LAUSR

e16566 Background: The indolent nature of many prostate cancers (PC) makes some men eligible to undergo active surveillance (AS) rather than immediate definitive treatment. Accurate risk classification is critical for selection of appropriate candidates for AS. The clinical cell-cycle risk (CCR) score, a combined clinical and molecular score, provides improved prognostic information about tumor aggressiveness over clinical parameters alone. This study aimed to evaluate the clinical outcomes of men with low-risk PC by NCCN guidelines and CCR score who selected AS. Methods: This study retrospectively reviewed men with localized PC who received CCR testing (2013-2017) and had low-risk disease according to NCCN guidelines and CCR score (N = 664). Low-risk by CCR score was defined as having a risk of disease-specific mortality < 3.2%. Men selected AS (no definitive treatment within 6 months of diagnosis) or underwent immediate definitive treatment. Durability of AS was evaluated beginning from diagnosis. Clinical outcomes were determined by reporting adverse events (biochemical recurrence (BCR), progression to metastasis as confirmed by radiographic imaging, prostate cancer specific mortality). Results: In this study, 547 men (82%) selected AS (median follow-up time 2.2 years [1.5, 3.1]). Of those managed by AS, two (0.4%) men experienced an adverse event. One man experienced BCR 3.7 years after diagnosis, and the other experienced metastasis 0.9 years after diagnosis. There were no reported cases of disease-specific mortality. The probability of remaining on AS for 3 years was 69.6%. Common reasons for exiting AS were patient choice (27.1%), increase in Gleason score (23.3%), and change in prostate specific antigen (PSA) (10.5%). Of those patients that left AS due to change in PSA (N = 14), only 4 exhibited a clinically significant increase in PSA ( > 10 ng/mL). Conclusions: The majority of men with molecularly-confirmed (CCR), NCCN low-risk PC selected AS in both academic and community settings. The incidence of metastatic disease or BCR after definitive treatment for disease progression was rare. The majority of men who selected AS remained on AS for the duration of the study.