Worse Survival Among Black or Hispanic Patients in Early Breast Cancer Trials

Breast Cancer Cells: © LASZLO- stock.adobe.com

In the United States, higher mortality rates are observed in Black women with breast cancer compared with White women due to racial and ethnic survival disparities, according to findings published in the JAMA Network.¹

To evaluate the correlation between race and ethnicity with survival, patients with early-stage breast cancer were enrolled in a cohort study and looked at based on their tumor subtype, age, and body mass index (BMI).

Findings from this cohort study show that racial and ethnic survival disparities exist among patients with early breast cancer who are being treated with standardized initial care. Potentially at-risk subgroups, including non-Hispanic Black patients with BMIs of 25 to less than 30, hormone receptor-positive (HR+)/ERBB2 (HER2)-negative (ERBB2–) tumors, and those aged <50 years were identified.

“In this cohort study of clinical trial participants treated for [early breast cancer], we observed worse survival among Black or Hispanic participants within subgroups defined by age, BMI, or tumor subtype. These data suggest that, in addition to addressing the social and structural factors that contribute to racial and ethnic disparities overall, it may be necessary to identify and address subgroup-specific mechanisms underlying the observed associations,” wrote the study authors.

Survival data from these patients were analyzed as of November 12, 2021, from 9479 patients enrolled across 4 chemotherapy trials between 1997 and 2010. These trials included Cancer and Leukemia Group B (CALGB) C9741 (NCT00003088), C49907 (NCT00005970), C40101 (NCT00024102) and North Central Cancer Treatment Group (NCCTG) N9831 (NCT00041119).

According to the pooled survival data, survival differences were observed even within clinical trial patients who were treated with similar initial care. Subgroups defined by tumor subtype, age, and/or BMI were noted and identified if they may drive racial and ethnic disparities in survival.

Investigators compared non-Hispanic Black patients and Hispanic patients with non-Hispanic White patients within subgroups of subtype, age and BMI. Subtypes included HR+/ERBB2–, ERBB2+, and HR–/ERBB2–, age consisted of <50, 50 to <65, and ≥65 years, and BMI was split between <18.5, 18.5 to <25.0, 25.0 to <30.0, and ≥30.0.

Among the 9479 patients included in the study, the median age was 52 (range, 19.0-89.7) years, 436 (4.4%) were Hispanic, 871 (8.8%) were non-Hispanic Black, and 7889 (79.5%) were non-Hispanic White. The median follow-up was 9.8 years (range, 6.7-13.2). A total of 435 participants (4.6%) were designated as lost to follow-up, and all patients were female.

Non-Hispanic Black patients with HR+/ERBB2– tumors had a worse 5-year recurrence-free survival (RFS) rate at 88.5% compared with non-Hispanic White patients at 93.2% (HR, 1.49; 95% CI, 1.04-2.12). However, the global test for association of race and ethnicity with RFS was not significant within any tumor subtype.

No differences in overall survival (OS) by race and ethnicity were observed across any subtype, but race and ethnicity were associated with OS in patients aged <50 years (global P = .008). Compared with young non-Hispanic White patients, young non-Hispanic Black patients had a worse OS at 5 years (HR, 1.34; 95% CI, 1.04-1.71; 5-year OS, 86.6% vs 92.0%), as well as young non-Hispanic White patient’s vs Hispanic patients (HR, 1.62; 95% CI, 1.16-2.29; 5-year OS, 86.2% vs 92.0%).

For BMI, race and ethnicity were associated with RFS in patients with BMIs of 25 to less than 30. Non-Hispanic Black patients had worse 5-year RFS rates at 83.2% vs non-Hispanic White patients at 87.3% (HR, 1.81; 95% CI, 1.23-2.68).

Further research is warranted to evaluate interventions and improve survival among these patients.

“It is critical to evaluate specific contributors to racial and ethnic disparities in survival as these may inform future interventions to improve these disparities,” concluded the study authors.

REFERENCE:

1. Lipsyc-Sharf M, Ballman KV, Campbell JD, et al. Age, body mass Index, tumor subtype, and racial and ethnic disparities in breast cancer survival. JAMA Netw Open. 2023;6(10):e2339584. Published 2023 Oct 2. doi:10.1001/jamanetworkopen.2023.39584