Which prostatic zone is most commonly involved in cancer?

• A. Central zone
• B. Peripheral zone
• C. Transitional zone
• D. Anterior fibromuscular stroma

Answer: (B)

Prostate cancer most often originates in the peripheral zone, the outer portion that contains the bulk of prostatic glands and lies toward the back of the gland. This abundant glandular tissue provides more targets for malignant transformation, and its posterior location makes cancers easier to detect on a digital rectal exam and with imaging. The transitional zone is where benign prostatic hyperplasia tends to develop, so cancers there are less common; the central zone has fewer glands and is less frequently involved in cancer; the anterior fibromuscular stroma contains little glandular tissue, making cancer there rare. So the peripheral zone stands out as the typical site for malignancy because of both its large amount of glandular tissue and its accessible, posterior location.