Purpose: We aimed to determine if, using baseline MRI-guided biopsy (MRGB), durability of active surveillance (AS) could be predetermined, follow-up biopsies avoided, and if by incorporating focal therapy (FT), AS extended.
Materials and methods: A cohort of 869 men in the University of California, Los Angeles, protocol study of AS (2010-2022) was analyzed. Inclusion criteria were baseline 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, the absence of progression (negative predictive value) 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, 5-year probability of radical prostatectomy/radiation therapy-free survival was 84% compared with 46% in the no-FT group (P < .01).
Conclusions: Durability of AS may be linked to baseline MRGB. In men starting AS with MRGB and low-risk prostate cancer, subsequent MRI exhibits high negative predictive value, indicating routine follow-up biopsy is avoidable. In some men, FT may allow extension of AS and deferral of surgery or radiation.
Keywords: MRI; MRI-guided biopsy; active surveillance; focal therapy; prostate cancer.