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14 July 2019

A study recently published in the journal Cancer* reports on disparities in triple negative breast cancer (TNBC). The researchers used the US cancer statistics database, and compared differences between TNBC and other breast cancer subtypes focusing on age, race / ethnicity, and stage at diagnosis. 

Between 2010 and 2014, approximately 1.15 million breast cancer cases were identified in the database. The mean age at diagnosis was 61.8, and 75% of patients were non-Hispanic white (NHW). 27.7% were diagnosed at stage III and 5% were diagnosed at stage IV. 

TNBC accounted for 8.4% of all breast cancer cases, but accounted for 21.4% of cases in non-Hispanic Black (NHB) women. Women diagnosed with TNBC had a lower mean age at diagnosis versus non-TNBC (59.3 versus 62.1). NHB women accounted for 11.8% of the study population, but 15.3% of TNBC cases. Women diagnosed with TNBC were also more likely to be younger than age 40 and diagnosed at Stage III or IV compared to those with other cancer subtypes. After controlling for late-stage diagnosis and age, NHB women had approximately twice the likelihood of diagnosis with TNBC compared with NHW women.

The researchers noted that their study validated previous literature, and had the advantage of being geographically very broad. Not discussed in this paper is the relationship of TNBC with genetic mutations, specifically mutations in the BRCA1 gene. Among patients with breast cancer, those who carry deleterious BRCA1 mutations are more likely to have TNBC versus BRCA2 carriers or non-carriers, and a diagnosis of TNBC should prompt genetic testing.

This study and others like it point to the need for more research on TNBC, and on breast cancer in black women. Dr. Lisa Newman, a breast surgical oncologist at Cornell, has published extensively on this topic. In this brief video, she notes that socioeconomic factors account for some of the disparities associated with breast cancer outcomes in black women. However, she also notes that there appears to be biologic differences between TNBC in black versus white women, which may also at least in part account for later stage at diagnosis and poorer prognosis.

*If you are not able to access the full study and would like a copy, please email me: contact at drattai dot com

15 October 2015

A recent study has noted that African American and Hispanic women are more likely to be diagnosed with aggressive forms of breast cancer. Drs. Lu Chen and Christopher Lee published their findings, Racial Disparities in Breast Cancer Diagnosis and Treatment by Hormone Receptor and Her2 Status, in a recent issue of the journal Cancer Epidemiology, Biomarkers and Prevention.

Using information from SEER Registries, they identified 120,000 women, age 20 and over, diagnosed with invasive breast cancer between 2010-2011, with documented information about tumor stage, hormone receptor, and Her2 status. They evaluated the associations between patient race / ethnicity and stage at diagnosis as well as receipt of guideline-appropriate care. Findings included:

  • African American and Hispanic women were 30-60% more likely to be diagnosed with stage II-IV breast cancer compared with non-Hispanic white women
  • African American women had 40-70% risks of being diagnosed with stage IV breast cancer depending on tumor subtype
  • American Indian and Alaska Native women had a 3.9 times higher risk of stage IV triple-negative breast cancer
  • African American and Hispanic women were 30-40% more likely to receive non-guideline concordant care for their breast cancer

The findings reflect those reported earlier this year in the Journal of the National Cancer Institute. It is not news that African American and Hispanic women have worse breast cancer outcomes compared to other populations. They are more likely to be diagnosed at advanced stages, are less likely to receive guideline-appropriate treatment, and have worse overall survival. It is becoming clear that breast cancer is a different disease in women of different racial and ethnic backgrounds – they are more likely to have higher-risk subtypes. This study confirms these points, with the exception of survival, which was not assessed due to the short time period of data analysis (2010-2011). This emphasizes the need for continued research regarding the racial and ethnic variations in tumor subtypes.

Presentation at more advanced stage and lack of guideline-concordant care for African American and Hispanic women should be of concern to us all. This points to racial, ethnic and socioeconomic disparities in education, access to screening, and access to quality care. The authors concluded by stating:  “As contributors to racial / ethnic disparities in breast cancer are complex and multifactorial, continued efforts, especially targeted, culturally appropriate interventions, to address these disparities across different subtypes of breast cancer have the potential to reduce these long-standing disparities and hopefully close the existing survival gaps.”

30 March 2015

Annual Report to the Nation on the Status of Cancer, 1975-2011, Featuring Incidence of Breast Cancer Subtypes by Race/Ethnicity, Poverty and State

Today, the Journal of the National Cancer Institute (JNCI) released a report reviewing cancer data, specifically breast cancer, from 1975-2011. For the first time, data regarding breast cancer subtypes was included in the report, and incidence of breast cancer subtypes by age, race/ethnicity, poverty level, and other factors are included. The following summarizes some of the information found in the report.

It is well known that breast cancer is not one disease. There are 4 primary molecular subtypes based on hormone receptor (HR) status (commonly reported as ER / estrogen receptor and PR / progesterone receptor) and Her2/neu status. The subtypes are:
– Luminal A: HR+ / Her2 negative; 72% of all breast cancers
– Luminal B: HR+ /  Her2 positive; 10% of all breast cancers
– Her2-enriched: HR- / Her2 positive; 5% of all breast cancers
– Basal-like / Triple Negative: HR- / Her2 negative; 13% of all breast cancers

The report demonstrated that there are some unique patterns breast cancer subtype related to race/ethnicity, poverty level, and geography.
– HR+ / Her2- breast cancer is considered to be the least aggressive subtype. Rates of this subtype were highest in non-Hispanic white women. The rates of this breast cancer subtype decreased with increasing poverty levels for every racial and ethnic group. This subtype of breast cancer also correlated strongly with use of screening mammography.

– In women younger than age 45, HR+ / Her2 negative breast cancer rates are comparable among racial / ethnic groups, but for older women this subtype was seen more often in non-Hispanic white women.

– Non-Hispanic Black women had the highest rate of HR- / Her2 – (triple negative) breast cancer, which has been known for some time. However, as triple negative breast cancer is less common than HR+ / Her2 negative disease, more women had the latter subtype. The report also confirmed that this population had the highest rates of late-stage disease and of poorly differentiated pathology (indicates more aggressive tumor behavior)  regardless of molecular subtype, and the highest rate of breast cancer deaths.

Overall trends in incidence and death rates from cancers were also noted in the report. Lung cancer remains the leading cause of death among both men and women. Black men had the highest cancer death rate of any racial or ethnic group. Lung, prostate and colorectal cancers were the leading causes of cancer death among men except in the Asian / Pacific Islander group where the leading causes were lung, liver and colorectal cancer.

Among women, the leading causes of death were found to be lung, breast and colorectal cancers. For both men and women, death rates for the 3 most common cancers declined. Exceptions were American Indian / Alaska Native men, lung cancer in Asian / Pacific Islander women (stable death rate) and colorectal cancer in American Indian / Alaska Native women (stable death rate). Death rates for liver, pancreatic, soft tissue and uterine cancers as well as melanoma were also reported. There are racial / ethnic differences present for these types of cancer as well.

There are many factors contributing to cancer incidence and death rates including race / ethnicity, socioeconomic status, geographic location and more. Reporting cancer incidence by subtype will give more insight into population-based factors, and will hopefully lead to innovative solutions  to the growing problem of disparities in cancer incidence and outcome.

Additional information from the National Cancer Institute.