Gural Z, Saglam S, Yucel S, Kaytan-Saglam E, Asoglu O, Ordu C, Acun H, Sharifov R, Onder S, Kizir A, Oral EN. Neoadjuvant hyperfractionated accelerated radiotherapy plus concomitant 5-fluorouracil infusion in locally advanced rectal cancer: A phase II study. World J Gastrointest Oncol 2018; 10(1): 40-47
Corresponding Author of This Article
Dr. Zeynep Gural, MD, Attending Doctor, Department of Radiation Oncology, Acibadem University Medical Faculty, Halkalı Merkez Mahallesi, Turgut Özal Blv No:16, Istanbul 34303, Turkey. email@example.com
Checklist of Responsibilities for the Scientific Editor of This Article
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Author contributions: All the authors contributed to this study; Gural Z and Saglam S contributed equally to the study.
Institutional review board statement: The study was reviewed and approved by the Istanbul Medical Faculty Institutional Review Board.
Informed consent statement: All information was obtained with the appropriate institutional review board waivers, and the data were collected without revealing any personal information.
Conflict-of-interest statement: The authors have no conflicts of interest, financial or otherwise.
Data sharing statement: Dataset is available from the corresponding author by e-mail at: firstname.lastname@example.org.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Dr. Zeynep Gural, MD, Attending Doctor, Department of Radiation Oncology, Acibadem University Medical Faculty, Halkalı Merkez Mahallesi, Turgut Özal Blv No:16, Istanbul 34303, Turkey. email@example.com
Telephone: +90-533-2696742 Fax: +90-212-4044445
Received: September 4, 2017 Peer-review started: September 7, 2017 First decision: October 9, 2017 Revised: November 26, 2017 Accepted: December 4, 2017 Article in press: December 4, 2017 Published online: January 15, 2018
To evaluate the efficacy and tolerability of neoadjuvant hyperfractionated accelerated radiotherapy (HART) and concurrent chemotherapy in patients with locally advanced infraperitoneal rectal cancer.
A total of 30 patients with histopathologically confirmed T2-3/N0+ infraperitoneal adenocarcinoma of rectum cancer patients received preoperative 42 Gy/1.5 Gy/18 days/bid radiotherapy and continuous infusion of 5-fluorouracil (325 mg/m2). All patients were operated 4-8 wk after neoadjuvant concomitant therapy.
In the early phase of treatment, 6 patients had grade III-IV gastrointestinal toxicity, 2 patients had grade III-IV hematologic toxicity, and 1 patient had grade V toxicity due to postoperative sepsis during chemotherapy. Only 1 patient had radiotherapy-related late side effects, i.e., grade IV tenesmus. Complete pathological response was achieved in 6 patients (21%), while near-complete pathological response was obtained in 9 (31%). After a median follow-up period of 60 mo, the local tumor control rate was 96.6%. In 13 patients, distant metastasis occurred. Disease-free survival rates at 2 and 5 years were 63.3% and 53%, and corresponding overall survival rates were 70% and 53.1%, respectively.
Although it has excellent local control and complete pathological response rates, neoadjuvant HART concurrent chemotherapy appears to not be a feasible treatment regimen in locally advanced rectal cancer, having high perioperative complication and intolerable side effects. Effects of reduced 5-fluorouracil dose or omission of chemotherapy with the aim of reducing toxicity may be examined in further studies.
Core tip: This study includes a first phase II study evaluating neoadjuvant hyperfractionated accelerated radiotherapy plus concomitant infusional 5-fluorouracil (5-FU) chemotherapy in locally advanced rectal cancer (not resectable cancer). This regimen may allow clinicians to design other neoadjuvant hyperfractionated accelerated radiotherapies. This study showed excellent local control but high rate of perioperative complications. Decreasing or modifying the 5-FU dose could provide better local control.
Citation: Gural Z, Saglam S, Yucel S, Kaytan-Saglam E, Asoglu O, Ordu C, Acun H, Sharifov R, Onder S, Kizir A, Oral EN. Neoadjuvant hyperfractionated accelerated radiotherapy plus concomitant 5-fluorouracil infusion in locally advanced rectal cancer: A phase II study. World J Gastrointest Oncol 2018; 10(1): 40-47
Rectal cancer is associated with a high incidence of local recurrence and distant metastasis[1,2]. In randomized studies, local-regional recurrence despite mesorectal resection has been reported to occur in 15% to 30% of the patients undergoing surgery alone[3-8]. In this regard, addition of preoperative and postoperative treatments to surgery have been shown to significantly improve local recurrence and survival rates[9-13], leading to standard administration of such treatments. Currently, preoperative chemoradiation (CRT) is the preferred treatment regimen in these patients, owing to low local recurrence rates and higher chance of sphincter-sparing surgery; although, studies comparing preoperative and postoperative CRT are relatively limited.
Besides conventional radiotherapy (RT) consisting of 45-50 Gy/1.8-2 Gy/5-6 wk, hypofractionated and hyperfractionated accelerated RT (HART; 42 Gy/1.5 Gy/18 d) are also used. HART reduces the risk of repopulation in tumor cells by shortening the treatment time and increases the repair capacity of normal tissues after sublethal damage through the reduction of the fraction dose. Thus, a survival advantage is provided in favor of normal cells, since tumor cells exhibit a poor repair mechanism. In this background, a fractionated HART scheme was examined in this study.
Therefore, this study was carried out to observe the early and late effects of HART regimen in combination with neoadjuvant chemotherapy in patients diagnosed with locally advanced rectal cancer.
MATERIALS AND METHODS
Previously untreated patients with histologically confirmed adenocarcinoma of the rectum (mid and distal ≤ 12 cm from the anal verge) were included in the study at Istanbul University Oncology Institute. Patient inclusion criteria were as follows: presence of resectable tumor; Karnofksy performance score ≥ 80; adequate bone marrow reserve (hemoglobin > 11 g/dL, white blood cell > 3500 mL, platelet count > 100000 mL), normal kidney and liver function tests (creatinine < 1.3 mg/dL, alanine aminotransferase and aspartate aminotransferase < 80 U/L), and ≤ 70 years of age. Patients who had received pelvic RT previously and patients with clinically detected distant metastases were excluded from the study. Clinical staging prior to treatment was accomplished based on physical examination, tumor markers (carcinoembryonic antigen, CA19-9), complete blood count and biochemistry tests, positron emission-computed tomography, pelvic-diffusion magnetic resonance imaging (MRI), and endorectal ultrasound. This prospective study was approved by the local ethics committee. A written informed consent was obtained from all patients prior to treatment.
All patients received preoperative HART (42 Gy/1.5 Gy/18 d/bid) and concurrent continuous infusion of 5-fluorouracil (5-FU; 325 mg/m2) and were hospitalized during treatments to observe the possible acute side effects.
Prior to RT planning, computed tomography was performed in prone position with belly board, with a 0.5 cm slice thickness for all patients. Gross tumor volume and clinical target volume were estimated by the radiologist and radiation oncologist. Patients were treated with a 3-D conformal RT technique, through posterior and lateral fields using a linear accelerator (18 MV) and with an isodose of 95% of planned target volume. RT regimen was defined by a fraction dose of 150 cGy/fr given 2 times/d, 5 d/wk, with a minimum 8 h between fractions. Total dose was 4200 cGy and total treatment duration was 18 d.
Port or subclavian catheter was used to give 5-FU in the form of a continuous infusion during the entire treatment. The daily dose of 5-FU that was given to patients was 325 mg/m2. Surgery was performed 4-8 wk after the completion of CRT.
Low anterior or abdominoperineal resection (total mesorectal excision) was performed depending on the location of the tumor and response rate. Four cycles of 5-FU (400 mg/m2, D1-5, q 28 d) plus folinic acid (20 mg/m2, D1-5, q 28 d) were administered postoperatively.
Assessment of efficacy and side effects
The primary endpoint was pathological response rate after CRT, and secondary endpoints included the local control rate, surgical margin positivity, survival and toxicity. Patients were assessed for toxicity during CRT on a daily basis. During the period between the end of CRT and surgery, patient assessments for side effects were performed weekly. Acute radiation toxicity criteria of the Radiation Therapy Oncology Group and the European Organization for Research and Treatment of Cancer (EORTC) were used for side effect assessments. Pathologic response and staging were defined according to the Dworak regression scoring system and TNM staging system, as described by the American Joint Committee on Cancer.
Statistical analyses were performed with SPSS 16.0 (SPSS Inc., Chicago, IL, United States) statistical software. Survival was calculated using the Kaplan-Meier method.
Thirty patients (19 males and 11 females) who were diagnosed with locally advanced rectum cancer between October 2007 and March 2009 were included. The median age was 53 years (range: 30-70 years). Patient characteristics are summarized in Table 1. There were only 2 patients with T3N0 disease, and one of them had positive circumferential margins in staging MRI.
Unless otherwise stated, data are presented as n (%). M: Male; F: Female.
Surgery was performed in all subjects except for one, who was found to have metastases during the early period after the CRT. Surgery was performed at week 4 in 15 patients and between weeks 6 and 8 in 13 patients. Twelve patients (41%) underwent sphincter-sparing surgery. According to the Dworak total regression scoring system, 6 of 29 (21%) patients who underwent surgery had grade IV (total) regression, and 9 patients (31%) had grade III (near total) regression. Corresponding figures for grade II, I and 0 regression were 11 patients (38%), 2 patients (7%) and 1 patient (3%), respectively.
Positive margins were found in 2 patients (6.6%). In 14 patients, mesorectal fascia invasion was detected in staging MRI and only 2 of those patients had positive radial surgical margin. Comparison of ypT and cT yielded a down-staging rate of 59%. Clinical and pathological tumor stages are shown in Table 2. The median number of lymph nodes that were excised was 25 (2-58), respectively. No pathologic lymph nodes were present in 19 (63%) patients. With regard to N stage, 20 (69%) patients were found to have down-staging.
Table 2 Clinical (cT2) and pathological (ypT) tumor stages.
Data are presented as n (%).
Local control and survival
One (3.3%) patient had local recurrence while distant metastases were found in 13 (43.3%) patients during a median follow up of 60 mo (5-78 mo). None of the patients with T3N0 disease had local recurrence. Overall, 14 patients (46.6%) died during the study period. The causes of death were systemic metastasis (13 patients) and chemotherapy-related toxicity (1 patient). Median time to progression was 59 mo (2-78 mo). The 2- and 5-year disease-free survival (DFS) rates were 63% and 53%, while the 2- and 5-year overall survival (OS) rates were 70% and 53.1%, respectively. The patients with complete or near-complete pathological response were compared to patients with less favorable group for survival. We found no significant difference in either group for DFS (P = 0.63) and OS (P = 0.32).
Toxicity and complications
Early side effects of preoperative CRT: The highest frequency of side effects occurred at weeks 3-4. During the acute phase 6 (20%) patients developed grade III-IV gastrointestinal system toxicity (3 grade III tenesmus/diarrhea and 3 grade IV tenesmus and diarrhea), and 2 (6.7%) patients developed grade III-IV hematopoietic system toxicity (1 grade III leucopenia and 1 grade IV neutropenia). There were no interruptions in RT due to toxicity, while in 4 patients chemotherapy was interrupted for 1 wk. Perianal abscess formation was observed in 3 patients before the planned date of surgery. One patient experienced spontaneous perforation at the tumor zone prior to surgery.
Perioperative complications: One patient had spontaneous perforation of the colon before surgery. Surgery was complicated in 4 patients with urethra-bladder injury, and in 1 patient with rectal perforation. Temporary nephrostomy tube was inserted in 3 patients. One patient developed incontinence and impotence due to nerve damage caused by bladder injury. Total proctotectomy procedure was performed in 1 patient due to sudden onset of ischemia during mesorectal resection. Perirectal abscesses developed in 2 patients. Surgical complications are shown in Table 3.
3Colovaginal fistula (n = 1), perirectal abscess (n = 1). Data are presented as n (%).
Postoperative chemotherapy: Sixteen (53%) patients underwent adjuvant chemotherapy. Chemotherapy was not given to 13 patients with pathologic complete response after surgery or who had preoperative grade IV toxicity due to CRT. Grade V toxicity (sepsis) was seen in only 1 patient after three cycles of chemotherapy. Adjuvant treatment was terminated prematurely in 2 patients due to grade IV hematologic toxicity.
Despite the continuous search for effective multidisciplinary treatment protocols, patients diagnosed with rectum cancer remain a high-risk population for local and distant recurrence. This study provided encouraging results with neoadjuvant HART plus chemotherapy.
A variety of preoperative RT regimens is used in patients with rectum cancer, and conventional RT (45-50 Gy/5 wk) represents the standard regimen for preoperative concurrent CRT. While a statistically significant advantage in terms of local recurrence rates was reported in 14 previous studies examining this regimen, a survival advantage could be shown in only 2 studies for preoperative RT[9,19]. In these studies, patients with early stage disease (I) and no requirement for preoperative CRT represented the majority of the participants. In a Polish study comparing short-term preoperative RT and conventional CRT, a statistically significant superiority of CRT was observed in terms of complete response rates (P < 0.0001); however, no difference was found in local control and survival. In a randomized study from France comparing preoperative RT and CRT, better pathologic complete response rate (11.4% vs 3.6%, P < 0.0001) and reduced local recurrence (8% vs 16.5%, P < 0.051) were observed in the CRT arm. In the similarly designed EORTC 22921 study, lower local recurrence was demonstrated in the CRT arm (P < 0.001).
Several phase II studies administrating HART alone or with concurrent chemotherapy have also been performed[22-28]. In the HART study by Bouzourene et al none of the patients had complete response and 8% of the patients had local remission. In another study by Voelter et al examining HART and CT, the reported positive circumferential resection margin was 21% and local control was 100%. In our study, radial surgical margin positivity was 7%, and after a median follow-up of 60-mo the local control rate was 97%. Local recurrence was seen in only 1 patient preoperatively staged as T3N1 and the radial surgical margin was pathologically positive in this patient. In contrast with a phase II study by Marsh et al, where 17 patients receiving preoperative capecitabine and HART had a complete response of 18%, the complete response rate was 21% (grade IV) and the near-complete response rate was 31% (grade III) among our participants. Studies with HART regimen are shown in Table 4.
The primary aim of this study was to search for possible therapeutic strategies that may help increase the rate of pathological tumor response and to decrease late side effects. In the regimen examined herein, decreased fraction size and shortened total treatment duration were hypothesized to result in decreased late and early side effects, respectively. Treatment duration and doses were different from those administered in conventional RT schemes. Therefore, a biological effective dose formula was used for dose calculations instead of the given dose, according to a time-corrected linear quadratic model[30,31]. Biological equivalent doses are shown in Table 5.
Tumor control/acute normal tissue complication probability
Late normal tissue complication probability
Bed (Gy) (α/β = 10 Gy)
Bed (Gy) (α/β = 3 Gy)
No time correction
With time correction
25 Gy/5 fr/5 d (d = 5 Gy)
50 Gy/25 fr/33 d (d = 2 Gy)
42 Gy/28 fr/18 d (d = 1.5 Gy)
Equation 1: Linear quadratic based isoeffect, basic formula without time correction, BED = nd (1+d/α/β), where n = number of fractions, d = dose (Gy) per fraction, α/β = the LQ quotient, Equation 2: Time-corrected LQ- formula, BED = nd (1+d/α/β)-γ/α (T- Tk), where γ/α = repair rate (set to 0.6 Gy/d), T = overall treatment time and Tk = proliferation delay (set to 7 d, or maximally T).
In this study combining HART and concurrent chemotherapy, 8 patients developed (26.6%) CRT-related grade III-IV toxicity. Although there was an increase in acute reactions, these effects were generally tolerable and RT was completed without interruption in all patients. In 4 patients, chemotherapy was interrupted shortly due to chemotherapy-related acute side effects. Toxicity was increased as a result of combined use of chemotherapy and RT regimen together with a higher chemotherapy dose as compared to conventional chemotherapy. The highest incidence of side effects was observed at weeks 3 and 4, which correspond to the development of acute mucosal side effects.
In addition, there is some literature data available on early side effects in rectum cancer patients treated with neoadjuvant conventional CRT. For example, in the EORTC 22921 study, grade III-IV toxicity occurred in 14% of the patients. In that study, the probable cause of increased side effects was the total treatment duration and impaired tissue repair as a consequence of shorter intervals between fractions of the chosen HART regimen. In a retrospective study where neoadjuvant CRT and HART alone were compared, no grade III-IV toxicity was reported in the HART arm of the study. In the Phase II 93-01 study, patients were treated with neoadjuvant HART with no significant increase in acute side effects. In another phase II study with preoperative HART and concurrent irinotecan (CPT-11), addition of chemotherapy was associated with an increase in grade III-IV toxicity, while the most common grade III-IV side effects observed in this study included diarrhea (24%) and infection (9%). In that phase II study, early side effects were more frequent than in our study. Probably, reduced incidence of diarrhea in this study could be explained on the basis of sparing the bowel volume out of the RT field.
Bowel perforation occurring in 2 of our patients raises the question of whether a period of 4 wk allows adequate time with normal tissue recovery following an intensive therapy regimen with neoadjuvant HART and concurrent chemotherapy. 5-FU is known to affect the repair mechanism in intestinal cells and the 5-FU dose used in this study might have played a role in the development of perforation in 2 of our patients.
The ideal duration between neoadjuvant therapy and surgery remains a source of debate. The objective of early surgery following short-term RT is to reduce or prevent long-term side effects. However, delayed surgery has been reported to result in increased rates of tumor regression and pathological complete response. In randomized studies utilizing short-term preoperative RT, the time between RT and surgery is relatively short[19,34], posing some challenges in the interpretation of the effects of the timing of surgery following RT. Early and delayed surgery were compared in the Stockholm III study where local control, DFS and OS were found to be similar in between three arms. In the randomized Istanbul R-01 study examining the ideal timing for surgery after preoperative CRT, no significant associations were observed between the time-to-surgery and regression rates or local control rates. Surgical margin seems to be the most important factor for local recurrence.
In our study, no surgery-related deaths occurred (0/29). In a phase II study utilizing HART and concurrent CPT-11, the postoperative complication rate was 27%, similar to other neoadjuvant CRT studies. Operative complications were recorded in 7% of the cases in this study. Occurrence of late toxicity only in 1 patient suggests that the strategy of utilizing HART to reduce late toxicity may prove to be successful. While no late side effects were observed in the 91-10 study with preoperative HART, in another study comparing conventional CRT with HART alone, late side effects were more frequently observed in the HART arm.
In this study, the ability of the HART regimen to achieve a higher tumor regression rate due to decreasing tumor repopulation was examined. In this regard, complete and near-complete response was achieved in 21% and 31% of the participants, respectively. In a previous study comparing HART alone vs conventional CRT regimens, lower complete response rates observed in the HART arm underscores the additive effect of chemotherapy. Similarly, in the French and EORTC studies comparing conventional RT and CRT, the reported pathological complete response rates in the CRT arm were 11.4% and 14%, respectively[38,39]. In our study, HART with concurrent chemotherapy was found to achieve complete or near-complete tumor regression in 52% of the patients. Preoperative HART scheme appeared to be capable of increasing tumor response and local control rates, but no difference was found for OS in phase II studies. This study showed no survival benefit despite a high pathological response rate. A study by Petrelli et al[36,40] and randomized Istanbul R-01 study did not find any correlation between pathological complete response rate and survival.
Circumferential (lateral) margin positivity was found in 2 patients, whereas only 1 patient showed local recurrence during a median follow-up period of 60 mo. Thirteen patients had distant metastases. Extensive hepatic metastases were found in early phase in 3 patients who died due to systemic disease.
In conclusion, earlier studies have proven the feasibility of HART treatment in terms of early and late side effects in this patient population. As in our study, improved local control rates and tumor regression may be achieved with HART but with higher toxicity. Toxicity could be reduced by giving chronomodulated concomitant capecitabine in Brunch Study. A plausible option would be to reduce the dose of 5-FU to reduce toxicity.
Currently, preoperative chemoradiation (CRT) is the preferred treatment regimen in locally advanced rectal cancer patients, owing to low local recurrence rates and higher chance of sphincter-sparing surgery. Besides conventional radiotherapy consisting of 45-50 Gy/1.8-2 Gy/5-6 wk, other radiotherapy schemes are also used. The hyperfractionated accelerated radiotherapy (HART) scheme reduces the risk of repopulation in tumor cells by shortening the treatment time and increases the repair capacity of normal tissues. In this background, a HART scheme and the combination of infusional 5-fluorouracil (5-FU) was examined in this study to augment the pathological complete response.
Local recurrence is still a substantial problem for locally advanced rectal cancers. Investigating tolerability and the effect of different radiotherapy schemes on local control other than conventional and hypofractionated radiotherapy can be a solution.
This study was mainly designed to observe the early and late effects of HART regimen in combination with neoadjuvant chemotherapy in patients diagnosed with locally advanced rectal cancer. The primary aim of this study was to search for possible therapeutic strategies that may help increase the rate of pathological tumor response and to decrease late side effects.
Previously untreated locally advanced rectal cancer patients with histological confirmation were included in the study. The patients were clinically staged according to positron emission-computed tomography and pelvic-diffusion magnetic resonance imaging. All patients received preoperative HART (42 Gy/1.5 Gy/18 d/bid) and concurrent continuous infusion of 5-FU (325 mg/m2) and were hospitalized during treatments to observe the possible acute side effects. Total mesorectal excision was performed 4-8 wk after the completion of chemoradiotherapy. Four cycles of 5-FU (400 mg/m2, D1-5, q 28 d) plus folinic acid (20 mg/m2, D1-5, q 28 d) were administered postoperatively. The primary endpoint was pathological response rate after CRT, and secondary endpoints included the local control rate, surgical margin positivity, survival and toxicity.
Thirty patients were included between October 2007 and March 2009. The median age was 53 years. Most of the patients clinically staged as T3N+ disease (90%). Surgery was performed at week 4 in half of the patients. Twelve patients (41%) underwent sphincter-sparing surgery. The Dworak total regression scoring system was used to evaluate pathological response, and grade IV (total) regression was found in 6 of 29 (21%) patients; nine patients (31%) had grade III (near total) regression. Positive margins were found in 2 patients (6.6%). One (3.3%) patient had local recurrence during a median follow-up of 60 mo. The 5-year disease-free survival rate was 53%, while the 5-year overall survival rate was 53.1%. There were no interruptions in RT due to toxicity, while in 4 patients chemotherapy was interrupted for 1 wk. Sixteen (53%) patients underwent adjuvant chemotherapy.
Improved local control rates and tumor regression may be achieved with HART but with higher acute toxicity. Toxicity could be reduced by giving chronomodulated concomitant chemotherapy or reducing the dose of 5-FU. Surgery timing has no effect on survival but still should be considered because of increased acute side effects due to HART fractionation. Besides an increased pathological response rate, this study showed no survival benefit.
Different HART schemes can be examined with concomitant chemotherapy in the future studies. Because of the high incidence of acute toxicity, fraction dose and chemotherapy doses should be designed properly for new studies.
Manuscript source: Unsolicited manuscript
Specialty type: Oncology
Country of origin: Turkey
Peer-review report classification
Grade A (Excellent): 0
Grade B (Very good): 0
Grade C (Good): C, C, C
Grade D (Fair): 0
Grade E (Poor): E
P- Reviewer: Avital S, Dirier A, Palacios-Eito A, Yeo SG S- Editor: Kong JX L- Editor: Filipodia E- Editor: Wang CH
Bosset JF, Arbez-Gindre F, Pelissier E, Mantion G, Camelot G, Gillet M, Oppermann A, Bourgeois P, Schraub S. Anatomo-pathological factors in the prognosis of rectal cancers. A mono- and multifactorial study.Gastroenterol Clin Biol. 1986;10:728-735.
Minsky BD, Mies C, Recht A, Rich TA, Chaffey JT. Resectable adenocarcinoma of the rectosigmoid and rectum. I. Patterns of failure and survival.Cancer. 1988;61:1408-1416.
Balslev I, Pedersen M, Teglbjaerg PS, Hanberg-Soerensen F, Bone J, Jacobsen NO, Overgaard J, Sell A, Bertelsen K, Hage E. Postoperative radiotherapy in Dukes’ B and C carcinoma of the rectum and rectosigmoid. A randomized multicenter study.Cancer. 1986;58:22-28.
Duncan W. Adjuvant radiotherapy in rectal cancer: the MRC trials.Br J Surg. 1985;72 Suppl:S59-S62.
Gérard A, Buyse M, Nordlinger B, Loygue J, Pène F, Kempf P, Bosset JF, Gignoux M, Arnaud JP, Desaive C. Preoperative radiotherapy as adjuvant treatment in rectal cancer. Final results of a randomized study of the European Organization for Research and Treatment of Cancer (EORTC).Ann Surg. 1988;208:606-614.
Horn A, Morild I, Dahl O. Tumour shrinkage and down staging after preoperative radiation of rectal adenocarcinomas.Radiother Oncol. 1990;18:19-28.
Rider WD, Palmer JA, Mahoney LJ, Robertson CT. Preoperative irradiation in operable cancer of the rectum: report of the Toronto trial.Can J Surg. 1977;20:335-338.
Preoperative short-term radiation therapy in operable rectal carcinoma. A prospective randomized trial. Stockholm Rectal Cancer Study Group.Cancer. 1990;66:49-55.
Swedish Rectal Cancer Trial. Cedermark B, Dahlberg M, Glimelius B, Påhlman L, Rutqvist LE, Wilking N. Improved survival with preoperative radiotherapy in resectable rectal cancer.N Engl J Med. 1997;336:980-987.
Compton CC, Fielding LP, Burgart LJ, Conley B, Cooper HS, Hamilton SR, Hammond ME, Henson DE, Hutter RV, Nagle RB. Prognostic factors in colorectal cancer. College of American Pathologists Consensus Statement 1999.Arch Pathol Lab Med. 2000;124:979-994.
Gastrointestinal Tumor Study Group. Prolongation of the disease-free interval in surgically treated rectal carcinoma.N Engl J Med. 1985;312:1465-1472.
Cammà C, Giunta M, Fiorica F, Pagliaro L, Craxì A, Cottone M. Preoperative radiotherapy for resectable rectal cancer: A meta-analysis.JAMA. 2000;284:1008-1015.
Colorectal Cancer Collaborative Group. Adjuvant radiotherapy for rectal cancer: a systematic overview of 8,507 patients from 22 randomised trials.Lancet. 2001;358:1291-1304.
Thames HD Jr, Peters LJ, Withers HR, Fletcher GH. Accelerated fractionation vs hyperfractionation: rationales for several treatments per day.Int J Radiat Oncol Biol Phys. 1983;9:127-138.
Cox JD, Stetz J, Pajak TF. Toxicity criteria of the Radiation Therapy Oncology Group (RTOG) and the European Organization for Research and Treatment of Cancer (EORTC).Int J Radiat Oncol Biol Phys. 1995;31:1341-1346.
Dworak O, Keilholz L, Hoffmann A. Pathological features of rectal cancer after preoperative radiochemotherapy.Int J Colorectal Dis. 1997;12:19-23.
Greene FL, Page DL, Fleming ID. AJCC (American Joint Committee on Cancer) cancer staging manual, 2002. Springer-Verlag, New York.
Randomized study on preoperative radiotherapy in rectal carcinoma. Stockholm Colorectal Cancer Study Group.Ann Surg Oncol. 1996;3:423-430.
Bujko K, Nowacki MP, Nasierowska-Guttmejer A, Michalski W, Bebenek M, Kryj M. Long-term results of a randomized trial comparing preoperative short-course radiotherapy with preoperative conventionally fractionated chemoradiation for rectal cancer.Br J Surg. 2006;93:1215-1223.
Bosset JF, Collette L, Calais G, Mineur L, Maingon P, Radosevic-Jelic L, Daban A, Bardet E, Beny A, Ollier JC; EORTC Radiotherapy Group Trial 22921. Chemotherapy with preoperative radiotherapy in rectal cancer.N Engl J Med. 2006;355:1114-1123.
Ceelen W, Boterberg T, Pattyn P, van Eijkeren M, Gillardin JM, Demetter P, Smeets P, Van Damme N, Monsaert E, Peeters M. Neoadjuvant chemoradiation versus hyperfractionated accelerated radiotherapy in locally advanced rectal cancer.Ann Surg Oncol. 2007;14:424-431.
Voelter V, Zouhair A, Vuilleumier H, Matter M, Bouzourene H, Leyvraz S, Bauer J, Coucke P, Stupp R. CPT-11 and concomitant hyperfractionated accelerated radiotherapy induce efficient local control in rectal cancer patients: results from a phase II.Br J Cancer. 2006;95:710-716.
Coucke PA, Notter M, Stamm B, Matter M, Fasolini F, Schlumpf R, Matzinger O, Bouzourene H; All Surgeons From Public Hospitals And Private Clinics. Preoperative hyper-fractionated accelerated radiotherapy (HART) in locally advanced rectal cancer (LARC) immediately followed by surgery. A prospective phase II trial.Radiother Oncol. 2006;79:52-58.
Suwinski R, Wydmanski J, Pawełczyk I, Starzewski J. A pilot study of accelerated preoperative hyperfractionated pelvic irradiation with or without low-dose preoperative prophylactic liver irradiation in patients with locally advanced rectal cancer.Radiother Oncol. 2006;80:27-32.
Marsh Rde W, George TJ, Siddiqui T, Mendenhall WM, Zlotecki RA, Grobmyer S, Hochwald S, Chang M, Larson B, King J. A phase II trial of neoadjuvant capecitabine combined with hyperfractionated accelerated radiation therapy in locally advanced rectal cancer.Am J Clin Oncol. 2010;33:251-256.
Nabhan C, Ragam A, Samuels B, Milton DT, Prasad L, Hooberman A, Hartsell W, Anthony A, Weisman R, Bitran JD. Mitomycin-C/5-fluorouracil/leucovorin and hyperfractionated radiation therapy for rectal carcinoma: a phase II study with long-term follow-up.Clin Colorectal Cancer. 2007;6:436-441.
Bouzourene H, Bosman FT, Matter M, Coucke P. Predictive factors in locally advanced rectal cancer treated with preoperative hyperfractionated and accelerated radiotherapy.Hum Pathol. 2003;34:541-548.
Fowler JF. The linear-quadratic formula and progress in fractionated radiotherapy.Br J Radiol. 1989;62:679-694.
Jones B, Dale RG. Mathematical models of tumour and normal tissue response.Acta Oncol. 1999;38:883-893.
Coucke PA, Notter M, Matter M, Fasolini F, Calmes JM, Schlumpf R, Schwegler N, Stamm B, Phuoc Do H, Bouzourene H. Effect of timing of surgery on survival after preoperative hyperfractionated accelerated radiotherapy (HART) for locally advanced rectal cancer (LARC): is it a matter of days?Acta Oncol. 2006;45:1086-1093.
Bozdag AD, Peker Y, Derici H, Gürkök C, Ozgönül M. The effect of preoperative 5-fluorouracil on colonic healing: an experimental study.Hepatogastroenterology. 2001;48:1631-1634.
Kapiteijn E, Marijnen CA, Nagtegaal ID, Putter H, Steup WH, Wiggers T, Rutten HJ, Pahlman L, Glimelius B, van Krieken JH. Preoperative radiotherapy combined with total mesorectal excision for resectable rectal cancer.N Engl J Med. 2001;345:638-646.
Erlandsson J, Holm T, Pettersson D, Berglund Å, Cedermark B, Radu C, Johansson H, Machado M, Hjern F, Hallböök O, Syk I, Glimelius B, Martling A. Optimal fractionation of preoperative radiotherapy and timing to surgery for rectal cancer (Stockholm III): a multicentre, randomised, non-blinded, phase 3, non-inferiority trial.Lancet Oncol. 2017;18:336-346.
Saglam S, Bugra D, Saglam EK, Asoglu O, Balik E, Yamaner S, Basaran M, Oral EN, Kizir A, Kapran Y. Fourth versus eighth week surgery after neoadjuvant radiochemotherapy in T3-4/N0+ rectal cancer: Istanbul R-01 study.J Gastrointest Oncol. 2014;5:9-17.
Coucke PA, Sartorelli B, Cuttat JF, Jeanneret W, Gillet M, Mirimanoff RO. The rationale to switch from postoperative hyperfractionated accelerated radiotherapy to preoperative hyperfractionated accelerated radiotherapy in rectal cancer.Int J Radiat Oncol Biol Phys. 1995;32:181-188.
Gerard J, Bonnetain F, Conroy T. Preoperative (preop) radiotherapy (RT) + 5 FU/folinic acid (FA) in T3–4 rectal cancers: Results of the FFCD 9203 randomized trial.J Clin Oncol. 2005;23:247S.
Boulis-Wassif S, Gerard A, Loygue J, Camelot D, Buyse M, Duez N. Final results of a randomized trial on the treatment of rectal cancer with preoperative radiotherapy alone or in combination with 5-fluorouracil, followed by radical surgery. Trial of the European Organization on Research and Treatment of Cancer Gastrointestinal Tract Cancer Cooperative Group.Cancer. 1984;53:1811-1818.
Petrelli F, Borgonovo K, Cabiddu M, Ghilardi M, Lonati V, Barni S. Pathologic complete response and disease-free survival are not surrogate endpoints for 5-year survival in rectal cancer: an analysis of 22 randomized trials.J Gastrointest Oncol. 2017;8:39-48.
Akgun Z, Saglam S, Yucel S, Gural Z, Balik E, Cipe G, Yildiz S, Kilickap S, Okyar A, Kaytan-Saglam E. Neoadjuvant chronomodulated capecitabine with radiotherapy in rectal cancer: a phase II brunch regimen study.Cancer Chemother Pharmacol. 2014;74:751-756.
Brooks S, Glynne-Jones R, Novell R, Harrison M, Brown K, Makris A. Short course continuous, hyperfractionated, accelerated radiation therapy (CHART) as preoperative treatment for rectal cancer.Acta Oncol. 2006;45:1079-1085.
Widder J, Herbst F, Dobrowsky W, Schmid R, Pokrajac B, Jech B, Chiari C, Stift A, Maier A, Karner-Hanusch J. Preoperative short-term radiation therapy (25 Gy, 2.5 Gy twice daily) for primary resectable rectal cancer (phase II).Br J Cancer. 2005;92:1209-1214.
Glimelius B. Rectal cancer irradiation. Long course, short course or something else?Acta Oncol. 2006;45:1013-1017.