Increasing age and treatment modality are predictors for subsequent diagnosis of bladder cancer following prostate cancer diagnosis

Purpose: To determine the effect of prostate cancer therapy (surgery or external beam irradiation, or both or none) on the actuarial incidence of subsequent bladder cancer. Methods and Materials: The Surveillance, Epidemiology, and End Results registry from 1973 to 2005 was analyzed. Treatment was stratified as radiotherapy, surgery, both surgery and adjuvant radiation, and neither modality. Brachytherapy was excluded. Results: In all, 555,337 prostate carcinoma patients were identified; 124,141 patients were irradiated; 235,341 patients were treated surgically; 32,744 patients had both surgery and radiation; and 163,111 patients received neither modality. Bladder cancers were diagnosed in: 1,836 (1.48%) men who were irradiated (mean age, 69.4 years), 2,753 (1.09%) men who were treated surgically (mean age, 66.9 years); 683 (2.09%) men who received both modalities (mean age, 67.4 years), and 1,603 (0.98%) men who were treated with neither modality (mean age, 71.8 years). In each treatment cohort, Kaplan-Meier analyses showed that increasing age (by decade) was a significant predictor of developing bladder cancer (p < 0.0001). Incidence of bladder cancer was significantly different for either radiation or surgery alone versus no treatment, radiation versus surgery alone, and both surgery and radiation versus either modality alone (p < 0.0001). On multivariate analysis, age and irradiation were highly significant predictors of being diagnosed with bladder cancer. Conclusions: Following prostate cancer, increasing age and irradiation were highly significant predictors of being diagnosed with bladder cancer. While use of radiation increased the risk of bladder cancer compared to surgery alone or no treatment, the overall incidence of subsequent bladder cancer remained low. Routine bladder cancer surveillance is not warranted.