Outcomes of Prostate Atypical Small Acinar Proliferation and High-Grade Prostate Intraepithelial Neoplasm Patients

Objective: Atypical small acinar proliferation (ASAP) and high-grade prostatic intraepithelial neoplasia (HGPIN) are two pathological findings occasionally noted in prostate biopsies. Previous Western studies reported that they were associated with prostate cancer. However, none Taiwanese series report the subsequent cancer detection in ASAP and HGPIN patients. This study aimed to examine the results of repeated biopsies in the patients with ASAP and HGPIN. Materials and Methods: A total of 220 consecutive patients with ASAP and/or HGPIN at our institute between January 1990 and December 2010 were enrolled. Patient demographics and clinical information were extracted from the electronic database of our institute. Prostate biopsies were performed through transrectal ultrasound guidance. The patients who had concurrent prostate cancer ( n = 51) and no repeated prostate biopsies ( n = 103) were excluded from the study. Patients with biopsy pathologies reporting low-grade prostatic intraepithelial neoplasia ( n = 2) were also excluded. The remaining 64 patients were available for the final analysis. Results: Nearly, 38, 24, and 2 patients were initially diagnosed as ASAP, HGPIN, and ASAP along with HGPIN, respectively. After 10 years of follow-up, 36.8% patients in ASAP group developed prostate cancer, while 16.7% in HGPIN group and 100% in ASAP + HGPIN group. Median time to developing prostate cancer were 20 months in ASAP group, 31 months in HGPIN group, and 48 months in ASAP + HGPIN group. There was no significant difference of prostate cancer development between ASAP and HGPIN group ( P = 0.291). Only older age, classified by 65 years, was significantly associated with a higher detection rate of prostate cancer. Conclusion: Patients with the initial diagnosis of ASAP or PIN has a high risk of developing prostate cancer. Therefore, those patients should be well announced and followed regularly.