Factors associated with lenvatinib adherence in thyroid cancer and hepatocellular carcinoma

BACKGROUND: Lenvatinib is an oral anticancer medication used to treat radioiodine-refractory thyroid cancer and unresectable hepatocellular carcinoma. The purpose of this study is to evaluate lenvatinib adherence by patients and to identify factors associated with decreased lenvatinib adherence. METHODS: Among 153 patients who started treatment with lenvatinib for unresectable thyroid cancer or unresectable hepatocellular carcinoma between May 1, 2015 and August 31 2021 at the Cancer Institute Hospital of the Japanese Foundation for Cancer Research, 102 were eligible for this study (55 thyroid cancer, 47 hepatocellular carcinoma). The lenvatinib adherence rate in a treatment cycle was defined as the number of times a patient took lenvatinib in a 28-day cycle divided by the prescribed 28 doses. The rate was determined by pill counting and self-reporting at the pharmaceutical outpatient clinic. Reasons for non-adherence were established by interview and analyzed. RESULTS: The median adherence rate of lenvatinib in the first cycle was 90.1% (n = 55) in thyroid cancer and 94.9% (n = 47) in hepatocellular carcinoma. In thyroid cancer, there were 255 incidents of lenvatinib non-adherence. Non-adherence was mainly associated with bleeding events (18.6%), followed by hand-foot skin reactions (10.6%). In hepatocellular carcinoma, there were 97 incidents of non-adherence. Hypertension accounted for 20.6%, followed by hoarseness (18.6%) and diarrhea (17.5%). CONCLUSION: The adherence rate for lenvatinib in Japanese patients with thyroid and hepatocellular carcinoma in real-world clinical practice was more than 90% in this study. Hypertension was a major reason for non-adherence, followed by hand-foot skin reactions and diarrhea.