To the brain can affect movement, coordination, intelligence and learning especially in young children with developing brains.

Children less than 3 years old are most affected. Between 3 and 6 years there is less risk of damaging brain function. The risk is even lower in children older than 6 years at the time of radiation.

Baseline developmental testing is done prior to radiation therapy and continued after completion to plan appropriate intervention at home and school and seek special services if necessary. Hormone production may be affected by radiation therapy to the pituitary gland (at base of brain), affecting growth, salt/fluid balance, sex hormone levels, etc.

Radiation therapy to the head or face can result in drying and irritation of the eyes and requires the use of artificial tears. Cataracts may develop. Radiation therapy in the region of the mouth or throat may cause a dry mouth, stone formation in the salivary glands or affect the growth of the jaws or destroy the jawbone. Dental problems are common and need regular follow up with a dentist. Taste, eating and bowel habits, or food absorption may be affected.

Thyroid function is decreased after neck and chest radiation resulting in weight gain, cold intolerance, etc... Radiation therapy to the chest can result in defective lung or heart function. These need monitoring, therapy and advice regarding restriction of activity, increased workload during pregnancy, etc.

The adrenal gland, ovaries and testes can have decreased function after radiation to the abdomen, pelvis and testes. Cortisol and sex hormone levels, the onset of puberty, etc. will need to be regularly assessed at follow up and hormones supplemented if necessary. Radiation to the abdomen can affect the kidneys and may result in increased blood pressure.

Bone growth is slowed by radiation therapy and can result in short stature (whole body or spine radiation) or decrease growth of isolated bones affected by radiation such as the teeth, jaws or a limb. Limitation of movement occurs if joints or muscles are affected. Some of these require medical or surgical correction if the side effects are significant. Skin is sensitive to sunburn following radiation. Regular use of sunscreen is essential.

Finally, radiation therapy results in an increased incidence of second cancers especially at a previously radiated site and should always be ruled out medically if unexplained symptoms develop. Routine screening in specific areas to detect a second cancer early is a good idea.

Examples are: Examination of the neck and thyroid gland or regular mammograms starting in the twenties to detect breast cancer developing in women after radiation to the chest.