Sequential Analysis of Neutrophil-to-lymphocyte Ratio for Differentiated Thyroid Cancer Patients Treated With Lenvatinib

Background/Aim: Neutrophil-to-lymphocyte ratio (NLR) has been reported to be associated with poor prognosis for radioactive iodine ablation refractory differentiated thyroid cancer (RR-DTC). Little is known whether NLR can be a tumor marker for RR-DTC patients treated with lenvatinib. Patients and Methods: We retrospectively analyzed RR-DTC patients treated with lenvatinib. NLR was calculated at 4 points before and during lenvatinib treatment. Results: The median NLR value increased at the start of lenvatinib treatment, compared to 6 months prior to initiation of lenvatinib treatment. The median overall survival was significantly longer in patients with the lower NLR (<3) at the start of lenvatinib treatment. The median NLR values decreased when the patients achieved best tumor response, and increased again upon disease progression. Conclusion: NLR values vary before and during lenvatinib treatment, suggesting that this ratio can reflect disease activity of RR-DTC. NLR can supportively be used as a tumor marker of RR-DTC and an indicator for starting lenvatinib treatment.