Histologic differentiation, cancer volume, and pelvic lymph node metastasis in adenocarcinoma of the prostate.

The Gleason grading system for prostate cancer was applied quantitatively to analysis of entire tumors in 209 radical prostatectomy specimens from patients with clinical Stage A and Stage B carcinoma. Percentage of poorly differentiated tumor (Gleason histologic pattern 4 and/or 5) was related to quantitated cancer volume, cancer location within the prostate, and presence or absence of pelvic lymph node metastasis. A strong correlation was found between cancer volume, percentage of poorly differentiated cancer, and nodal metastasis. Twenty-two of 38 patients with more than 3.2 cc of Gleason histologic pattern 4-5 cancer had nodes with positive results, compared with one of 171 patients with less than 3.2 cc of pattern 4-5 cancer. Gleason histologic patterns 1 and 2 cancer was found mainly in a small subgroup of tumors whose site of origin was in the anatomic transition zone and whose volume was less than 1 cc. Gleason "cribriform" histologic pattern 3 cancer was thought to represent mainly intraductal carcinoma. Its increase in area with increasing cancer volume paralleled the increase in pattern 4 cancer and was counter to the decrease in other types of pattern 3 cancer.