Low Dose Rate Brachytherapy and Long-Term Treatment Outcomes In Patients Less Than 60 Years of Age

Abstract

Low Dose Rate (LDR) brachytherapy in young men remains controversial amongst urologists due to their concerns regarding long term biochemical control and treatment related toxicities. The purpose of this study is to evaluate the treatment outcomes of men under 60 years of age who underwent LDR brachytherapy with Iodine 125 (125I) for clinically localized low to intermediate risk prostate cancer. A total of 156 patients with clinically localized prostate cancer were treated at our institution from 2003 to 2016 with 125I monotherapy. The prescription was 145.0Gy modified peripheral loading (MPD). Median age at implant was 56 years (range 42-60). Median PSA level at diagnosis was 4.5 ng/mL (range 0.3-13.9). Staging was T1 in 46% and T2 in 54% of patients. 62 patients (40.5%) underwent trans urethral resection of the prostate (TURP) prior to implant. All patients were assessed clinically for biochemical response based on Phoenix definition (nadir +2ng/ml), biochemical relapse free survival (bRFS), progression free survival (PFS), overall survival (OS) and any associated treatment toxicities. With median follow up of 6.7 years, bRFS at 10 years post LDR implant is 94% for the entire cohort; 99% and 82% for low and intermediate risk groups respectively. PFS at 10 years for the entire cohort is 94%; low and intermediate risk groups are 99% and 82% respectively. OS is 95% for our entire cohort. Late grade 2+ genito-urinary (GU) toxicities were reported in 5 patients (3.2%) with only one patient experiencing late grade 3 toxicity. Three patients (1.9%) developed secondary cancers, all considered unrelated to their LDR brachytherapy. Five (3.2%) deaths were reported but only 1 was secondary to prostate cancer. Four patients (2.6%) experienced late grade 2+ gastro-intestinal (GI) toxicity. No patients who underwent TURP prior to implant reported any late grade 2+ GU toxicity. With excellent long-term treatment outcomes and minimal associated toxicities, our results indicated that LDR brachytherapy is an effective treatment of choice for this younger cohort of men diagnosed with localized prostate cancer.