Triple-negative breast cancer (TNBC) disproportionately affects Black women in the U.S., contributing to higher breast cancer mortality rates in this population. A recent study published in the JAMA Network Open has revealed significant racial disparities in the administration of immunotherapy, a treatment that improves outcomes in early-stage and metastatic TNBC.
What is Immunotherapy?
Immunotherapy is a type of cancer treatment that uses the body’s own immune system to fight cancer cells. It involves using biological or chemical factors that change the immune system or the patient’s response to tumor cells. In the context of TNBC, immunotherapy often involves the use of immune checkpoint inhibitors, like atezolizumab and pembrolizumab, which work by blocking proteins that stop the immune system from attacking cancer cells.
Why is Immunotherapy Important for TNBC?
In the context of cancer, clinical trials are essential for developing and improving life-saving treatments like immunotherapy. They provide a structured way to test the safety and effectiveness of new therapies and can offer patients access to cutting-edge treatments that are not yet widely available. However, clinical trials must include diverse patient populations, including Black women, to ensure that the findings apply to all who may benefit from these treatments.
Immunotherapy has been shown to significantly improve outcomes for patients with TNBC. For metastatic TNBC, studies have demonstrated that immunotherapy in combination with chemotherapy can improve overall survival. In early-stage TNBC, immunotherapy has been shown to increase the rate of pathologic complete response (pCR), which is the absence of any signs of cancer in tissue removed during surgery after treatment. Achieving pCR is a key indicator of treatment success and is associated with better long-term survival.
Racial Disparities in Immunotherapy Use
The study, which analyzed data from 10,724 patients with TNBC between 2019 and 2021, revealed that while immunotherapy use has increased overall, Black patients with metastatic TNBC are less likely to receive this treatment compared to White patients. This disparity persists even when socioeconomic factors are taken into account.
Researchers found that immunotherapy use increased from 5.5 percent in 2017 to 38.8 percent in 2021 for metastatic TNBC, and from 4.2 percent in 2017 to 48.0 percent in 2021 for early-stage TNBC. However, the increase was lower among Black patients.
The study also found that socioeconomic factors play a role in the disparities seen in early-stage TNBC treatment. When factors such as insurance status and treatment facility type were considered, the differences in immunotherapy use between Black and White patients were no longer significant.
The authors of the study suggest that there may be other unmeasured factors contributing to the lower use of immunotherapy in Black patients with metastatic TNBC, such as racial differences in PD-L1 status (a protein that affects how well immunotherapy works), differences in the tests used to determine PD-L1 status, or differences in access to biomarker testing.
The study shows the urgent need to address the racial disparities in cancer care. The researchers emphasize that efforts should be made to ensure equal access to immunotherapy for all patients, which could help improve the survival and disproportionate impact of TNBC on Black women.