Evolution of Active Surveillance of Prostate Cancer: Impact of MRI, MRI-guided Biopsy and Focal Therapy.

PURPOSE We aimed to determine if, using baseline MRI-guided biopsy (MRGB), durability of active surveillance (AS) could be pre-determined, follow-up biopsies avoided, and if by incorporating focal therapy (FT), AS extended. MATERIALS AND METHODS A cohort of 869 men in the UCLA protocol study of AS (2010-2022) was analyzed. Inclusion criteria were baseline MRI-guided biopsy (MRGB) showing Grade Group (GG) ≤ 2 and >1 year enrollment. After 2016, FT was offered to men with GG2 and those progressing to GG3. RESULTS The 869 men accrued 3500 patient-years of follow-up (median follow-up 4.1 years). At baseline, men were GG1 (505), GG2 (174), and 'GG0' (190), the latter describing those with prior diagnostic GG1 or 2, but negative baseline MRGB. Overall, progression to ≥ GG3 among the 664 with serial MRGB was 7% for GG0, 19% for GG1, and 34% for GG2. During follow-up, absence of progression (negative predictive value, NPV) was correctly identified by MRI in nearly 95% of men with baseline GG0; 90% of men with GG1; and 70% of men with GG2. FT was performed in 99/393 eligible men (25%); among them, five-year probability of RP/RT-free survival was 84% compared to 46% in the no-FT group (p<0.01). CONCLUSIONS AND RELEVANCE Durability of AS may be linked to baseline MRGB. In men starting AS with MRGB and low-risk prostate cancer, subsequent MRI exhibits high NPV, indicating routine follow-up biopsy is avoidable. In some men, FT may allow extension of AS and deferral of surgery or radiation.