Receipt of Guideline-Concordant Care Does Not Explain Breast Cancer Mortality Disparities by Race in Metropolitan Atlanta

Racial disparities in initiation of chemotherapy among breast cancer patients with discretionary treatment indication in the state of Georgia

PURPOSE

The majority of breast cancer patients are diagnosed with early-stage estrogen receptor (ER) positive disease. Despite effective treatments for these cancers, Black women have higher mortality than White women. We investigated demographic and clinical factors associated with receipt of chemotherapy among those with a discretionary indication who are at risk for overtreatment.

METHODS

Using Georgia Cancer Registry data, we identified females diagnosed with ER positive breast cancer who had a discretionary indication for chemotherapy (2010-2017). We used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) associating patient demographic and clinical characteristics with chemotherapy initiation overall, and comparing non-Hispanic Black (NHB) with non-Hispanic White (NHW) women within strata of patient factors.

RESULTS

We identified 11,993 ER positive breast cancer patients with a discretionary indication for chemotherapy. NHB patients were more likely to initiate chemotherapy compared with NHW women (OR = 1.41, 95% CI: 1.28, 1.56). Race differences in chemotherapy initiation were pronounced among those who did not receive Oncotype DX testing (OR = 1.47, 95% CI: 1.31, 1.65) and among those residing in high socioeconomic status neighborhoods (OR = 2.48, 95% CI: 1.70, 3.61). However, we observed equitable chemotherapy receipt among patients who received Oncotype DX testing (OR = 0.90, 95% CI: 0.71, 1.14), were diagnosed with grade 1 disease (OR = 1.00, 95% CI: 0.74, 1.37), and those resided in rural areas (OR = 1.01, 95% CI: 0.76, 1.36).

CONCLUSION

We observed racial disparities in the initiation of chemotherapy overall and by sociodemographic and clinical factors, and more equitable outcomes when clinical guidelines were followed.

A Public Health Emergency: Breast Cancer Among Black Communities in the United States

While Black people have a similar incidence of breast cancer compared to White people, they have a 40% increased death rate. Black people are more likely to be diagnosed with aggressive subtypes such as triple-negative breast cancer. However, despite biological factors, systemic racism and social determinants of health create delays in care and barriers to treatment. While genetic testing holds incredible promise for Black people, uptake remains low and results may be challenging to interpret. There is a need for more robust, multidisciplinary, and antiracist interventions to reverse breast cancer-related racial disparities.

Neighborhood factors and triple negative breast cancer: The role of cumulative exposure to area-level risk factors

BACKGROUND

Despite similar incidence rates among Black and White women, breast cancer mortality rates are 40% higher among Black women. More than half of the racial difference in breast cancer mortality can be attributed to triple negative breast cancer (TNBC), an aggressive subtype of invasive breast cancer that disproportionately affects Black women. Recent research has implicated neighborhood conditions in the etiology of TNBC. This study investigated the relationship between cumulative neighborhood-level exposures and TNBC risk.

METHODS

This single-institution retrospective study was conducted on a cohort of 3316 breast cancer cases from New Castle County, Delaware (from 2012 to 2020), an area of the country with elevated TNBC rates. Cases were stratified into TNBC and "Non-TNBC" diagnosis and geocoded by residential address. Neighborhood exposures included census tract-level measures of unhealthy alcohol use, metabolic dysfunction, breastfeeding, and environmental hazards. An overall cumulative risk score was calculated based on tract-level exposures.

RESULTS

Univariate analyses showed each tract-level exposure was associated with greater TNBC odds. In multivariate analyses that controlled for patient-level race and age, tract-level exposures were not associated with TNBC odds. However, in a second multivariate model that included patient-level variables and considered tract-level risk factors as a cumulative exposure risk score, each one unit increase in cumulative exposure was significantly associated with a 10% increase in TNBC odds. Higher cumulative exposure risk scores were found in census tracts with relatively high proportions of Black residents.

CONCLUSIONS

Cumulative exposure to neighborhood-level risk factors that disproportionately affect Black communities was associated with greater TNBC risk.

Racial differences in predictive value of the 21-gene recurrence score assay: a population-based study using the SEER database

Purpose

The 21-gene recurrence score (RS) assay is currently used for predicting chemotherapeutic benefits for hormone receptor-positive (HR +) early-stage breast cancer patients without consideration regarding racial differences in that predictive value. This study aimed at demonstrating racial differences in the predictive values of the 21-gene RS assay.

Methods

The study cohort was selected from the Surveillance, Epidemiology, and End Results (SEER) database. Breast cancer-specific mortality (BCSM) was compared between patients who received chemotherapy (the “CTx group”) and those who did not (the “no CTx group”) to estimate the predictive value of the assay. This comparison was repeated for each racial group.

Results

Among 88,498 T1 − 2N0 HR + breast cancer patients who had results of 21-gene RS, 13,123 patients had RS > 25, which included 10,697 Whites, 1282 Blacks, and 1,144 Asian Americans/Pacific Islanders (AAPIs). Chemotherapy was administered to 8364 patients (63.4%). The adjusted hazard ratio for BCSM in the CTx group (vs. no CTx group) was 0.734 (95% confidence interval [CI] 0.588–0.917) in Whites, 0.748 (95% CI 0.428–1.307) in Blacks, and 1.343 (95% CI 0.558–3.233) in AAPIs. No subgroup within patients with RS > 25 among non-White women showed a significant predictive value of the 21-gene RS assay, except for Black women with grade 3 tumors.

Conclusion

The predictive value of the 21-gene RS assay for assessing chemotherapy benefit was validated in White women based on the SEER database, although the predictive value was not warranted in non-White women.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12282-022-01371-z.

Endocrine therapy initiation among women with stage I-III invasive, hormone receptor-positive breast cancer from 2001-2016

PURPOSE

This retrospective cohort study examined patterns of endocrine therapy initiation over time and by demographic, tumor, and treatment characteristics.

METHODS

We included 7777 women from three U.S. integrated healthcare systems diagnosed with incident stage I-III hormone receptor-positive breast cancer between 2001 and 2016. We extracted endocrine therapy from pharmacy dispensings, defining initiation as dispensings within 12 months of diagnosis. Demographic, tumor, and treatment characteristics were collected from electronic health records. Using generalized linear models with a log link and Poisson distribution, we estimated initiation of any endocrine therapy, tamoxifen, and aromatase inhibitors (AI) over time with relative risks (RR) and 95% confidence intervals (CI) adjusted for age, tumor characteristics, diagnosis year, other treatment, and study site.

RESULTS

Among women aged 20+ (mean 62 years), 6329 (81.4%) initiated any endocrine therapy, and 1448 (18.6%) did not initiate endocrine therapy. Tamoxifen initiation declined from 67 to 15% between 2001 and 2016. AI initiation increased from 6 to 69% between 2001 and 2016 in women aged ≥ 55 years. The proportion of women who did not initiate endocrine therapy decreased from 19 to 12% between 2002 and 2014 then increased to 17% by 2016. After adjustment, women least likely to initiate endocrine therapy were older (RR = 0.81, 95% CI 0.77-0.85 for age 75+ vs. 55-64), Black (RR = 0.93, 95% CI 0.87-1.00 vs. white), and had stage I disease (RR = 0.88, 95% CI 0.85-0.91 vs. stage III).

CONCLUSIONS

Despite an increase in AI use over time, at least one in six eligible women did not initiate endocrine therapy, highlighting opportunities for improving endocrine therapy uptake in breast cancer survivors.