PCN16: CHEMOTHERAPY TREATMENT IN NEWLY DIAGNOSED BREAST CANCER PATIENTS IN A MANAGED CARE POPULATION

Abstract

OBJECTIVE: To characterize the antineoplastic treatment of newly diagnosed breast cancer patients in a managed care population. METHODS: Adult subjects contained within PharMetric's Integrated Outcomes database possessing a diagnosis of breast cancer (ICD-9-CM = 174) followed by a procedure code for chemotherapy during 1997?1999 were eligible for study inclusion. Patients with diagnoses for other neoplasms and pre-diagnosis treatment were excluded. Utilization of antineoplastic agents, radiation therapy (RT) and mastectomy during the 6-month post-diagnosis period was measured. RESULTS: 6,652 patients met the inclusion criteria. The mean age was 53.7 years. 3,396 (51.1%) patients received RT, while 3,469 (52.2%) patients underwent mastectomy. Patients 61 year of age and older were significantly less likely to undergo RT or mastectomy as compared to younger patients (p < 0.0001). Doxorubicin and cyclophosphamide were extensively used in younger patients (ADR: 32.7% in 71+ vs. 64.4% in <40; cyclophosphamide: 53.3% in 71+ vs. 73.2% in 71+). In contrast, fluorouracil and methotrexate appeared to be the drug of choice in elderly (5-FU: 49.1% in 71+ vs. 33.3% in <41; MTX: 30.9% in 71+ vs. 19.8% in <41). Use of paclitaxol was consistent across all age categories (24.4%). Elderly were less likely to undergo partial mastectomy (8.7% in 71+ vs. 23.1% in <41). The difference in the rate of modified radical mastectomy between age groups was less pronounced (22.3% in 71+ vs. 29.5% in <41). After adjusting for age, RT and health plan identifier, the administration of cyclophosphamide or doxorubicin was more likely to follow any mastectomy, while the association between mastectomy and fluorouracil use was limited to modified radical. RT was likely to be used as adjunct therapy to all antineoplastics, with the exception of cyclophosphamide. CONCLUSIONS: The elderly appeared to be treated less aggressively with anti-neoplastic agents. The choice of agent is governed by age and the mode of other treatments.