Abstract A116: Pre-diagnostic allostatic load is associated with mortality in adults diagnosed with incident colorectal cancer

Abstract Introduction: Colorectal cancer (CRC) outcomes may be improved by integrating a holistic blood-based biomarker for chronic stress into medical treatment. Allostatic load is an emerging clinical biomarker of the physiological consequences of chronic stress that has been linked to outcomes including all-cause, cardiovascular and cancer mortality. We present associations of pre-diagnostic allostatic load with mortality in a sample including Black and low-income patients with incident CRC. Notably, we establish consistency in the associations of allostatic load association with CRC outcomes using an existing allostatic load score and our new abbreviated score designed for implementation. Methods: We included 308 Southern Community Cohort Study (SCCS) participants diagnosed with incident CRC after enrollment; 73% identified as Black, 65% reported income <$15,000. At entry, participants completed questionnaires and provided blood samples analyzed for 10 immune, metabolic, and cardiovascular biomarkers included in the allostatic load score. Mortality data were obtained from the National Death Index through December 31, 2020. Allostatic load score is calculated as the sum of biomarkers above clinical risk cutoffs; counts above median indicate high allostatic load. With an established score (10 biomarkers), we present a new abbreviated score including a subset of 6 biomarkers chosen for wide availability in electronic medical records and associations with mortality among marginalized cancer patients. We estimated hazard ratios and 95% confidence intervals (HRs[95%CIs]) for multivariate associations of allostatic load with mortality using Cox proportional hazards models. A community advisory board and clinical partners informed hypotheses and conclusions. Results: High allostatic load based on the standard score was associated with higher risk of all-cause mortality among patients with incident CRCs (HR:1.45 [0.98-2.15]). This association strengthened when adjusting for CRC stage (HR:1.97 [1.27-3.05]). Associations were replicated when employing the abbreviated score (HR: 1.59 [1.06-2.38]). High allostatic load was associated with higher risk of CRC-specific mortality only among those with educational attainment less than high school (p-interaction=.04; HR:1.32 [0.96-1.82]). For those with an education of high school or more, allostatic load was not associated with CRC-specific mortality (HR: 0.90[0.69-1.17]). Effect modification by education remained apparent but not statistically significant when employing the abbreviated score (p-interaction=0.13). Conclusions: We demonstrate that pre-diagnostic allostatic load is associated with higher mortality among a sample of CRC survivors representing understudied patient populations. We highlight allostatic load as a likely driver of CRC-specific mortality disparities. This study supports the implementation of an allostatic load score as a clinically actionable biomarker of poor CRC prognosis. Citation Format: Zoe L. Walts, Nicci Owusu-Brackett, Amy Cochran, Amy Trentham-Dietz, Melissa Rosenkranz, Anne Ersig, Armen Byrd, Martha J. Shrubsole, Shaneda Warren Andersen. Pre-diagnostic allostatic load is associated with mortality in adults diagnosed with incident colorectal cancer [abstract]. In: Proceedings of the 18th AACR Conference on the Science of Cancer Health Disparities; 2025 Sep 18-21; Baltimore, MD. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2025;34(9 Suppl):Abstract nr A116.