Patterns of spread of adenocarcinoma in the prostate as related to cancer volume

Background. Peripheral zone (PZ) and transition zone (TZ) cancers of the pr ostate remain confined to their zone of origin under 4 cc volume, with prog ressive molding to TZ boundary. In PZ cancer, growth in perineural spaces o ver 4 cc volume directs cancer toward the base, around subcapsular nerve tr unks, and often transcapsular. This tendency to stereotyped patterns of can cer spread in the prostate is investigated systematically here for the firs t time. Methods. Cancers in 571 radical prostatectomy specimens were sorted by zone of origin and tumor volume. A traced map of each cancer at 3 mm transverse intervals was assessed for location, contour, selected linear measures and the "transverse (largest) reference plane". Results. Spread along prostate capsule characterized all but the smallest P Z cancers and was most extensive transversely, By 4 cc volume, most PZ canc ers' transverse reference plane filled one side of PZ Above 4 cc, bilateral spread, TZ invasion, and nodularity progressively increased, but dominant growth was toward the base along nerves to the superior pedicle; here capsu le penetration was most common. TZ cancers arose mainly in anterior-mid TZ, invading anterior fibromuscular stroma (ATM) while small. AFM was massivel y invaded in many large tumors. Larger TZ cancers (>4 cc) invaded anterolat eral PZ but seldom penetrated posterior PZ. Conclusions. Patterns and extent of spread of carcinoma in the prostate are stereotyped following a few principles regarding stromal interactions. Usi ng these, sequential maps were presented of evolving prostate cancer contou rs at consecutive increasing volumes. Prostate 49: 48-57,2001. (C) 2001 Wil ey-Liss, Inc.