Allostatic Load As a Predictor of Recurrence in Patients with estrogen receptor positive Breast Cancer: A Case-Control study

Background: Allostatic load (AL), a biomarker of chronic stress, has been linked to an increased breast cancer risk, aggressive tumor characteristics, and worse survival among breast cancer patients. However, its role in breast cancer recurrence is unknown. Materials and Methods: In this nested case-control study, we analyzed the association between AL and breast cancer recurrence among patients who were diagnosed with ER+, HER2-, and stage I to III breast cancer and completed definitive surgery with adjuvant radiation and hormone therapy as the standard of care. The study population included 49 patients who had relapsed after the treatment and 147 patients who had no relapse within three years after cancer treatment. Results: In the analysis, we found that per one unit increase of AL was associated with a 17% increase in breast cancer recurrence (Odds ratio (OR)=1.17, 95% confidence interval (CI): 1.01, 3.62) after the adjustment of sociodemographic, healthy behavioral, and clinical factors. A significant association was further confirmed in the categorical analysis. Compared to those in the low AL group (AL≤2), those in the higher AL group (AL>2) had a 1.62-fold increased risk of breast cancer recurrence (OR=1.62, 95%CI: 1.02, 5.36). Conclusion: In brief, the results from this study have presented evidence to support the role of AL in breast cancer recurrence. More research is needed to further confirm the association.