|The following article features coverage from the 2021 AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved. Click here to read more of Cancer Therapy Advisor’s conference coverage.|
Allostatic load may impact chemotherapy completion and survival outcomes in patients with breast cancer, according to a study presented at the 2021 AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved.
“Allostatic load describes cumulative, multisystem physiologic dysregulation secondary to repeated or chronic environmental challenges,” explained Samilia Obeng-Gyasi, MD, of The Ohio State University in Columbus, who presented the study at the conference.
Dr Obeng-Gyasi noted that elevated allostatic load and African ancestry have both been implicated in poor outcomes of breast cancer. She and her colleagues set out to evaluate the potential impact of genetic ancestry and allostatic load on trial completion and overall mortality among patients in the phase 3 ECOG-ACRIN E5103 trial (ClinicalTrials.gov Identifier: NCT00433511).
The trial was designed to evaluate the efficacy of doxorubicin hydrochloride, cyclophosphamide, and paclitaxel, with or without bevacizumab, in patients with lymph node-positive or high-risk lymph node-negative, HER2-negative breast cancer.
The cohort included 348 patients, 80% of them with European ancestry, 10% with African ancestry, and 10% with other ancestries. Genetic ancestries were determined using genome-wide single nucleotide polymorphisms.
Allostatic load was measured at trial entry using several biomarkers, including body mass index, systolic and diastolic blood pressure, creatinine, interleukin 6 and 10, and tumor necrosis factor-alpha. To calculate allostatic load, patients were assigned a point if their biomarker value was above the 75th percentile of the study sample.
Overall, the median allostatic load score was 2 (interquartile range, 0-6). The mean allostatic load score at study entry was higher for patients of African ancestry (2.1) and European ancestry (1.88) than for patients of other ancestries (0.91).
On adjusted analysis, a 1-unit increase in allostatic load was associated with a 15% reduction in the odds of completing chemotherapy per protocol (odds ratio, 0.85; 95% CI, 0.72-0.99) and a 14% increase in the risk of death (hazard ratio, 1.14; 95% CI, 1.02-1.29).
On the other hand, there was no association between genetic ancestry and chemotherapy completion or mortality. There was also no interaction between allostatic load and genetic ancestry.
“Our study results suggest that, among patients enrolled in the ECOG-ACRIN clinical trial E5103, allostatic load appeared to be a better predictor of chemotherapy completion and overall survival than genetic ancestry,” Dr Obeng-Gyasi said.
“These results suggest life course exposure to chronic stress has implications on clinical outcomes, even within the context of equivalent access to and quality of care,” she added.
Obeng-Gyasi S, ONeill A, Miller K, et al. The implications of genetic ancestry and allostatic load on clinical outcomes in the ECOG-ACRIN adjuvant breast cancer trial E5103. Presented at: AACR 2021 Virtual Cancer Health Disparities; October 6-8, 2021. Abstract PO-219.