Prostate cancer is the second most prevalent malignancy among men. Although curative treatments such as prostatectomy and radiotherapy provide favorable oncological outcomes, they are often associated with significant side effects. In recent years, tissue-sparing treatments like high-intensity focused ultrasound (HIFU) have gained popularity due to their ability to reduce treatment-related morbidity and complications. The prostate-specific antigen (PSA) nadir has been identified as a potential predictor of treatment outcomes after HIFU, including disease-free survival and biochemical failure. The aim of this study is to investigate the correlation between pretreatment clinical parameters and PSA nadir following HIFU treatment.

Patients with clinically localized prostate cancer who underwent HIFU as primary treatment were retrospectively collected between November 2020 and March 2024. A total of 19 patients were included. Whole-gland HIFU treatment was performed using the Ablatherm Integrated Imaging system (EDAP TMS, France). Patients with a history of transurethral resection of the prostate (TURP) or GreenLight photoselective vaporization of the prostate (PVP) were included in the study. Patients who received androgen deprivation therapy (ADT) before or after HIFU were also included.Univariate analyses were conducted to evaluate pretreatment clinical variables, including age, BMI, PSA, prostate volume, Gleason grade group, D'Amico risk group, and ADT pretreatment, to identify independent predictors of PSA nadir (≤ 0.2 ng/mL vs. > 0.2 ng/mL). Biochemical failure was defined according to the Phoenix criteria. Biochemical disease-free survival (BDFS) was assessed using Kaplan-Meier survival analysis and compared using the log-rank test. Statistical analyses were performed using the 'R' software (version 4.4.3). A p value of < 0.05 was considered significant.

The median follow up for the patient is 14 months(12~24). The mean time to reach PSA nadir was 5.2 +/-3.7 months. 7 patient had ADT pretreatment, median treatment time is 2.5 months(IQR 1-3.75). Post operative ADT was given in 18 patient. Median PSA nadir(IQR) was 0.006(0.006 - 0.545), and 17(89.5%) reached PSA nadir of ≤ 0.2, and > 0.2 in 2(10.5%) patients. Univariate analysis was conducted for pretreatment clinical parameters failed to find significant corrolation to lower PSA nadir. Non of the patient had biochemical failure during follow up.

Our study demonstrated that HIFU is effective in achieving a low PSA nadir and favorable oncological outcomes. However, univariate analysis did not identify significant pretreatment predictors of PSA nadir. The high proportion of patients receiving postoperative ADT may have influenced PSA nadir levels. Further studies with larger cohorts, longer follow-up, and stratification based on ADT use are needed to clarify the correlation between PSA nadir and oncological outcomes after HIFU treatment.