OBJECTIVE

To determine whether the predictive value of isolated high-grade prostatic intraepithelial neoplasia (HGPIN) for an unsampled prostate cancer on an extended biopsy is lower due to more thorough prostate sampling, and whether the proportion of cores with HGPIN is associated with prostate cancer, as isolated HGPIN on sextant prostate biopsy is associated with a 27-57% risk of prostate cancer on repeat biopsy.

PATIENTS AND METHODS

All extended prostate biopsies taken by one urologist over 6 years were reviewed for patients with isolated HGPIN on initial biopsy. Biopsies were evaluated for histological features and the proportion of cores with HGPIN. The clinical characteristics and pathological findings from subsequent biopsies were determined.

RESULTS

Of 577 men having extended biopsies, 48 had isolated HGPIN, followed by one to four site-directed repeat biopsies. Although only 10 (21%) had cancer on the first repeat biopsy, overall 15 (31%) had cancer. Those with cancer on repeat biopsy had a significantly higher proportion of cores with HGPIN, i.e. 29% vs 15%, cancer vs no cancer, respectively (P = 0.04).

CONCLUSIONS

Isolated HGPIN on extended biopsy conferred a 31% risk of unsampled prostate cancer. The proportion of cores with HGPIN on initial biopsy was significantly associated with the risk of cancer. The same was not true for age, race, prostate-specific antigen level, or the findings on digital rectal examination. The significant association between the proportion of cores with HGPIN and the risk of cancer suggests that patients with unifocal HGPIN on extended biopsy be managed expectantly, whereas those with multifocal HGPIN be re-biopsied.