Analysis of LDR Outcomes in Clinically Localized Prostate Cancer Incorporating a Significant TURP Cohort: A Community Experience

Abstract

To report the 5 year biochemical relapse free survival (BRFS), overall survival (OS) and long term toxicity outcomes of patients treated with 125Iodine (125I) brachytherapy as monotherapy for clinically localised, low to intermediate risk prostate cancer in the community setting with 3 radiation oncologists and 16 urologists. 371 patients (median age 67 years) with clinically localised prostate cancer were treated from 2004 to 2011 with 125I monotherapy. Median PSA at diagnosis was 5.6 (range 0.6-15.1). T stage was T1 (51%) and T2 (49%) Gleason score was ≤5 (1%); 6 (73%) and 7 (26%). Neoadjuvant hormonal therapy (median 4.5 month course) was used in 84 patients (23%). 102 patients (27%) underwent TURP prior to implant. Patients were evaluated for BRFS, OS and long-term toxicity outcomes. Biochemical relapse was defined by the Phoenix (nadir+2ng/ml) definition. Kaplan-Meier method was used to estimate BRFS and OS, with close-out (censoring) 5 years after implant. Median follow-up time for relapse was 5.2 years with 95% followed up for ≥4 years. 5 year BRFS for the entire cohort was 95%. BRFS by Gleason score classification cohort analysis was 96% and 91% for <6 and 7 respectively. Differences in BRFS between T1 and T2 stages, risk groups (low, low-intermediate, intermediate) and prostate volumes (<30, <40, <50, ≥50 cc) were not significant (p>0.1), probably because the number of relapses was so small. Overall survival was 96% at 5 years, with no deaths from prostate cancer, 7 deaths from other cancers and 7 deaths from other causes. Late grade 2 or 3 toxicities were reported in 10% and 5% of patients respectively with urinary retention in 12% and haematuria in 2%. Urinary incontinence requiring at least 1 pad per day occurred in 3 patients (<1%). Patients with a prior TURP had a greater incidence of late grade 2 or 3 urinary retention (p=0.0011). No patient developed urethral necrosis or recto-prostatic fistula. BRFS and OS results are comparable with published series, as is the incidence and severity of late toxicities. Our results indicate prior TURP is not a contraindication for LDR brachytherapy in cases where implant is technically feasible. However, the risk of subsequent urinary retention is increased.