Influence of vascular comorbities and race on erectile dysfunction after prostate cancer radiotherapy.

Abstract

29 Background: Vascular comorbidities (VC’s) [hypertension (HTN), diabetes (DM) and/or hyperlipidemia (HL)] are known factors related to erectile dysfunction (ED) prior to radiotherapy (XRT). We have undertaken this study to understand the influence of VC’s on post-XRT ED incidence, and to further characterize ED incidence by racial groups. Methods: We reviewed the charts of 732 prostate cancer patients [267 white (W) and 465 African American (AA)] who received XRT [external beam radiotherapy (EBRT) and/or brachytherapy (BT)] with or without use of hormone therapy between 1999 and 2010. The number of pre-XRT VC’s (0, 1, 2, or 3) was determined by medical history and medication list. ED (defined by use of erectile aids or by documentation of moderate or high sexual dysfunction on patient history) was determined pre-XRT as well as 1, 6, and 12 months post-XRT and compared by follow-up interval since XRT, by number of VC’s, and by race in each case using the two sample proportion test. Results: ED incidence progressively increased with time from 22% pre-XRT to 52% 12 months post-XRT (p<0.001). Additionally, ED incidence increased with increasing of number of VC’s – 12-month incidences between patients with 0 vs 2 (p=0.024), 0 vs 3 (p<0.001), 1 vs 3 (p<0.001), and 2 vs 3 (p=0.004) VC’s were statistically significant (0 vs 1 and 1 vs 2 were non-significant). Pre-XRT ED incidence was 20% vs 23% (for W vs AA patients, p=0.156) due to higher incidence of VC’s in the AA group. At 12 month follow-up, ED incidences for W vs AA patients were 38% vs 45%, 46% vs 49%, 52% vs 57%, and 71% vs 75% with 0, 1, 2 and 3 co-morbidities, respectively (all p-values non-significant). Conclusions: Our analysis represents the first effort exploring post-XRT ED as determined by the number VC’s and by race. Our results suggest that number of VC’s have a significant effect on development of post-XRT ED. Pre- and post-XRT ED appear to be independent of race when number of VC’s are considered. Our results can be used to guide physicians in counseling patients on the incidence of ED by number of VC’s and as preliminary data for prospective efforts aimed at reducing post-XRT ED.