Carcinoma of the urinary bladder: long-term results of interstitial radiotherapy

Between January 1974 and December 1988, 46 patients with cancer of the urinary bladder, stages T1 or T2, and one patient with stage T3, were treated with an interstitial implant at the radiotherapy department of the Catharina Ziekenhuis at Eindhoven, The Netherlands. Prior to implantation, one patient received no external radiotherapy, all other 46 patients were treated by either a low dose (40 patients: 12 Gy median) or an intermediate dose (six patients: 38-40 Gy) of external radiotherapy. Loco-regional relapse was observed in 14/47 (30%) of the patients (1/14 also had distant metastases). The site of loco-regional relapse was the bladder in 11 patients and the immediate vicinity of the bladder in three patients. Only four patients died due to uncontrolled locoregional disease. A salvage cystectomy was performed in five patients. Distant metastases alone were observed in 3/47 (6.4%) of patients. The intercurrent death corrected actuarial 5 and 10-year survival was 79.5% (72.2% for T1; 85.7% for T2). The difference between T1 and T2 tumors was not significant (P = 0.55). During follow-up, 17/47 (36%) patients died. Cause of death was intercurrent disease in eight patients, bladder cancer in eight patients and unknown cause in one patient. For the whole group, seven patients developed second or third malignancies. Multivariate analyses using survival as the endpoint showed no significant prognostic variables, while using relapse-free survival (RFS) as the endpoint (calculated from the date of interstitial implant and with censoring for death from intercurrent disease) the number of TUR before implant (P = 0.01) and the dose of external radiation before interstitial implant (P = 0.045) were of prognostic significance, both being negatively correlated with RFS. As six patients had received an intermediate dose of interstitial radiotherapy, separate multivariate analyses were performed on the subgroup of 41 patients who had received a high dose of interstitial radiation. Using survival as the endpoint, again no prognostic significant factors were found, but in the analyses using local relapse-free period (LRFP) as the endpoint, dose rate (P = 0.026) and duration of implant (P = 0.021) were inversely correlated with LRFP. The higher the dose rate, the better the LRFP, while a long duration of implantation had a negative impact on the LRFP. Information concerning radiotherapy-related complications was not available in one patient, ulceration of the bladder mucosa was observed in 9/46 (19.6%) and bladder stone formation in 3/46 (6.5%) patients.(ABSTRACT TRUNCATED AT 400 WORDS)