INCIDENCE, MORTALITY, AND RISK FACTORS OF THYROID CANCER IN THE WORLD: A REVIEW

Objective: Thyroid cancer is the most common endocrine disorder. This study aimed to investigate the incidence, mortality and risk factors for thyroid cancer in the world. Materials and Methods: A through literature search strategy was conducted for all English language literature published before December 2017. The search was conducted using the electronic databases PubMed, Scopus, and Web of Sciences. The search strategy included the keywords 'thyroid cancer', 'epidemiology', 'incidence', 'mortality', 'risk factor, and 'world'. The search method was adjusted according to different requirements for each database. Results: The standardized incidence of the cancer was 4 in both sexes and 1.9 and 6.1 out of 100,000 in men and women, respectively, in the world. The standardized mortality rate of the cancer was 0.5 in both sexes and 0.4 and 0.6 per 100,000 in men and women, respectively, in the world. The major risk factors for thyroid cancer include radiation, smoking, alcohol and nutrition elements. Conclusions: The incidence of thyroid cancer varies considerably according to the geographical area. This study may provide considerable evidence for thyroid cancer as well as major and minor risk factors. This may be helpful in identifying subsets of the population who are more at risk of developing thyroid cancer. Effective preventive actions, such as less exposure to radiation, health education, nutritional intervention, and screening programs, are needed especially in high- risk areas of the world.