Tyrosine Kinase Inhibitor Therapy in Locally Advanced Differentiated Thyroid Cancer: A Case Report.

A 73-year-old female presenting with haemoptysis and dyspnoea was found to have a locally advanced left thyroid mass and vocal cord palsy. A CT scan of the neck and thorax and endoscopy demonstrated invasion into the tracheal lumen. Histopathology of the intraluminal tracheal mass confirmed a papillary thyroid cancer (PTC). The tumour was deemed unresectable due to local extent and patient comorbidities. TKI therapy with lenvatinib was used for 14 months. On serial scanning, a marked reduction in tumour volume from 31 × 59 × 32 mm to 17 × 28 × 22 mm was noted. This subsequently allowed a successful surgical resection with a total thyroidectomy and central neck dissection with no evidence of residual macroscopic disease. Histopathology confirmed a well-differentiated PTC with features of tumour regression. In this case, TKI therapy in a locally advanced unresectable DTC reduced tumour size and infiltration to a degree that surgical resection of macroscopic disease was possible, without requiring airway resection. This raises the possibility that TKIs may have a neoadjuvant role in selected cases of locally advanced DTC to reduce tumour volume and therefore morbidity of subsequent surgical resection.