Study Notes Racial Differences in Risk of Recurrence Among Patients With Breast Cancer

Non-Hispanic black (NHB) women diagnosed with human epidermal growth factor receptor 2 (HER2)-negative, lymph node-negative breast cancer who had recurrence score (RS) testing had higher estimated risks of distant recurrence than their non-Hispanic white (NHW) counterparts, according to a study published in the Journal of Clinical Oncology.

Previous studies have proven that NHB women have higher mortality rates and poorer prognoses, which reflect the disparities of healthcare across races and ethnicities as women of color often have a more difficult time accessing preventive care than white women. However, there is another possibility that racial differences in tumor biology vary among NHB and NHW women. If this were true, then the results would prove that NHB women generally suffer from a more aggressive tumor compared to NHWs.

The 21-gene RS breast cancer assay is a medical decision-making tool that assesses the necessary strength of chemotherapy and endocrine therapy regimens for a patient. The assessment categorizes patient’s 10-year distant recurrence risk into 3 categories: low (<18), intermediate (18 to 30), and high (>31). Patients scoring low are unlikely to develop cancer after treatment compared with those with a high risk.

The researchers gathered a cohort of 2242 women diagnosed with hormone receptor-positive, HER2-negative, node-negative breast cancer with 21-gene RS risk information who underwent surgery. These patients with breast cancer were diagnosed from 2010 to 2014 compromising of 1824 NHW patients and 392 NHB patients. The information collected from the Metropolitan Detroit Cancer Surveillance System.

The data show that the mean RS for NHB women was in the intermediate-risk category while NHW women were categorized as low risk. NHB women had a greater possibility of being classified as high-risk (14.8%) compared to NHW women (8.3%). The mean age of patients with a high-risk diagnosis was younger among NHB patients (55.4 years) than NHW patients (60.6 years). NHBs were more likely to develop larger tumors than NHW patients.

There was no overall difference in the mean age of diagnosis among NHBs and NHWs. It was also recorded that NHB patients were more likely to be insured under Medicare or Medicaid while NHWs were quite often insured through a private company. Among both cohorts, there were trends in uptake of chemotherapy as age decreased and RS increased.

“These data highlight the need for long-term studies to evaluate whether these racial differences in 21-gene RS translate to differences in distant recurrence rates,” the authors concluded. “Studies such as these, as well as further studies of the molecular and clinical characteristics of these breast tumors, are needed to explore whether recurrence score classification should be tailored by race.”

References

Holowatyj AN, Cote ML, Ruterbusch JJ, Ghanem K, Schwartz AG, Vigneau FD. Racial differences in 21-gene recurrence scores among patients with hormone receptor—positive, node-negative breast cancer. J Clin Oncol. Published online ahead of print January 17, 2018.