Material and methods: Radioiodine (RAI) therapy was used for the treatment of 363 DTC patients from 1977 to the end of 2000 with follow-up to the end of 2004. Among them 74 patients had M1. Thirty-nine DTC patients with M1 died during follow-up. Cox-Regression and Kaplan-Meier's method were used in the analysis of data.

Results: Analyzing the death causes of 74 DTC patients with M1 we found 31 (41.9%) disease related deaths and 8 (10.8%) deaths independent of thyroid carcinoma. Among the patients with disease-related deaths there were 17 (54.8%) women and 14 (45.2%) men; 6 patients were <45 years old and 25 patients were ?45 years old (range=37-69 years, median age=54.2 years); there were 15 papillary carcinomas, 15 follicular carcinomas, and one inconclusive histological report. The causes of disease related deaths were: M1 in 21 patients, locoregional progression of disease combined with M1 in 6 patients, locoregional progression of disease in 2 patients, and late complications of initial treatment in 2 patients. Probability of survival after appearance of M1 was 60.7% after 5 years, 51.2% after 10, and 38.4% after 15 years. All patients with M1 were divided into three groups according to the initial treatment: (1) adequate surgery and RAI therapy; (2) insufficient surgery and RAI therapy or adequate surgery only; and (3) insufficient surgery only. Significant dependence (p=0.0237) was found between initial treatment and survival of patients with M1 - the longest survival was in group 1.

Conclusion: Disease related deaths in DTC patients with M1 are relatively frequent, but their frequency may be decreased by adequate initial treatment (proper surgery and RAI therapy).