2004 年 203 巻 1 号 p. 31-36
In order to clarify the incidence of bladder cancer with and without prostate cancer, we investigated bladder cancer discovered incidentally by urethrocystoscopy at prostate biopsy. Between April 1997 and December 2003, 498 patients who were suspected prostate cancer were performed prostate biopsy and urethrocystoscopy simultaneously. We investigate possible invasion of prostate cancer into the urethra or bladder mucosa as well as bladder cancer, including other benign lesions of the bladder by urethrocystoscopy. Prostate cancer was confirmed in 175 (35.1%) of the 498 patients histologically, and bladder cancer was discovered incidentally in 12 patients (2.4 %). The incidence of bladder cancer in patients with prostate cancer of 2.3% (4/175) was not significantly different from that in patients without prostate cancer, which was 2.5% (8/323). Superficial and those with a size less than 1 cm were noted in 11 patients (92%) and 10 patients (83%) respectively. High incidence rate of bladder cancer with prostate cancer was reported previously, however, there was no study to compare the incidence rate of bladder cancer between cases with and without prostate cancer. The present study suggests that asymptomatic tiny bladder cancer may be present at an unexpectedly high incidence rate in elderly males.
