Persistence with bisphosphonates in patients with metastatic breast cancer: a retrospective database analysis.

BACKGROUND: In women with breast cancer and bone metastasis, compliance to antiresorptive treatment is of upmost importance to ensure maximum effectiveness in clinical practice. The aim of our study was to investigate persistence with oral and intravenous bisphosphonates (BIS) in a large group of women with metastatic breast cancer and to identify the determinants of non-persistence. PATIENTS AND METHODS: We used data from the Disease Analyzer database (IMS Health, Germany), which includes 2,067 general practices and 397 gynaecological practices. From a dataset of 20 million patients, we identified 1,045 patients diagnosed between January 2001 and December 2010 with bone metastasis (ICD 10: C795) following breast cancer (ICD 10: C50) with first-time cancer-related bisphosphonate prescriptions (ATC: M03B4). Of these, 763 patients received intravenous treatment, and 280 patients received oral BIS treatment. RESULTS: After 1 year, 35.3 % of patients treated with intravenous, and 45.6 % of patients treated with oral bisphosphonates discontinued their therapy (p = 0.002). Multivariate Cox Regression analyses showed a significant increased risk of treatment discontinuation in patients using intravenous BIS (HR: 0.82) compared with oral BIS. Patients younger than 50 (HR: 1.52) were most likely to discontinue treatment compared with the reference group of women over 70. The use of other treatments, such as chemotherapy or hormone therapy, was associated with a decreased risk of treatment discontinuation. Moreover, treatment discontinuation was higher in West Germany compared with East Germany (HR: 1.65) and in patients covered under private health insurance (HR: 1.33). CONCLUSIONS: Persistence with all bisphosphonate treatments in women with breast cancer and bone metastasis is low and needs to be significantly increased to improved outcomes in clinical practice. Further research is required to understand this complex issue.

Persistence in patients with breast cancer treated with tamoxifen or aromatase inhibitors: a retrospective database analysis.

Compliance and persistence are often underestimated in breast cancer (BC) treatment. The aim of our study was to analyze the persistence with tamoxifen (TAM) and aromatase inhibitors (AI) in postmenopausal women with hormone-receptor-positive BC and to identify determinants of non-persistence. We used data of the Disease Analyzer database (IMS HEALTH, Germany) including 2,067 general practices and 397 gynecological practices. Out of a dataset of 15 million patients, we identified BC patients with a first-time TAM or AI prescriptions from October 2001 to December 2010. For persistence analyses, 12,412 women on tamoxifen, 2,796 on anastrozole, 647 on exemestane, and 1,657 on letrozole met the inclusion/exclusion criteria. Within 3 years of follow-up, the discontinuation rates increased to 52.2 % for tamoxifen, 47 % for anastrozole, 55.1 % for exemestane, and 44.3 % for letrozole treated women. A minor proportion of patients switched to a different endocrine treatment; 33 % tamoxifen, 20 % anastrozole, 22.9 % exemestane, and 23 % letrozole. The multivariate hazard ratios of the cox regression models showed that patients younger than 50 were most likely to discontinue initial therapy when compared with the reference group of women over 70 (p < 0.001). In contrast, patients treated in gynecologist practice had significantly longer persistence than patients who obtained their prescriptions in general practitioner practice (p < 0.001). In addition, the presence of the co morbidities like diabetes (p < 0.001) or depression (p < 0.002) was also associated with decreased risk of treatment discontinuation. Persistence with all endocrine treatments in women with hormone-receptor-positive BC is low and needs to be significantly increased to improved outcome in clinical practice. Further research is required to understand this complex issue.