Precancerous conditions of the prostate are those that have the potential to cause cancer. Precancerous tissues contain cells with abnormalities that have arisen from DNA mutation. Sometimes, these abnormal cells proliferate and cancer develops. The main precancerous states that carry a risk for prostate cancer are:

• Prostate intraepithelial neoplasia
• Proliferative inflammatory atrophy
• Atypical small acinar proliferation

Prostate intraepithelial neoplasia (PIN)

This condition is widely recognised as a precancerous condition of the prostate. PIN may occur in different parts of the prostate but is most often found in the peripheral zone, where prostate cancer usually develops. PIN may be of various grades and only high-grade PIN is classed as precancerous, although even high-grade PIN may not develop into cancer.

If PIN is high-grade and present in several areas of the prostate, preventative treatment may be administered. The treatment may reverse PIN but this has not yet been proven. Examples of treatments include anti-androgen agents, 5-alpha-reductase inhibitors and selective estrogen receptor modulators.

Men who have been administered medication are monitored regularly for changes in the prostate that indicate cancer. Monitoring involves blood tests for protein-specific antigen (PSA) and digital rectal examinations. If cancer development is suspected, a biopsy is ordered.

Proliferative inflammatory atrophy (PIA)

This condition is characterized by abnormally small cells in areas of the prostate that may also be inflamed. Some studies have suggested that PIA is associated with an increased risk for PIN and prostate cancer.

Atypical small acinar proliferation (ASAP)

In this condition, gland cells grow in an abnormal fashion and men with ASAP have a 40% to 50% increased chance of developing prostate cancer.