Hypopharyngeal cancer radiation treatment involves the use of high energy beams to kill cancer cells in the neck and throat area. This can cause fatigue, throat and mouth sores, taste changes, and difficulty speaking. You may also have trouble swallowing food, which, along with uncomfortable mouth and throat sores, may cause you to lose weight. The radiation can affect your salivary glands, causing your mouth to feel dry as you are unable to produce adequate saliva. This predisposes you to cavities, and if your salivary glands are damaged, your dry mouth and predisposition to cavities may persist. Radiation treatment may also damage the thyroid gland so you may need blood tests to measure your levels of thyroid stimulating hormone.