Precancerous conditions of the prostate
Precancerous conditions of the prostate have the potential to develop into prostate cancer. With a precancerous condition, abnormal changes have taken place in the cells of the prostate. Some of these abnormal changes may turn into prostate cancer.
The most common precancerous conditions of the prostate are:
- prostatic intraepithelial neoplasia (PIN)
- proliferative inflammatory atrophy (PIA)
- atypical small acinar proliferation (ASAP)
Prostatic intraepithelial neoplasia (PIN)
The well recognized precancerous condition of the prostate is prostatic intraepithelial neoplasia (PIN). It may occur in several different areas of the prostate at the same time (multifocal). PIN is often found in the peripheral zone of the prostate, where most prostate cancers are also found. PIN may be either low or high gradegradeA description of a tumour that includes how different the cancer cells look from normal cells (differentiation), how quickly the cancer cells are growing and dividing, and how likely they are to spread.. Only high-grade PIN is considered a precancerous condition.
Not all high-grade PIN sites will advance to prostate cancer during a man's lifetime. It is difficult to predict in an individual man if PIN will progress to cancer. It may take more than 10 years for PIN to progress to prostate cancer.
The risk factors for developing PIN are thought to be the same as those for developing prostate cancer. PIN is found more frequently in men older than 50 years of age.
Signs and symptoms
PIN does not cause any signs or symptoms.
Diagnostic tests are not done for PIN. It is found when a biopsy sample is examined by a pathologist after a man has had a transrectal ultrasound guided biopsy of the prostate. A biopsy is ordered if the doctor suspects prostate cancer.
PIN is usually not treated unless it progresses to cancer. Not all men with PIN will develop prostate cancer.
If multiple sites of high-grade PIN are found on a repeat biopsy, then treatment may be considered. Treatment with 5-alpha-reductase inhibitors, anti-androgens or selective estrogen receptor modulators (SERMs) may be used as a form of prostate cancer prevention. These drugs may reverse high-grade PIN, possibly reducing the risk of prostate cancer, but this has not been shown.
Men who have been diagnosed with high-grade PIN are followed closely to watch for evidence of prostate cancer. Any new symptoms or symptoms that don't go away should be reported to the doctor without waiting for the next scheduled appointment. Follow-up visits will usually be scheduled every 6 months, for at least 2 years.
Follow-up visits usually include:
- complete physical examination, including a digital rectal examination (DRE)
- prostate-specific antigen (PSA) test
- Follow-up biopsies are not usually done on a regular basis.
- The urologist will order another biopsy if there is any suspicion of cancer.
If prostate cancer is found during follow-up for PIN, the specialist (urologist) will discuss the treatment options with the man.
Proliferative inflammatory atrophy (PIA)
PIA is characterized by abnormal epithelial cells that are dividing more rapidly in areas of chronic inflammation. Areas of the prostate with PIA changes are 20% more likely to develop prostate cancer. Some studies suggest that PIA is an early change that may later develop into prostatic intraepithelial neoplasia (PIN) or prostate cancer.
Atypical small acinar proliferation (ASAP)
ASAP is abnormal growth of gland cells that can change into prostate cancer. In men with ASAP, the likelihood of finding prostate cancer in a future biopsy sample is about 40–50%.