Thrombotic Events during Lenvatinib Treatment: A Single Institution Experience

Lenvatinib is the standard treatment for radioiodine-refractory differentiated thyroid cancer (RR-DTC). Thromboembolic (TE) side effects are quite rare (1–3% of treated patients) in clinical trials. Nevertheless, patients with predisposing factors are at a higher risk of developing cardiovascular adverse events. Reduction of lenvatinib starting dose and cardiologic counselling to provide appropriate supportive therapies are usually recommended for high-risk patients. From 2016 to 2022, we analyzed a series of 16 patients who were consecutively treated at our institution. All except one patient received a reduction in their dosage after two cycles of therapy because of toxicities, and four patients (25%) suffered from TE. The observed incidence in our patient sample seemed to be higher than expected. We hypothesized that our patient sample might be at higher risk probably because of the heavy prior loco-regional treatments performed.