- 作者：Soichiro Yoshida ; M.D. ; Ph.D.&lowast ; ; Fumitaka Koga ; M.D. ; Ph.D.&lowast ; ; f-koga.uro@tmd.ac.jp ; Shuichiro Kobayashi ; M.D.&lowast ; ; Chikako Ishii ; M.D. ; Ph.D.&dagger ; ; Hiroshi Tanaka ; M.D. ; Ph.D.&dagger ; ; Hajime Tanaka ; M.D.&lowast ; ; Yoshinobu Komai ; M.D. ; Ph.D.&lowast ; ; Kazutaka Saito ; M.D. ; Ph.D.&lowast ; ; Hitoshi Masuda ; M.D. ; Ph.D.&lowast ; ; Yasuhisa Fujii ; M.D. ; Ph.D.&lowast ; ; Satoru Kawakami ; M.D. ; Ph.D.&lowast ; ; Kazunori Kihara ; M.D. ; Ph.D.&lowast ;
- 关键词：Diffusion magnetic resonance imaging ; Chemoradiation ; Ki-67 antigen ; Bladder cancer
- 刊名：International Journal of Radiation Oncology*Biology*Physics
- 出版年：2012
- 出版时间：1 May, 2012
- 年：2012
- 卷：83
- 期：1
- 页码：e21-e27
- 全文大小：342 K
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 ¡Á 10? mm2/s; range, 0.43-0.77) than CRT-resistant (no pCR) MIBCs (median, 0.84 ¡Á 10? mm2/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 ¡Á10? mm2/s increase, 1.03; 95 % confidence interval, 1.01-1.08). With a cutoff ADC value at 0.74 ¡Á 10? mm2/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 (¦Ñ?= ?.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.