Primary whole-gland ablation for localized prostate cancer with high-intensity focused ultrasound: The important predictors of biochemical recurrence.

OBJECTIVES: To identify predictive factors of biochemical recurrence for patients undergoing high-intensity focused ultrasound treatment for localized prostate cancer.
METHODS: We retrospectively identified patients receiving whole-gland prostate ablation with high-intensity focused ultrasound for localized prostate cancer from 2009 to 2015. All the patients received pre-high-intensity focused ultrasound radical transurethral resection of the prostate. We included perioperative parameters as follows: age, preoperative prostate volume, stage of operation, initial prostate-specific antigen, T stage, postoperative prostate-specific antigen nadir, Gleason score, time to prostate-specific antigen nadir and the presence of prostate-specific antigen biochemical recurrence. Multivariable Cox regression and Kaplan-Meier analysis were used for investigating predictors of recurrence, and receiver operating characteristic analysis was used for the cut-off values of prostate-specific antigen nadir.
RESULTS: Among 182 patients, 26.9% had prostate-specific antigen biochemical recurrence after high-intensity focused ultrasound during the median follow-up period of 32.21 months. Gleason score ≥7 (Gleason score 7, hazard ratio 2.877, P = 0.027), stage ≥T2b (T2b, hazard ratio 3.16, P = 0.027) and prostate-specific antigen nadir (hazard ratio 1.11, P < 0.001) were statistically significant, whereas there was no significance in prostate volume and initial prostate-specific antigen. We posit that a cut-off level of prostate-specific antigen nadir 0.43 ng/mL might be considered as an independent predictive factor for prostate-specific antigen biochemical recurrence in high-intensity focused ultrasound patients in multivariate analysis (P < 0.001, hazard ratio 7.39, 95% confidence interval 3.56-15.37), and created a new nadir-related prediction model for biochemical recurrence prediction.
CONCLUSIONS: Postoperative prostate-specific antigen nadir of 0.43 ng/mL can be considered an important predictive factor for biochemical recurrence in primary whole-prostate gland high-intensity focused ultrasound treatment, and the nadir-related prediction model might provide a reference for early salvage treatment. Furthermore, Gleason score ≥7, stage ≥T2b might be associated with unfavorable outcomes, although prostate volume and higher initial prostate-specific antigen appear not to be associated with biochemical recurrence for the high-intensity focused ultrasound treatment.