Intracavitary cobalt-60 irradiation in the prophylactic treatment of bladder cancer

This paper describes the technique and preliminary clinical results of transurethral intracavitary whole bladder mucosal irradiation (IWI) for the prophylaxis of bladder cancer. In this procedure, first, the balloon catheter (22 Fr.) is inserted into the bladder, and next the balloon is inflated with 100 ml of air. Then a Co-60 pellet with about 110 GBq of activity is driven into the center of the bladder. With this method, we can irradiate the whole bladder mucosa almost equally. From April 1985, 36 patients with recurrent tumor and 26 patients with primary and multiple tumors of the bladder have been treated with IWI after transurethral resection or microwave coagulation of the tumors. Tumor stage and grade were as follows: Tis (7), Ta, T1 (41), T2 (14), G1 (16), G2 (30) and G3 (16). The tumors were transitional cell carcinoma in all patients. IWI was performed once a week, usually 3 to 5 times, depending on the patients. The total dose to the bladder mucosa ranged from 20 to 58.5 Gy with an average dose of 37.6 Gy. Recurrence rates before and after IWI were calculated using the following formula: recurrence rates (RR)=(total number of recurrences/total months of follow up)x100. RR in the 36 patients with recurrent tumor was 14.0 before IWI and 1.8 after IWI (mean follow up 37.6 mos.). RR in the 26 patients with multiple tumors was 1.4 after IWI (mean follow up 34.8 mos.). RR in patients with G1, G2 and G3 tumors were 1.2, 1.7 and 2.2. The most common side effect was temporary urinary frequency observed in 36 patients (52.9%). Three patients had contracted bladder, and two had hydronephrosis. However, proctitis or incontinence was not evident. Although the preliminary clinical results suggest that our new technique is an effective prophylactic treatment for bladder cancer, further investigation is needed to determine its efficacy. (author)