Comparison of Magnetic Resonance Imaging and Histopathological Response to Chemoradiotherapy in Locally Advanced Rectal Cancer
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Magnetic resonance imaging (MRI) methods for chemoradiotherapy (CRT) response assessment of rectal cancer include posttreatment T staging (ymrT), tumor regression grading (mrTRG), volume reduction posttreatment, and modified RECIST measurement. We compared these methods in identifying good versus poor responders with the histopathological standards of T stage (ypT) and tumor regression grading (TRG).
A total of 86 patients underwent CRT in a prospective phase II trial for MRI-defined locally advanced rectal cancer. Two readers independently assessed MRIs for ymrT, mrTRG, volume change, and RECIST. Parameters for each case were categorized as good or poor response and analyzed against ypT and TRG by univariate logistic regression.
A total of 83 patients had evaluable imaging, and 78 had final pathology (five did not undergo surgery). Of these, 34 patients had good response (ypT0-3a) and 44 had poor response (>ypT3a). Also, 27 patients had favorable pathologic TRG (predominant fibrosis) and 51 had unfavorable TRG (predominant tumor). Good mrTRG and ymr <T3b stage were both significantly (P = 0.001) associated with favorable pathology odds ratio [OR] = 16.11 (95 % confidence interval [95 % CI]: 3.36–77.29) and 17.50 (95 % CI: 5.38–56.89), respectively. RECIST measurements and volume reduction of >80 % showed an OR of 3.23 (95 % CI: 1.14–9.17), 4.25 (95 % CI: 0.92–15.45), respectively, for a good ypT score (P = 0.028), but there was no association for histopathological TRG.
Favorable and unfavorable histopathology are predicted by both ymrT and mrTRG, and we recommend these parameters for post-treatment assessment of rectal cancers treated with CRT.
KeywordsRectal Cancer Circumferential Resection Margin Advanced Rectal Cancer Tumor Regression Grade Tumor Length
GB., H. R., D. S. M., R. G. J., E. R., M. P., S. R., C. V. V., and P. Q. were paid honoraria by Sanofi-Aventis for the design of study protocol. E.V.C. received research funding at the University Hospital Leuven paid by Sanofi-Aventis.
- 1.MERCURY. Extramural depth of tumor invasion at thin-section MR in patients with rectal cancer: results of the MERCURY study. Radiology. 2007;243:132–9.Google Scholar
- 6.Suarez J, Vera R, Balen E, Gomez M, Arias F, Lera JM, et al. Pathologic response assessed by Mandard grade is a better prognostic factor than down staging for disease-free survival after preoperative radiochemotherapy for advanced rectal cancer. Colorectal Dis. 2008;10:563–8.PubMedCrossRefGoogle Scholar
- 7.Theodoropoulos G, Wise WE, Padmanabhan A, Kerner BA, Taylor CW, Aguilar PS, et al. T-level downstaging and complete pathologic response after preoperative chemoradiation for advanced rectal cancer result in decreased recurrence and improved disease-free survival. Dis Colon Rectum. 2002;4:895–903.CrossRefGoogle Scholar
- 9.Valentini V, Coco C, Picciocchi A, Morganti AG, Trodella L, Ciabattoni A, et al. Does downstaging predict improved outcome after preoperative chemoradiation for extraperitoneal locally advanced rectal cancer? A long-term analysis of 165 patients. Int J Radiat Oncol Biol Phys. 2002;53:664–74.PubMedCrossRefGoogle Scholar
- 17.Sobin LH, Gospodarowicz MK, Wittekind C. TNM Classification of Malignant Tumours (UICC International Union Against Cancer). Wiley, Oxford; 2009.Google Scholar
- 23.Machida N, Boku N, Yoshino S, Hironaka Y, Onozawa A, Fukutomi K, et al. editors. Impact of baseline sum longest diameter of target lesions by RECIST on survival of patients with metastatic colorectal cancer (MCRC). Abstract No. 266, 2007 Gastrointestinal Cancers Symposium. American Society of Clinical Oncology: Orlando; 2007.Google Scholar
- 24.Therasse P, Arbuck SG, Eisenhauer EA, Wanders J, Kaplan RS, Rubinstein L, et al. New guidelines to evaluate the response to treatment in solid tumors. European Organization for Research and Treatment of Cancer, National Cancer Institute of the United States, National Cancer Institute of Canada. J Natl Cancer Inst. 2000;92:205–16.PubMedCrossRefGoogle Scholar
- 25.Francois Y, Nemoz CJ, Baulieux J, Vignal J, Grandjean JP, Partensky C, et al. Influence of the interval between preoperative radiation therapy and surgery on downstaging and on the rate of sphincter-sparing surgery for rectal cancer: the Lyon R90-01 randomized trial. J Clin Oncol. 1999;17:2396.PubMedGoogle Scholar
- 26.Dresen RC, Beets GL, Rutten HJ, Engelen SM, Lahaye MJ, Vliegen RF, et al. Locally advanced rectal cancer: MR imaging for restaging after neoadjuvant radiation therapy with concomitant chemotherapy. Part I. Are we able to predict tumor confined to the rectal wall? Radiology. 2009;252:71–80.PubMedCrossRefGoogle Scholar
- 27.Kang JH, Kim YC, Kim H, Kim YW, Hur H, Kim JS, et al. Tumor volume changes assessed by three-dimensional magnetic resonance volumetry in rectal cancer patients after preoperative chemoradiation: the impact of the volume reduction ratio on the prediction of pathologic complete response. Int J Radiat Oncol Biol Phys. 2010;76:1018–25.PubMedCrossRefGoogle Scholar