Adverse Disease Features in Gleason Score 3 + 4 "Favorable Intermediate-Risk" Prostate Cancer: Implications for Active Surveillance

Background: According to a recent National Comprehensive Cancer Network (NCCN) guidelines update, patients with Gleason score (GS) 3 + 4 prostate cancer (PCa) and "favorable intermediate-risk" (FIR) characteristics might be offered active surveillance (AS). However, the risk of unfavorable disease features and its prediction in this subset of patients is not completely understood. Objective: To identify the risk of unfavorable disease and potential predictors of adverse outcomes among GS 3 + 4 FIR PCa patients. Design, setting, and participants: The study included patients with biopsy GS 3 + 4 and otherwise fulfilling the NCCN low-risk definition (prostate-specific antigen [PSA] <10 ng/ml, cT2a or lower) undergoing radical prostatectomy (RP) from 2006 to 2014 at a single institution. Outcome measurements and statistical analysis: Complete information on PSA, PSA density (PSAD), clinical stage, percentage of positive cores, percentage of maximum surface specimen involvement, and RP pathology were available. GS upgrade and downgrade, non-organ-confined and non-specimen-confined disease, unfavorable disease (pT3-T4 and/or pN1 and/or a pGS ≥4 + 3) were the outcomes. Statistical analysis included descriptive statistics and multivariable logistic regression. Results and limitations: A total of 156 patients (13.1%) experienced GS upgrade; 201 (16.9%) were downgraded. Overall, 205 men (17.2%) harbored non-organ-confined disease, and 295 (24.8%) had unfavorable disease. Age (odds ratio [OR]: 1.06), percentage surface involvement (OR: 1.01), and PSAD (OR: 1.83) were the only significant predictors of upgrade. Age (OR: 1.05), clinical stage (OR: 1.74), percentage of positive cores >50% (OR 1.57), percentage of surface area (OR: 1.02), and perineural invasion (OR: 1.89) were significant predictors of unfavorable disease at RP. The retrospective design is a limitation. Conclusions: AS is a possible option for a subset of men with FIR GS 3 + 4. However, clinical models alone have a limited role in GS upgrade prediction, and alternative tools warrant further investigation. Patient summary: Patients with Gleason score 3 + 4 at biopsy, low prostate-specific antigen, and low stage might consider the option of active surveillance, but the use of clinical information alone might be not adequate for thorough risk-adapted counseling. Active surveillance might be an option for a selected subset of men with favorable intermediate Gleason Score (GS) 3 + 4; however, clinical models alone have a limited role in GS upgrade prediction in this setting, and alternative tools may warrant further investigation.