Combination of Lenvatinib and Pembrolizumab as Salvage Treatment for Paucicellular Variant of Anaplastic Thyroid Cancer: A Case Report

Abstract

Anaplastic thyroid cancer (ATC) is a rare but aggressive thyroid cancer, responsible for about 50% of all thyroid cancer-related deaths. During the last two decades, the development of a multimodal personalized approach resulted in an increased survival. Here, we present an unusual case of a 54-year old woman with a paucicellular metastatic ATC, a rare variant of ATC, who was treated with a combination of surgery, radiation therapy and cytotoxic chemotherapy. More than two years later, when the disease was rapidly growing, a combination of lenvatinib and pembrolizumab induced a partial tumor response of lung metastasis that persisted over 18 months. Paucicellular ATC may initially show a less aggressive behavior compared to other histological ATC variants. However, over the time, its clinical course can rapidly progress like common ATC. The combination of lenvatinib and pembrolizumab was effective as a salvage therapy for a long period of time.

Keywords: anaplastic thyroid cancer; immunotherapy; tyrosine kinase inhibitors.

Figure 1

Schematic representation of disease progression and treatments; PD: progression disease, PR: partial response.

Figure 2

Immunohistochemical staining of the ATC primary tumor that developed in the context of a Hürthle cell carcinoma. (A) H&E staining of ATC with epithelial-paucicellular pattern (40×), (B) Tg staining was negative; positively stained follicles (stars) were normal cells entrapped by the tumor cells (internal control); (10×) (C) PD-L1 staining was negative (10×).

Figure 3

Axial CT image of lung (A) lesion before the start of combined lenvatinib/pembrolizumab treatment and (B) after 18 months of treatment; representative 18FDG-PET/CT images (C) at the initiation of the combined lenvatinib/pembrolizumab treatment and (D) after 18 months of treatment.