Subclinical inflammation as a predictor for erectile dysfunction after brachytherapy for localized prostate cancer.

PURPOSE: Neutrophil-to-lymphocyte ratio (NLR), a marker for subclinical inflammation, has been previously shown to be associated with erectile dysfunction (ED). We studied the potential predictive value of the NLR on ED after prostate brachytherapy (PB) for PCa. METHODS AND MATERIALS: Between July 2005 and January 2021, 842 patients were included in this retrospective study of a prospectively maintained database. ED was assessed using the Common Terminology Criteria for Adverse Events (CTCAE) physician-reported scale. ED was defined as a Grade 2 or 3 function. NLR count was determined 1-2 months before PB and separated into values PB <2 and ≥2. Patient characteristics and erectile function at last follow-up were compared for patients with a Univariate and multivariate analyses were performed to evaluate the predictive value of baseline NLR ≥2 on post-PB ED. RESULTS: Baseline NLR ≥2 was found to be a statistically significant predictor of post-PB ED on both univariate (p = 0.002) and multivariate analyses (p = 0.008). Furthermore, the difference in ED prevalence between the NLR <2 and NLR ≥2 groups became more pronounced with longer follow-up after PB. The ED rate at 5 years post-PB was 43% for the NLR ≥2 groups, compared to 29% for the NLR <2 groups. CONCLUSIONS: Subclinical systemic inflammation is a potentially important factor for predicting sexual toxicity after pelvic radiotherapy. NLR may be used as a proxy for predicting post-PB ED.