for cancer screening/surveillance within distinct IIM subtypes and myositis-specific autoantibody strata.

We conducted a single-center, retrospective cohort study in IIM patients. Overall diagnostic yield (number of cancers diagnosed/number of tests performed), percentage of false positives (number of biopsies performed not leading to cancer diagnosis/number of tests performed), and test characteristics were determined on CT of the chest and abdomen/pelvis.

Within the first 3 years since IIM symptom onset, a total of 9 of 1,011 (0.9%) chest CT scans and 12 of 657 (1.8%) abdomen/pelvis CT scans detected cancer. Diagnostic yields for both CT of the chest and CT of the abdomen/pelvis were highest in dermatomyositis, specifically anti-transcription intermediary factor 1γ (2.9% and 2.4% for CT of the chest and abdomen/pelvis, respectively). The highest percentage of false positives was in patients with antisynthetase syndrome (ASyS) (4.4%) and immune-mediated necrotizing myopathy (4.4%) on CT of the chest, and ASyS (3.8%) on CT of the abdomen/pelvis. Patients ages <40 years old at IIM onset had both low diagnostic yields (0% and 0.5%) and high false-positive rates (1.9% and 4.4%) for CT of the chest and abdomen/pelvis, respectively.

In a tertiary referral cohort of IIM patients, CT imaging has a wide range of diagnostic yield and frequency of false positives for contemporaneous cancer. These findings suggest that cancer detection strategies targeted according to IIM subtype, autoantibody positivity, and age may maximize cancer detection while minimizing the harms and costs of over-screening.

Colorectal cancer (CRC) is one of the most common digestive diseases worldwide. It has steadily ascended to the top three cancers in terms of incidence and mortality. The primary cause is the inability to diagnose it at an early stage. Therefore, early detection and diagnosis are essential for colorectal cancer prevention. Although there are now various methods for CRC early detection, in addition to recent developments in surgical and multimodal therapy, the poor prognosis and late detection of CRC still remain significant. Thus, it is important to investigate novel technologies and biomarkers to improve the sensitization and specification of CRC diagnosis. Here, we present some common methods and biomarkers for early detection and diagnosis of CRC, we hope this review will encourage the adoption of screening programs and the clinical use of these potential molecules as biomarkers for CRC early detection and prognosis.

To evaluate if an adequate bowel preparation for CT colonography, can be achieved without diet restriction, using a reduced amount of cathartic agent and fecal tagging. To investigate the influence of patients' characteristics on bowel preparation and the impact on patients' compliance.

In total, 1446 outpatients scheduled for elective CT colonography were prospectively enrolled. All patients had the same bowel preparation based on a reduced amount of cathartic agent (120 g of macrogol in 1.5 l of water) the day before the exam and a fecal tagging agent (60 ml of hyperosmolar oral iodinated agent) the day of the exam. No dietary restrictions were imposed before the exam. The bowel preparation was evaluated using a qualitative and quantitative score. Patients were grouped by age, gender, and presence of diverticula in both scores. Patients' compliance has been evaluated with a questionnaire after the end of the exam and with a phone-calling interview the day after the exam.

According to the qualitative score, adequate bowel preparation was achieved in 1349 patients (93.29%) and no statistical differences were observed among the subgroups of patients. Quantitative scores demonstrated that colon distension was significantly better in younger patients and without diverticula. A good patients' compliance was observed and most patients (96.5%) were willing to repeat it.

The lack of diet restriction does not affect the quality of CTC preparation and good patient's compliance could potentially increase the participation rate in CRC screening programs.

• An adequate quality bowel preparation for CT colonography can be achieved without diet restriction, using a reduced amount of cathartic agent (120 g of macrogol in 1.5 l of water) and fecal tagging (60 ml of hyperosmolar oral iodinated agent). • A bowel preparation based on the combination of a reduced amount of cathartic agent and fecal tagging, without diet restriction, allows obtaining good quality in more than 90% of patients. • The bowel preparation scheme proposed reduces the distress and discomfort experienced by the patients improving adherence to CTC.

Dedicated radiological expertise and a high-quality examination, performed according to current technical standards and for accepted indications, are prerequisite to achieve excellent results with CT colonography (CTC).

The aim of this article is to review current standards of the examination technique as well as indications and contraindications for CTC based on recent recommendations and guidelines.

Based on extensive literature research, current knowledge about the examination technique and the indications and contraindications is summarized.

CTC is the radiological examination of choice for the detection of colorectal neoplasia. Beside incomplete or refused colonoscopy and contraindications to colonoscopy, CTC is also a noninvasive option for opportunistic colorectal cancer screening. The examination technique is based on a CTC-specific patient preparation scheme that includes fecal tagging, colonic distension, low-dose CT scans in two patient positions and a combined 2D and 3D data evaluation.

Performing CTC according to current technical standards is prerequisite for high-quality examinations and is, thus, also a key factor to obtain a correct diagnosis. CTC is a noninvasive examination, capable of providing clinically relevant diagnoses for a wide range of indications.

To determine the level of heterogeneity in delivery of computed tomography (CT) colonography services and develop a workforce calculator that accommodates the variation identified.

A national survey, based on the "WHO workforce indicators of staffing need", established activity standards for essential tasks in delivery of the service. From these data a workforce calculator was designed to guide the required staffing and equipment resource by service size.

Activity standards were established as mode responses >70%. Service homogeneity was greater in areas where professional standards and guidance were available. The mean service size was 1,101. Did not attend (DNA) rates were lower where direct booking was available (p<0.0001). Service sizes were larger where radiographer reporting was embedded in reporting paradigms (p<0.024).

The survey identified benefits of radiographer-led direct booking and reporting. The workforce calculator derived from the survey provides a framework to guide the resourcing of expansion while maintaining standards.

Colorectal cancer (CRC) is the third most common cancer and the second largest cause of cancer-related death worldwide. Current CRC screening in various countries involves stool-based faecal immunochemical testing (FIT) and/or colonoscopy, yet public uptake remains sub-optimal. This review assessed the literature regarding acceptability of alternative CRC screening modalities compared to standard care in average-risk adults.

Systematic searches of MEDLINE, EMBASE, CINAHL, Cochrane and Web of Science were conducted up to February 3rd, 2022. The alternative interventions examined were computed tomography colonography, flexible sigmoidoscopy, colon capsule endoscopy and blood-based biomarkers. Outcomes for acceptability were uptake, discomfort associated with bowel preparation, discomfort associated with screening procedure, screening preferences and willingness to repeat screening method. A narrative data synthesis was conducted.

Twenty-one studies met the inclusion criteria. Differences between intervention and comparison modalities in uptake did not reach statistical significance in most of the included studies. The findings do suggest FIT as being more acceptable as a screening modality than flexible sigmoidoscopy. There were no consistent significant differences in bowel preparation discomfort, screening procedure discomfort, screening preference and willingness to repeat screening between the standard care and alternative modalities.

Current evidence comparing standard colonoscopy and stool-based CRC screening with novel modalities does not demonstrate any clear difference in acceptability. Due to the small number of studies available and included in each screening comparison and lack of observed differences, further research is needed to explore factors influencing acceptability of alternative CRC modalities that might result in improvement in population uptake within different contexts.

The screening yield and related cost of a risk-adapted screening approach compared with established screening strategies in population-based colorectal cancer (CRC) screening are not clear.

We randomly allocated 19,373 participants into 1 of the 3 screening arms in a 1:2:2 ratio: (1) one-time colonoscopy (n = 3883); (2) annual fecal immunochemical test (FIT) (n = 7793); (3) annual risk-adapted screening (n = 7697), in which, based on the risk-stratification score, high-risk participants were referred for colonoscopy and low-risk ones were referred for FIT. Three consecutive screening rounds were conducted for both the FIT and the risk-adapted screening arms. Follow-up to trace the health outcome for all the participants was conducted over the 3-year study period. The detection rate of advanced colorectal neoplasia (CRC and advanced precancerous lesions) was the main outcome. The trial was registered in the Chinese Clinical Trial Registry (number: ChiCTR1800015506).

In the colonoscopy, FIT, and risk-adapted screening arms over 3 screening rounds, the participation rates were 42.4%, 99.3%, and 89.2%, respectively; the detection rates for advanced neoplasm (intention-to-treat analysis) were 2.76%, 2.17%, and 2.35%, respectively, with an odds ratio (OR)colonoscopy vs FIT of 1.27 (95% confidence interval [CI]: 0.99-1.63; P = .056), an ORcolonoscopy vsrisk-adapted screening of 1.17 (95% CI, 0.91-1.49; P = .218), and an ORrisk-adapted screeningvs FIT of 1.09 (95% CI, 0.88-1.35; P = .438); the numbers of colonoscopies needed to detect 1 advanced neoplasm were 15.4, 7.8, and 10.2, respectively; the costs for detecting 1 advanced neoplasm from a government perspective using package payment format were 6928 Chinese Yuan (CNY) ($1004), 5821 CNY ($844), and 6694 CNY ($970), respectively.

The risk-adapted approach is a feasible and cost-favorable strategy for population-based CRC screening and therefore could complement the well-established one-time colonoscopy and annual repeated FIT screening strategies. (Chinese Clinical Trial Registry; ChiCTR1800015506).

In 2014, the national population-based colorectal cancer (CRC) screening program was implemented in the Netherlands. Biennial fecal immunochemical testing (FIT) for hemoglobin (Hb) is used at a cut-off of 47 µg Hb per gram feces. The CRC screening program successfully started, with high participation rates and yield of screening. Now that the program has reached a steady state, there is potential to further optimize the program. Previous studies showed that prior fecal Hb (f-Hb) concentrations just below the FIT cut-off are associated with a higher risk for detection of advanced neoplasia (AN) at subsequent screening rounds. We aim to achieve a better balance between the harms and benefits of CRC screening by offering participants tailored invitation intervals based on prior f-Hb concentrations after negative FIT.

This mixed-methods study will be performed within the Dutch national CRC screening program and will consist of: (1) a randomized controlled trial (RCT), (2) focus group studies, and (3) decision modelling. The primary outcome is the yield of AN per screened individual in personalized screening vs. uniform screening. Secondary outcomes are perspectives on, acceptability of and adherence to personalized screening, as well as long-term outcomes of personalized vs. uniform screening. The RCT will include 20,000 participants of the Dutch CRC screening program; 10,000 in the intervention and 10,000 in the control arm. The intervention arm will receive a personalized screening interval based on the prior f-Hb concentration (1, 2 or 3 years). The control arm will receive a screening interval according to current practice (2 years). The focus group studies are designed to understand individuals' perspectives on and acceptability of personalized CRC screening. Results of the RCT will be incorporated into the MISCAN-Colon model to determine long-term benefits, harms, and costs of personalized vs. uniform CRC screening.

The aim of this study is to evaluate the yield, feasibility, acceptability and (cost-) effectiveness of personalized CRC screening through tailored invitation intervals based on prior f-Hb concentrations. This knowledge may be of guidance for health policy makers and may provide evidence for implementing personalized CRC screening in The Netherlands and/or other countries using FIT as screening modality.

ClinicalTrials.gov, NCT05423886, June 21, 2022, https://clinicaltrials.gov/ct2/show/NCT05423886.

Hodgkin lymphoma survivors treated with infradiaphragmatic radiotherapy (IRT) and/or procarbazine have an increased risk of developing colorectal cancer. We investigated the cost-effectiveness of colorectal cancer surveillance in Dutch Hodgkin lymphoma survivors to determine the optimal surveillance strategy for different Hodgkin lymphoma subgroups.

The Microsimulation Screening Analysis-Colon model was adjusted to reflect colorectal cancer and other-cause mortality risk in Hodgkin lymphoma survivors. Ninety colorectal cancer surveillance strategies were evaluated varying in starting and stopping age, interval, and modality [colonoscopy, fecal immunochemical test (FIT, OC-Sensor; cutoffs: 10/20/47 μg Hb/g feces), and multi-target stool DNA test (Cologuard)]. Analyses were also stratified per primary treatment (IRT and procarbazine or procarbazine without IRT). Colorectal cancer deaths averted (compared with no surveillance) and incremental cost-effectiveness ratios (ICER) were primary outcomes. The optimal surveillance strategy was identified assuming a willingness-to-pay threshold of €20,000 per life-years gained (LYG).

Overall, the optimal surveillance strategy was annual FIT (47 μg) from age 45 to 70 years, which might avert 70% of colorectal cancer deaths in Hodgkin lymphoma survivors (compared with no surveillance; ICER:€18,000/LYG). The optimal surveillance strategy in Hodgkin lymphoma survivors treated with procarbazine without IRT was biennial FIT (47 μg) from age 45 to 70 years (colorectal cancer mortality averted 56%; ICER:€15,000/LYG), and when treated with IRT and procarbazine, annual FIT (47 μg) surveillance from age 40 to 70 was most cost-effective (colorectal cancer mortality averted 75%; ICER:€13,000/LYG).

Colorectal cancer surveillance in Hodgkin lymphoma survivors is cost-effective and should commence earlier than screening occurs in population screening programs. For all subgroups, FIT surveillance was the most cost-effective strategy.

Colorectal cancer surveillance should be implemented in Hodgkin lymphoma survivors.

Longitudinal adherence to colorectal cancer (CRC) screening is reported using different summarizing measures, which hampers international comparison. We provide evidence to guide recommendations on which longitudinal adherence measure to report. Using adherence data over four stool-based CRC screening rounds in three countries, we calculated six summarizing adherence measures; adherence over all rounds, adherence per round, rescreening, full programme adherence (yes/no), regularity (never/inconsistent/consistent screenees) and number of times participated. For each measure, we calculated the accuracy in capturing the observed adherence patterns. Using the ASCCA model, we predicted screening effectiveness when using summarizing measures as model input versus the observed adherence patterns. Adherence over all rounds in the Italian, Spanish and Dutch cohorts was 64.9%, 42.8% and 61.5%, respectively, and the proportion of consistent screenees was 50.9%, 26.3% and 45.7%. Number of times participated and regularity were most accurate and resulted in similar model-predicted screening effectiveness as simulating the observed adherence patterns of Italy, Spain and the Netherlands (mortality reductions: 24.4%, 16.9% and 23.5%). Adherence over all rounds and adherence per round were least accurate. Screening effectiveness was overestimated when using adherence over all rounds (mortality reductions: 26.8%, 19.4% and 25.7%) and adherence per round (mortality reductions: 26.8%, 19.5% and 25.9%). To conclude, number of times participated and regularity were most accurate and resulted in similar model-predicted screening effectiveness as using the observed adherence patterns. However they require longitudinal data. To facilitate international comparison of CRC screening programme performance, consensus on an accurate adherence measure to report should be reached.

Colorectal cancer screening is recommended for people aged 50-75 years, but the optimal screening test and strategy are not established. We aimed to compare single CT colonography versus three faecal immunochemical test (FIT) rounds for population-based screening of colorectal cancer.

This randomised controlled trial was done in Florence, Italy. Adults aged 54-65 years, never screened for colorectal cancer, were randomly assigned (1:2) by simple randomisation and invited by post to either a single CT colonography (CT colonography group) or three FIT rounds (FIT group; each round was done 2 years apart). Exclusion criteria included previous colorectal cancer, advanced adenoma, or inflammatory bowel disease, colonoscopy within the last 5 years or FIT within the last 2 years, and severe medical conditions. Participants who had a colonic mass or at least one polyp of 6 mm or more in diameter in the CT colonography group and those who had at least 20 μg haemoglobin per g faeces in the FIT group were referred for work-up optical colonoscopy. The primary outcome was detection rate for advanced neoplasia. Outcomes were assessed in the modified intention-to-screen and per-protocol populations. The trial is registered with ClinicalTrials.gov, NCT01651624.

From Dec 12, 2012, to March 5, 2018, 14 981 adults were randomised and invited to screening interventions. 5242 (35·0%) individuals (2809 [53·6%] women and 2433 [46·4%] men) were assigned to the CT colonography group and 9739 (65·0%) individuals (5208 [53·5%] women and 4531 [46·5%] men) were assigned to the FIT group. Participation in the screening intervention was lower in the CT colonography group (1286 [26·7%] of the 4825 eligible invitees) than it was for the FIT group (6027 [64·9%] of the 9288 eligible invitees took part in at least one screening round, 4573 [49·2%] in at least two rounds, and 3105 [33·4%] in all three rounds). The detection rate for advanced neoplasia of CT colonography was significantly lower than the detection rate after three FIT rounds (1·4% [95% CI 1·1-1·8] vs 2·0% [1·7-2·3]; p=0·0094) in the modified intention-to-screen analysis, but the detection rate was significantly higher in the CT colonography group than in the FIT group (5·2% [95% CI 4·1-6·6] vs 3·1% [2·7-3·6]; p=0·0002]) in the per-protocol analysis. Referral rate to work-up optical colonoscopy (the secondary outcome of the trial) was significantly lower for the CT colonography group than for the FIT group after three FIT rounds (2·7% [95% CI 2·2-3·1] vs 7·5% [7·0-8·1]; p<0·0001) in the modified intention-to-screen analysis, whereas no significant difference was observed in the per-protocol analysis (10·0% [8·4-11·8] vs 11·6% [10·8-12·4]). No major complications were observed in the CT colonography group after screening and work-up optical colonoscopy, whereas three cases of bleeding were reported in the FIT group after work-up optical colonoscopy (two after the first FIT and one after the second FIT).

Greater participation makes FIT more efficient than single CT colonography for detection of advanced neoplasia in population screening for colorectal cancer. Nonetheless, higher detection rate in participants and fewer work-up colonoscopies are possible advantages of CT colonography as a screening tool, which might deserve consideration in future trials.

Government of Tuscany and Cassa di Risparmio di Firenze Foundation.

For the Italian translation of the abstract see Supplementary Materials section.

The Asia-Pacific region has the largest number of cases of colorectal cancer (CRC) and one of the highest levels of mortality due to this condition in the world. Since the publishing of two consensus recommendations in 2008 and 2015, significant advancements have been made in our knowledge of epidemiology, pathology and the natural history of the adenoma-carcinoma progression. Based on the most updated epidemiological and clinical studies in this region, considering literature from international studies, and adopting the modified Delphi process, the Asia-Pacific Working Group on Colorectal Cancer Screening has updated and revised their recommendations on (1) screening methods and preferred strategies; (2) age for starting and terminating screening for CRC; (3) screening for individuals with a family history of CRC or advanced adenoma; (4) surveillance for those with adenomas; (5) screening and surveillance for sessile serrated lesions and (6) quality assurance of screening programmes. Thirteen countries/regions in the Asia-Pacific region were represented in this exercise. International advisors from North America and Europe were invited to participate.

To compare the performance of conventional versus spectral-based electronic stool cleansing for iodine-tagged CT colonography (CTC) using a dual-layer spectral detector scanner.

We retrospectively evaluated iodine contrast stool-tagged CTC scans of 30 consecutive patients (mean age: 69 ± 8 years) undergoing colorectal cancer screening obtained on a dual-layer spectral detector CT scanner. One reader identified locations of electronic cleansing artifacts (n = 229) on conventional and spectral cleansed images. Three additional independent readers evaluated these locations using a conventional cleansing algorithm (Intellispace Portal) and two experimental spectral cleansing algorithms (i.e., fully transparent and translucent tagged stool). For each cleansed image set, readers recorded the severity of over- and under-cleansing artifacts on a 5-point Likert scale (0 = none to 4 = severe) and readability compared to uncleansed images. Wilcoxon's signed-rank tests were used to assess artifact severity, type, and readability (worse, unchanged, or better).

Compared with conventional cleansing (66% score ≥ 2), the severity of overall cleansing artifacts was lower in transparent (60% score ≥ 2, p = 0.011) and translucent (50% score ≥ 2, p < 0.001) spectral cleansing. Under-cleansing artifact severity was lower in transparent (49% score ≥ 2, p < 0.001) and translucent (39% score ≥ 2, p < 0.001) spectral cleansing compared with conventional cleansing (60% score ≥ 2). Over-cleansing artifact severity was worse in transparent (17% score ≥ 2, p < 0.001) and translucent (14% score ≥ 2, p = 0.023) spectral cleansing compared with conventional cleansing (9% score ≥ 2). Overall readability was significantly improved in transparent (p < 0.001) and translucent (p < 0.001) spectral cleansing compared with conventional cleansing.

Spectral cleansing provided more robust electronic stool cleansing of iodine-tagged stool at CTC than conventional cleansing.

• Spectral-based electronic cleansing of tagged stool at CT colonography provides higher quality images with less perception of artifacts than does conventional cleansing. • Spectral-based electronic cleansing could potentially advance minimally cathartic approach for CT colonography. Further clinical trials are warranted.