Willingness of women with early estrogen receptor-positive breast cancer to take adjuvant CDK4/6 inhibitors

Background The steady decline in breast cancer (Bca) mortality has come at the cost of increasingly toxic and expensive adjuvant therapies. Trials evaluating the addition of 2 or 3 years of cyclin-dependent kinase 4/6 (cDK4/6) inhibitors to adjuvant endocrine therapy (Et) are ongoing, but the willingness of patients to take such additional therapy is unknown. Methods We surveyed 100 consecutive postmenopausal women with nonmetastatic estrogen receptor-positive Bca who had initiated adjuvant ET within the preceding 2 years. Participants were asked about perceived recurrence risk, ma worry, and overall health. They were then asked about their willingness to accept 2 years of treatment with an additional oral drug that would reduce recurrence by 40% for a range of baseline recurrence risks in 2 hypothetical scenarios. Results Mean age of the 99 evaluable participants was 61.7 years. In the scenario with no drug toxicity, 85% of respondents were likely to accept the new drug for a reduction in recurrence to 30% from 50%, but only 49% would take the drug if risk was reduced to 3% from 5%. In a scenario with drug-induced fatigue, the corresponding drug acceptance rates were 55% and 39% respectively. For the second scenario, Bca worry was correlated with increased willingness to take the drug, even for only a 2% absolute reduction in recurrence risk. Conclusions The willingness of patients with estrogen receptor-positive BCa to take an adjuvant. CDK4/6 inhibitor will greatly depend on the expected benefit and toxicities described to them as well as on worry about Bca recurrence.