Iodine-131 avid distant metastasis in differentiated thyroid cancer: An initial institutional experience from the northern part of India

OBJECTIVE: The aim of the study was to study the clinical profile in patients of differentiated thyroid cancer (DTC) with Iodine-131 avid distant metastasis at presentation. The study also attempted to evaluate factors influencing survival among these patients. MATERIAL AND METHODS: The cohort includes 35 patients (26 Female, 9 Male) studied retrospectively and prospectively over a period of 5 years at the Sher-I-Kashmir Institute of Medical Sciences, Srinagar, India. RESULTS: The five years cause specific survival among patients of DTC with distant metastasis in the study group was 74.3%. The mean age at presentation was 41.4 years with female patients outnumbering the male patients in a ratio of 5:1. Papillary histopathology was the commonest in 65.7% followed by Follicular in 31.4% and poorly differentiated cancer in 2.9% of patients.31.4% 0f patients presented with relatively advanced AJC/UICC tumor stage of T3-T4. Bone was the commonest site of metastasis in 42.85% of patients followed by lung in 40% 0f patients. 82.9% of patients had only single organ metastasis. Therapeutic Radioiodine was administered in 31 (88.6%) patients. On univariate analysis of various factors that may be influencing the cause specific survival at 5 years, age ≥ 45 years, T3-T4 tumor stage, regional lymph node metastasis, follicular histopathology and non administration of radioiodine revealed significant (P<0.05) association with a poor 5 year survival. However multivariate analysis identified advanced tumor stage (T3-T4) and non administration of radioiodine to be the only independent factors associated with poor survival. CONCLUSION: Patients of differentiated thyroid cancer with distant metastasis having advanced tumor stage (T3-T4) and those in whom therapeutic radioiodine (I-131) is not administered seem to have an unfavorable prognosis in terms of a 5 years cause specific survival.