Potency preservation following stereotactic body radiation therapy for prostate cancer

Abstract

BackgroundErectile dysfunction after prostate radiation therapy remains an ongoing challenge and critical quality of life issue. Given the higher dose of radiation per fraction using stereotactic body radiation therapy (SBRT) there is concern that post-SBRT impotency would be higher than conventional radiation therapy approaches. This study sought to evaluate potency preservation and sexual function following SBRT for prostate cancer.MethodsBetween February 2008 and March 2011, 216 men with clinically localized prostate cancer were treated definitively with SBRT monotherapy at Georgetown University Hospital. Potency was defined as the ability to have an erection firm enough for intercourse with or without sexual aids while sexual activity was defined as the ability to have an erection firm enough for masturbation and foreplay. Patients who received androgen deprivation therapy (ADT) were excluded from this study. Ninety-seven hormone-naïve men were identified as being potent at the initiation of therapy and were included in this review. All patients were treated to 35–36.25 Gy in 5 fractions delivered with the CyberKnife Radiosurgical System (Accuray). Prostate specific antigen (PSA) and total testosterone levels were obtained pre-treatment, every 3 months for the first year and every 6 months for the subsequent year. Sexual function was assessed with the Sexual Health Inventory for Men (SHIM), the Expanded Prostate Index Composite (EPIC)-26 and Utilization of Sexual Medication/Device questionnaires at baseline and all follow-up visits.ResultsNinety-seven men (43 low-, 50 intermediate- and 4 high-risk) at a median age of 68 years (range, 48–82 years) received SBRT. The median pre-treatment PSA was 5.9 ng/ml and the minimum follow-up was 24 months. The median pre-treatment total serum testosterone level was 11.4 nmol/L (range, 4.4-27.9 nmol/L). The median baseline SHIM was 22 and 36% of patients utilized sexual aids prior to treatment. Although potency rates declined following treatment: 100% (baseline); 68% (6 months); 62% (12 months); 57% (18 months) and 54.4% (24 months), 78% of previously potent patients had erections sufficient for sexual activity at 24 months post-treatment. Overall sexual aid utilization increased from 36% at baseline to 49% at 24 months. Average EPIC sexual scores showed a slow decline over the first two years following treatment: 77.6 (baseline); 68.7 (6 months); 63.2 (12 months); 61.9 (18 months); 59.3 (24 months). All sexual functions including orgasm declined with time. Prior to treatment, 13.4% of men felt their sexual function was a moderate to big problem which increased to 26.7% two years post treatment. Post-treatment testosterone levels gradually decreased with a median value at two year follow-up of 10.7 nmol/L. However, the average EPIC hormonal scores did not illustrate a statistically significant difference two years post-treatment. Review of the radiation doses to the penile bulb in this study, a potential marker of post-treatment sexual function, revealed that the dose was ...

Stereotactic body radiation therapy for low and intermediate risk prostate cancer—Results from a multi-institutional clinical trial

“…A systematic review of RP techniques reported potency rates of 11-40% for open, 13-56% for unilateral and 31-84% for bilateral nerve sparing RP [39]. The 25.6% ED rate in this study is encouraging even when compared to other SBRT studies [17,40]. The QOL analysis of this study was limited by low questionnaire compliance.…”

Dosimetric benefits of hemigland stereotactic body radiotherapy for prostate cancer: implications for focal therapy

“…39 In terms of the development of ED following SBRT, EPIC-26 sexual domain scores appear to decrease by 5.1 points at 3 months, but rather than normalizing, they continue to decrease, with an average decrease of 7.3 points at 3 years and 13.7 points at 6 years. 35 Another study 44 found that the baseline ED rate increased from 38% to 71% after treatment but noted that more than half of the 40,41,48 have confirmed these findings, noting a stable, long-term decline in EPIC sexual scores, and ED incidence rates that depend on baseline potency and age. Mean doses to both the penile bulb and the contralateral neurovascular bundles were significantly reduced with HG plans.…”

Robotic Stereotactic Body Radiotherapy (SBRT) for Low- and Intermediate Risk Localized Prostate Cancer. Feasibility, Outcome and Toxicity.

“…Two years post RT 77.8% had erections satisfactory for sexual activity. Sexual aid usage prior to SBRT was associated with increased probability of potency preservation in uni-and multivariate analysis 23 .…”