Non-Hispanic black women and young women are at much greater risk of being diagnosed with triple-negative breast cancer compared with white or younger women, US research has revealed. The authors of the study*, published in Cancer, called for more research to better inform practice and policy around screenable cancers such as breast cancer.
Because triple-negative breast cancer (TNBC) has been associated with a more aggressive histology, poorer prognosis, and non-responsiveness to hormone therapy, explained the researchers, it is imperative to know which people are likely to be at greatest risk and to understand the factors that drive disparities between patient groups – and focus on prevention.
They analysed data from the United States Cancer Statistics database to examine differences between TNBCs compared with all other breast cancers, in terms of age at diagnosis, race/ethnicity, and stage at diagnosis.
They found that of the total of 1,151,724 cases of breast cancer identified between 2010 and 2014, only about 8.4% overall were the triple‐negative phenotype. But in unadjusted analyses, non‐Hispanic black women were more than twice as likely as non-Hispanic white women to be diagnosed with TNBC (odds ratio, OR 2.27). Hispanic women were at a significantly higher relative risk compared with non‐Hispanic white women (OR 1.22).
They also found that women who were less than 40 years old had almost twice the relative risk of TNBC compared with women aged 50-64 years (OR 1.95).
Diagnosis at American Joint Committee on Cancer stage III and beyond was associated with significantly higher odds of the diagnosis of TNBC (OR for stage III, 1.69; OR for stage IV, 1.47).
The study authors concluded: “The results… demonstrated that there is a significant burden of disease in TNBC diagnosed among women of colour, specifically non‐Hispanic black women, and younger women. Additional studies are needed to determine drivers of disparities between race, age, and stage of disease at diagnosis.”
They added: “With the advent and availability of more comprehensive cancer data, such as the United States Cancer Statistics database, it is important that we continue to explore disparities in order to better inform practice and policy around screenable cancers like breast cancer.”
*Scott LC, Mobley LR, Kuo T, et al. Update on triple‐negative breast cancer disparities for the United States: A population‐based study from the United States Cancer Statistics database, 2010 through 2014. Cancer, published online 8 July 2019. doi:10.1002/cncr.32207