['Brachytherapy is increasingly used as a treatment for localized prostate cancer but information regarding long-term, postimplantation, patient-reported sexual health-related quality-of-life (HRQOL) is scant. Neoadjuvant hormonal therapy is commonly administered with brachytherapy, yet its potentially adverse effects on subsequent sexual health have not been described using a validated HRQOL instrument. We used a validated HRQOL survey to characterize the significance of neoadjuvant hormonal therapy and other baseline factors on postimplantation sexual function and impairment.', 'A cross-sectional survey using the expanded prostate cancer index composite HRQOL instrument was administered to all 114 localized prostate cancer patients who underwent ultrasound-guided, transperineal brachytherapy during a 4-year period and to 142 age-matched control men. Multivariable models measured the association of baseline factors and covariates with postimplantation sexual HRQOL.', 'Older age (P = 0.01) and neoadjuvant hormonal therapy (P = 0.009) were independently associated with diminished sexual HRQOL after prostate brachytherapy. Among patients younger than 69 years old, 33% reported at least fair sexual function after brachytherapy alone compared with 19% of men after brachytherapy with neoadjuvant hormonal therapy. Of the age-matched control men younger than 69 years old, 78% reported at least fair sexual function. Among patients older than 69 years, 26% reported at least fair sexual function after brachytherapy alone compared with 5% after brachytherapy with neoadjuvant hormonal therapy, and 61% of age-matched controls reported at least fair sexual function.'] Are neoadjuvant hormonal therapy and older age associated with adverse sexual health-related quality-of-life outcome after prostate brachytherapy?