Limited relevance of the “very low risk” prostate cancer classification in the modern era: Results from a large institutional active surveillance cohort.

381 Background: Although the American Urological Association recently dropped the “very low risk” (VLR) category for prostate cancer (PCa), the National Comprehensive Cancer Network (NCCN) guidelines still maintain this stratum based on number of positive biopsy cores, tumor extent in each core, and PSA density. This subdivision may be outdated in the modern era in which targeted prostate biopsies are common practice. We identified the proportion of VLR patients at our institution to determine whether an alternative classification may be more appropriate for risk-stratification in the modern era. Methods: Participants were diagnosed from 2000-2019 with cT1-2N0/xM0/x PCa, PSA <20ng/ml, biopsy Gleason grade group (GG) 1-2, and initially managed with AS. VLR PCa was defined as <3 positive cores, ≤50% cancer per core, and PSA density <0.15. UCSF-CAPRA score was calculated for each patient. The primary outcome was major upgrade (≥GG3) on subsequent biopsy. Multivariable Cox proportional hazards regression models were used to calculate associations between CAPRA score and risk of major upgrade, adjusting for age, genomic testing, and prostate MRI finding. Results: Of 1554 patients initially managed with AS, 364 (23%) met NCCN VLR criteria. 49 (3%), 781 (50%), 505 (33%), and 219 (14%) patients had CAPRA scores of 0, 1, 2, and 3, respectively. Proportion of patients deemed VLR decreased over time; among 84 patients initially managed with AS during or after 2018, only one patient (1%) met VLR criteria in 2018, while the stratification by CAPRA demonstrated that 21 (25%), 25 (30%), and 38 (45%) patients had CAPRA scores of 1, 2, and 3, respectively, over the same period. CAPRA score was significantly associated with major upgrade on biopsy on multivariable Cox proportional hazards regression modeling independent of age, genomic testing, and MRI finding (HR 1.46, 95%CI 1.22-1.74, p<0.01). Conclusions: The relevance of VLR PCa in the modern targeted biopsy era has diminished, with no cases meeting VLR criteria in a large AS cohort after 2018. CAPRA score is an option for a more contemporary risk stratification tool for men on AS.