Audit of Demographics, Treatment Patterns and Outcomes of Differentiated Thyroid Cancers Treated with Tyrosine Kinase Inhibitors.

The real-world patterns of TKI use in differentiated thyroid cancer (DTC) are largely governed by the accessibility and financial feasibility of the patient with more sorafenib use compared to lenvatinib. There are limited data available on the toxicity profile, safety and tolerance of sorafenib and lenvatinib in DTC. Hence, we audited our practice on DTC. This is a retrospective single-centre analysis of patients with DTC who were referred to the Department of Medical Oncology for systemic therapy. Baseline demographics (age, sex, ECOG PS, comorbidities, substance use), tumour details (site of metastasis), previous treatment details, clinical features at metastasis (symptoms), the pattern of treatment, adverse events and outcomes including progression and death were extracted. There were 67 patients with DTC referred for systemic therapy; the median age was 56 (33-81) with a male preponderance (55.6%). The most common reason to start TKI therapy was radioactive iodine (RAI) cumulative dose > 600 milliCurie, followed by low iodine uptake in the RAI low-dose scan done at progression. The most common TKI used in the first line was sorafenib in 56 (83.6%) patients followed by lenvatinib in 9 (13.4%) patients. Papillary thyroid carcinoma was the most common histology (51, 76.1%), and the rest were follicular carcinoma (16, 23.9%). With a median follow-up of 36 months, the median PFS was 13.2 months (95% CI 10.4-16.0). The median OS was 18.8 months (95% CI 10.0-27.6). Among variables tested, no factors had a significant impact on the PFS or OS. The most common adverse events were hand-foot syndrome (54, 80.5%), diarrhoea (23, 33.3%) and transaminitis (24, 34.4%). The pattern of care of patients with RAI-refractory DTC is TKI therapy, especially sorafenib and lenvatinib in the real-world settings with comparable efficacy and safety profile compared to international literature.