There are four types of thyroid cancer
- The most common type, making up 70-80% of all thyroid cancers. This type tends to grow slowly. It can spread to the lymph nodes, but even so, the outlook is generally good.
- This type makes up 10-15% of thyroid cancers and tends to occur in somewhat older patients than papillary. Like papillary cancer, it tends to grow slowly and can grow into lymph nodes in the neck. Follicular cancer is more likely than papillary cancer to grow into blood vessels and spread to distant areas, particularly the lungs and bones.
- About 5-10% of thyroid cancers, medullary cancer is more likely to run in families and be associated with other endocrine problems. Medullary thyroid cancer is the only thyroid cancer that can be diagnosed by genetic testing of the blood cells. A positive test for the RET proto-oncogene can lead to an early diagnosis.
- This is the most advanced and aggressive thyroid cancer. It is least likely to respond to treatment, but fortunately accounts for less than 5% of thyroid cancers.