Thyroid Cancer in Kazakhstan: Component Analysis of Incidence Dynamics

Abstract

Background: The International Agency for Research on Cancer (IARC) reports that 567,000 new cases of thyroid<br />cancer (TC) were registered in the world in 2018, and the age-standardized incidence rate was 6.7 per 100,000. The<br />Global Cancer Observation forecasts a 35% growth in the number of new cases worldwide by 2040. The number of<br />patients with TC in Kazakhstan is also increasing steadily. This investigation was the first epidemiological study of TC<br />trends by component analysis among the population of Kazakhstan. This paper presents the results of the component<br />analysis of TC incidence trends in Kazakhstan. Methods: The study covers primary data of TC cases (ICD 10 – C73)<br />registered throughout Kazakhstan from 2009 to 2018. TC incidence trends were evaluated using component analysis<br />according to the methodological recommendations. Results: 5,559 new TC cases were registered during the 10-year<br />study period. The average age of patients was 52.0±0.2 years, the average annual age-standardized rate in 2009-2018<br />was 3.3±0.20/0000, with a constant upward trend (Т=+6.6%). According to the component analysis results, the increase<br />in incidence was mainly due to the combined effect of the two factors: the increased disease risk (ΔR=+61.7%), and<br />the population growth (ΔP=+15.4%). Conclusion: The noted increase in incidence was mainly caused by the changes<br />in risk factors, such as the worsening environmental aspects and the increase in detection of clinically non-manifesting<br />cases. The results of the study shall be taken into account when planning anticancer activities for TC.