Older Age Predicts Biopsy and Radical Prostatectomy Grade Reclassification to Aggressive Prostate Cancer in Men on Active Surveillance.

PURPOSE

Age at prostate cancer diagnosis has been positively associated with prostate cancer specific mortality and in men on active surveillance with a higher risk of biopsy grade reclassification to Gleason score 3 + 4 or greater (Grade Group 2 or greater). However, to our knowledge the association between age and biopsy grade reclassification to an aggressive phenotype (Gleason score 4 + 3 or greater [Grade Group 3 or greater]) has not been explored.

MATERIALS AND METHODS

From 1995 to 2016 we followed 1,625 men 41 to 81 years old with NCCN® (National Comprehensive Cancer Network®) very low (68%) or low (32%) risk prostate cancer on active surveillance. We determined the rate of biopsy grade reclassification to Grade Group 3 or greater. Competing risk analysis was applied to evaluate the association between age at enrollment and the risk of biopsy grade reclassification. Additionally, in men who underwent radical prostatectomy after biopsy grade reclassification we assessed the rate of radical prostatectomy grade reclassification (ie radical prostatectomy Grade Group greater than biopsy Grade Group).

RESULTS

The 5-year incidence of biopsy grade reclassification to Grade Group 3 or greater was 4%, 7% and 14% in men younger than 60, 60 to 69 and 70 years old or older, respectively (p <0.001). On univariate analysis older age was associated with biopsy grade reclassification to Grade Group 3 or greater (per 10-year increase HR 2.43, p <0.001). On multivariable analysis adjusting for year of diagnosis, race, prostate specific antigen density and cancer volume at diagnosis older age remained associated with biopsy grade reclassification to Grade Group 3 or greater (per 10-year increase HR 2.19, p <0.001). In men who underwent radical prostatectomy after biopsy grade reclassification those who were older had a higher rate of radical prostatectomy grade reclassification (p <0.05).

CONCLUSIONS

In men on active surveillance older age at diagnosis was positively associated with biopsy grade reclassification to Grade Group 3 or greater and radical prostatectomy grade reclassification. These observations imply that for many older men, active surveillance as opposed to watchful waiting remains a more appropriate management strategy.