Which factors predict survival in lenvatinib-treated radioiodine-refractory differentiated thyroid cancer?

Patients with radioiodine-refractory differentiated thyroid cancer (RR-DTC) with good ECOG* performance status and radioactive iodine (RAI) avidity benefit the most from treatment with lenvatinib, a study has shown. Moreover, the only independent predictor of survival after treatment initiation is objective response.

This multicentre, retrospective, cohort study included 55 RR-DTC patients treated with lenvatinib at three Italian thyroid cancer referral centres. Progression-free survival (PFS) and overall survival (OS) were the primary endpoints.

Of the RR-DTC patients, 96.4 percent received lenvatinib as first-line kinase-inhibitor. Over a median follow-up of 48 months, patients had a median PFS of 26 months (95 percent confidence interval [CI], 19.06–32.93) and a median OS of 70 months (95 percent CI, 36–111.99).

In the pretreatment setting, ECOG performance status independently correlated with PFS (score 0–1 as reference; hazard ration [HR], 18.82, 95 percent CI, 3.65–97.08; p<0.001) and OS (score 0–1 as reference; HR, 6.20, 95 percent CI, 2.11–18.20; p=0.001). RAI avidity also showed an independent association with PFS (HR, 3.74, 95 percent CI, 1.01–13.76; p=0.047).

Patients with good ECOG status (0–1) and RAI-avid disease achieved a 100-percent objective response and a median PFS of 45 months with no death upon a median follow-up of 81 months.

In the post-treatment setting, only the best radiological response was independently predictive of PFS (HR, 4.6, 95 percent CI, 1.89–11.18; p=0.001) and OS (HR, 2.94, 95 percent CI, 1.25–6.89; p=0.013).

*Eastern Cooperative Oncology Group