Presentation Authors: Ashwin Balakrishnan*, Janet Cowan, Peter Carroll, San Francisco, CA
Introduction: As enrollment in active surveillance (AS) expands, it is increasingly important to assess potential risks of deferred treatment. We evaluate the risk of prostate specific antigen (PSA) recurrence in a large cohort of men undergoing radical prostatectomy (RP) after initial AS.
Methods: The study included men undergoing RP after a period of AS with Gleason score (GS) 3+3 or 3+4 at diagnosis, clinical â‰¤T2, and a low or intermediate risk Cancer of the Prostate Risk Assessment (CAPRA) score. Men were stratified by a composite variable of GS and volume of high grade cores at diagnosis. Primary outcome was recurrence after RP, defined as two consecutive PSAs â‰¥0.2 ng/ml or any secondary treatment within 12 months of RP.
Results: Of 1,812 men enrolled in AS between 1994 and 2016, 431 (23.8%) underwent deferred RP. Median time to RP was 26 months (IQR 15-46). At diagnosis, 378 men (87.7%) had GS 3+3 disease, 25 men (5.8%) had GS 3+4 disease with one high grade core, and 28 men (6.5%) had GS 3+4 with two or more high grade cores. Reasons for undergoing RP included biopsy upgrade to GS â‰¥3+4 (289 men, 67.1%), greater than 33% positive cores on surveillance biopsy (55 men, 12.8%), and PSA doubling time less than 36 months (9 men, 2.1%). At surgery, 92 (21.3%) had GS â‰¥4+3 tumors, 169 (39.2%) had pT3/4 disease, and 10 (2.3%) had positive lymph nodes. Recurrence free survival was 88% at 2 years after RP. Among men with PSA recurrence, median time to recurrence was 15 months (IQR 6-40). Kaplan-Meier analysis showed a significant difference in the risk of recurrence between patients with GS 3+3, 3+4 with one high grade core, and 3+4 with two or more high grade cores at diagnosis (log-rank p=0.02). On multivariable analysis GS 3+4 with two or more high grade cores at diagnosis was associated with risk of recurrence when compared to GS 3+3 disease (HR 2.65, 95%CI 1.23-5.69), while GS 3+4 with one high grade core did not differ from GS 3+3, adjusted for age and PSA density (see table).
Conclusions: The majority of patients undergoing deferred RP after a period of AS did not have any adverse features at the time of surgery. Our results support the careful use of AS in men with GS 3+4 and one high grade core at diagnosis. Men with GS 3+4 and two or more high grade cores at diagnosis had a significantly greater risk of recurrence, and likely benefit from immediate treatment.
Source of Funding: Grant from US Department of Defense Prostate Cancer Research Program (W81XWH-13-2-0074)