Sustained lower incidence of thyroid cancer in West Cumbria, UK

Background: In recent years, incidences of thyroid cancer have increased in developed countries; one of the known risk factors for thyroid cancer is exposure to radioiodine. Previous research by Bowlt and Tiplady [5] has shown an inverse link between radioactive iodine levels contained in thyroid tissue of deceased inhabitants and the distance they lived from the Sellafield nuclear facility in Cumbria, UK. Objectives: The present study aimed to determine what thyroid cancer incidences were in the regional localities in Cumbria for the last decade. Methods: An ethics-approved retrospective cohort study in which age-standardised incidence of thyroid cancer per 100,000 population was compared between localities within Cumbria and with UK average figures. Conclusions: The present study shows that the apparent lower incidence of thyroid cancer in West Cumbria has persisted, although due to the limited number of thyroid cancers diagnosed, a statistically significant difference was not observed. Further research – potentially involving populations living near sources of radioiodine emission - is indicated to investigate if there are any mechanisms that underlie this apparent trend.