Tumor Volume on Biopsy in Low-Risk Prostate Cancers Managed on Active Surveillance

Contemporary clinical guidelines recommend use of active surveillance (AS) in men with low-risk prostate cancer. Low-risk disease spans any potential volume of Gleason score 6 cancer without sufficient attention to tumor volume in the past. We therefore compared tumor characteristics in low-risk men managed on AS to men undergoing RP.

We evaluated an institutional cohort of 1633 men with very low-risk (clinical stage=T1c, PSA density<0.15, ≤2 positive cores, ≤50% core involvement) and low-risk disease (clinical stage≤T2a, PSA<10ng/ml, and Gleason score≤6). Among low-risk patients, we calculated the proportion failing to meet very low-risk volume criteria (>2 positive cores or >50% core involvement). Clinical and pathological metrics in the AS cohort were compared to a cohort of low-risk men undergoing radical prostatectomy (RP) in the current era (2011-2016).

Among the AS cohort, 1119 men (69%) met very low-risk criteria and 514 (31%) had low-risk disease. Of the low-risk population, only 138 men (27%) harbored higher-volume cancer exceeding very low-risk criteria as compared to 815 (82%) low-risk men undergoing RP (p<0.001). Overall, the low-risk AS population had fewer positive biopsy cores (median 1 vs. 3, p<0.001) and lower maximum percentage core involvement (median 10% vs. 40%, p<0.001) compared to low-risk RP patients.

Data supporting safety of AS in low-risk men at our institution are derived from a distinct subgroup harboring limited cancer volume. Until acceptable outcomes are confirmed in higher-volume tumors, it is important to remain mindful of these limitations before broadly recommending AS to all low-risk men.

The Journal of urology. 2017 Oct 23 [Epub ahead of print]

Jeffrey J Tosoian, Mufaddal Mamawala, Hiten D Patel, Ridwan Alam, Jonathan I Epstein, Ashley E Ross, H Ballentine Carter

The James Buchanan Brady Urological Institute, Department of Urology. Electronic address: ., The James Buchanan Brady Urological Institute, Department of Urology., Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.