PURPOSE: Evaluation of the risk of prostate cancer reclassification over time in active surveillance.
METHODS: From 1995 to 2014, 808 men (557 very-low-risk and 251 low-risk) on active surveillance who were compliant with prostate biopsies were evaluated for the primary outcome of reclassification to higher-risk disease by grade or extent. Freedom from reclassification was estimated using the Kaplan-Meier approach with adjustment for covariates using a Cox proportional hazards model.
RESULTS: Within the first two years of surveillance, the survival free of reclassification by grade (P = 0.20) and any biopsy criteria (P = 0.25) were similar between men with very-low-risk and low-risk disease. After two years, men with low-risk disease were 2.4 times more likely to be diagnosed with a Gleason score above 6 as compared to men with very-low-risk disease (P = 0.002, HR = 2.4, 95% CI = 1.9-3.5). Additionally, beyond two years in surveillance, the risk of lifetime reclassification by grade and any criteria decreased by 30% (P < 0.0001, HR = 0.70, 95% CI = 0.60-0.76) and 35% (P < 0.0001, HR = 0.65, 95% CI = 0.57-0.72), respectively, with each biopsy showing no reclassification.
CONCLUSIONS: The rate of reclassification during surveillance is not equally distributed across time or risk groups. Due to misclassification at the time of diagnosis, the rates of reclassification between very-low-risk and low-risk groups are similar within the first two years but differ significantly beyond two years. The risk of reclassification falls over time with each non-reclassifying biopsy beyond two years.
Alam R, Carter HB, Landis P, Epstein JI, Mamawala M. Are you the author?
The James Buchanan Brady Urological Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.
Reference: J Urol. 2015 Jan 5. pii: S0022-5347(14)05219-7.