Favorable Preliminary Outcomes for Men with Low- and Intermediate-Risk Prostate Cancer Treated with 19 Gy Single Fraction High-Dose-Rate Brachytherapy

Abstract Purpose To report toxicity and preliminary clinical outcomes of a prospective trial evaluating 19 Gy single fraction high-dose-rate (HDR) brachytherapy for men with low- and intermediate-risk prostate cancer. Materials and Methods 63 patients were treated according to an IRB-approved prospective study of single fraction HDR brachytherapy. Eligible patients had tumor stage < T2a, PSA < 15, and Gleason score < 7. Patients with prostate gland volume > 50 cc and baseline American Urologic Association (AUA) symptom score > 12 were ineligible. Patients underwent trans-rectal ultrasound (TRUS)-guided trans-perineal implant of the prostate followed by single fraction HDR brachytherapy. Treatment was delivered via Ir-192 to a dose of 19 Gy prescribed to the prostate with no additional margin applied. Results 58 patients were available for analysis. Five withdrew consent during the follow-up period. Median follow up was 2.9 years [range 0.3-5.2 years]. Median age was 61.4 years. Median gland volume at the time of treatment was 34.8 cc. 91% of patients had T1 disease, 71% had Gleason score < 6 (29% Gleason 7), and median pre-treatment PSA was 5.1 ng/mL. Acute and chronic grade 2 genitourinary toxicity incidence was 12.1% and 10.3%, respectively. No grade 3 urinary toxicity occurred. No patients experienced acute rectal toxicity > grade 2, and 2 experienced > grade 2 chronic GI toxicity. 3 patients have experienced biochemical failure yielding a 3-year cumulative incidence estimate of 6.8%. Conclusions Single fraction HDR brachytherapy is well-tolerated with favorable preliminary biochemical and clinical disease control rates.