2. In regards to the the zonal anatomy of the prostate gland, where do most carcinomas originate?

The peripheral zone is in the outer most part of the prostate, and the lower peripheral zone is fairly close to the rectal wall. The peripheral zone is the most common site for prostatic adenocarcinoma. The central zone is in the center of the prostate and cancer does not originate there often.

Explanation:

The peripheral zone (PZ) contains the majority of prostatic glandular tissue ...

The central zone (CZ) is the area that surrounds the ejaculatory ducts ...

The transition zone (TZ) surrounds the urethra as it enters the prostate gland.