(P144) Radiation-Associated Toxicities in Obese Women With Endometrial Cancer: More Than Just BMI?

Savita Dandapani, MD, PhD, Ying Zhang, MD, Richard Jennelle, MD, Yvonne Lin, MD; City of Hope; USC

PURPOSE: The current study characterizes the impact of obesity on postoperative radiation-associated toxicities in women with endometrial cancer (EC).

MATERIALS AND METHODS: A retrospective cohort 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, clinicopathologic, and patient-reported toxicity data were obtained from medical records. Anthropometric information, including body mass index (BMI), was collected from nursing intake records at each clinic visit. Radiation-related toxicities were graded according to Radiation Therapy Oncology Group (RTOG) Acute Radiation Morbidity Scoring Criteria. The follow-up period ranged from 1 month to 11 years (median 2 yr). The data were analyzed by chi-square, logistic regression, and recursive partitioning analyses.

RESULTS: A total of 68 evaluable EC patients who received WPRT and/or ICBT were included in the primary analysis. The median age was 52 years (range: 29–73 yr). The majority of patients were Hispanic (48, 71%), with 6 (9%) Caucasian, 1 (1%) African-American, and 13 (19%) Asian. The median BMI at diagnosis was 34.5 kg/m² (range: 20.5–56.6 kg/m²). A total of 58 patients (85%) had abdominal hysterectomies, and 10 (15%) had laparoscopic hysterectomies; 43(63%) had a pelvic lymphadenectomy, and 15 (22%) had para-aortic lymphadenectomies. BMI was independently associated with reported radiation-related cutaneous toxicities (P = .022) and gynecologic toxicities (P = .027). Younger women also reported more gynecologic toxicities (P = .039). Adjuvant radiation technique was associated with increased gastrointestinal- and genitourinary-related toxicities but not gynecologic toxicity. There was no association of International Federation of Gynecology and Obstetrics (FIGO) stage, use of adjuvant chemotherapy, or hysterectomy type with reported radiation toxicities.

CONCLUSIONS: The impact of obesity on adjuvant treatment is poorly understood. 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.

Proceedings of the 97th Annual Meeting of the American Radium Society - americanradiumsociety.org