OBJECTIVE: To determine the clinicopathological features of impalpable prostate cancer. PATIENTS, MATERIALS AND METHODS: The numbers of T1a and T1b cancers detected in transurethral resections of the prostate (TURP) performed before and after the advent of the test for serum prostate-specific antigen (PSA) were compared and the incidence of T1 disease in specimens from 400 consecutive radical prostatectomies examined. RESULTS: The incidence of T1b disease detected at TURP decreased significantly between the periods examined, but that of T1a was unaffected. Similarly, in radical prostatectomy specimens, T1b cancers were largely replaced by T1c and impalpable T2 cancers detected by ultrasonography. CONCLUSIONS: Cancers detected incidentally at TURP tend to be small T1a tumours, possibly suitable for conservative management. T1b cancers are likely to be detected by PSA level and treated radically. T1c and impalpable T2 cancers are morphologically unlike T1b disease and justifiably belong in separate stages in the current UICC staging system.
