Radiation-Associated Toxicities in Obese Women with Endometrial Cancer: More Than Just BMI?

PURPOSE: The study characterizes the impact of obesity on postoperative radiation-associated toxicities in women with endometrial cancer (EC). MATERIAL AND METHODS: A retrospective study identified 96 women with EC referred to a large urban institution's radiation oncology practice for postoperative whole pelvic radiotherapy (WPRT) and/or intracavitary vaginal brachytherapy (ICBT). Demographic and clinicopathologic data were obtained. Toxicities were graded according to RTOG Acute Radiation Morbidity Scoring Criteria. Follow-up period ranged from 1 month to 11 years (median 2 years). Data were analyzed by χ(2), logistic regression, and recursive partitioning analyses. RESULTS: 68 EC patients who received WPRT and/or ICBT were analyzed. Median age was 52 years (29-73). The majority were Hispanic (71%). Median BMI at diagnosis was 34.5 kg/m(2) (20.5-56.6 kg/m(2)). BMI was independently associated with radiation-related cutaneous (p = 0.022) and gynecologic-related (p = 0.027) toxicities. Younger women also reported more gynecologic-related toxicities (p = 0.039). Adjuvant radiation technique was associated with increased gastrointestinal- and genitourinary-related toxicities but not gynecologic-related toxicity. CONCLUSIONS: Increasing BMI was associated with increased frequency of gynecologic and cutaneous radiation-associated toxicities. Additional studies to critically evaluate the radiation treatment dosing and treatment fields in obese EC patients are warranted to identify strategies to mitigate the radiation-associated toxicities in these women.