Abstract 1615: C-Reactive protein and radiotherapy-induced skin toxicity in breast cancer

Abstract

Abstract Background: Post-surgery adjuvant radiotherapy (RT) for breast cancer significantly reduced the local recurrence rate. However, many patients develop early adverse skin reactions (EASRs) that impact quality of life. Methods: In a large prospective study of 1,000 breast cancer patients undergoing RT, we evaluated an inflammatory biomarker, C-reactive protein (CRP) in predicting RT-induced EASRs. In each patient, we measured pre- and post-RT plasma CRP levels using a highly-sensitive ELISA CRP assay. RT-induced EASRs were assessed using the Oncology Nursing Society Skin Toxicity Criteria. Association between EASRs and CRP were assessed using logistic regression models after adjusting for potential confounders. Results: The study population includes 405 non-Hispanic White, 280 African Americans, 218 Hispanic Whites, 52 Asians, and 45 others. RT-induced grade 3+ and 4+ skin toxicity at the end of RT were observed in 42% and 15% patients, respectively. CRP levels differ significantly by race/ethnicity at baseline and at the end of RT. RT-induced grade 4+ skin toxicity was significantly associated with: obesity and pre-RT CRP > 2mg/L (OR=3.27; 95%CI=1.88, 5.68), obesity and post-RT CRP > 2mg/L (OR=4.42; 95%CI=2.38, 8.23), or obesity and change of CRP > 1mg/L (OR=3.58; 95%CI=2.00, 6.39). Conclusion: The current data validate our previous findings that the inflammatory biomarker CRP is associated with RT-induced EASRs, particularly combined with obesity. Impact: Our current findings support the discovery and development of anti-inflammatory agents to protect normal tissue from RT-induced EASRs and improve quality of life in breast cancer patients undergoing RT. Citation Format: Jennifer J. Hu, Doug Case, Mark O. Lively, Eunkyung Lee, Cristiane Takita, James J. Urbanic, Glenn J. Lesser, Edward G. Shaw. C-Reactive protein and radiotherapy-induced skin toxicity in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1615. doi:10.1158/1538-7445.AM2017-1615