Treatment patterns in patients with advanced breast cancer who were exposed to an anthracycline, a taxane, and capecitabine: a descriptive report

Objective: The aim of this work was to analyze chemotherapy treatment patterns in patients with advanced breast cancer who had been previously exposed to an anthracycline, a taxane, and capecitabine.

Methods: This retrospective cohort study used medical and pharmacy administrative claims with health-plan enrollment data and medical-record review from a large, US-based health insurer database, the HealthCore Integrated Research Database. Women were included if they were aged > or =18 years at the initial breast cancer diagnosis between January 1999 and July 2005 and had received all 3 drug classes of interest, as well as an initial diagnosis of American Joint Committee on Cancer stage I to III breast cancer with metastatic recurrence or an initial diagnosis of stage IV disease. Information about demographics, clinical and pathologic characteristics, survival, and treatments were obtained from computerized data and medical record review. Descriptive analyses were conducted to characterize the treatment patterns.

Results: One hundred forty-four women with advanced breast cancer were identified. Patients ranged in age from 28 to 76 years, with a mean (SD) age of 48.2 (9.1) years, and with 54 patients (37.5%) aged 40 to 49 years and 48 patients (33.3%) aged 50 to 59 years at the time of initial diagnosis. Ninety-three patients (64.6%) were white, 15 (10.4%) were black, 7 (4.9%) were Hispanic, and 4 (2.8%) were Asian. Overall, 89 patients (61.8%) received > or =1 additional chemotherapy regimen after exposure to all 3 chemotherapy agents of interest; 55 (38.2%) received > or =2 additional regimens. A variety of chemotherapeutic regimens were prescribed; 14 monotherapy regimens and 37 combination therapy regimens were used. The most common regimens (both as single agents and combination therapy) included gemcitabine, vinorelbine, or retreatment with a taxane. Of the 89 patients who received > or =1 retreatment, 7 (7.9%) were retreated with anthracycline, 12 (13.5%) with a taxane, and 9 (10.1%) with capecitabine. For first and second treatment after exposure to all 3 agents of interest, the most common single-agent regimens were gemcitabine (first: 17 patients [19.1%]; second: 9 patients [16.4%]) and vinorelbine (first: 14 patients [15.7%]; second: 9 patients [16.4%]). The most common combination therapies for first retreatment were carboplatin based (6 patients [6.7%]).

Conclusions: Of these patients with advanced breast cancer, 61.8% received > or =1 additional chemotherapy regimen after previous treatment with an anthracycline, a taxane, and capecitabine. The variety of agents prescribed suggests a lack of standard of care. Rigorous clinical effectiveness studies of common regimens in heavily pretreated and chemotherapy-resistant populations with breast cancer are warranted.