It can become large and press on the throat. When that happens, the person may become hoarse and have difficulty swallowing . In most cases, the cause of thyroid cancer is unknown. The risk is increased if the neck is exposed to radiation from any source. This happens very rarely.
Some families tend to develop thyroid and other cancers.
This is also rare. Countries where the iodine content in the food supply is either low or high also show increased risk for thyroid cancer. Nothing can be done to prevent thyroid cancer except to avoid exposure to radiation. If a person has a lump growing on the neck near the thyroid gland, a healthcare provider may suspect cancer. Special x-rays can show that the lump might be cancerous but cannot prove it.