Tyrosine kinase inhibitors in iodine-refractory differentiated thyroid cancer: experience in clinical practice

The aim of this study is to describe our clinical experience with tyrosine kinase inhibitors (TKIs) and to evaluate their efficacy and tolerability in patients with iodine-refractory differentiated thyroid cancer (DTC).

There were 17 patients (47.1% women, mean age: 65.7) with DTC iodine-refractory (9 papillary, 2 follicular and 3 Hürthle cell), treated with TKIs: 16 with sorafenib and 1 with lenvatinib as first-line treatment; 7 required second-line treatment (4 lenvatinib and 3 axitinib). Primary endpoints were progression-free survival (PFS) and radiographic response (determinate at 3, 6, 12, 18, and 24 months after the initiation of treatment) and second endpoints were determining differences in baseline characteristics depending on clinical course and describing toxicities and tolerability.

Median PFS was 18 months. During the first 24 months of treatment with TKIs PR rate was 35.3% (only 5.8% ≥ 6 months) and SD ≥ 6 months was observed in 58.8%. There were no significant differences in baseline characteristics between patients with good and poor evolution. Adverse events (AEs) were present in 100% of patients, but most of them were grade 1 and 2.

In our population of patients with iodine-refractory DTC, treatment with sorafenib, lenvatinib, and axitinib allows the stabilization of the disease in a high percentage of cases, with acceptable tolerability.