ABSTRACT
Thyroid cancer is by far the most common malignancy of endocrine glands with a recent increase of incidence over the past decade. In 1995 there were approximately 17 000 new cases of thyroid cancer in the US and in 2007 it is estimated that there will be 33 550 new cases of thyroid cancer 1 . The reason for this increase is not clear but since the overall mortality rate from thyroid cancer has been relatively stable over that time period ( Figure 29.1 ), it is thought to be due to better detection. The primary etiology for well-differentiated thyroid cancer which comprises the majority of this increased incidence is radiation exposure and, if anything, there is less radiation exposure due to external beam treatment for benign disease which stopped in the 1950s and environmental catastrophes. Furthermore, the majority of these lesions are small and can be detected by increased use of ultrasound screening and attention to and biopsy of smaller lesions 2 .
