A population-based study of the use and outcome of radical radiotherapy for invasive bladder cancer

Purpose: The objective of this study is to describe the use and outcome of radical radiotherapy for bladder cancer in the province of Ontario, Canada, between 1982 and 1994. Methods: Electronic records of invasive bladder cancer (ICD code 188) from the Ontario Cancer Registry were linked to surgical records from all Ontari o hospitals and radiotherapy (RT) records from all Ontario cancer centers. We identified cases receiving radical RT by selecting RT records containing "bladder" or "pelvis" anatomic region codes and a radical or curative inte nt code (or dose > 39.5 Gy if intent missing). We identified cases receivin g salvage total cystectomy by selecting total cystectomy procedure codes oc curring at any time beyond 4 months from the start of radical RT. We used l ife table methods to compute the following: the time from diagnosis to radi cal RT, the time from radical RT to salvage cystectomy, overall and cause-s pecific survival from radical radiotherapy to death, and overall and cause- specific survival from salvage cystectomy to death. We modeled the factors associated with time to death, time to cystectomy conditional on survival, and time to cystectomy or death, whichever came first, using Cox proportion al hazards regression. Results: From the 20,906 new cases of bladder cancer diagnosed in Ontario f rom 1982 to 1994, we identified 1,372 cases treated by radical radiotherapy (78% male, 22% female; mean age 69.8 years). The median interval to start of radical RT from diagnosis was 13.4 weeks. Ninety-three percent of patien ts were treated on high-energy-linacs, and the most common dose/fractionati on scheme was 60 Gy/30 (31% of cases). Five-year survival rates were as fol lows: bladder cancer cause-specific, 41%; overall, 28%; cystectomy-free, 25 %; bladder cancer cause-specific following salvage cystectomy, 36%; overall following salvage cystectomy, 28%, Factors associated,vith a higher risk o f death and a poorer cystectomy-free survival were histology (squamous or n onpapillary transitional cell carcinoma [TCC]) and advanced age. Conclusion: This population-based study confirms previous institutional stu dies and clinical trials and shows that radical RT has a curative role in t he management of invasive bladder cancer and allows about one-quarter of pa tients receiving radiotherapy to survive 5 years while retaining the bladde r. Salvage cystectomy following RT provides a chance of cure at the time of bladder relapse. (C) 1999 Elsevier Science Inc.