Objectives. To measure the effect of treatment choice (pelvic irradiation [XRT] versus radical prostatectomy [RP] with or without nerve sparing) on sexual function and sexual bother during the first 2 years after treatment.

Methods. We studied sexual function and sexual bother in 438 men recently diagnosed with early-stage prostate cancer and treated with XRT or RP with or without nerve sparing. Outcomes were assessed with the University of California, Los Angeles Prostate Cancer Index, a validated health-related quality-of-life instrument that includes these two domains. To minimize the influence of other factors, we adjusted for age, comorbidity, general health, and previous treatment for erectile dysfunction. All subjects were drawn from CaPSURE, a national, longitudinal data base.

Results. Sexual function improved over time during the first year in all treatment groups; however, during the second year, sexual function began to decline in the XRT group. Older patients who received XRT showed substantial declines in sexual function throughout the 2 years, and older patients who underwent RP experienced a return of very low baseline sexual function. Sexual function was improved by the use of nerve-sparing procedures or erectile aids. Alterations in sexual bother were ameliorated by many factors, including age, general health perceptions, and sexual function.

Conclusions. Patients undergoing XRT or RP with or without nerve sparing all showed comparable rates of improvement in sexual function during the first year after treatment for early-stage prostate cancer. However, in the second year after treatment, patients treated with XRT began to show declining sexual function; patients treated with RP did not.