Objective: To determine the incidence and features of urothelial carcinoma (UC) involving the prostate (UCP) and of prostate adenocarcinoma (PA) in radical cystoprostatectomy (RCP) for bladder cancer.
Patients and methods: The whole-mount prostate sections of 248 RCP consecutively examined from 1995 to 2007 were reviewed to determine the incidence and features of UCP and PA. UCP was separately evaluated for UC originating from the urethra and peri-urethral ducts (PUC) and for direct extension of bladder UC.
Results: There was UCP in 94 (37.9%) of 248 patients, whereas PUC was present in 78 (31.5%). UC in situ and noninvasive papillary PUC was present in 42 (53.9%) of the 78, whereas stromal invasion was present in 36 (46.1%). Direct extension of UC from the bladder only was present in 16 (6.5%) patients. PA was present in 123 (49.6%) of 248 patients; 96 (78.1%) were in the peripheral zone. In 107 patients (87%) the Gleason score was <or=6; 96 (78.1%) were pT2a, with a lower frequency in other pT categories. The margins were negative in 96.7% of cases. All patients were pN0 for PA; in 116 (95.1%) the volume was <0.5 mL. Of the 123 patients with incidental prostate cancer, 100 cancers (81.3%) were considered clinically insignificant. UCP coexisted with PA in 43 (17.3%) of 248 patients, whereas PUC and PA occurred together in the same prostate in 32 (12.9%). Direct extension of UC from the bladder and PA occurred together in the same prostate in 11 (4.4%) patients.
Conclusions: UC involving the prostate and PA are present in most RCP specimens. UC can arise from extension of trigonal or bladder-neck tumours, proximal prostate ducts/urethra, or from cell implantation from manipulation of vesical neoplasms. The frequent high coincidence of prostate and bladder cancer can be explained by a common pathway of carcinogenesis.