Cancer-specific Mortality of Grade Group 1 Prostate Cancer: Results from Surveillance, Epidemiology, and End Results Database, 2004–2021

Background: The nomenclature designation of grade group (GG) 1 prostate cancer (PCa) as “cancer” has recently become controversial because of its generally indolent clinical course and the associated psychological burden, which may contribute to overtreatment. We aimed to investigate PCa-specific mortality (PCSM) among patients with GG1 PCa using the Surveillance, Epidemiology, and End Results database with extended follow-up. Materials and methods: Patients diagnosed with GG1 prostatic adenocarcinoma between 2004 and 2021 were enrolled. From 2010 to 2021, GG1 disease was identified as Gleason Score ≤6, whereas from 2004 to 2009, it was classified as well-differentiated (Gleason Score 2–4) and moderately differentiated (Gleason Score 5–6) PCa. Only patients with available follow-up information were included. Because death from other causes represents a potential confounder of the primary outcome of PCSM, we conducted competing-risk analyses to evaluate cumulative mortality and assessed factors associated with PCSM using competing-risk regression models. Results: In total, 240,966 patients with GG1 PCa aged ≥30 years were identified. With a median follow-up of 10.1 years, 5086 patients (2.1%) died of PCa, and 34,168 patients (14.2%) died of other causes. Factors associated with worse PCSM included old age (hazard ratio [HR], 1.06 per year; 95% confidence interval [CI], 1.05–1.06), Black race (reference: White; HR, 1.28; 95% CI, 1.18–1.39), Hispanic ethnicity (HR, 1.11; 95% CI, 1.01–1.22), unmarried status (HR, 1.34; 95% CI, 1.25–1.44), high prostate-specific antigen level (HR, 1.02 per 0.1 ng/mL; 95% CI, 1.02–1.02), and locally advanced T stage ≥3 (reference: T ≤2; HR, 2.18; 95% CI, 1.82–2.61). Conversely, radical prostatectomy (HR, 0.35; 95% CI, 0.32–0.39), radiation therapy (HR, 0.85; 95% CI, 0.80–0.91), and high household income (HR, 0.95 per $10,000; 95% CI, 0.93–0.96) were associated with improved PCSM. Conclusions: Although GG1 PCa is typically indolent, 5086 patients died of PCa during extended follow-up. These findings support the continued classification of GG1 disease as “cancer,” with vigilant active surveillance to detect disease progression.