100 Long Term Impact of LDR Brachytherapy for Prostate Cancer on Erectile Function: Single Centre Tertiary Referral Outcomes with 8-Year Follow Up. (1st May 2022) - Katelaris, A
ABSTRACT: Introduction: Low dose rate (LDR) brachytherapy is an established treatment for localised low and intermediate risk prostate cancer, whereby multiple radioactive seeds are permanently implanted into the prostate. Brachytherapy is considered to be a less invasive option with a more favourable side effect profile compared to radical prostatectomy. Erectile dysfunction (ED) is still common after brachytherapy further understanding of this relationship would enable enhanced patient counselling. Objective: To assess rate and severity of ED following LDR Brachytherapy monotherapy for low and intermediate risk prostate cancer in a tertiary referral centre. Methods: We conducted a retrospective observational cohort study of patients who underwent LDR Brachytherapy as monotherapy in our institution between 2002 -2019. We extracted and analysed data from a prospective database obtaining baseline demographic data and simplified International Index of Erectile Function (IIEF-5) scores at regular intervals during follow up. The proportion of patients in each IIEF-5 category: severe ED (<12), moderate ED (12-16), mild ED (17-21) and no ED (22-25) were recorded at baseline, at regular intervals for up to 8 years. The degree of ED was assessed by calculating the mean differences between baseline (n=1017) and values at various timepoints; 6 weeks (1-3 months, n=905), 6 months (3-9 months, n=884), 1 year (9-18months, n=838), 2 years (18-30 months, n=705), 3 years, (30-48 months, n=561), 5 years (48-72 months, n= 489) and 8 years (72-120 months, n=262). Results: A total of 1491 suitable patients were identified. Baseline IIEF scores were available for 1017 patients. The median age was 63 (40-84), with 98% of patients being between 50 and 80. The proportion of patients with severe ED doubles at 6 weeks, and remains similar throughout the duration of follow up, as can be seen in Figure 1 . The distribution of IIEF-5 scores overtime are seen in figure 2 . Compared to baseline, at 6 weeks the mean difference in IIEF score is -6.37 (p<0.001), which is also similar to the remainder of the follow up period, with a mean difference of -7.45 at 8 years (p<0.001). These results are seen in Table 1. Conclusion: Patients who underwent LDR brachytherapy experienced a mild, early decline in sexual function, which may be explained by the implantation procedure. Sexual function then remained relatively stable with no significant further late deterioration over the subsequent 5-10 years, aside from a slight decrease which would be expected with aging. The majority of patients with no dysfunction at baseline experienced at least mild early and long-term ED over time. We plan to build on this study by conducting multi-variate analysis for predictors of ED post brachytherapy.