Patterns of use of chemotherapy for breast cancer in older women: Findingsfrom Medicare claims data

Purpose: There is little population-based information available on the use of chemotherapy in women with breast cancer. This study describes the use o f chemotherapy through analysis of Medicare claims and determines the corre lates of chemotherapy use. Patients and Methods: We used the merged Surveillance, Epidemiology, and En d Results-Medicare database and identified women greater than or equal to 65 years of age diagnosed with breast cancer in 1991 and 1992. Chemotherapy wa s ascertained from Medicare claims through procedure codes for chemotherapy made within 24 months of the diagnosis. Results: In women with stages I, I I, III, and IV breast cancer, the percentage receiving chemotherapy within 24 months of diagnosis was 5.1%, 19.5%, 33.9%, and 35.2%, respectively. Mos t women receiving chemotherapy had two to 12 claims; the median number was eight. Use of chemotherapy decreased significantly with age across all tumo r stages; eg, in women with stage III cancer, the use of chemotherapy decli ned from 49% in those aged 65 to 69 years to 10% in those greater than or e qual to 80 years old. In a multivariate analysis, there was little variatio n by ethnicity. Chemotherapy use was highest (70%) in women aged 65 to 69 y ears with node-positive and estrogen receptor-negative tumors and lowest (5 %) in those with node-negative and estrogen receptor-positive tumors. Compa red with those without comorbid diseases, patients with a comorbidity score of 2 had significantly lower use of chemotherapy. Conclusion: Medicare claims data seem to provide valuable information on th e use of chemotherapy for breast cancer in older women. However, external v alidation of the accuracy and completeness of these data is required before any firm conclusion can be drawn. J Clin Oncol 19:1455-1461. (C) 2001 by A merican Society of Clinical Oncology.