Factors influencing the use of extended adjuvant endocrine therapy

Extending adjuvant endocrine therapy (ET) beyond 5 years has been shown to improve outcomes in breast cancer; however, limited data are available about if and why women pursue extended ET. The primary objective was to estimate the proportion of women who were willing to receive extended ET if recommended by their physician and secondarily, to determine what factors were associated with this decision.

This descriptive cross-sectional study surveyed 131 women with AJCC 7th Edition stages I-III breast cancer who had been taking adjuvant ET for 3-5 years. The survey inquired about the willingness to continue ET, quality of life (FACT-ES), and beliefs about medications (BMQ). Logistic regression was used to test for associations between clinical and disease factors, FACT-ES, BMQ, and the primary outcome.

One hundred and twelve (85%) patients reported "moderate" (n = 30, 23%), "quite a bit" (n = 41, 31%), or "extreme" (n = 41, 31%) willingness to pursue extended ET; 19 (14%) patients were "not at all" or were "unlikely" to be willing to take extended ET. On univariate analysis, lower total and social well-being FACT-ES scores, and lower perceived necessity and higher concerns on BMQ were associated with lower willingness to pursue extended ET. On multivariable analysis, greater patient perception of necessity of ET was the only factor associated with willingness to pursue extended ET (OR 1.34, 95% CI 1.15-1.57, p = 0.0005).

Most women who have taken ET for multiple years report being willing to pursue extended ET if recommended. When discussing extended ET, the data from this study support exploring patients' belief of medication necessity.