Presentation Authors: Mary E Westerman*, Vidit Sharma, Adam T. Froemming, Robert H. McLaren, Lance A. Mynderse, R. Jeffrey Karnes, Rochester, MN
Introduction: High Grade Prostatic Intraepithelial Neoplasia (HGPIN) and atypical small acinar proliferation (ASAP) are identified in 5-10% of prostate biopsies. Repeat biopsy is typically performed, but the optimal management is unknown. Multiparameteric MRI (mpMRI) is increasingly utilized to identify foci of prostate cancer (PCa). However, no study has analyzed the utility of mpMRI in men with HGPIN/ASAP. Therefore, we aim to assess the clinical utility of mpMRI among patients who have HGPIN or ASAP on prostate biopsy
Methods: We identified 27,233 prostate biopsies performed between 1994-2016 at our institution, of which 4,748 contained HGPIN or ASAP. Patients with concurrent or prior PCa were excluded, leaving 586 patients. A final cohort of 30 men who underwent mpMRI following a HGPIN/ASAP diagnosis was identified. Descriptive statistics were performed to determine associations between mpMRI findings and subsequent PCa diagnosis.
Results: Median age at HGPIN/ASAP diagnosis was 59 years (IQR 55, 77) and median PSA was 5.8 (IQR 4.5, 7.7). Median follow up from initial diagnosis was 43.2 months (IQR 24.5, 55.4) and 23.6 months (IQR 4, 32.6) from mpMRI. Overall, 13/30 (43%) were PI-RADS â‰¤2, 8/30 (27%) were PI-RADS 3, and 9/30 (30%) were PI-RADS â‰¥4. Following mpMRI, 15 (50%) underwent targeted biopsy while 6(20%) underwent targeted biopsy. 13 patients (43%) were diagnosed with PCa at a median of 1.73 months (IQR 0.37, 29.6) following mpMRI. 92% of all PCa and 100% of clinically significant PCa was diagnosed by targeted biopsy. Patients with a PI-RADS lesion â‰¥4 were significantly more likely to be diagnosed with PCa (89% vs. 24%, p=0.002) compared to those with a PI-RADS lesion â‰¤3. Two-thirds (6/9) of patients with a PI-RADS lesion â‰¥4 were diagnosed with intermediate or high risk cancer, while no patient with PI-RADS â‰¤ 2 was diagnosed with clinically significant disease. On univariate analysis, mpMRI was more predictive of prostate cancer diagnosis than patient age, PSA, PSA kinetics, and Prostate Cancer Prevention Trial Risk Score.
Conclusions: Multiparametric MRI demonstrated utility in stratifying patients with HGPIN/ASAP in terms of the risk of developing any PCa as well as intermediate/high risk disease. In fact, 30% of HGPIN/ASAP patients will have a PI-RADS â‰¥4 lesion and a significant chance (~67%) of harboring intermediate to high risk PCa; while 43% of patients have a PI-RADS â‰¤2 mpMRI, which was associated with a low chance of harboring clinically significant PCa. Thus, if verified in other pure HGPIN/ASAP cohorts, mpMRI with targeted biopsies may provide valuable clinical risk stratification to 73% of patients with HGPIN/ASAP.