Black Women With Metastatic TNBC Have Lower Median Survival

The study covered in this summary was published as a preprint and has not yet been peer reviewed.

Key Takeaways

• This study focused on differences in outcomes based on race among women with metastatic triple-negative breast cancer (TNBC). Survival and treatment patterns among Black women with metastatic TNBC were compared to those of women of other races.

• A difference in mortality was observed with respect to race among patients with TNBC. Median survival was lower among Black women with metastatic TNBC than among White women (P < .01).

• Differences in treatment also varied by race. Black women underwent radiotherapy less frequently than White women (P < .01).

Why This Matters

• While other studies have established that Black women are more likely to have TNBC, subgroup analyses of TNBC racial group survival and associated treatments received by race have not been undertaken.

• Breast, lung, and colorectal cancers are the three most frequent cancers among women, accounting for more than half of all new cancer diagnoses by 2020.

• More Black women than White women were diagnosed at ages younger than 45. The breast cancer mortality rate was also higher among Black women with breast cancer, and more Black women presented with high-risk characteristics, such as cancer of aggressive histopathology, greater tumor size at appearance, more nodal involvement, and negative estrogen receptor status.

Study Design

• This retrospective study included patients in the Surveillance, Epidemiology, and End Results (SEER) program who had metastatic TNBC from 2012–2016.

• Participants were divided into five categories on the basis of race/ethnicity: non-Hispanic White, non-Hispanic Black, non-Hispanic Asian or Pacific Islander, non-Hispanic American Indian/Alaska Native, and Hispanic.

• Sociodemographic factors were considered. The study defined neighborhood socioeconomic status (nSES) using the Yost index, which involves measures of income, education, housing, and employment.

• Receipt of therapies, including surgery, radiotherapy, and chemotherapy, was analyzed with respect to race.

Key Results

• A total of 1420 women who presented with metastatic TNBC were included in the study. Of these women, 70.1% were White, and 29.9% were Black.

• The average age at diagnosis was 62.5 years for both groups, but White women were significantly older than Black women at diagnosis (63.7 years vs 59.5 years; P < .001).

• The percentage of patients with low nSES was higher among Black women than White women (62.3% vs 29.3%; P = .001).

• Median survival was lower for Black women compared to White women (13 months vs 15 months; P = .01).

• Fewer Black women underwent radiotherapy compared to White women (27.1% vs 32.6%; P = .04).

• Undergoing surgery and chemotherapy reduced the risk of mortality (P < .01).

• All women were less likely to undergo treatment if unmarried (P < .01).

Limitations

• Retrospective SEER data were used for individual variables such as race, and census data were used for nSES. The nSES was assessed at one point in time and did not reflect potential changes in residence. Furthermore, nSES may not reflect individual SES accurately.

• For patients who received either radiotherapy or chemotherapy, patients who received treatment appropriately could not be distinguished from patients who received inappropriate treatment.

• Biases as to whether treatment was offered and refused, including patient and provider treatment preferences, were not assessed.

• Categories for distant disease were not consistent in variables used by the SEER program across the study period, so the definition of metastatic changes was heterogeneous.

Disclosures

• The study received no commercial funding.

• The authors have disclosed no relevant financial relationships.

This is a summary of a preprint research study, “Are There Differences in Outcomes by Race Among Women With Metastatic Triple Negative Breast Cancer,” published July 1 on ResearchSquare.com and led by Oindrila Bhattacharyya of Indiana University Purdue University at Indianapolis. This study has not yet been peer reviewed. The full text of the study can be found on ResearchSquare.com.

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