Follow-up of prostatic intraepithelial neoplasia.

Biopsy or fine-needle aspiration cytology are the only appropriate methods for detection of prostatic intraepithelial neoplasia (PIN). PIN has been suggested to be a principal precursor of invasive carcinoma of the prostate. Most reports on an association of PIN and invasive prostatic cancer have a follow-up of less than 1 year, indicating that the successively diagnosed cancer most probably was present at the time of diagnosis of PIN. The natural history of PIN is unknown and detection of PIN should therefore not influence therapeutic decisions. If coexistent carcinoma is not found, close surveillance is recommended to identify a possible subsequent cancer at an early stage. Follow-up examinations should be performed at 6-month intervals for 2 years and thereafter annually.