Disparities in Use of Human Epidermal Growth Hormone Receptor 2-Targeted Therapy for Early-Stage Breast Cancer

Authors: Reeder-Hayes, K et. al.

Source: J Clin Oncol 10.1200/JCO.2015.65.8716

jco.ascopubs.org/content/34/17/2003.abstract?sid=1b534308-5c08-4a64-8845-0037ff5671d3

Trastuzumab (Herceptin) has become the standard of care for treatment of women with stage II and III HER2+ breast cancer, and it is frequently considered for stage I breast cancer as well. So far, there has been no evaluation of the use of this medication within a large population. These investigators evaluated the use of Trastuzumab among eligible women enrolled in Medicare from 2009-2013.

Over 1,300 women were included in the study. Rates of Trastuzumab use by race were examined. Within one year of diagnosis, Trastuzumab was used by 50% of white patients and 40% of black patients. It was used by 52% of other minority patients. Regarding white and black patients, the use of HER2 targeted therapy was lower in the black patients for all breast cancer stages.

When adjusting for age, other health issues and socioeconomic status, black women were 25% less likely than white women to receive Trastuzumab. The effect of race on use of Trastuzumab persisted regardless of the type of comorbidity modeling used.

It was notable that the time frame used in this study (2009-2013) was recent. The results illuminate the fact that, despite increased awareness of healthcare discrepancies between black and white patients, these discrepancies still exist.

The group proposed several reasons for the observed difference in treatment delivery. Trastuzumab is routinely paired with other chemotherapy agents, and the administration is intense and demanding. The treatment schedule may be impossible to keep for women who have unreliable transportation, job insecurity or poor social support (the group did control for socioeconomic status but admitted that all contributing factors could not possibly be assessed). It is also possible that, among these Medicare patients, black women were less likely to have the supplemental insurance that would make treatment more affordable. Decision making strategies may be different between black and white women, such that presentation of treatment options would lead black women to decline HER2-targeted therapy. Finally, Trastuzumab is given over a year. Other studies have shown that black women are more likely to stop Trastuzumab before the year is up, and the reasons for this may also be reasons why some women don’t even start it. Trastuzumab is a newer breast cancer treatment and it has been previously demonstrated that the adoption of cancer treatment innovation lags among nonwhite patients.

This group observed underuse of Trastuzumab among qualified black patients. There is great opportunity for improvement of our healthcare delivery systems to shrink this difference in care.