How common is anaplastic thyroid cancer?

Anaplastic thyroid cancer is the most uncommon form of the thyroid cancer. Only about 37,000 people in the United States of America are diagnosed with thyroid cancer each year. Anaplastic thyroid cancer affects only between one and 2 percent of those people. With new technology, however, the numbers may increase as doctors become better equipped to detect tumors in the thyroid gland while they are still very small.