The exact cause of thyroid cancer is not known. Similar to how other cancer forms develop, changes in the DNA of cells is responsible for the development of thyroid cancer. These alterations could either be genetically inherited or occur over a period of time. But, it is well established that cancer is not contagious.
Thyroid cancer risk factors
Exposure to radiation increases one’s chances of getting thyroid cancer. A mere dental X-ray, however, does not increase the chances of developing thyroid cancer, but a radiation therapy to the head, neck or chest surely does.
There has been significant amount of research to understand DNA changes that become cancerous. Most cancers are not inherited, which means that DNA gets damaged by the exposure to something in the environment such as radiation or smoke during the course of one’s life. The cancer may also occur when unexpected changes take place inside a cell without a specific external cause.