Risk of Metastasis in Men with Grade Group 2 Prostate Cancer Managed with Active Surveillance at a Tertiary Cancer Center

Purpose: We studied the risk of metastatic prostate cancer development in men with Grade Group 2 disease managed with active surveillance at Memorial Sloan Kettering Cancer Center. Materials and Methods: A total of 219 men with Grade Group 2 prostate cancer had disease managed with active surveillance between 2000 and 2017. Biopsy was performed every 2 to 3 years, or upon changes in magnetic resonance imaging, prostate specific antigen level or digital rectal examination. The primary outcome was development of distant metastasis. The Kaplan-Meier method was used to estimate treatment-free survival. Results: Median age at diagnosis was 67 years (IQR 61-72), median prostate specific antigen was 5 ng/ml (IQR 4-7) and most patients (69%) had nonpalpable disease. During followup 64 men received treatment, including radical prostatectomy in 36 (56%), radiotherapy in 20 (31%), hormone therapy in 3 (5%) and focal therapy in 5 (8%). Of the 36 patients who underwent radical prostatectomy 32 (89%) had Grade Group 2 disease on pathology and 4 (11%) had Grade Group 3 disease. Treatment-free survival was 61% (95% CI 52-70) at 5 years and 49% (95% CI 37-60) at 10 years. Three men experienced biochemical recurrence, no men had distant metastasis and no men died of prostate cancer during the followup. Median followup was 3.1 years (IQR 1.9-4.9). Conclusions: Active surveillance appears to be a safe initial management strategy in the short term for carefully selected and closely monitored men with Grade Group 2 prostate cancer treated at a tertiary cancer center. Definitive conclusions await further followup.