ABSTRACT: Overview Epidemiology Thyroid nodules are approximately 4 times more common in women than in men. Palpable nodules increase in frequency throughout life, reaching a prevalence of approximately 5% in the United States population aged 50 years and older.(1-3) Nodules are even more prevalent when the thyroid gland is examined at autopsy or surgery, or when using ultrasonography, and 50% of these have nodules, which are almost always benign.(2,4) New nodules develop at a rate of approximately 0.1% per year beginning in early life, but at a much higher rate (∼2% per year) after exposure to head and neck irradiation.(5,6) By contrast, thyroid carcinoma is uncommon. For the United States population, the lifetime risk of being diagnosed with thyroid carcinoma is less than 1% (0.83% for women and 0.33% for men).(7) Approximately 37,200 new cases of thyroid carcinoma were diagnosed in the United States in 2009.(8) As with thyroid nodules, thyroid carcinoma occurs 2 to 3 times more often in women than in men. With the incidence increasing by 6.2% per year, thyroid carcinoma is currently the sixth most common malignancy diagnosed in women.(8) Among persons age 15 to 24 years, thyroid carcinoma accounts for 7.5% to 10% of all diagnosed malignancies.(9-11) The disease is also diagnosed more often in white North Americans than in African Americans. Although thyroid carcinoma can occur at any age, the peak incidence from 2004 to 2006 was near age 45 to 49 years in women and 65 to 69 years in men.(7) Thyroid carcinoma has...
Journal of the National Comprehensive Cancer Network: JNCCN 11/2010; 8(11):1228-74. · 4.41 Impact Factor