The long-term risks of metastases in men on active surveillance for early stage prostate cancer

Purpose: We assessd the long-term outcomes from a large prospective cohort of men diagnosed with prostate cancer managed with active surveillance and determined the clinical prognostic factors that may predict the risk of metastases. Materials and methods: We retrospectively reviewed data of men enrolled on active surveillance at our institution between 1990 and 2018 with low or intermediate risk disease (stage cT1-2, prostate specific antigen less than 20 ng/ml, and biopsy Grade Group [GG]1-2). Patients were classified into 3 groups by diagnostic GG and prostate specific antigen density. Primary outcome was metastatic prostate cancer detected on imaging or at prostatectomy. In addition, upgrade at surveillance biopsy, active treatment, and overall and prostate cancer specific survival outcomes were assessed. Cox proportional hazards regression models were used. Results: A total of 1,450 men met the inclusion criteria. Median followup was 77 months (IQR 49-114). The 7-year metastasis-free survival rate was 99%. Metastases developed in 15 men at a median of 62 months (IQR 29-104), of which 69% were confined to lymph nodes. Men with GG2 had a lower metastasis-free survival rate compared to those with GG1 disease. GG2, prostate specific antigen velocity and PI-RADS® 4-5 lesions on multiparametric magnetic resonance imaging were associated with a higher risk of metastases. The 7-year prostate cancer specific survival was greater than 99%. Conclusions: Active surveillance seems to preserve favorable long-term prognosis, as metastases and prostate cancer specific death are rare. However, the higher risk of metastases associated with higher Gleason grade, prostate specific antigen velocity, and characteristics on multiparametric magnetic resonance imaging should be considered when selecting and counseling patients for active surveillance.