Pathomorphological study of local extension and progression of prostate cancer

Abstract

The interrelationship among localization of tumor, local extension, lymph node metastasis and various histological grades was investigated in 31 consecutive series of prostate cancer treated by radical prostatectomy. Surgical specimens were examined by step sections cut perpendicular to the urethra. Each tumor was graded histologically in accordance with WHO-Mostofi grading (evaluated by nuclear anaplasia and structural differentiation), Gleason's and M.D. Anderson's grading systems. The areas of the prostate was divided into 4 quadrants delimited vertically along the urethral axis and transversely at the level of utricle, i.e. anterior/superior, anterior/inferior, posterior/superior and posterior/inferior quadrants. Topographical localization and extension of each tumor was examined in accordance with the above area subdivision. Every tumor was growing at least in the posterior/inferior area. All cases with tumor progression to the anterior/superior area also revealed extensive tumor growth in the other two or three quadrants. Therefore, prostate cancer appears to be originated from the posterior/inferior area of the prostate and terminated in the anterior/superior area as local extension. In 31 cases examined, capsular invasion was noted in 22, seminal vesicle invasion in 16, and lymph node metastasis in 12 cases. All cases with seminal vesicle invasion also showed capsular invasion. None of the cases without capsular and/or seminal vesicle invasion had lymph node metastasis. Thus, it is inferred that prostate cancer is initially growing locally, extending to the capsule and seminal vesicle and then metastasizes to the pelvic lymph nodes. As for the histological grading, higher grade tumors tended to show higher incidence of capsular and seminal vesicle invasion and lymph node metastasis.(ABSTRACT TRUNCATED AT 250 WORDS)