Introduction: Soluble tumor necrosis factor receptor-II (sTNF-R2), a circulating pro-inflammatory biomarker, has been found to associated with obesity and increased risk of breast cancer. No studies to date have examined the association between sTNF-R2 and risk of mortality among Hispanic breast cancer survivors, an at-risk population due to their high prevalence of obesity and poor prognosis. The current study examined the long-term effects of sTNF-R2 on risk of mortality among Hispanic and non-Hispanic white (NHW) breast cancer survivors from the New Mexico Health Eating Activity and Lifestyle Study. Methods: A total of 397 invasive breast cancer survivors (96 Hispanic, 301 NHW) contributed data for the present study. Women with breast cancer diagnosed between July 1996 and March 1999 were ascertained through the National Cancer Institute's Surveillance Epidemiology and End Results registry in New Mexico. Baseline demographic characteristics, anthropometric measures, and blood samples were collected approximately 5 months post diagnosis by trained interviewers. Plasma levels of sTNF-R2 were assayed and measures were log-transformed to conform to normality. The main predictor of low (referent) vs high sTNF-R2 levels was based on the median value. Adjusted hazard ratios (HR) and 95% confidence intervals (CI) for the associations between sTNF-R2 and all-cause mortality were calculated using Cox proportional hazards regression models overall and by ethnicity. Models were adjusted for age at diagnosis, education, breast cancer stage, treatment, and body mass index (BMI). Results: A total of 133 deaths (53 breast cancer-specific deaths) were observed after a median follow-up time of 13 years. While Hispanic women had higher baseline BMI (mean= 27.21, standard deviation (SD)= 5.83) compared to NHW women (mean= 25.68, SD= 5.36) (p< 0.001), significant differences by ethnicity for sTNF-R2 levels were not observed. In models adjusted for ethnicity and other covariates, the association between high vs low levels of plasma sTNF-R2 and risk of mortality was not statistically significant among all women (HR, 1.36; 95% CI 0.90-2.03). However, in models stratified by ethnicity, Hispanic women had increased risk of mortality of almost 3-fold (HR, 2.83; 95% CI 1.21-6.63), while the association among NHW women was attenuated and was not statistically significant (HR, 0.99; 95% CI 0.61-1.61). The statistical interaction between sTNF-R2 and ethnicity with risk of mortality was not statistically significant (p= 0.10). Conclusion: Our study results suggest Hispanic breast cancer survivors with high levels of systemic inflammation measured by sTNF-R2 are at increased risk of mortality. These results could inform targeted intervention studies to decrease inflammation and reduce risk of mortality among this at-risk population.

Citation Format: Avonne E. Connor, Stephanie D. Boone, Kathy B. Baumgartner, Richard N. Baumgartner. Systemic inflammation is associated with increased risk of mortality after invasive breast cancer among Hispanic women from New Mexico [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB081.