Experience of lenvatinib therapy for patients with differentiated thyroid cancer in our hospital

Background It has been shown that lenvatinib is effective in patients with radioactive iodine- (RAI) refractory differentiated thyroid cancer; however, there are few reports of its use in clinical practice. Purpose We investigated the efficacy, toxicity, and optimal dose of lenvatinib that had been administered for differentiated thyroid cancer in our hospital. Method We examined dose reduction, dose-limiting toxicity (DLT), optimal dose, response rate (RR), and disease control rate (DCR) in 10 patients who had received lenvatinib for differentiated thyroid cancer from January 2016 to December 2018. Results The mean patient age was 70.5 (50-80) years; there were four men and three women, and all had papillary thyroid cancer. Eight patients had received RAI. In all cases, the starting dose of lenvatinib was 24 mg/day; all patients required interruption and dose reduction. DLT was related to arthralgia in one patient, hand-foot syndrome in one, hypertension in one, and proteinuria in seven. The mean optimal dose of lenvatinib was 10.4 mg/day; 14 mg/day in two patients, 10 mg/day in six, and 8 mg/day in two. The mean interval to optimal dose was 2.4 (1.4-4.7) months. The RR was 40% (partial response in four patients and stable disease in six), making the DCR 100%. Seven patients continued receiving lenvatinib therapy. Discussion In the SELECT study, 67.8% of participants receiving lenvatinib required dose reduction; the mean dose was 17.2 mg/day. However, in the present study, dose reduction was required in all 10 patients, the mean optimum dose being 10.4 mg/day. Conclusion We consider that revision of starting doses and guidelines for reducing the dose of lenvatinib for differentiated thyroid cancer may be necessary.