Age is Associated with Upgrading at Confirmatory Biopsy among Men with Prostate Cancer Treated with Active Surveillance

Purpose: Active surveillance is increasingly recommended for older men with low risk prostate cancer. Although older men have higher all cause mortality, they also have higher prostate cancer specific mortality. We hypothesized that older age is associated with an increased risk of Gleason score upgrading at confirmatory biopsy when controlling for prostate volume. Materials and Methods: We retrospectively reviewed data on 1,130 patients with prostate cancer who were treated with active surveillance from 1991 through 2011. We included 646 patients with clinical Gleason 6 or less, stage T2a or less prostate cancer, a confirmatory biopsy within 2 years of diagnostic biopsy and prostate magnetic resonance imaging before confirmatory biopsy. The primary outcome was Gleason score upgrading to 7 or greater on confirmatory biopsy. We used logistic regression to estimate the effect of age on upgrading, adjusting for magnetic resonance imaging prostate volume and other potential confounders. Results: Median age was 66 years (IQR 61-72) and median magnetic resonance imaging prostate volume was 41 ml (IQR 29-55). At confirmatory biopsy disease was upgraded in 55 of 646 patients (9%) and unchanged in 290 (45%) and biopsy was negative in 297 (46%). Older age was associated with higher odds of upgrading (adjusted OR 1.05, 95% CI 1.01-1.09, p = 0.009). Larger prostate volume was associated with lower odds of upgrading (adjusted OR 0.80/10 ml increase, 95% CI 0.7-0.9, p = 0.012). Conclusions: Our findings suggest that older age is associated with an increased risk of misclassification on diagnostic biopsy. Older men who are interested in active surveillance should be counseled about the risks and benefits of confirmatory biopsy.