An age-corrected matched-pair study of erectile function in patients treated with dose-escalated adaptive image-guided intensity-modulated radiation therapy vs. high-dose-rate brachytherapy for prostate cancer.

Purpose: To compare erectile dysfunction (ED) after adaptive dose-escalated image-guided intensity-modulated radiotherapy (IG-IMRT) and high-dose-rate interstitial brachytherapy (HDR) monotherapy.

Methods And Materials: Low- and intermediate-risk prostate cancer patients treated with IG-IMRT or HDR were matched on pretreatment ED, age, Gleason score, T-stage, and prostate specific antigen. Patients who received androgen deprivation therapy were excluded. ED was graded by Common Terminology Criteria for Adverse Events v4. Actuarial rates of ED were computed by the Kaplan-Meier method.

Results: There were 384 patients with median followup of 2.0 years (0.5-6.1) for IG-IMRT and 2.0 years (0.5-8.7) for HDR. The median IG-IMRT dose was 75.6 Gy and HDR dose 38 Gy in four fractions. For patients with no pretreatment ED, actuarial rates of requiring intervention (Grade ≥2 ED) at 3 years were 31% for IG-IMRT and 19% for HDR (p=0.23), and impotence despite medical intervention (Grade 3) were 0% for IG-IMRT and 6% for HDR (p=0.06). For patients with Grade 1 pretreatment ED, Grade ≥2 ED at 3 years were 47% for IG-IMRT and 34% for HDR (p=0.79), and Grade 3 ED were 15% in both groups (p=0.59). For patients with Grade 2 pretreatment ED, Grade 3 ED at 3 years were 22% for IG-IMRT and 37% for HDR (p=0.70). No variables were predictive of Grade ≥2 ED following treatment.

Conclusions: Rates of ED requiring medical intervention for both IG-IMRT and HDR are low and equivalent. Even patients with ED before treatment are likely to maintain potency with medication use at 3 years following treatment.