Endocrine therapy for breast cancer patients in South Africa

Abstract

Background: Endocrine therapy (tamoxifen and aromatase inhibitors (AIs)) has been shown to reduce the risk of recurrence and death in estrogen receptor positive(ER+) breast cancer patients. Objectives: The aim of this study is to assess access to these medicines by comparing the estimated number of ER + breast cancer patients with actual use in a middle income country (South Africa). Methods: Total annual sales data of tamoxifen and AIs for the period 2005-2012 (except 2010,2011) was retrieved from the IMS Health database. The data was converted into years of patient treatment using the defined daily does (DDD) for each medicine. The annual number of new cases of breast cancer patients per ethnicity was estimated using the national cancer registry reports of South Africa (2000-2005). The proportion of South African ER+ patients was based on literature. The estimates were then stratified for menopausal status and disease stage. The total number of patients needing endocrine therapy was calculated assuming a 5-year treatment period. Scenario analyses were performed to compare utilization rates in different treatment combinations. Results: Annual utilization of tamoxifen and AIs increased from 12,274 to 16,492 and from 1,961 to 6,106 patients treated per year during the study period, respectively. Assuming that all the ER + patients had been treated with (1) only tamoxifen or with (2) either tamoxifen or AIs, the median proportion of patients receiving treatment was 62% and 85%, respectively. Assuming that (3) only premenopausal patients were treated with tamoxifen and post-menopausal patients with AIs, all premenopausal patients were fully treated while only 38.5% of postmenopausal patients were treated. If in similar situation (4) post-menopausal patients were treated with tamoxifen or AIs (1:1 ratio), a median of 92% of premenopausal and 77% of postmenopausal patients were treated. Conclusions: According to our data access to treatment in patients with ER + breast cancer has improved over the study period. Besides, the more realistic scenarios (2 and 4) suggest that endocrine therapy was sufficiently available for the patients in the last two years of the study.