Pathologic aspects of prostate cancer: prediction of malignant potential

Despite our expanding knowledge of prostatic histopathology, several controversies regarding the prediction of a tumor's biologic behavior still exist. Numerous histologic grading schemes specific for prostate carcinomas have been developed, but pathologists and urologists do not agree on which system is most accurate. Unfortunately, the Broders system, which is frequently used, tends to underestimate tumor grade and malignant potential. Recently, computer-assisted nuclear morphometry has added objectivity to the formerly subjective grading process, and improved prognostic accuracy for early and advanced disease. The relationship between tumor volume and grade remains controversial. Although it has been stated that volume and grade are directly related, our examination of radical prostatectomy specimens casts some doubt on this. While it can be shown that tumor volume is proportional to the surface area of capsular penetration by malignant cells, tumor penetration is more closely related to histologic grade.