Significance of atypical and suspicious small acinar proliferations, and high grade prostatic intraepithelial neoplasia on prostate biopsy: implications for cancer detection and biopsy strategy.

PURPOSE: We reviewed our results from a urological pathology reference laboratory with respect to the incidence of HGPIN, and atypical and suspicious lesions in the spectrum of ASAP. Subsequent CaP findings on repeat biopsy with relevant clinical implications were assessed.
MATERIALS AND METHODS: A review of 42,667 prostate biopsies was performed. We defined atypical and suspicious as variants of ASAP with suspicious being more worrisome for CaP. Findings were correlated with the location of CaP on repeat prostate biopsy.
RESULTS: The rate of subsequent CaP detection was significantly higher for an initial diagnosis of suspicious findings (51% or 54 of 107 cases) than for atypical findings (34% or 39 of 116) or HGPIN (22% or 79 of 358, p < 0.001). CaP was found on the same side of the prostate in 61 of 78 (78%), 30 of 39 (77%) and 41 of 54 patients (76%) with initial HGPIN, atypical and suspicious biopsies, respectively. There was no significant difference among the 3 groups in the likelihood of future CaP at the same site or the same side of the prostate.
CONCLUSIONS: Patients with a suspicious biopsy were significantly more likely to have CaP on future biopsy than those with atypical findings or HGPIN, suggesting that there may be divisions with prognostic significance in the larger category of ASAP. To our knowledge the reproducibility of recognizing such divisions remains to be established. Neither atypical nor suspicious lesions were more likely than HGPIN to predict CaP at the same site or side of the prostate as the original diagnosis. Repeat biopsy may be indicated in any patient with HGPIN, or atypical or suspicious lesions and this biopsy should not be limited to the site or side of the original pathological findings.