Salvage HIFU oncologic outcomes were reported in the previously cited meta-analysis of local salvage therapies after radiotherapy by Valle et al. They included 20 HIFU studies. Two- and five-year recurrence-free survival rates were 52 and 46%, respectively. When compared to salvage prostatectomy, the 2-year recurrence-free survival was found to be significantly lower with HIFU (52% vs. 72%). Ingrosso et al. included 13 HIFU studies in their meta-analysis. Biochemical control was reported in 10 of the included studies with a pooled-prevalence of 58% with a follow-up range of 9–59.3 months.
Several recent studies have also reported on oncologic outcomes of salvage HIFU (Table 2). Nair et al. reported a 10-year Kaplan–Meier estimated BCR rate of 71.3%. The 10-year estimates of metastasis and prostate cancer-specific mortality rate were 23.8% and 15.2%, respectively. ADT initiation rate was 52% at 10 years. Devos et al. compared salvage whole gland HIFU to salvage prostatectomy in radiorecurrent prostate cancer in a retrospective cohort of 52 patients (27 HIFU, 25 prostatectomy). Five-year biochemical disease-free survival for HIFU was 51%. Five-year overall survival, cancer-specific survival, and metastasis-free survival were 80.9, 84.0, and 60.4%, respectively. These were not significantly different in the prostatectomy group at 61.9, 74.0, and 55.2%, respectively. One recent study evaluated the use of HIFU after brachytherapy. Failure-free survival defined as BCR in addition to any recurrence or persistence of clinically significant prostate cancer or need for retreatment, was 41% at 6 years. Progression-free survival, overall survival, cancer-specific survival, and metastasis-free survival rates were 45, 93, 98, and 80%, respectively. Fifteen patients with unilateral disease underwent hemigland HIFU. Progression-free survival was not significantly different between hemigland and whole gland ablation. Other oncologic outcomes were not compared between the two techniques.
Another focused ultrasound-based ablation technology that has been explored in the salvage setting is MRI-guided transurethral ultrasound ablation. In a prospective phase 1 study of 11 patients, 10 were free of cancer in the ablation zone on 1 year per-protocol biopsy. Two patients developed out of field recurrences and one patient experienced BCR at 1 year.
Curr Opin Urol. 2021;31(3):188-193. © 2021 Wolters Kluwer Health, Inc.