MON-560 Thyroid Cancer and Iodine Nutritional Status in Asturias (Spain)

Abstract

INTRODUCTION Iodine deficiency may play a role in thyroid cancer carcinogenesis. Because Spain has region-specific historical iodine deficiency, it is ideal to evaluate the potential impact of recent national iodine supplementation policies on thyroid cancer incidence trends. In Asturias there have been several population studies of iodine nutritional status (in 1983, 1992, 2000 and 2010), showing a progressive and significant increase in urinary iodine concentration, probably due to promotion of iodized salt use. OBJECTIVES Evaluate the potential impact of iodine nutrition status changes in the last 30 years in subtypes thyroid cancer distribution trends MATERIAL AND METHODSDescriptive, observational study of the different histological subtypes of thyroid cancer in a tertiary referral hospital. Cases were divided into 3 periods of time (1981-1990, 1991-2000, and 2001-2010), according with our epidemiological studies on iodine nutrition. For the statistical analysis SPSS v17 was used. RESULTSA total of 697 patients with histologic report were included. Proportion of papillary cancer has significantly increased (group 1 1981-1990 44.8%, [95%CI 36.6-53], group 3 2001-2010 66.2%, [95%CI 61.2-71.1] p < 0.001) whereas follicular cancer significantly decreased between 1981 and 2010 (group 1 1981-1990 43.8% [95%CI 35.3-51.6], group 3 2001-2010 27% [95%CI 22.3-31.6] p < 0.001). Anaplastic cancer also significantly decreased (group 1 1981-1990 7.6% [95%CI 3.2-11.9], group 3 2.6% [95%CI 0.9-4.2] p < 0.001. These changes occurred in a historically iodine deficient region. Median urinary iodine concentration increased from 63 µg/L in the 80’s until 181 µg/L in the last study in 2010. CONCLUSIONSTrends among different histological subtypes of thyroid cancer change as the nutritional status of iodine improves, with a greater proportion of papillary thyroid cancer compared to the follicular and anaplastic subtypes.