Methods. Prostates were examined after 139 consecutive unselected cystoprostatectomies from patients with bladder cancers in whom it was unknown whether they had prostate cancer. Prostate cancer was found in 55 patients (40%); the volume of the largest cancer in each specimen was determined using histologic morphometry. The authors identified the 8% of these 139 cystoprostatectomy specimens with the largest volume of prostate cancer.

Results. The largest 11 of the 55 cancers represented 7.9% of the total 139 samples. These cancers ranged in volume from 0.5-6.1 ml, representing only 20% of all patients with prostate cancer.

Conclusions. If the strong evidence is accepted that cancer progression is proportional to cancer volume, it was concluded that prostate cancers larger than 0.5 ml appear to correspond to the 8% of men who will be diagnosed with a clinically significant carcinoma, as derived previously. Conversely, those 80% of prostate cancers smaller than 0.5 ml probably are not likely to reach a clinically significant size in view of the long doubling time of this cancer.