An 80 year old female who presented with headaches, blurry vision and GTC seizures post starting Lenvatinib.
She has a history of a 75mm papillary thyroid cancer with stage T4aN1aM0. She had a total thyroidectomy followed by Iodine 131 RAI ablation. She had two RAI remnant ablations with 3 withdrawal scans. She developed multiple lungs nodules up to 19mm which were metastatic thyroid papillary carcinoma. She preferred to start on the best available treatment (Lenvatinib) due to deteriorating general health. Her other history includes high blood pressure.
Her CTB showed extensive posterior cerebral oedema. Her MRI brain showed extensive increased signal in the occipital lobe regions consistent with widespread changes of PRES. She was managed with a hydralazine infusion in ICU. Amlodipine was added and Lenvatinib was stopped. She was started on levetiracetam 1g BD for her multiple seizures. 5 weeks later, her repeat MRI brain showed resolution of her PRES changes.
Metastatic papillary thyroid cancer is an indolent malignancy with a median survival of 3 to 6 years. There is no drug therapy that has demonstrated an overall survival benefit in RAI refractory metastatic differentiated thyroid cancer.1 Kinase inhibitor therapy is considered in RAI refractory DTC patients with metastatic, rapidly progressive and symptomatic disease. Lenvatinib is an oral multikinase inhibitor that mainly targets VEGFR 1-3 and FGFR 1-4. It delays time to disease progression by 14.7 months.2
The risk of hypertension is high when starting Lenvatinib with 73% of patients on the drug having high blood pressure. PRES is a neuroradiological phenomenon that can progress to seizures, coma and death. High blood pressure induces vasoconstriction to reduce cerebral perfusion pressures, resulting in cerebral oedema. Treatment is usually supportive. PRES is reversible with signs and symptoms resolving within days to weeks although in one case series, 27% were fatal.3