Long-Term Gastrointestinal Toxicity After Surgery And Radiation In Prostate Cancer

Purpose/Objective(s)Adjuvant or salvage radiation therapy (RT) represents a common treatment option among men with prostate cancer after prostatectomy. RT alone carries a risk of long-term gastrointestinal (GI) toxicity, though the risks of GI toxicity with radiation after prostatectomy remain unclear. The purpose of this population-based study was to compare rates of GI toxicity in men with localized prostate cancer treated with either radical prostatectomy, RT, or both.Materials/MethodsUsing the Surveillance, Epidemiology and End Results (SEER)-Medicare linked database we identified men who were diagnosed with localized prostate cancer and actively treated between the years 2004 and 2009. This study population was divided into 3 cohorts based on prostate cancer treatment(s): surgery only, radiation only, and surgery followed by radiation. The treatments and GI toxicities were identified from Medicare claims data. The GI toxicity outcomes examined included rectal bleeding, radiation enteritis, fistula, colectomy, and colostomy. The association between prostate cancer treatment and GI toxicity was determined using cumulative incidence analyses and multivariable Fine-Gray regressions to control for potential confounding factors.ResultsWe identified 34,895 men with localized prostate cancer of which 20,738 (59.4%) were treated with radiation only, 12,554 (36.0%) were treated with surgery only, and 1,603 (4.6%) were treated with surgery followed by radiation. Within the study population, the most common GI toxicities were bleeding (n=5,017) and radiation enteritis (n=1,070). The 5-year cumulative incidence of any GI toxicity for the surgery cohort, radiation cohort, and surgery and radiation cohort was 12.8%, 29.4%, and 23.9%, respectively (P