A proposed clinical scoring system for initiation of lenvatinib treatment in radioiodine-refractory thyroid cancer patients.

Abstract

The optimal timing for starting lenvatinib treatment in patients with radioiodine-refractory differentiated thyroid cancer (RR-DTC) has long been controversial because of the relatively slow-growing nature of differentiated thyroid cancer. The aim of this study was to establish a scoring system using known clinical factors to simplify decision-making in when to start lenvatinib in RR-DTC patients. We retrospectively analyzed RR-DTC patients treated with lenvatinib. We developed the clinical indication scoring algorithm on the basis of age, tumor-related symptoms, histology, metastatic sites, neutrophil-to-lymphocyte ratio, size of lung metastases, baseline sum of tumor diameters, and tumor-volume doubling time that was used to categorize patients into low-, intermediate-, and high-risk groups. A total of 59 patients were analyzed; 13 low-risk, 36 intermediate-risk, and 10 high-risk. The respective median progression-free survival from the initiation of lenvatinib was 93.7 months in the low-risk group, 20.3 months in the intermediate-risk group, and 6.2 months in the high-risk group (p < 0.02). Patients in the high-risk group had significantly worse overall survival compared with those in the low-risk (hazard ratio [HR] 6.59, 95% confidence interval [CI] 1.25-34.90, p < 0.03) or intermediate-risk (HR 2.99, 95% CI 1.03-8.63, p < 0.05) group. Using our proposed algorithm, patients in the intermediate-risk group showed treatment outcomes similar to that were observed in the pivotal trial of lenvatinib, and were the optimal patients to start lenvatinib. Our proposed scoring system can separate treatment outcomes and prognosis of RR-DTC patients treated with lenvatinib. This simple algorithm can be helpful for oncologists in deciding whether to start lenvatinib treatment in patients with RR-DTC.