Medullary thyroid cancer is a rare form of thyroid cancer, accounting for 5% of thyroid cancers. Detecting medullary thyroid cancer early can be difficult. Undiagnosed medullary thyroid cancer can spread into the tissues of other organs and eventually to the liver, lungs, bones, and brain. The following information will provide insights into the prognosis, life expectancy, and survival of medullary thyroid cancer.