Long-Term (10-Year) Gastrointestinal and Genitourinary Toxicity after Treatment with External Beam Radiotherapy, Radical Prostatectomy, or Brachytherapy for Prostate Cancer

Objective.To examine gastrointestinal (GI) and genitourinary (GU) toxicity profiles of patients treated in 1999 with external beam radiotherapy (RT), prostate interstitial brachytherapy (PI) or radical prostatectomy (RP). Methods. TThe records of 525 patients treated in 1999 were reviewed to evaluate toxicity. Late GI and GU morbidities were graded according to the RTOG late morbidity criteria. Other factors examined were patient age, BMI, smoking history, and medical co-morbidities. Due to the low event rate for late GU and GI toxicities, a competing risk regression (CRR) analysis was done with death as the competing event. Results. Median follow-up time was 8.5 years. On CRR univariate analysis, only the presence of DM was significantly associated with GU toxicity grade >2 ( , HR 2.35, Cl = 1.03–5.39). On univariate analysis, RT and DM were significantly associated with late GI toxicity. On multivariable analysis, both variables remained significant (RT: , , –20.3; DM: , , Cl = 1.42–10.2). Conclusions. Late effects occur with all treatment modalities. The presence of DM at the time of treatment was significantly associated with worse late GI and GU toxicity. RT was significantly associated with worse late GI toxicity compared to PI and RP. 1. Introduction For patients with localized prostate cancer, treatment options include active surveillance, radical prostatectomy (RP), external beam radiation therapy (RT), or low-dose-rate prostate interstitial brachytherapy (PI). There is data showing that in low-risk disease, excellent prostate-specific antigen (PSA) relapse-free survival outcomes are obtained with a low risk of significant treatment-related morbidity [1–4]. Low-risk patients do well with any of the three treatment modalities but there is no data comparing late toxicity. Due to lack of randomized data comparing these modalities, treatment decisions are often made by patient or physician preference based on the side effect profiles exhibited by each treatment type. While all modalities have generally similar toxicity profiles, there are slight differences between each that can impact long-term quality of life [5]. There are reports comparing the late toxicity rates between different types of radiation treatment options with noted improvement in morbidity with newer treatment techniques such as intensity-modulated radiation therapy (IMRT) [6]. However, there have been few reports comparing potential long-term toxicity profiles of patients treated with radiation treatment modalities to those who have undergone surgical resection. In the present