Older Age at Diagnosis and Initial Disease Volume Predict Grade Reclassification Risk on Confirmatory Biopsy in...

To identify which active surveillance candidates benefit most from confirmatory biopsies to exclude grade underclassification.

This observational study includes 556 men diagnosed between 2002 and 2015 with Gleason 3 + 3 (GG1) disease on initial diagnostic biopsy, of whom 406 received a confirmatory biopsy within 12 months for active surveillance. Multivariable logistic regression analysis was performed to determine clinicopathologic features associated with Gleason 7 or higher (GG2+) on a confirmatory biopsy. Regression tree analysis was employed to stratify patients into select risk groups.

Eighty-five of 406 patients (20.9%) with initially GG1 disease were reclassified to GG2+ on a confirmatory biopsy. On multivariable analysis, increasing age (per year odds ratio 1.07; 95% confidence interval 1.02-1.12; P <.01) and more positive cores at diagnosis (per core, odds ratio 1.37, 95% confidence interval 1.09-1.72; P <.01) were significantly associated with reclassification, independent of prostate volume, clinical stage, initial PSA, or confirmatory biopsy type (including magnetic resonance imaging-targeted approaches or transrectal saturation random sampling). Recursive partitioning demonstrated that age over 73 and 5 or more positive cores were factors associated with the greatest reclassification risk.

In our cohort, both advancing age and additional positive cores were associated with increased odds of reclassification to GG2+ on confirmatory biopsy. In men over age 73 or with 5 or more positive cores, a repeat biopsy within 12 months may be particularly beneficial to minimize tumor grade underclassification.