Social Determinants and Genetics Work in Tandem to Drive Disparities in Breast Cancer Care

Adana A.M. Llanos, PhD, MPH

Although genetic and biologic factors play a key role in outcomes for patients with breast cancer, social and structural determinants also have a place in the equation. Addressing these existing genetic factors and social determinants, thereby improving prevention and detection, can help reduce disparities in metastatic breast cancer, where Black women historically present more frequently at advanced stages and have worse outcomes, according to Adana A.M. Llanos, PhD, MPH.

In a presentation during the 2022 ASCO Annual Meeting, Llanos highlighted how understanding the genetic and etiological aspects of breast cancer can help inform prevention and screening techniques. The next challenge for physicians will be implementing these ideas into community practice to better serve underrepresented patient populations.¹

“Focusing on all of the different time points throughout [the cancer care] continuum will be a critical aspect of achieving more health equity and more equitable outcomes,” Llanos said. “This is a major goal throughout my long-term research interests.”

In an interview with OncLive^®, Llanos discussed other key research on the social and biological factors that influence disparities in breast cancer, how these factors work in tandem to affect patient outcomes, and how this knowledge can be deployed in the real world. She is an associate professor of Epidemiology at the Mailman School of Public Health at Columbia University and an adjunct associate professor at Rutgers School of Public Health.

OncLive^®: Why is it vital to examine both the social and genetic factors that play a role in the diagnosis and outcomes of metastatic breast cancer?

Llanos: My talk was part of a discussion involving 2 selected abstracts. The session included abstracts that focused on some of the racial, ethnic, and regional disparities in metastatic breast cancer.

The lead author for the first abstract is Sachi Singhal, MD, [who explored racial and regional disparities in metastatic breast cancer].² The second abstract focused on the variation of genetic mutations, specifically pathogenic variants in breast cancer predisposition genes, and how they're related to triple-negative breast cancer [TNBC].³ That abstract was presented by Michael J. Hall, MD, MS.

In my talk, I provided an overview of some of the existing racial and ethnic disparities that we see in breast cancer in the United States, highlighting stage distribution and focusing on the fact that the distribution of tumor stage varies by race and ethnicity. We see high rates [of advanced stages of disease] among Black women. Moreover, I talked about some of the factors related to this disparity in advanced stage diagnosis by race.

I also presented the distribution of tumor subtypes, focusing on TNBC, which tend to be among the most aggressive forms of breast cancer. We see that the incidence of TNBC is substantially higher in Black women. [Our goal is to gain a greater] understanding of how some of the racial, ethnic, and ancestral [factors of breast cancer intersect and interact with] genetics and social determinants of health to contribute to these disparities and how they impact poor outcomes among some patient groups.

What are some of the key factors that need to be investigated to better understand disparities in breast cancer?

This session highlighted some of the facts that clinicians already know. The abstracts [by Drs Singhal and Hall] got at the biology [of breast cancer] and the social/structural determinants that could be related and working together to impact outcomes.

I’m an epidemiologist, and I’m interested in studying social and biological factors that contribute to disparities. One of the takeaways in my talk was how we can address breast cancer disparities at multiple phases in the cancer control continuum. This includes looking at etiology and biology, which is more focused on genetics and ancestry. These are things that we cannot change but understanding them better will give us a good sense of ways that we can address disparities.

Looking at prevention, we talk a lot about precision medicine and treatment. However, maybe we should be talking more about precision prevention, [which includes] detection and diagnosis. There are disparities [in these spaces], and [it is important to consider] how we can address those disparities.

Guideline-concordant treatment was not a major focus of my talk but understanding the genetics behind some of these disparities will contribute to improving the treatment options and guideline-concordant treatment for patients with breast cancer. Lastly, public health is important. [We need to learn] how to deploy all this knowledge to have a broader impact on patients and communities.

What can ongoing and future studies do to better address disparities in breast cancer?

[Considering] the emerging data and studies around the genetics of TNBC, one of the limitations of a lot of the existing and past research is the historical underrepresentation of racial and ethnic minority groups, especially those of African ancestry. As new studies and larger studies are initiated, it is critical to have broad representation of diverse ancestral backgrounds to [allow investigators] to get a sense of some of the genetic and etiological differences, why they exist, and how [these factors] can impact treatment.

How should social factors be considered when considering disparities in breast cancer?

As important as biology and genetics are, we need to consider the social determinants and structural determinants across the entire cancer care continuum, not just for breast cancer, but for all cancers.

References

1. Llanos AA. Past as prologue: examining ancestry and disparities to move forward. Presented at: 2022 ASCO Annual Meeting; June 3-7, 2022; Chicago, IL.
2. Singhal S, Desai D, Khosla A, Lanade O, Potdar R. Racial and regional disparities in metastatic breast cancer. J Clin Oncol. 2022;40(suppl 16):10516. doi:10.1200/JCO.2022.40.16_suppl.10516
3. Hall MJ, Hughes E, Kucera M, et al. Ancestry-specific risk of TNBC associated with pathogenic variants in hereditary cancer predisposition genes. J Clin Oncol. 2022;40(suppl 16):10517. doi:10.1200/JCO.2022.40.16_suppl.10517