Healthcare Resource Use and Expenditures among Metastatic Breast Cancer Patients Treated with HER2-Targeted Agents

Objective. To compare healthcare utilization (HCU) and costs of women newly diagnosed with metastatic breast cancer (mBC) by receipt of HER2-targeted agents (H2T) and among H2T subgroups. Methods. Adult women newly diagnosed with mBC (index date) during 2008–2012 were followed until enrollment end or inpatient death. Study cohorts were antineoplastic ± H2Ts, and no treatment; and subgroups of H2T patients stratified by receipt of hormonal therapy (HT+/HT−), by de novo versus recurrent disease status, and by age group. All-cause (ALL) and breast cancer related (BCR) HCU and costs (in 2012 dollars) were estimated using a generalized linear model. Results. Of 18,059 women, 14.6% were H2T users 71.1% nonusers, and 14.3% untreated. No treatment patients had the highest ALL and BCR inpatient HCU, and ALL emergency room HCU. H2Ts users had the highest ALL and BCR office visits, lab and diagnostic radiology, radiation treatments, other outpatient services, and prescription antineoplastics. Adjusted ALL and BCR costs were the highest for H2T users and, in H2T subgroups, higher for HT—versus HT+ and de novo versus recurrent, and declined with older age. Conclusions. Receipt of H2Ts was associated with greater levels of ALL and BCR HCU and costs. H2T subgroups of HT−, de novo, and younger age had higher HCU and costs, possibly indicating more aggressive treatments.