Brief Article
Copyright ©2013 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Sep 7, 2013; 19(33): 5520-5527
Published online Sep 7, 2013. doi: 10.3748/wjg.v19.i33.5520
Diffusion-weighted magnetic resonance imaging for predicting the response of rectal cancer to neoadjuvant concurrent chemoradiation
Gang Cai, Ye Xu, Ji Zhu, Wei-Lie Gu, Shuai Zhang, Xue-Jun Ma, San-Jun Cai, Zhen Zhang
Gang Cai, Ji Zhu, Xue-Jun Ma, Zhen Zhang, Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, China
Gang Cai, Ji Zhu, Xue-Jun Ma, Zhen Zhang, Ye Xu, Wei-Lie Gu, San-Jun Cai, Shuai Zhang, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China
Ye Xu, Wei-Lie Gu, San-Jun Cai, Department of Colorectal Surgery, Fudan University Shanghai Cancer Center, Shanghai 200032, China
Shuai Zhang, Department of Radiology, Fudan University Shanghai Cancer Cente, Shanghai 200032, China
Author contributions: Cai G and Zhang Z performed the study conception and design, neoadjuvant therapy, collection and assembly of data, data analysis, and manuscript writing; Zhu J and Ma XJ performed the study design and neoadjuvant therapy; Xu Y, Gu WL and Cai SJ participated in the study design and conducted the tumor biopsy and surgery; Zhang S performed the radiological work.
Correspondence to: Zhen Zhang, MD, Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Xuhui District, Shanghai 200032, China. zhenzhang666@163.com
Telephone: +86-21-64175590 Fax: +86-21-64174774
Received: April 15, 2013
Revised: July 15, 2013
Accepted: July 30, 2013
Published online: September 7, 2013
Abstract

AIM: To evaluate the clinical value of diffusion-weighted magnetic resonance imaging (DW-MRI) in predicting the response of rectal cancer to neoadjuvant chemoradiation.

METHODS: This prospective study was approved by our institutional review board, and informed consent was obtained from each patient. Fifteen patients (median age 56 years) with locally advanced rectal cancer were treated in our hospital from June 2006 to December 2007. All patients were stage IIIB-C according to the results of MRI and endorectal ultrasound examinations. All patients underwent pelvic irradiation with 45 Gy/25 fx per 35 days. The concurrent chemotherapy regimen consisted of capecitabine 625 mg/m2, bid (Monday-Friday), and oxaliplatin 50 mg/m2, weekly. The patients underwent surgery 5-8 wk after the completion of neoadjuvant therapy. T downstaging was defined as the downstaging of the tumor from cT3 to ypT0-2 or from cT4 to ypT0-3. Good regression was defined as TRG 3-4, and poor regression was defined as TRG 0-2. Diffusion-weighted magnetic resonance images were obtained prior to and weekly during the course of neoadjuvant chemoradiation, and the apparent diffusion coefficient (ADC) values were calculated from the acquired tumor images.

RESULTS: Comparison with the mean pretreatment tumor ADC revealed an increase in the mean tumor ADC during the course of neoadjuvant chemoradiation, especially at the 2nd week (P = 0.004). We found a strong negative correlation between the mean pretreatment tumor ADC and tumor regression after neoadjuvant chemoradiation (P = 0.021). In the T downstage and tumor regression groups, we found a significant increase in the mean ADC at the 2nd week of neoadjuvant therapy (P = 0.011; 0.004).

CONCLUSION: DW-MRI might be a valuable clinical tool to help predict or assess the response of rectal cancer to neoadjuvant chemoradiation at an early timepoint.

Keywords: Locally advanced rectal cancer, Neoadjuvant chemoradiation, Diffusion-weighted magnetic resonance imaging, Apparent diffusion coefficient

Core tip: This original study prospectively evaluated the clinical value of diffusion-weighted magnetic resonance imaging (DW-MRI) in predicting the response of rectal cancer to neoadjuvant chemoradiation. We found a strong negative correlation between the mean pretreatment tumor apparent diffusion coefficient (ADC) and tumor regression after neoadjuvant chemoradiation, as well as a significant increase in the mean ADC at the 2nd week in the T downstage and tumor regression groups. Therefore, DW-MRI might be a valuable clinical tool to help predict or assess the response of rectal cancer to neoadjuvant chemoradiation at an early timepoint.