Racial disparities in overall survival after the introduction of cyclin-dependent kinase 4/6 inhibitors for patients with hormone receptor-positive, HER2-negative metastatic breast cancer

Trends in Incidence of Invasive Lobular Carcinoma of the Breast by Race: Patterns by Age, Cancer Stage, and Socioeconomic Factors in the United States, 1992-2019

PURPOSE

There is scarce literature about the role of race/ethnicity and socioeconomic status on the incidence of invasive lobular carcinoma (ILC). We sought to assess trends in ILC incidence by race/ethnicity across age, cancer stage, and socioeconomic status subgroups in the United States from 1992 to 2019.

METHODS

This population-based cross-sectional study included data from SEER12 registries. We used the NCI's Join point Regression Program to estimate longitudinal trends in age-adjusted breast cancer incidence rates from 1992 to 2019, reported as average annual percent change (AAPC) or annual percent change (APC). We evaluated incidence trends by a combination of race/ethnicity and stage, county-level poverty, county-level metro/nonmetro status, high school education, and age.

RESULTS

From 1992 to 2019, ILC incidence rates increased across all race/ethnicity groups, with the greatest increase in non Hispanic Black (AAPC 2.6%), followed by Hispanic (AAPC 2.2%), and non Hispanic White women (AAPC 1.6%). The stronger increase in ILC incidence among Hispanic and non Hispanic Black women was predominantly seen among those living in low poverty or metropolitan areas and those older than 70. In recent years, from 2002 to 2019, the largest increase in ILC incidence was found in Hispanic women (APC 3.3%).

CONCLUSION

Although the incidence of ILC continues to be highest in non Hispanic White women, in recent years the largest increases are seen in non Hispanic Black women and Hispanic women. Further research is warranted to better understand these trends and appropriately target at-risk populations for screening.

Survey of Health Care Providers on Social Determinants of Health and Treatment Decision-Making for Patients With HR+/HER2- Metastatic Breast Cancer

INTRODUCTION

Social determinants of health (SDOH) are a range of nonmedical factors that contribute to outcome disparities among certain groups of patients; however, little is known about how SDOH affect treatment decision-making for patients with cancer, particularly those with metastatic breast cancer (mBC). This study sought to gain insights from physicians and advanced practice providers on the impact of SDOH on practice- and patient-level cancer care decision-making with a nationwide online survey.

METHODS

The Social Determinants of Health in Metastatic Breast Cancer Survey was developed by the Association of Cancer Care Centers (ACCC) in partnership with Pfizer Inc, and in consultation with SDOH specialists. The 23-question survey captured experiences with SDOH-informed treatment decision-making for patients with cancer via multiple choice, Likert-scale, and free-response questions. ACCC-member physicians and advanced practice providers in the USA completed the survey between 23 January and 8 February 2024.

RESULTS

Respondents (n = 145), a majority of whom were medical oncologists (60%), represented clinics from diverse geographic regions of the USA; approximately 65% of respondents' clinics served patient populations with ≥ 10% Black, Indigenous, or People of Color. Common comprehensive cancer care services were provided by at least 59% of clinics, and SDOH factors were assessed by approximately 75% of clinics at diagnosis. Navigation services were available for patients with mBC at approximately 75% of respondents' clinics. Financial considerations (51%) and the presence of a caregiver (35%) were the most frequently cited SDOH-related factors that impacted mBC treatment decision-making.

CONCLUSION

The surveyed ACCC-member care providers displayed a high degree of awareness regarding SDOH impacts on their practice and patients, but resource limitations were identified as barriers to comprehensive, SDOH-informed cancer care. Harnessing existing resources from local and national advocacy groups, especially navigator training programs, is an actionable, real-world solution for improving mBC care for patients facing SDOH barriers.

Racial disparities in treatment and outcomes between Hispanic and non-Hispanic black women with triple-negative breast cancer

INTRODUCTION

Triple-negative breast cancer (TNBC) is an aggressive breast cancer (BC) subtype with higher incidence and mortality rates in non-Hispanic Black (NHB) women than non-Hispanic Whites. Studies assessing disparities between NHB and Hispanic women, the two largest US racial/ethnic minorities, are lacking. This study evaluates disparities in the treatment and outcomes between NHB and Hispanic women with non-metastatic TNBC.

METHODS

This observational, population-based study using the SEER database included adult, female patients diagnosed with non-metastatic TNBC between 2010 and 2015 and identified as NHB or Hispanic. Logistic regression analysis was used to examine the adjusted odds of receiving breast cancer-directed treatment. Kaplan-Meier and cumulative incidence of death curves were plotted to assess overall survival (OS) and risk of breast cancer-related death, respectively. Multivariate regression analyses with Cox and Fine-Gray methods were calculated to assess factors associated with OS and breast cancer-related death, respectively.

RESULTS

There were 3426 Hispanic and 5419 NHB patients with non-metastatic TNBC. Hispanics had better 5-year OS relative to NHB (76% vs. 72%). No differences in the odds of receiving chemotherapy or surgery between cohorts was seen. However, the odds of undergoing breast-conserving surgery (BCS) and receiving radiation was higher in NHB than Hispanics, (OR, 1.22; 95% CI, 1.10-1.36) and (OR, 1.50; 95% CI, 1.36-1.66), respectively. Lack of radiation therapy was associated with increased BC-related death in NHB relative to Hispanics (sHR, 1.40; 95% CI, 1.19-1.65). Nevertheless, this difference was not seen when radiation was given, (sHR, 1.03; 95% CI, 0.87-1.23).

CONCLUSIONS

We found racial disparities in treatment and outcomes between NHB and Hispanics. NHB were more likely to receive radiation therapy and have BCS. Still, after adjusting for demographic and treatment-related factors, NHB had worse OS and BCSS relative to Hispanics. Additional research is needed to understand the drivers of these disparities.

Trends in HR+ metastatic breast cancer survival before and after CDK4/6 inhibitor introduction in the United States: a SEER registry analysis of patients with HER2- and HER2+ metastatic breast cancer

PURPOSE

Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) have improved patient survival in hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) metastatic breast cancer (mBC) in clinical trials and real-world studies. However, investigations of survival gains in broader HR+/HER2- mBC populations using epidemiological approaches are limited.

METHODS

This retrospective study used SEER registry data to assess breast cancer-specific survival (BCSS) in patients diagnosed with HR+/HER2- de novo mBC from 2010 to 2019. Kaplan-Meier and Cox proportional hazards models were used to compare BCSS in patients diagnosed before (2010‒2013 with follow-up to 2014) and after (2015‒2018 with follow-up to 2019) the 2015 guideline recommendations for CDK4/6i use. A comparison was made to patients with HR+/HER2-positive (HER2+) de novo mBC, for which no major guideline changes occurred during 2015-2018.

RESULTS

Data from 11,467 women with HR+/HER2- mBC and 3260 women with HR+/HER2+ mBC were included. After baseline characteristic adjustment, patients with HR+/HER2- mBC diagnosed post-2015 (n = 6163), had an approximately 10% reduction in risk of BC-specific death compared with patients diagnosed pre-2015 (n = 5304; HR = 0.895, p < 0.0001). Conversely, no significant change was observed in HR+/HER2+ BCSS post-2015 (n = 1798) versus pre-2015 (n = 1462). Similar results were found in patients aged ≥ 65 years.

CONCLUSION

Using one of the largest US population-based longitudinal cancer databases, significant improvements in BCSS were noted in patients with HR+/HER2- mBC post-2015 versus pre-2015, potentially due to the introduction of CDK4/6i post-2015. No significant improvement in BCSS was observed in patients with HR+/HER2+ mBC post-2015 versus pre-2015, likely due to the availability of HER2-directed therapies in both time periods.

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.

Multiplex Imaging Reveals Novel Subcellular, Microenvironmental, and Racial Patterns of MRTFA/B Activation in Invasive Breast Cancers and Metastases

Breast cancer progression and metastasis involve the action of multiple transcription factors in tumors and in the cells of the tumor microenvironment (TME) and understanding how these transcription factors are coordinated can guide novel therapeutic strategies. Myocardin related transcription factors A and B (MRTFA/B) are two related transcription factors that redundantly control cancer cell invasion and metastasis in mouse models of breast cancer, but their roles in human cancer are incompletely understood. Here, we used a combination of multiplexed immunofluorescence and bioinformatics analyses to show that MRTFA/B are concurrently activated in tumor cells, but they show distinct patterns of expression across different histological subtypes and in the TME. Importantly, MRTFA expression was elevated in metastatic tumors of African American patients, who disproportionately die from breast cancer. Interestingly, in contrast to publicly available mRNA expression data, MRTFA was similarly expressed across estrogen receptor (ER) positive and negative breast tumors, while MRTFB expression was highest in ER+ breast tumors. Furthermore, MRTFA was specifically expressed in the perivascular antigen presenting cells (APCs) and its expression correlated with the expression of the immune checkpoint protein V-set immunoregulatory receptor (VSIR). These results provide unique insights into how MRTFA and MRTFB can promote metastasis in human cancer, into the racial disparities of their expression patterns, and their function within the complex breast cancer TME.

Racial Disparities in Breast Cancer: from Detection to Treatment

PURPOSE OF REVIEW

Update on current racial disparities in the detection and treatment of breast cancer.

RECENT FINDINGS

Breast cancer remains the leading cause of cancer death among Black and Hispanic women. Mammography rates among Black and Hispanic women have surpassed those among White women, with studies now advocating for earlier initiation of breast cancer screening in Black women. Black, Hispanic, Asian, and American Indian and Alaskan Native women continue to experience delays in diagnosis and time to treatment. Further, racial discrepancies in receipt of guideline-concordant care, access to genetic testing and surgical reconstruction persist. Disparities in the initiation, completion, toxicity, and efficacy of chemotherapy, endocrine therapy, and targeted drug therapy remain for racially marginalized women. Efforts to evaluate the impact of race and ethnicity across the breast cancer spectrum are increasing, but knowledge gaps remain and further research is necessary to reduce the disparity gap.

Retrospective cohort study of CDK4/6-inhibitor-induced alopecia in breast cancer patients

PURPOSE

Dermatologic adverse events commonly result in the interruption of oncologic treatment, and targeted therapies are the most frequently interrupted class of anticancer agents. Alopecia is a common cutaneous adverse event reported with CK4/6i therapy. Though the clinical characteristics and therapeutic response of EIA have been well documented, few studies have characterized alopecia in patients treated with CDK4/6i.

METHODS

This study analyzed a retrospective cohort of 28 breast cancer patients diagnosed with endocrine-induced alopecia (EIA) or CDKiA. Comparative analysis of the clinical characteristics of alopecia and therapeutic response to minoxidil was conducted. Therapeutic response to minoxidil (LDOM or topical [5%] solution or foam) was assessed by both Dean Scale and qualitative clinical improvement by comparison of pretreatment and posttreatment clinical images by single-blinded, board-certified academic dermatologists (ST and BD).

RESULTS

CDKiA was clinically similar to androgenetic alopecia and specific vertex involvement was more common in patients treated with CDK4/6i + ET than endocrine monotherapy (n = 7 [70.0%] vs n = 4 [36.4%]; p = 0.04), respectively. After 4-6 months of minoxidil, there was a moderate to significant qualitative alopecia improvement in 80% of CDKiA patients versus 94.4% of EIA patients. Additionally, superior improvement of mean Dean Score grade was observed in EIA (with change from pre- to posttreatment - 0.44; p = 0.0002).

CONCLUSION

Compared to endocrine monotherapy, patients on combination CDK4/6i + ET had greater extent of vertex involvement and were more recalcitrant to minoxidil. The preferential vertex involvement observed in CDKiA suggests that combination therapy with minoxidil and topical antiandrogens with poor systemic absorption should be studied in this setting.

Assessment of Use and Impact of Chemotherapy in Lymph Node-Negative, T1a Triple-Negative Breast Cancer

BACKGROUND

Current treatment guidelines suggest considering adjuvant chemotherapy in high-risk patients with T1a, node-negative triple-negative breast cancer (TNBC); however, limited quality data support this statement. Our population-based study assessed the efficacy of adjuvant chemotherapy and factors associated with its administration in node-negative, T1a TNBC.

MATERIALS AND METHODS

We obtained data from the Surveillance, Epidemiology, and End Results database for patients with T1aN0 TNBC diagnosed between 2010 and 2019. We utilized the Kaplan-Meier method and Cox regression model to analyze the overall survival (OS) and breast cancer-specific survival (BCSS) in chemotherapy benefit. We performed stratified models to identify differences in OS and BCSS between those who received chemotherapy and those who did not across subgroups. Competing risk analysis was conducted to assess differences in risk of breast cancer death in patients with chemotherapy administration versus no chemotherapy. Additionally, propensity score matching was executed to assess survival analysis in a matched cohort.

RESULTS

We included 1739 patients with T1a TNBC. Patients who received chemotherapy were younger, had higher histological grade and ductal histology subtype, were more likely to be married and undergo mastectomy. Our study did not show improvement in OS (HR, 0.63; 95% CI, 0.35-1.13; P = .122) or BCSS (HR, 0.95; 95% CI, 0.37-2.43; P = .908) after chemotherapy use. We did not identify any subgroup of patients that may benefit from chemotherapy. Without chemotherapy, 8-year risk of breast cancer death is 2.75% for these patients.

CONCLUSION

Adjuvant chemotherapy is not associated with benefit on OS or BCSS in node-negative, T1a TNBC.