Five-Year Outcomes From a Prospective Comparative Effectiveness Study Evaluating External Beam Radiotherapy With Low Dose-Rate Brachytherapy Boost and Prostatectomy for Localized Prostate Cancer.

Abstract

PURPOSE/OBJECTIVE(S)\nHigh-quality data comparing radical prostatectomy (RP) and external beam radiotherapy plus low dose-rate brachytherapy boost (EBRT-LDR) are lacking. To better inform treatment selection, we compared patient reported functional outcomes (PROs) through 5 years following RP or EBRT-LDR for localized prostate cancer.\n\n\nMATERIALS/METHODS\nMen were enrolled from 2011-2012 on this multicenter prospective study. Enrollment criteria were: 1) age < 80 years, 2) prostate-specific antigen < 50 ng/dL, and 3) a pathologically-confirmed diagnosis of localized prostate adenocarcinoma within 6 months of enrollment. PROs collected at baseline, 0.5, 1, 3, and 5 years included the Expanded Prostate Index Composite (EPIC), Short Form Health Survey (SF-36), and the Clark treatment-related regret scale. Regression models adjusted for patient characteristics and baseline function. Minimum clinically important point differences for EPIC domains were defined: 4-6 bowel function, 5-7 urinary irritation, 6-9 urinary incontinence, and 10-12 sexual function.\n\n\nRESULTS\nAmong the entire cohort, 112 received EBRT-LDR and 1553 RP. EBRT-LDR patients were older (median [quartiles]: 66 [60-71] vs. 62 [57-66); P < 0.001) and more commonly had high-risk disease (24% vs. 17%; P\u202f=\u202f0.039). Compared to treatment with RP, treatment with EBRT-LDR was associated with clinically meaningful worse bowel (adjusted mean difference, [95% confidence interval]: -9.1 [-11.9, -6.4] P < 0.001 at 1 year; -4.0 [-6.9, -1.1], P\u202f=\u202f0.006 at 5 years), worse urinary irritative (1 year: -13.4 [-17.6, -9.2], P < 0.001; 5 year: -5.0 [-8.7, -1.3], P\u202f=\u202f0.008), and better urinary incontinence function (1 year: 15.1 [11.0, 19.2], P < 0.001; 5 years: 13.3 [7.7, 18.9], P < 0.001) through 5 years. Men reported similar frequency of moderate to big problem with urinary function between treatment groups through 5 years (1 year: 12% RP vs. 15% EBRT-LDR, P\u202f=\u202f0.52; 5 years: 13% vs. 15%, P\u202f=\u202f0.50). EBRT-LDR was associated with clinically meaningful better sexual function through 1 year (12 [6.5, 17.5]; P < 0.001 at 1 year), however, sexual function was not clinically different at subsequent timepoints (6.7 [-0.1, 13.4], P\u202f=\u202f0.05 at 5 years). There were no clinically meaningful differences between treatment groups in physical functioning, emotional well-being, or energy and fatigue. There was no difference in treatment-related regret between groups at 5 years.\n\n\nCONCLUSION\nCompared to RP, EBRT-LDR was associated with clinically meaningful worse urinary irritative and bowel function and better urinary incontinence function through 5 years after treatment. These patient-reported functional outcomes may clarify treatment expectations and help men make informed treatment choices for their localized prostate cancer.