Abstract
Abstract Elevated levels of the inflammatory biomarker C-reactive protein (CRP) has been associated with multiple medical conditions and worse breast cancer survival. However, most prior studies have examined the effect of individual medical conditions and CRP on all-cause mortality. Therefore, this study examined the combined effects of multiple medical conditions and high-sensitivity CRP (hsCRP) before and after radiotherapy (RT) on overall survival in a tri-racial/ethnic breast cancer patient population (n=506). Blood samples were collected on the first (pre-RT) and last day of RT (post-RT), and patients were followed for up to 10 years through regular review of electronic medical records. Overall survival was calculated from the date of diagnosis to the date of death or last follow-up. hsCRP level was dichotomized at the cut-off values of 10 or 9 mg/L. Univariable and multivariable Cox proportional hazards regression models were used to evaluate the associations between overall survival and patient/clinical characteristics, multiple medical conditions, and hsCRP. The study population was comprised of 319 Hispanic whites (63%), 104 black/African Americans (21%), 67 non-Hispanic whites (13%), and 16 others (3%). In the univariable analyses, the hazard for death was significantly higher in patients with tumor stage III-IV (hazard ratio [HR]: 6.25; 95%CI: 2.92-13.38; p<0.001), triple-negative breast cancer (HR: 2.22; 95%CI: 1.07-4.60; p=0.033), 3+ medical conditions (HR: 3.41; 95%CI: 1.04-11.15; p=0.043), ≥10 mg/L pre-RT hsCRP (HR: 2.54; 95%CI: 1.22-5.29; p=0.013), and ≥10 mg/L post-RT hsCRP (HR: 3.92; 95%CI: 1.91-8.03; p<0.001). In the multivariable model, tumor stage III-IV (HR: 7.44; 95%CI: 2.88-19.24; p<0.001) and ≥10 mg/L post-RT hsCRP (HR: 2.46; 95%CI: 1.03-5.89; p=0.043) remained significant. The addition of pre- and post-RT CRP (10 mg/L as the cut-off value) to a patient/clinical characteristic model increased the AUC/C-statistic for 5-year survival from 0.826 to 0.872, which further increased to 0.897 when 9 mg/L was used as the cut-off value for hsCRP. In summary, our current results validate previous reports on the association between hsCRP and overall survival in breast cancer patients in addition to its association with RT-related skin toxicities and pain. Although RT reduces local recurrence rates and improves survival compared to breast-conserving surgery alone, there has been active debate regarding the risk/benefit ratio of RT in some breast cancer patients. We demonstrate that hsCRP at post-RT is significantly associated with worse overall survival, and these results may help in the assessment of breast cancer prognosis and provide guidance in the clinical decision-making process. Citation Format: George R. Yang, Cristiane Takita, Jean L. Wright, Eunkyung Lee, Isildinha M. Reis, Omar L. Nelson, Laura G. Acosta, Jennifer J. Hu. Inflammatory biomarker C-reactive protein in predicting overall survival in breast cancer patients who underwent radiotherapy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5786.
