EVALUATION OF CHEMOTHERAPY IN ADVANCED URINARY-BLADDER CANCER WITH FAST DYNAMIC CONTRAST-ENHANCED MR-IMAGING

PURPOSE: To evaluate if the failure of chemotherapy in patients with a dvanced urinary bladder cancer can be predicted early in the course of chemotherapy with fast dynamic contrast material-enhanced magnetic re sonance (MR) imaging. MATERIALS AND METHODS: In this prospective study , 22 consecutive patients with histologically proved advanced urinary bladder cancer underwent MR imaging before and after two, four, and si x cycles of chemotherapy with methotrexate vinblastine, adriamycin, an d cisplatin (MVAC). The response after two chemotherapy cycles was eva luated by using conventional tumor size parameters at unenhanced MR im aging and with changes in the time to the start of tumor or lymph node enhancement at fast dynamic contrast-enhanced MR imaging. The results obtained with these techniques were compared with the findings at his topathology in cystectomy (n=9) or multiple transurethral resection (n =13) specimens obtained after completion of chemotherapy. RESULTS: Aft er two MVAC cycles, the accuracy, sensitivity, and specificity in dist inguishing responders from nonresponders with conventional MR imaging were 73%, 79%, and 63%, respectively. With the dynamic technique, thes e were 95%, 93%, and 100%, respectively. Although the differences betw een these values are not significant (P=.48 for sensitivity, .25 for s pecificity, and .07 for accuracy), the data indicate that dynamic enha nced MR imaging performed better than unenhanced MR imaging. Dynamic i maging yielded correct results after two MVAC cycles in 21 cases, and in all cases after four cycles. After four MVAC cycles, the accuracy o f dynamic MR imaging was significantly better (P < .05). Persisting ea rly enhancement after four MVAC cycles correctly corresponded with lac k of response in all nine cases, and after two cycles in eight of thes e cases. The unenhanced MR technique showed initial tumor size reducti on in three of these cases. CONCLUSION: Conventional and dynamic enhan ced MR imaging were used to evaluate chemotherapy after two, four, and six cycles of MVAC in 22 patients with bladder cancer. After two cycl es, dynamic MR imaging helped detect 13 of 14 responders and eight of eight nonresponders. It helped detect five of seven lymph node respond ers and two of two nonresponders. Thus, it may be possible to predict after two MVAC cycles whether a patient will respond to chemotherapy.