Rising incidence of thyroid cancer in Serbia

Hippokratia. Jan-Mar 2016;20(1):9-23.

Abstract

Background: In the past decade, the incidence of thyroid cancer (TC) has shown a stable increase, for both sexes, in many parts of the world at a rate faster than for any other type of malignancy. The aim of our study was to analyze and report changes in TC incidence in Serbia, as well as to evaluate potential reasons for these changes. So far, the incidence of TC in Serbia has not been reported.

Material and methods: This is a retrospective descriptive epidemiological study of TC data from the Cancer Register for Serbia for a ten year period, from 1999 to 2008. Crude rates (CR), age-specific rates (ASR), age-adjusted rates (AAR), linear trends and average annual percentage changes (AAPC) were calculated and analyzed.

Results: TC incidence increased substantially for both genders with the highest increase in 2007 for the age group 50-59 (females 14.2, males 10.3). TC was three times more common in females (CR 4.7:1.5). The AAR for females ranged 1.9-4.8 (3.3, 95% CI 2.6-4.0), for males 1.0-2.6 (1.0, 95% CI 0.8-1.2) and for both sexes combined 1.4-3.2 (2.2, 95% CI 1.7-2.6). The incidence trend for males showed an increase (y =0.05x + 0.70, p =0.058). It was highly statistically significant for females (y =0.31x + 1.61, p <0.001) and both genders combined (y =0.18x + 1.18, p <0.001). AAPC was highest for ages 20-29 and 30-39, for females (+25.2%) and males (+17.3%), respectively.

Conclusions: We found a substantial increase in TC incidence in Serbia for both genders. The highest increase in TC incidence was found in females aged 20 to 29 years while the highest incidence was found in the age group 50 to 59.

Keywords: Serbia; Thyroid cancer; age-adjusted rates; age-specific rates; average annual percentage changes; crude rates; incidence.