PSA Nadir Is a Significant Predictor of Treatment Failure after High-Intensity Focussed Ultrasound (HIFU) Treatment of Localised Prostate Cancer

ObjectivesTo assess if prostate-specific antigen (PSA) nadir is an independent predictor of treatment failure and disease-free survival after high-intensity focussed ultrasound (HIFU) therapy for localised prostate cancer as defined by the new ASTRO criteria.MethodsOne hundred three patients after HIFU treatment (Ablatherm®, EDAP, Lyon, France) for localised prostate cancer without previous hormonal therapy were evaluated retrospectively. Patients attended regular follow-up visits every 3 mo. Treatment failure was defined by the revised ASTRO criteria (PSA ≥2 ng/ml above nadir PSA, positive biopsy, if salvage treatment was administered). Patients were divided into three PSA nadir subgroups (group 1, ≤0.2 ng/ml; group 2, 0.21–1 ng/ml; group 3, >1 ng/ml). The disease-free survival rate (DFSR) was calculated by using life table methods. The log-rank test was used to compare the curves based on Kaplan-Meier models.ResultsThe median follow–up was 4.9 (3–8.6) yr. Mean time to PSA nadir was 6.4 ± 5.1 mo. A PSA nadir of ≤0.2 ng/ml, 0.21–1 ng/ml, and >1 ng/ml was reached by 64%, 22.3%, and 13.6% of patients, respectively. Treatment failure rates during follow-up were 4.5%, 30.4%, and 100%, respectively, for the three groups (p < 0.001). The actuarial DFSRs at 5 yr were 95%, 55%, and 0%, respectively, for the 3 groups (p < 0.001).ConclusionsThe PSA nadir after HIFU correlates highly significantly with treatment failure and DFSR, and can be applied in daily clinical practice. Promising oncological outcome is obtained if a PSA nadir of ≤0.2 ng/ml is reached.