Observational Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Radiol. Dec 28, 2015; 7(12): 509-520
Published online Dec 28, 2015. doi: 10.4329/wjr.v7.i12.509
Combined value of apparent diffusion coefficient-standardized uptake value max in evaluation of post-treated locally advanced rectal cancer
Davide Ippolito, Davide Fior, Chiara Trattenero, Elena De Ponti, Silvia Drago, Luca Guerra, Cammillo Talei Franzesi, Sandro Sironi
Davide Ippolito, Davide Fior, Chiara Trattenero, Elena De Ponti, Silvia Drago, Luca Guerra, Cammillo Talei Franzesi, Sandro Sironi, School of Medicine, University of Milano-Bicocca, 20126 Milan, Italy
Davide Ippolito, Davide Fior, Chiara Trattenero, Silvia Drago, Cammillo Talei Franzesi, Sandro Sironi, Department of Diagnostic Radiology, H S.Gerardo Monza, 20052 Milan, Italy
Luca Guerra, Department of Nuclear Medicine and PET Unit-Molecular Bioimaging Centre, San Gerardo Hospital, 20052 Monza, Italy
Elena De Ponti, Department of Medical Physics, San Gerardo Hospital, 20052 Monza, Italy
Author contributions: Ippolito D was the guarantor of integrity of entire study and contributed to study concepts; Ippolito D, Fior D and Trattenero C contributed to study design; Drago S and Franzesi CT contributed to literature research; Ippolito D and Guerra L contributed to clinical studies; Ippolito D, Fior D and Guerra L contributed to data acquisition; Ippolito D, Fior D, Trattenero C and De Ponti E contributed to data analysis/interpretation; De Ponti E contributed to statistical analysis; Ippolito D, Fior D, Trattenero C and Drago S contributed to manuscript preparation; Ippolito D and Sironi S contributed to manuscript definition of intellectual content and manuscript editing; all the authors contributed to manuscript revision/review; Ippolito D gave the manuscript final version approval.
Institutional review board statement: No ethical approval is needed, because the used data have been generated as part of the routine work of our organization.
Informed consent statement: This prospective study was approved by our institutional review board, and informed consent was obtained from all patients.
Conflict-of-interest statement: No Conflict-of-interest. Authors declare no competing financial interests in relation to the work described.
Data sharing statement: No additional data are available.
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: Davide Ippolito, MD, Department of Diagnostic Radiology, H S.Gerardo Monza, Via Pergolesi 11, 20052 Milan, Italy. davide.atena@tiscalinet.it
Telephone: +39-039-2333463
Received: January 25, 2015
Peer-review started: January 26, 2015
First decision: March 6, 2015
Revised: July 1, 2015
Accepted: November 3, 2015
Article in press: November 4, 2015
Published online: December 28, 2015
Processing time: 336 Days and 9.1 Hours
Abstract

AIM: To assess the clinical diagnostic value of functional imaging, combining quantitative parameters of apparent diffusion coefficient (ADC) and standardized uptake value (SUV)max, before and after chemo-radiation therapy, in prediction of tumor response of patients with rectal cancer, related to tumor regression grade at histology.

METHODS: A total of 31 patients with biopsy proven diagnosis of rectal carcinoma were enrolled in our study. All patients underwent a whole body 18FDG positron emission tomography (PET)/computed tomography (CT) scan and a pelvic magnetic resonance (MR) examination including diffusion weighted (DW) imaging for staging (PET1, RM1) and after completion (6.6 wk) of neoadjuvant treatment (PET2, RM2). Subsequently all patients underwent total mesorectal excision and the histological results were compared with imaging findings. The MR scanning, performed on 1.5 T magnet (Philips, Achieva), included T2-weighted multiplanar imaging and in addition DW images with b-value of 0 and 1000 mm²/s. On PET/CT the SUVmax of the rectal lesion were calculated in PET1 and PET2. The percentage decrease of SUVmax (ΔSUV) and ADC (ΔADC) values from baseline to presurgical scan were assessed and correlated with pathologic response classified as tumor regression grade (Mandard’s criteria; TRG1 = complete regression, TRG5 = no regression).

RESULTS: After completion of therapy, all the patients were submitted to surgery. According to the Mandard’s criteria, 22 tumors showed complete (TRG1) or subtotal regression (TRG2) and were classified as responders; 9 tumors were classified as non responders (TRG3, 4 and 5). Considering all patients the mean values of SUVmax in PET 1 was higher than the mean value of SUVmax in PET 2 (P < 0.001), whereas the mean ADC values was lower in RM1 than RM2 (P < 0.001), with a ΔSUV and ΔADC respectively of 60.2% and 66.8%. The best predictors for TRG response were SUV2 (threshold of 4.4) and ADC2 (1.29 × 10-3 mm2/s) with high sensitivity and specificity. Combining in a single analysis both the obtained median value, the positive predictive value, in predicting the different group category response in related to TRG system, presented R2 of 0.95.

CONCLUSION: The functional imaging combining ADC and SUVmax in a single analysis permits to detect changes in cellular tissue structures useful for the assessment of tumour response after the neoadjuvant therapy in rectal cancer, increasing the sensitivity in correct depiction of treatment response than either method alone.

Keywords: Advanced rectal cancer; Functional imaging; FDG-PET/CT; Magnetic resonance imaging; Apparent diffusion coefficient; Neoadjuvant treatment; Tumor regression grade

Core tip: In our study we evaluated the combination of changes of glucose metabolism values expressed as SUVmax and the changes of apparent diffusion coefficient (ADC map) values, before and after neoadjuvant therapy, in patients with advanced rectal cancer in order to predict, in vivo, the therapy response. The importance of this work consist of the possibility to offer, in the era of positron emission tomography (PET)/magnetic resonance imaging scanner, a new advanced tool that allows the non-invasive evaluation of response to neoadjuvant chemotherapy treatment in patients with rectal cancer, by adding quantitative value information on diffusion weighted images and on PET/computed tomography imaging.