Abstract
Background: Lenvatinib is one of the few therapeutic options available for radioiodine-refractory thyroid cancer. However, the factors that determine the therapeutic outcomes remain unknown. Methods: Patients with thyroid carcinoma treated with lenvatinib who had been dead or who had survived for longer than a halfyear were retrospectively compared. We evaluated the clinical parameters when lenvatinib was started, and also studied the tumor volume reduction ratio, the duration until re-growth of the largest metastatic lesion, the thyroglobulin (Tg) reduction rate, and the duration until re-elevation of Tg after lenvatinib between survivors and dead patients. Results: We identified 16 patients, with an average age of 73.1±7.6 yrs and a male-to-female ratio of 5 to 11, who had advanced differentiated thyroid cancer that was treated with lenvatinib. Nine patients had died after 8.9±6.1 months, whereas 7 survived for 13.0±2.0 months after starting lenvatinib. The patients who died were older than the survivors (76.7±6.5 vs. 68.6±6.6 yrs, p=0.03). Malignant pleural effusion (p=0.017) and symptomatic metastatic disease (SMD) (p=0.039) were associated with death in a Kaplan-Meier survival analysis. Age (p=0.012, HR 1.150, CI 1.030-1.320) and SMD (p=0.014, HR 8.069, CI 1.503-61.34) were associated with poor outcome in a multivariate Cox proportional hazard model. The duration until the re-elevation of Tg was longer in survivors than in patients who died (6.43±4.55 vs. 2.17±1.39 months, p=0.025). Conclusions: We identified multiple factors, including SMD, that were related to poor outcomes after lenvatinib treatment. This study suggests that lenvatinib might be started before patients develop SMD.
