Purpose: The objective of this study is to determine demographic, clinical, and pharmaceutical factors that are associated with longer endocrine therapy usage duration.
Methods: South Carolina Central Cancer Registry incidence data linked with South Carolina Medicaid prescription claims and administrative data were used. The study included a sample (N = 1399) of female South Carolina Medicaid recipients with hormone receptor-positive breast cancer diagnosed between 2000 and 2012 who filled at least one ET prescription. A series of multiple regression models were built to explore the association of demographic, clinical, and pharmaceutical factors with the endocrine therapy usage duration.
Results: Multiple linear regression analysis showed that none of the demographic or clinical factors tested were significantly associated with the endocrine therapy usage duration. However, the type of endocrine therapy taken as well as receipt of the prescriptions that could have been used to alleviate side-effects (adrenals, nonsteroidal anti-inflammatory agents, anti-inflammatory agents, and vitamins) were significantly associated.
Conclusion: Our study highlights the potential value of concurrent prescriptions for improving the endocrine therapy usage duration, with an optimal intervention point before 14 months post ET initiation. This work informs further research needed to test pharmacologic interventions that may significantly increase the endocrine therapy duration as well as other nonpharmacologic strategies for side-effect management.
Keywords: Endocrine therapy; Tamoxifen; aromatase inhibitors; breast cancer; cancer surviorship.