Care Not in Line With Guidelines for HER2-Negative MBC Has Worse Outcomes in Elderly Women

More than 80% of metastatic breast cancer (MBC) is human epidermal growth factor receptor 2 (HER2)-negative, and has worse outcomes than HER2-positive MBC.

Despite that, more than one-quarter of elderly women with HER2-negative metastatic breast cancer did not receive care in accordance with National Comprehensive Cancer Network (NCCN) treatment guidelines, according to a recent study presented at Virtual ISPOR 2020. And care that is not in line with guidelines was linked to higher mortality as well as higher Medicare costs, according to the report.

Older patients are usually excluded from randomized controlled trials, noted study author Ami M. Vyas, PhD, MBA, of the University of Rhode Island, in her presentation. In addition, there is very limited evidence about the extent of the effect of care in line with guidelines among patience in this group.

The aim of this study was to examine the effect of guideline-concordant treatment among elderly women with HER2-negative MBC on all-cause mortality, breast cancer-specific mortality, and Medicare costs.

They performed a retrospective cohort study using the Surveillance, Epidemiology, End Results-Medicare (SEER) database, including women aged 66 years and older diagnosed with HER2-negative MBC during 2010-2013.

The aim of the study was to evaluate how guideline-concordant treatment impacted all-cause and breast cancer-specific mortality using adjusted Cox proportional hazards models. They also conducted a generalized linear model with log link and gamma distribution to examine the impact of guideline-concordant treatment on average monthly Medicare costs. The models were adjusted for patient demographic and socioeconomic characteristics, clinical and tumor characteristics, healthcare access, and external healthcare environmental factors.

Endocrine therapies and infused or oral therapies were pulled from the database. The analysis included a total of 1089 women. Of those, 72.3% received guideline-concordant initial treatment.

An unadjusted analysis showed that those who received guideline-concordant treatment survived longer than those who did not receive guideline-concordant treatment.

In adjusted analyses, women who did not receive guideline-concordant treatment had significantly higher hazards of all-cause mortality (hazard ratio [HR] = 2.143, P <.001) and deaths specific to breast cancer (HR = 1.989, P <.001) than those who received guideline-concordant treatment.

Average monthly Medicare costs among women who received guideline-concordant treatment were significantly lower than those who did not receive guideline-concordant care ($3036 vs. $6172, P <.0001) in the adjusted analysis.

The results show that clinical and economic outcomes can improve with care that aligns with guidelines.

Reference

Vyas A, Mantaian T, Kogut SJ. Guideline-concordant treatment and its impact on survival and costs among elderly women with HER2-negative metastatic breast cancer. Presented at: ISPOR 2020; May 18-20, 2020; Abstract TP1.