Short-term effects appear quickly and then subside, but long-term side effects may not become apparent for months or years after treatment ends. Specific late effects depend on the age of the child when radiation was given, the dose of radiation, and what part of the brain was irradiated.

The effects of radiation on cognitive functioning, bone growth, soft tissue growth, teeth and sinuses, puberty, and fertility, range from none to severe and life-long impacts. Brain tumor survivors can develop seizure disorders, gait and balance problems, hand/eye coordination problems, personality changes, and learning disabilities. Vision problems and cataracts can develop after radiation, and second tumors in the radiation field are a rare but possible long-term side effect. Detailed information about possible late effects are described in Childhood Cancer Survivors: A Practical Guide to Your Future, 3rd edition by Nancy Keene, Wendy Hobbie, and Kathy Ruccione (see www.childhoodcancerguides.org/survivors).

Cognitive problems

Injury to the brain can result from a multitude of factors, including tumor extension, surgical procedures, radiation, and chemotherapy. Children with brain and spinal cord tumors often develop mild to severe learning disabilities that can start immediately or develop later. Whole brain radiation can result in problems with mathematics, understanding visual/spatial relationships, problem solving, attention span, memory, and concentration skills.

Children at greatest risk for significant cognitive problems are those treated with radiation when younger than 5 years of age, with those younger than 2 at the highest risk. Children treated with radiation after age 5 or into adolescence are also at risk for developing early or late cognitive difficulties. Chapter 18, School, discusses in great detail the types of educational problems some children face and methods to deal with the problems.

Endocrine function

The endocrine system is composed of glands that secrete hormones into the blood. The endocrine glands that can be damaged by brain or spinal cord radiation include the pituitary gland, thyroid gland, ovaries, and adrenal glands. Problems with these glands may develop years after treatment, so long-term follow-up by experts in the late effects after childhood cancer is essential. Long-term followup should include careful monitoring by an endocrinologist, a doctor who specializes in hormonal issues.

Growth

The brain contains the hypothalamus and the pituitary gland, which control many body processes, including growth and reproduction. Effects on growth usually begin to be seen in children who receive 2.4 Gy or more of radiation to these two glands. If your child receives radiation therapy to the brain and/or spine, her growth will require close observation, and she should be measured (sitting and standing) at every follow-up visit. Your child’s growth chart should be kept up to date so that it will be easier to quickly observe subtle changes that may indicate early plateauing of your child’s growth.

If your child is one of the rare individuals who experience precocious puberty (before the age of 8 for girls and 10 for boys), growth may also be affected. An early growth spurt with early sexual maturation results in short stature because bones stop growing when sexual maturity is reached. When this happens at a young age, the child loses 2 to 3 years of additional growth. After treatment for a brain or spinal cord tumor, growth hormone injections are sometimes given to support your child’s growth until he reaches his final height.

Early or delayed puberty

Some young children who receive radiation to the brain do not experience puberty at the appropriate age. As mentioned earlier, a very small percentage of children develop precocious puberty, which means puberty begins several years earlier than normal. This is most common in children who also have impaired growth. Conversely, puberty is significantly delayed in some children who have received cranial radiation.

A pediatric endocrinologist with extensive experience treating children and adolescents who had cancer should evaluate girls and boys who show signs of early or delayed puberty.

Vision

Problems with vision may occur as a result of tumor location, tumor spread, surgery, or radiation therapy. If such problems are present, the early involvement of a pediatric ophthalmologist and serial evaluations are important. Your child may need special glasses, selective seating in the classroom, or a reading machine. If your child has significant visual impairment or is considered legally blind, she is probably eligible for a variety of services, including Talking Books, a free library service (www.nlstalkingbooks.org). It is important that you keep a copy of all reports of your child’s vision testing for your records. Such reports are very useful when dealing with your child’s teachers and school administrators.

Teeth

Although newer conformal treatments have reduced the late effects of radiation on teeth, cranial radiation given in previous decades often resulted in disrupted tooth development and in the blunting of roots of children’s permanent teeth. This resulted in some children missing certain permanent teeth or in early tooth loss because of shortened roots. Even with newer treatments, the involvement of a pedodontist (children’s dentist) is important.

Any child who received cranial or spinal radiation is at additional risk for dental decay because of diminished function of the salivary glands. Appropriate dental evaluations and treatment with fluoride preparations may be necessary. You should ask your radiation oncologist for a summary of the dose to the teeth and to let you know whether the dose is enough to be concerned about future dental problems.

Secondary cancers

Children who receive radiation to the brain have an increased risk of developing another tumor years after treatment. The risk is reported to range from 1 to 5 percent.

Despite the possibility of these short- and long-term effects, radiation therapy remains an important treatment for children with brain and spinal cord tumors. Technological advances have allowed for more targeted treatments intended to cure the child while minimizing or avoiding these complications.

As I carried my unconscious son back to the waiting room after radiation treatment, a woman there stared intently. On impulse, I took the seat next to her. As I arranged Ben into a bear hug with my arms wrapped around him, she whispered to me, “I’m so jealous.” I was taken aback by the heat in her voice. She told me she was making these daily treks with her son, too. Only, he was 21 years old, and wouldn’t let her hold him or hug him. It broke her heart to see Ben and I wrapped up in ourselves in that unique mom-child world of clinging hugs, multiple kisses, and rubby-faces. Her son was brave, a valiant independent young man, and she was proud of him. But what she really wanted to do was wrap herself around him, tuck his head under her chin, and make everything all better like she used to.