Cause
From the 1940s to 1960s, external, low-dose radiation to the head and neck during infancy and childhood was used to treat many benign diseases. This type of therapy has been shown to predispose persons to thyroid cancer. The younger the patient was at time of exposure, the higher the risk of developing cancer.
Another cause may be due to high-dose irradiation to the head and neck. Patients with Hodgkin lymphoma treated with mantlefield irradiation have an increased risk of developing thyroid cancer, although hypothyroidism is more likely.
Read more about this topic: Thyroid Cancer