What is the Most Common Type of Thyroid Cancer?

Typically, thyroid cancers can be broken down into three types: papillary carcinoma, follicular carcinoma and anaplastic. Other rare types of thyroid cancer include medullary thyroid cancer and primary thyroid lymphoma. Papillary is the most common type of thyroid cancer, accounting for 85% of thyroid cancers diagnosed annually (follicular accounts for 12% and anaplastic <5%).

Regardless of its type, thyroid cancer stays mostly asymptomatic or may present just as lump in the neck. It often is discovered incidentally as a thyroid nodule during clinical exams or imaging studies like CT scans or sonograms (most of the thyroid nodules are benign and only 5-15% are malignant thyroid cancers). If the cancer is not found, it can eventually grow large enough to cause pain, swallowing issues and hoarseness.

Common Thyroid Cancer Treatments

While different types of thyroid cancers have similar symptoms, these cancers’ treatments are not the same.

Broadly, patients with papillary and follicular carcinoma undergo surgery to remove the thyroid followed by radioactive iodine therapy. Medullary thyroid cancer patients also undergo surgery, but are not required to have radioactive iodine therapy. All patients whose thyroids are removed need to have lifelong thyroid hormone replacement. Anaplastic thyroid cancer may require local radiation therapy to the neck.

Typically, patients with differentiated thyroid cancers like papillary and follicular have an excellent prognosis for survival, especially if the cancers are discovered before spreading outside the neck area. However, anaplastic thyroid cancers are defined as undifferentiated cancers, meaning their cells do not look like the cells in the tissue from where they arose. Undifferentiated cancers are known to be more malignant, and thus have a poor prognosis and decreased survival rates.