Document Detail

Role of Diffusion-Weighted Magnetic Resonance Imaging in Predicting Sensitivity to Chemoradiotherapy in Muscle-Invasive Bladder Cancer.
MedLine Citation:
PMID:  22414281     Owner:  NLM     Status:  Publisher    
PURPOSE: In chemoradiation (CRT)-based bladder-sparing approaches for muscle invasive bladder cancer (MIBC), patients who respond favorably to induction CRT enjoy the benefits of bladder preservation, whereas nonresponders do not. Thus, accurate prediction of CRT sensitivity would optimize patient selection for bladder-sparing protocols. Diffusion-weighted MRI (DW-MRI) is a functional imaging technique that quantifies the diffusion of water molecules in a noninvasive manner. We investigated whether DW-MRI predicts CRT sensitivity of MIBC. METHODS AND MATERIALS: The study cohort consisted of 23 MIBC patients (cT2/T3 = 7/16) who underwent induction CRT consisting of radiotherapy to the small pelvis (40 Gy) with two cycles of cisplatin (20 mg/day for 5 days), followed by partial or radical cystectomy. All patients underwent DW-MRI before the initiation of treatment. Associations of apparent diffusion coefficient (ADC) values with CRT sensitivity were analyzed. The proliferative potential of MIBC was also assessed by analyzing the Ki-67 labeling index (LI) in pretherapeutic biopsy specimens. RESULTS: Thirteen patients (57%) achieved pathologic complete response (pCR) to CRT. These CRT-sensitive MIBCs showed significantly lower ADC values (median, 0.63 × 10(-3) mm(2)/s; range, 0.43-0.77) than CRT-resistant (no pCR) MIBCs (median, 0.84 × 10(-3) mm(2)/s; range, 0.69-1.09; p = 0.0003). Multivariate analysis identified ADC value as the only significant and independent predictor of CRT sensitivity (p < 0.0001; odds ratio per 0.001 ×10(-3) mm(2)/s increase, 1.03; 95% confidence interval, 1.01-1.08). With a cutoff ADC value at 0.74 × 10(-3) mm(2)/s, sensitivity/specificity/accuracy in predicting CRT sensitivity was 92/90/91%. Ki-67 LI was significantly higher in CRT-sensitive MIBCs (p = 0.0005) and significantly and inversely correlated with ADC values (ρ = -0.67, p = 0.0007). CONCLUSIONS: DW-MRI is a potential biomarker for predicting CRT sensitivity in MIBC. DW-MRI may be useful to optimize patient selection for CRT-based bladder-sparing approaches.
Soichiro Yoshida; Fumitaka Koga; Shuichiro Kobayashi; Chikako Ishii; Hiroshi Tanaka; Hajime Tanaka; Yoshinobu Komai; Kazutaka Saito; Hitoshi Masuda; Yasuhisa Fujii; Satoru Kawakami; Kazunori Kihara
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-3-11
Journal Detail:
Title:  International journal of radiation oncology, biology, physics     Volume:  -     ISSN:  1879-355X     ISO Abbreviation:  -     Publication Date:  2012 Mar 
Date Detail:
Created Date:  2012-3-14     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7603616     Medline TA:  Int J Radiat Oncol Biol Phys     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2012 Elsevier Inc. All rights reserved.
Department of Urology, Tokyo Medical and Dental University Graduate School, Tokyo, Japan.
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