Clinicopathological Characteristics and Treatment Outcome of Patients with Metastatic Differentiated Thyroid Cancer.

Background and Objective: Differentiated thyroid carcinoma (DTC) is a slow-growing tumour with 20% of the cases having distant metastasis. Its prognosis can vary by its histological characteristics, extension and spread. The data on metastatic DTC patients in Pakistan is scarce; therefore, the purpose of our study was to assess the clinicopathological characteristics and treatment outcomes of metastatic DTC in our population. Methods: This retrospective, single-centre study was carried out on 117 patients with metastatic DTC with their age at diagnosis, gender, tumour size and extent and spread of the tumour, and its histologic characteristic recorded. The treatment they received and the outcome in terms of status, at last, follow-up were also recorded. Results: The mean age of diagnosis was found to be 46.6 ± 17.2 years with an almost equal male to female ratio. The most common site of metastasis was the lung followed by bone. Papillary carcinoma was the most common subtype with 89.7% of the cases followed by follicular carcinoma occurring in 7.7%. The overall survival in years was found to be 5.6 ± 2.6 years. Ninety-six per cent had complete surgical resection followed by radioactive iodine (RAI) in 91.5%. Conclusion: Our study shows that the most significant factors in predicting the outcome in metastatic DTC are age, an extrathyroidal extension of the primary tumour and distant metastasis. However, further multicentric studies done on a much larger population will be needed to further support and strengthen our results.