219 Case Report Open Access Lenvatinib in Metastatic DTC (Differentiated Thyroid Cancer)- A Pragmatic Approach with Dosing *Arif Shaukat and J Ansari Prince Sultan Military Medical City Riyadh, Saudi Arabia Received: June 18, 2017; Published: June 29, 2017 *Corresponding author: Arif Adnan Shaukat, Prince Sultan Military Medical City Riyadh, KSA, Saudi Arabia, Email: Introduction Thyroid cancer has become one of the fastest-increasing cancers in recent years. There are nearly 300,000 new cases of thyroid cancer annually and approximately 40,000 people die from thyroid cancer worldwide each year [1]. Differentiated thyroid cancer is a highly treatable and curable cancer (DTC). 90% of the patients with DTC will be alive at 10 yrs after the diagnosis. However, in patients who develop radio iodine resistance these survival rates are reduced down to 10% over the same period [2- 4]. After a long struggle of finding a suitable alternative to largely ineffective treatment with chemotherapy, Multikinase Inhibitors Sorafenib and Lenvatinib after demonstrated success in Decision [5] and Select [6] trials respectively, have gained FDA and EMA approval for the treatment of Radio iodine refractory Differentiated Thyroid Cancers ( RR-DTC). Although effective, these agents as a class effect carry a considerable toxicity profile. In both the registration trials, a significant portion of patients required dose modifications in order to maintain compliance and tolerability. Common toxicities of fatigue, hypertension, palmoplantar effect diarrhoea and weight loss of more than 10% and proteinuria played a common theme effecting majority of the patients. In the SELECT trial 67.8% of the patients required dose modifications and although the intended dose was 24mg, median dose was calculated at 17.2 mg. The time for first dose reduction was observed at 3 months. We present a real time experience of cases with RR DTC treated with Lenvatinib at our facility that fall outside of the spectrum of patients recruited to the trials as above. In view of rapid onset of toxicities or co morbidities we initiated the treatment at a dose of 14mg which proved to be reasonably well tolerated and effective with demonstrable clinical responses within 1 month of initiation of treatment. Case 1 Patient is a female of 67 yrs of age. She has significant co morbidities of moderate obesity and long standing Diabetes controlled on oral hypoglycaemic. She is also a long standing hypertensive controlled on 2 anti-hypertensive agents. She has osteoarthritis and hence requires assistance with activities of daily living. She presented with right neck swelling in 2013 and underwent total thyroidectomy with neck dissection. Pathology confirmed PTC T3 N2 M0 with extra capsular spread. She had multiple doses of radio iodine due to persistent residual disease in the neck. In 2016 she was restaged due to progressive neck disease that was negative on radio iodine scan. Her staging CT confirmed bilateral neck nodes. She underwent neck dissection followed by external beam radiation but within 3 months she had further recurrence in the neck. Restaging also confirmed bilateral lung metastasis. She was initially started on Sorefanib. She presented within 3 days of start of Sorefanib at recommended doses of 400 mg twice daily. She refused to be re-challenged with Sorafenib even with dose modification. We then proceeded with Lenvatinib at 14 mg (instead of 24mg due to toxicity concerns) which she tolerated reasonably well with problems with occasional headache and grade 2 fatigues. No problems with hypertension were observed. She demonstrated a clinical response within 4 weeks of initiation of treatment with reduction in size of neck nodes to half. She continues on Lenvatinib waiting restaging. Case 2 71yrs old lady with no known co morbidities. Resident of the southern region of KSA. She was diagnosed with DTC, Insular variant of papillary thyroid carcinoma, in 2007. She had had multiple surgeries and radio iodine ablative doses since 2007. Patient re-presented in 2016 Dec with a mass in the left thyroid bed invading into the trachea. No distal metastasis was observed. She proceeded to have external beam radiation after refusal to undergo surgery. Following radiation she underwent restaging CT and PET which showed intense tracer uptake in the tumour with minimal change post radiation. Due to the critical position of the tumour that was active even after radiotherapy, treatment with Lenvatinib Cite this article: Arif Shaukat, J Ansari . Lenvatinib in Metastatic DTC (Differentiated Thyroid Cancer)- A Pragmatic Approach with Dosing. Biomed J Sci & Tech Res. 1(1)-2017. BJSTR.MS.ID.000156. DOI: 10.26717/BJSTR.2017.01.000156 Keywords: Differentiated thyroid cancer (DTC); Lenvatinib; Multi kinase inhibitors; Metastatic; Radio iodine refractory Abbreviations: RR-DTC: Radio iodine refractory Differentiated Thyroid Cancers DOI: 10.26717/BJSTR.2017.01.000156 Arif Adnan Shaukat. Biomed J Sci & Tech Res ISSN: 2574-1241