Three-year outcomes of 324 prostate carcinoma patients treated with combination high-dose-rate brachytherapy and intensity modulated radiation therapy

Background: To report 3-year outcomes of patients treated with combination high-dose-rate (HDR) brachytherapy with intensity modulated radiation therapy (IMRT) for prostate carcinoma. Methods: Between 2002 and 2014, 324 prostate carcinoma patients received combination HDR brachytherapy [Iridium-192 (Ir-192)] and external beam IMRT. A total of 16 Gray (Gy) over 4 fractions was administered with HDR brachytherapy followed by 59.4 Gy over 33 fractions of external beam IMRT. Rates of biochemical control and distant metastasis were recorded along with incidence of late genitourinary (GU) and gastrointestinal (GI) toxicities. Results: Three-year prostate specific antigen (PSA) biochemical control rates for low, intermediate, and high risk patients were 95%, 99%, and 83%, respectively. Three-year incidence of distant metastases for low, intermediate, and high risk patients were 0%, 0%, and 7%, respectively. Three-year incidence of late grade 1, 2, and 3 GU toxicities were 9.0%, 3.0%, and 1.5%, respectively, and the 3-year incidence of grade 1, 2, and 3 GI toxicities were 6%, 2.2% and 0.4%, respectively. Multivariate analysis showed that age (>65), PSA (>10), and Gleason scores (>= 8) were predictive of decreased biochemical control. Conclusions: Combination HDR/IMRT for the treatment of clinically localized prostate cancer yields excellent clinical outcomes. High rates of PSA control and low incidence of late GI and GU toxicities are achievable with combination HDR/IMRT treatment for prostate cancer.