5-Year Outcomes of a Single Institution Prospective Trial of 19 Gy Single-Fraction HDR Brachytherapy for Low- and Intermediate-Risk Prostate Cancer
Mené sur 68 patients atteints d'un cancer de la prostate à risque faible ou intermédiaire de récidive (âge médian : 62 ans ; durée médiane de suivi : 3,9 ans), cet essai évalue la toxicité à 5 ans d'une curiethérapie à haut débit de dose délivrant 19 Gy en une seule fraction
Purpose : To update outcome and toxicity results of a prospective trial of 19 Gy single-fraction high-dose-rate (HDR) brachytherapy for men with low- and intermediate-risk prostate cancer. Materials and Methods : Patients were treated on a prospective study of single-fraction HDR brachytherapy. All patients had low- or intermediate-risk prostate cancer. Patients with prostate volumes > 50 cc, taking alpha-blockers for urinary symptoms, or baseline American Urologic Association (AUA) symptom scores > 12 were ineligible. Patients underwent trans-rectal ultrasound (TRUS)-guided interstitial implant of the prostate followed by single-fraction HDR brachytherapy to a prescription dose of 19 Gy. Results : 68 patients were enrolled with a median follow-up of 3.9 years. Median age was 62 years. Median gland volume at the time of treatment was 35 cc. 92.6% of patients had T1 disease, 63.2% had a Gleason score of 6, and median pre-treatment PSA was 5.0 ng/mL. Chronic grade 2 genitourinary toxicity was 14.7%. No grade 3 urinary toxicity occurred. A single patient experienced grade 2+ rectal toxicity (grade 3 diarrhea) that was transient and resolved with medical management. The 5-year estimated disease-free survival was 77.2% with no significant difference between low- and intermediate-risk patients. A single patient developed distant metastases during the follow-up period. Biopsy-proven local failure at 5-years was 18.8% occurring at a median interval of 4.0 years post-treatment. No deaths occurred during follow-up. Conclusions : With extended follow-up, toxicity rates following single-fraction 19 Gy HDR brachytherapy remain low. Higher than expected rates of biochemical and local failure, however, raise concerns regarding the adequacy of this dose. Additional investigation to define the optimal single-fraction HDR brachytherapy dose is warranted, and single-fraction treatment should not currently be offered outside the context of a clinical trial.