The diagnostic and therapeutic window for localized carcinoma of the prostate.

The natural history of prostate cancer has been regarded as unpredictable for a long period of time. The discrepancy between histologically identifiable (40%) and clinically diagnosed carcinomas (8%) led to the term of "latent" prostate cancer and to a considerable diagnostic and therapeutic dilemma. Based on previous studies showing that biological aggressiveness of prostate cancer is a direct function of tumor volume and that tumor volume and serum-PSA are proportional, two basically different groups of patients were evaluated. The first group consisted of 43 patients with untreated carcinomas of the prostate followed with serial PSA determinations. The exponential (log-linear) rise in PSA led to the conclusion of an exponential tumor growth rate. The median doubling time of clinically organ-confined tumors was 4 years and became shorter with higher clinical stages and poorly differentiated histological grades. The second group consisted of 139 patients who underwent cystoprostatectomy for bladder cancer and had no evidence for simultaneously identifiable prostate cancer. In 55 patients (40%) unsuspected prostate cancer was found in the specimen; the volume distribution of these carcinomas was exponential. Eleven of the 139 men (7.9%) had a prostate cancer greater than 0.5 cc, corresponding to the 8% risk for a man being diagnosed within his life-time with a clinically significant carcinoma of the prostate. In conclusion, the other 44 carcinomas below 0.5 cc may never reach clinical significance due to their small size and their long doubling time; in this sense they can be considered "latent".(ABSTRACT TRUNCATED AT 250 WORDS)