[Epidemiological characteristics of thyroid cancer in Dalmatia, Croatia]

To determine epidemiological characteristics of thyroid carcinoma in Dalmatia, and to compare the incidence rate in Dalmatia with that in Croatia.

Retrospective epidemiological study.

Epidemiological indicators of thyroid carcinoma were compared between Dalmatia and Croatia as a whole, while some epidemiological indicators were compared with the characteristics of persons suffering from thyroid carcinoma in Croatia. The study included 651 persons suffering from and/or operated for thyroid carcinoma in Dalmatia between 1997 and 2006. Data were obtained from case histories, including the results of histopathologic analysis. The area of Dalmatia includes Zadar, Sibenik-Knin, Split-Dalmatia and Dubrovnik-Neretva counties (overall 861,060 inhabitants, surface 11,960 square kilometers).

The incidence of thyroid carcinoma in Dalmatia ranged from 5.2 (1997) to 10.2 per 100,000 inhabitants (2006). The mean age adjusted incidence rate of thyroid cancer in the last 10 years was 8.1 in Croatia and 9.32 per 100,000 inhabitants in Dalmatia. All incidence rates observed (Europe and world-age standardized rates, crude incidence, incidence based on research) showed a rising trend and were significantly higher in Dalmatia than in Croatia. According to sex structure, in both study areas thyroid cancer affected predominantly women, who had four times more chances of falling ill. In Dalmatia, in the overall sample, women accounted for 81.4% of all patients. In Dalmatia, papillary thyroid carcinoma was diagnosed in 80.0% of the overall sample. The median age of newly diagnosed thyroid cancer patients was 50 in Dalmatia. There was no statistically significant sex difference in the prevalence of histologic types of thyroid carcinoma in Dalmatia (P=0.318). In both sexes, papillary carcinoma was the most common type, followed by follicular, medullary and anaplastic thyroid carcinomas.

The incidence rate of thyroid cancer showed a rising trend and was significantly higher in Dalmatia than in Croatia. Epidemiological characteristics of thyroid gland carcinoma in Dalmatia were consistent with the reported characteristics of this carcinoma in iodine-sufficient areas: papillary carcinoma was prevalent and the papillary to follicular carcinoma ratio was 6.4:1.