Bladder-Preserving Therapy Patterns of Care: A Survey of US Radiation Oncologists.

PURPOSE: Clinical trials have demonstrated the efficacy of bladder-preserving chemoradiation therapy (BPT) in muscle-invasive bladder cancer but have differed in the radiation therapy dose/fractionations, radiation therapy targets, and concurrent chemotherapy regimens used. No data exist on the technical and practical approaches actually used in clinical practice throughout the United States when delivering BPT. We performed a survey to explore radiation oncologists' practice patterns.

METHODS AND MATERIALS: We conducted an electronic survey of US radiation oncologists regarding the management of patients with cT2-3N0M0 transitional cell muscle-invasive bladder cancer. The instrument included questions regarding the types of patients treated with BPT, as well as several aspects of treatment delivery. Descriptive statistics were reported for all responses. Pearson χ2 tests were used for univariate analysis.

RESULTS: In total, 277 physicians completed our survey. Most respondents (58%) stated that they only treated 1 to 3 patients in the prior year. Seventy-four percent of respondents primarily treated patients deemed unfit for cystectomy, while only 28% saw patients prior to cystectomy for consultation to discuss BPT. The majority of radiation oncologists used conventional fractionation (91%) instead of hypofractionation (7.6%), but more variability existed for radiation therapy targets. Sixty percent used a small pelvis field, 29% used a whole-pelvis field, and 12% treated the bladder only. There was increased use of hypofractionation (29%) and bladder-only radiation therapy (34%) in patients who were not candidates for cystectomy or chemotherapy (P<.001). Cisplatin-based concurrent chemotherapy was most commonly preferred (89%). In non-cisplatin candidates, most respondents preferred 5-fluorouracil plus mitomycin C (32%) or carboplatin (32%). Intensity modulated radiation therapy use and midtreatment cystoscopic re-evaluation were variable, while hyperfractionation use was low.

CONCLUSIONS: Our study describes radiation oncologists' practice patterns for patients undergoing BPT. Although there are areas of consistency, variability exists in many technical and practical aspects of treatment delivery. Further research and education are needed to determine the optimal radiation therapy target, dose/fractionation, and concurrent chemotherapy regimen.