In the latest focal therapy consensus (FALCON), it is controversial whether control biopsies should be done in centers with extensive experience in focal therapy (FT) of prostate cancer. The aim of this study is to test the feasibility of combining percentage prostate specific antigen (%PSA) reduction and multiparametric magnetic resonance imaging (mpMRI) to determine the clinical scenario in which routine biopsy could be avoided after FT with high-intensity focused ultrasound (HIFU).

This is a retrospective analysis of a prospectively collected database. We analyzed 90 men treated by FT with HIFU. %PSA reduction was calculated by PSA nadir within postop 6 months. mpMRI was done at postop 6 months, followed by routine follow-up biopsy. Logistic regression analysis was done to identify predictors for clinically significant prostate cancer (csPC) on follow-up biopsy. Receiver operating characteristic curve analysis was done to obtain the area under curve (AUC) of each variable. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of %PSA reduction and mpMRI to predict csPC on follow-up biopsy were assessed.

The median age was 70 years old (range 39-85 years). The median PSA level was 7.26 ng/mL (range 2.48-19.95 ng/mL). By D’Amico risk classification, 31, 44, and 15 men had low risk, intermediate risk, and high risk disease, respectively. After FT with HIFU, the median PSA nadir was 1.23 ng/mL (range 0.04-8.57 ng/mL), and the median time to PSA nadir was 6 months (range 3-6 months). Eight men had csPC on follow-up biopsy. %PSA reduction and mpMRI at postop 6 months were significant predictors for csPC on follow-up biopsy (p = 0.033 and 0.02, respectively) on multivariate logistic regression analysis. The AUC of mpMRI, %PSA reduction, and their combination were 0.95, 0.816, and 0.982, respectively. The sensitivity, specificity, PPV and NPV of PSA reduction < 70% and Prostate Imaging Reporting & Data System (PI-RADS) ≥ 3 at postop 6 months to predict csPC were 87.5%, 69.5%, 21.9%, 98.3%, and 87.5%, 96.3%, 70%, 98.8%, respectively. Restricting biopsy in men with PSA reduction < 70% or PI-RADS ≥ 3 could avoid 60% of biopsy without missing csPC.

For men with PSA reduction > 70% and no suspicious mpMRI after FT with HIFU, routine follow-up biopsy at postop 6 months might be avoided.