Outcomes and Toxicities in Intermediate-Risk Prostate Cancer Patients Treated with Brachytherapy Alone or Brachytherapy and Supplemental External Beam Radiation Therapy

To evaluate the cancer control outcomes and long-term treatment-related morbidity of brachytherapy as well as combination brachytherapy and EBRT in patients with intermediate-risk prostate cancer.

A retrospective review was conducted in a prospectively collected database of patients with intermediate-risk prostate cancer who were treated either with brachytherapy or brachytherapy and EBRT, with or without ADT, from 1990-2014. Urinary and erectile dysfunction symptoms are measured using the International Prostate Symptom Score (IPSS) and the Mount Sinai erectile function scale, and the Sexual Health Inventory for Men (SHIM), respectively. Cancer control endpoints include biochemical failure and development of distant metastases. All statistical analyses were done using the Statistical Package for Social Science (SPSS). Survival curves were calculated using Kaplan-Meier actuarial methods and compared using log-rank tests. Cox regression multivariate analyses were used to test the effect of multiple variables on treatment outcomes.

902 patients were identified with a median follow up of 91 months. 390 patients received brachytherapy and 512 received combination with EBRT. In patients with one intermediate risk factor, the addition of EBRT did not significantly affect freedom from biochemical failure or distant metastases. Among patients with two or three intermediate-risk factors, added EBRT did not improve freedom from biochemical failure. Significant differences in late toxicity between patients treated with brachytherapy versus combination brachytherapy and EBRT were identified including urge incontinence (p<0.001), hematuria (p<0.001), and dysuria (p<0.001), and change in ISPP QoL score (p=0.002). These symptoms were reported by patients at any point during treatment follow up. An analysis of men who were potent before treatment using actuarial methods revealed that men receiving combination therapy more frequently experienced loss of potency, as measured by the Mount Sinai erectile function scale (p=0.040).

Brachytherapy monotherapy results in equal biochemical and distant control in both patients with one and more than one intermediate-risk features. While no significant benefit was shown, we believe that the addition of EBRT may prevent recurrence in patients with multiple intermediate-risk features and should be considered. This article is protected by copyright. All rights reserved.

BJU international. 2018 Jan 10 [Epub ahead of print]

Emily Schlussel Markovic, Michael Buckstein, Nelson N Stone, Richard G Stock

Department of Radiation Oncology, Icahn School of Medicine at Mount Sinai, New York, NY.