For patients with stage I to III human epidermal growth factor receptor 2 (HER2)-positive breast cancer, the monoclonal antibody trastuzumab is central to their adjuvant therapy. A recent study sought to explore the possible disparities for trastuzumab therapy.1
A team of researchers, based at the University of North Carolina at Chapel Hill, reviewed the records of 1362 Medicare recipients that had stage I to III HER2-positive breast cancer. All cancers were diagnosed in 2010 or 2011. The investigators tracked both trastuzumab therapy as well as chemotherapy used in combination with trastuzumab. Use of trastuzumab was identified via patient insurance claims.
The researchers judged the likelihood of patients receiving trastuzumab therapy based on race, with modifiers for factors such as medical necessity and socioeconomic status. A modified Poisson regression analysis was employed to determine trastuzumab use by race.
The research team determined that racial disparities indeed exist with regard to the receipt of trastuzumab therapy for HER2-positive breast cancer. Half of the patients age 65 years or older did not receive trastuzumab, and among women overall, the rates of trastuzumab use were 50% for white women and 40% for black women. For women with stage III breast cancer, the gap grew, with 74% of white women and 56% of black women receiving this adjuvant therapy.
1. Reeder-Hayes K, Hinton S, Meng K, et al. Disparities in use of human epidermal growth hormone receptor 2-targeted therapy for early-stage breast cancer [published online ahead of print April 11, 2016]. J Clin Oncol. doi:10.1200/JCO.2015.65.8716.