Abstract P1-09-02: Health Care Costs Incurred by Post-Menopausal Women with Hormone-Positive Breast Cancer Following the Initial Diagnosis of Metastasis
Authors: Chastek B , Gao S , O'Malley C , Loh E , Barber B. 
Published: April 2011

Abstract
Objectives: Estimate the healthcare costs before and after progression to chemotherapy in a population of post-menopausal hormone-receptor positive (HR+) metastatic breast cancer (mBC) patients. Methods:
This retrospective cohort study used claims from a large national US health plan. Females age 55 to 63 were selected if they were diagnosed with metastatic breast cancer between 7/1/01 and 12/31/07, and initiated hormonal therapy before progressing to chemotherapy. Incident metastatic patients were followed until the earliest of disenrollment from the health plan, death, or 12/31/08. The pre-chemotherapy period was defined as the period between the incident diagnosis of metastases and the earlier of the initiation of chemotherapy and the end of the study period. Among the subset of patients with use of chemotherapy, the post-chemotherapy period was defined as the time following chemotherapy initiation until the end of the study. Inflation-adjusted costs were examined during the pre-and post-chemotherapy periods. Descriptive analyses were supplemented with Kaplan-Meier sample-average to adjust for variable follow-up time and censoring. Results:
A total of 1,202 patients were identified, 366 (30.4%) of whom progressed to chemotherapy following the onset of metastases. The mean age ± SD was 58.9 ± 2.6 years.
On average, patients incurred $79,139 (SD± $121,489) per year in total health care costs before the initiation of chemotherapy and $132,786 (SD± $117,635) after the initiation of chemotherapy. In the pre-chemotherapy and post-chemotherapy phases, medical expenses were $74,149 (SD± $119,838) and $120,942 (SD± $116,225) per patient-year, respectively, while outpatient medications filled at a retail pharmacy or through a mail system pharmacy cost $4,990 (SD± $5033) and $11,843 (SD± $14,431) per patient-year, respectively. On average, most of the observed medical expenses were incurred during outpatient visits with $44,405 (SD± $55,710) and $87,299 (SD± $75,360) per patient-year in the pre-and post-chemotherapy phases respectively. Inpatient stays accounted for $27,147 (SD± $101,405) and $30,118 (SD± $73,216) per patient-year during the pre-and post-chemotherapy periods, respectively. ER visits cost an average of $424 (SD± $1,871) per patient-year during the pre-chemotherapy period and $1,274 (SD± $5,686) per patient-year during the post chemotherapy period, on average. During the post-chemotherapy period, combined costs for both inpatient and outpatient chemotherapy were $33,559 (SD± $38,692) per patient-year on average, and costs for services associated with supportive care for chemotherapy during the same time period accounted for an additional $18,676 (SD± $30,281) per patient-year on average. After adjusting for variable follow-up times, cumulative total healthcare costs were $54,725, $73,107, and $84,200 for years one, two, and three of the pre-chemotherapy period, respectively, and were $92,639, $148,228, and $176,163 during the same portions of the post-chemotherapy period. Conclusions:
Post-menopausal HR+ mBC patients incur significant healthcare costs both before and after progressing to chemotherapy. The main cost driver was medical costs in both the pre-and post-chemotherapy periods.
Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-09-02.