Abstract P3-06-08: Patterns of health care utilization and costs by chemotherapy and endocrine therapy sequencing among patients with hormone receptor positive (HR+)/HER2- negative advanced breast cancer

Abstract

Background: Little is known about health care costs and health services utilization of patients with HR+/HER2- advanced breast cancer, particularly in relation to the order in which patient receive endocrine and chemotherapy treatments. Methods: A proprietary database with physician-reported clinical data on patients with breast cancer was linked to medical and pharmacy claims (2008-2012) from a national US health plan. Patients included in the study had HR+ and HER2- status. Advanced cancer included stage III or IV (SIV) at initial diagnosis, or developed metastases following initial diagnosis. The first date of advanced cancer diagnosis or date of metastases following initial diagnosis was designated as the index date. Health plan enrollment for 3 months pre- and ≥12-months post- index date was required; patients who died within 12 months after index date and were continuously enrolled were retained. A 3-month baseline period assessed prior treatment; variable follow-up (until disenrollment or 31 Oct 2012) assessed patterns of endocrine and chemotherapy treatments following index date. All-cause and cancer-specific health care utilization and paid costs were assessed over 12-months following index date. Costs were calculated as per-patient-per-month (PPPM), and utilization measured as rates per patient-month. Cancer-related medication costs included drug costs for endocrine, chemotherapy, targeted therapy, and treatments for pain or chemotherapy-induced nausea/ vomiting. In addition, costs for anti-cancer systemic therapies (chemotherapy, endocrine, and targeted therapy) were calculated PPPM including costs for medication administration. Results: Of 651 study patients, 65% initiated chemotherapy prior to initiating endocrine therapy (CH). Remaining patients (OT) either had no chemotherapy (n = 132 endocrine only, n = 16 neither endocrine nor chemotherapy), or used endocrine therapy prior to chemotherapy (n = 77). Compared with OT, the CH group had more office (4.04 vs. 2.68 visits, P<0.001) and outpatient hospital visits (3.08 vs. 2.10 visits, P<0.001). In addition, 56% of CH vs. 41% of OT had inpatient hospital admissions during the follow-up (P<0.001; rate ratio 0.97, P = NS). Similarly, 60% of CH patients were admitted to emergency rooms vs. 51% of OT (P = 0.033; rate ratio 1.01, P = NS). Mean total all-cause health care costs varied ($11,525 CH vs. $8,196 OT, P<0.001). The largest source of difference in costs were office visits (mean $3,257 CH vs. $1,896 OT, P<0.001), and outpatient hospital ($5,813 CH vs. $3,721 OT, P<0.001). Cancer-related costs comprised the majority of costs (mean $10,249 CH vs. $7,118 OT, P<0.001). The CH group had higher mean cancer-related medication costs than the OT group ($2,051 vs. $1,405 respectively, P = 0.040). Overall mean anti-cancer systemic therapy costs (including administration) were higher in the CH than OT group ($2,934 vs. $1,875, P = 0.012). Conclusions: Among HR+/HER2- advanced breast cancer patients, health care utilization and costs were higher for patients who initiated chemotherapy prior to endocrine therapy compared to other patients. Further investigation of the drivers behind these differences is warranted. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-06-08.