Racial and Ethnic Inequality in Survival Outcomes of Women With Triple Negative Breast Cancer

Racial disparities in outcomes of patients with stage I-III triple-negative breast cancer after adjuvant chemotherapy: a post-hoc analysis of the E5103 randomized trial

PURPOSE

Breast cancer mortality is higher in Black women than other racial groups. This difference has been partially attributed to a higher proportion of triple-negative breast cancer (TNBC). However, it is uncertain if survival disparities exist in racially diverse TNBC patients receiving similar treatments. Here, we examine racial differences in disease-related outcomes in TNBC patients treated on the E5103 clinical trial.

METHODS

From 2007 to 2011, 4,994 patients with stage I-III HER2-negative breast cancer were randomized to adjuvant chemotherapy with or without bevacizumab. This analysis was limited to the subset of 1,742 TNBC patients with known self-reported race. Unadjusted Kaplan-Meier curves and adjusted Cox-Proportional Hazards models were used to determine breast cancer events and survival outcomes.

RESULTS

Of the analysis population, 51 (2.9%) were Asian, 269 (15.4%) Black, and 1422 (81.6%) White. Median age was 51 years. Patient characteristics, treatment arm, and local therapies were similar across racial groups. White women were more commonly node-negative (56% vs. 49% and 44% in Asian and Black women, respectively; p < 0.01). At a median follow-up of 46 months, unadjusted Kaplan-Meier locoregional and distant recurrence, and disease-free and overall survival, did not differ significantly by race. In Cox models adjusted for patient and tumor characteristics and treatment arm, race was not associated with any disease event. Larger tumor size and nodal involvement were consistently associated with breast cancer events.

CONCLUSION

This clinical trial population of similarly treated TNBC patients showed no racial differences in breast cancer outcomes. Disease extent, rather than race, was associated with disease events.

Disparities in Receipt of National Comprehensive Cancer Network Guideline-Adherent Care and Outcomes among Women with Triple-Negative Breast Cancer by Race/Ethnicity, Socioeconomic Status, and Insurance Type

BACKGROUND

The National Comprehensive Cancer Network guidelines were designed to improve patient outcomes. Here, we examine factors that may contribute to outcomes and guideline adherence in patients with triple-negative breast cancer.

METHODS

This was a retrospective cohort study of women with triple-negative breast cancer using the California Cancer Registry. Adherent treatment was defined as the receipt of a combination of surgery, lymph node assessment, adjuvant radiation, and/or chemotherapy. A multivariable logistic regression was used to determine the effects of independent variables on adherence to the NCCN guidelines. Disease-specific survival was calculated using Cox regression analysis.

RESULTS

A total of 16,858 women were analyzed. Black and Hispanic patients were less likely to receive guideline-adherent care (OR 0.82, 95%CI 0.73-0.92 and OR 0.87, 95%CI 0.79-0.95, respectively) compared to White patients. Hazard ratios adjusted for adherent care showed that Black patients had increased disease-specific mortality (HR 1.28, 95%CI 1.16-1.42, p < 0.0001) compared to White patients.

CONCLUSIONS

A significant majority of breast cancer patients in California continue to receive non-guideline-adherent care. Non-Hispanic Black patients and patients from lower SES quintile groups were less likely to receive guideline-adherent care. Patients with non-adherent care had worse disease-specific survival compared to recipients of NCCN guideline-adherent care.