Introduction: Anaplastic thyroid cancers (ATC) are aggressive malignancies and have a disease specific mortality approaching 100%. There are few therapies for ATC in clinical use and all have limited efficacy. Lenvatinib is a tyrosine kinase inhibitor targeting VEGF, which has shown substantial improvements in progression free survival in radioiodine refractory differentiated thyroid cancer. Phase II trials have shown some promise in utilising lenvatinib following surgery in ATC, but Phase III trials were abandoned due to disappointing results.
Case Report: We report a 67 year old male with a 70x45x48mm right sided thyroid calcified cyst which on core biopsy was confirmed as anaplastic thyroid carcinoma of spindle cell type. The lesion marginated the medial 180 degrees of the right common coronary artery and was thought to be surgically precarious. Baseline imaging confirmed pulmonary metastases at diagnosis. The patient was commenced on 24mg lenvatinib daily. He received one fraction (3Gy) of radiotherapy at diagnosis. Side effects including hypertension, fatigue and foot ulcers necessitated a single dose reduction after 2 months to 20mg. He continued lenvatinib until he progressed with a new liver lesion. At 6 weeks the lesion had dramatically reduced to 33x33mm. Following 18 weeks of treatment the primary lesion reduced to 23x17mm (>70% reduction) which facilitated surgery, and he had a successful hemithyroidectomy with central neck dissection three months after completion of lenvatinib. Pathology confirmed extensive necrosis in the specimen with morphological features and immunoprofile consistent with ATC.
Discussion: This case highlights the effectiveness of lenvatinib in ATC in a neoadjuvent setting, which has not been previously reported. The lenvatinib facilitated surgery in an otherwise inoperable lesion.