• prostatic intraepithelial neoplasia (PIN);
  • high-grade PIN (HGPIN);
  • prostate biopsy;
  • prostate cancer;

What's known on the subject? and What does the study add?

In the era of extended biopsy sampling of the prostate, multifocal high-grade prostatic intraepithelial neoplasia (HGPIN) is associated with a significantly higher rate of cancer diagnosis than unifocal HGPIN or a benign diagnosis. In addition, the cancers that are subsequently diagnosed in men with HGPIN on their initial biopsy tend to be smaller, lower grade and more commonly organ-confined. This has led to a reappraisal of the need and timing of repeat biopsies.

The present paper provides a series of recommendations on the optimal timing of repeat biopsies in men with HGPIN on biopsy, based on the current available evidence.

  • • 
    This is the first of a two part series reviewing the nature and clinical significance of in situ cellular proliferations in the prostate gland.
  • • 
    This first part examines prostatic intraepithelial neoplasia (PIN), while the second part in the next supplement discusses intraductal carcinoma and ductal adenocarcinoma of the prostate.
  • • 
    PIN is a precursor lesion in the development of some forms of adenocarcinoma of the prostate. In the 1990s, high-grade PIN (HGPIN) on biopsy was a significant predictor of carcinoma, but this was due to incomplete sampling with sextant biopsies. With more extensive sampling in the last decade, the likelihood of identifying cancer after a diagnosis of HGPIN is not significantly different from a benign diagnosis.
  • • 
    In several recent studies, it is now recognised that multifocal HGPIN is a better predictor of cancer than unifocal HGPIN. Most cases of cancer will be detected in the vicinity of the HGPIN, but up to 40% of cancers will occur in different sextants.
  • • 
    In assessing potential markers for carcinoma in men with HGPIN on biopsy, α-methylacyl coenzyme-A racemase (AMACR) has emerged as a promising diagnostic tool.
  • • 
    HGPIN with strong staining for AMACR is associated with a higher rate of cancer detection in subsequent biopsies compared with AMACR-negative HGPIN. Also, AMACR positivity in HGPIN is more commonly seen adjacent to carcinoma, and this may provide guidance as to the site of future biopsies.