High-intensity Focused Ultrasound As Salvage Therapy for Patients with Recurrent Prostate Cancer After External Beam Radiation, Brachytherapy or Proton Therapy

Objective: To investigate the use of high-intensity focused ultrasound (HIFU) as a salvage therapy in patients with recurrence of localized prostate cancer after external beam radiation (EBRT), brachytherapy, or proton therapy.

Patients And Methods: We retrospectively reviewed the charts of all patients who had undergone salvage HIFU for biopsy-proven prostate cancer after primary radiation therapy. Patient characteristics and oncological outcomes were assessed.

Results: Records of 22 patients with a median (range) follow-up of 24 (5-80) months were reviewed. Patients were men with presumed organ-confined disease who had been treated with salvage HIFU following recurrent disease after EBRT (fourteen patients), brachytherapy (five patients: four with high-dose brachytherapy using In(192) ; and one with low-dose brachytherapy using Au(98) ) or proton therapy (three patients). The median (range) age at salvage HIFU was 65 (52-80) years, with a median (range) prostate-specific antigen (PSA) level before radiation therapy of 14.3 (5.7-118) ng/mL and a median (range) PSA level of 4.0 (1.2-30.1) ng/mL before HIFU. The median (range) period to HIFU after radiation therapy was 36 (4-96) months. The biochemical disease-free survival (bDFS) rate in all patients at 5 years was 52%. Rates of bDFS in low-, intermediate- and high-risk groups were 100%, 86%, and 14%, respectively. One of the twelve patients who received post-HIFU prostate biopsy showed malignancy. Side effects included urethral stricture in four patients, grade I urinary incontinence in four patients, rectourethral fistula and epididymitis in one of each patient.

Conclusion: Salvage HIFU is a promising treatment option for local recurrence after radiation therapy, with morbidity comparable with other forms of salvage treatment.