Retrospective evaluation of clinicopathological characteristics of differentiated thyroid cancer patients with iodine-131-avid distant metastasis: A tertiary care centre experience

Abstract

Introduction: Among various prognostic indicators, distant metastases have a strong impact on the overall survival of differentiated thyroid cancer (DTC) patients. Aim: The aim of this study was to know the incidence, pattern of iodine-131-avid distant metastases in DTC patients at presentation, long-term survival probability in DTC patients with distant metastases and also to know the relationship between the distant metastases and clinicopathological variables such as age, gender, and histopathological subtypes. Materials and Methods: Retrospective evaluation of case records and whole-body iodine scans of DTC patients referred to our hospital between January 2013 and December 2018 was done. Results: A total of 1336 DTC patients' case records were analyzed. Among them, 157 patients (11.7%) had distant metastases at presentation. Majority were female patients (63%). The mean age of patients in the study group was 48.4 years. Most of the patients had papillary histopathology (58.6%), followed by follicular (34.4%), poorly differentiated (5.73%), and Hurthle cell carcinoma (1.27%). Bone was the most common site of metastases in 49% of patients, followed by the lung in 25% of patients. Two (1.27%) patients had an unusual site of metastases involving the kidney and adrenal gland. Nearly one-third patients (25.5%) had multi-organ metastases. The 5 years specific survival probability of DTC patients with distant metastases at presentation was 47.3%. Conclusion: The incidence of distant metastases in our study is similar to the incidence rate reported in the literature. Distant metastasis is higher in female patients and in the age group of 45 years and above. Bone is the most common organ site of metastases rather than lung in the present study, which is pointing towards the high incidence of skeletal metastases in Indian patients. The specific survival probability at 5 years is 47.3%.