Predictors of Discontinuation of Adjuvant Hormone Therapy in Patients With Breast Cancer

Abstract

Purpose To identify predictors of discontinuation of adjuvant hormone therapy in patients with breast cancer. Patients and Methods We conducted a record-linkage study based on data from Stockholm-Gotland Breast Cancer Register, Swedish Prescribed Drug Register, and self-reported questionnaire. Women diagnosed with breast cancer between 2005 and 2008 in Stockholm, Sweden, were prospectively followed for 5 years until 2013, starting from their first prescription of tamoxifen or aromatase inhibitors (N = 3,395). Results Family history of ovarian cancer (hazard ratio [HR], 1.55; 95% CI, 1.19 to 2.02); younger (< 40 years; HR, 1.39; 95% CI, 1.08 to 1.78) and older (≥ 65 years; HR, 1.15; 95% CI, 1.03 to 1.28) age; higher Charlson comorbidity index (≥ 2 v 0; HR, 1.35; 95% CI, 1.03 to 1.76); and use of analgesics (HR, 1.33; 95% CI, 1.16 to 1.52), hypnotics/sedatives (HR, 1.24; 95% CI, 1.07 to 1.43), GI drugs (HR, 1.25; 95% CI, 1.08 to 1.43), and hormone replacement therapy (HR, 1.27; 95% CI, 1.08 to 1.49) were identified as baseline predictors for hormonal treatment discontinuation. Use of analgesics (HR, 1.22; 95% CI, 1.08 to 1.37), hypnotics/sedatives (HR, 1.21; 95% CI, 1.07 to 1.37), antidepressants (HR, 1.22; 95% CI, 1.06 to 1.40), or GI drugs (HR, 1.27; 95% CI, 1.13 to 1.43), and switching therapy between tamoxifen and aromatase inhibitors (HR, 1.50; 95% CI, 1.23 to 1.83) during the first year of hormonal treatment were associated with increased risk of discontinuation during the next 4 years. Conclusion Predictors identified in our study can be used in developing targeted intervention to prevent adjuvant hormone therapy discontinuation and subsequently to improve breast cancer outcomes.