Late Effects of Cancer and Cancer Treatment
If your child has cancer, you're probably familiar with the short-term effects of the disease and its treatment: pain, nausea, fatigue, skin rashes, and more. But even when the disease is in remission and your child has been cancer-free for years, long-term side effects may arise. These problems are called "late effects."
About two-thirds of cancer survivors will develop at least one late effect sometime in their lifetimes. With early diagnosis and proper follow-up care, most late effects can be treated or cured.
The cancer itself is not what typically causes the late effects — rather, it's the treatment. Chemotherapy and radiation both work by killing fast-growing cells. Cancer cells are among those, but unfortunately so are lots of other healthy cells.
More research needs to be done to fully understand the mechanism that causes late effects, but it is likely that damage to these cells at critical points in a child's development leads to late effects.
The study of late effects in childhood cancer survivors is still relatively new. In many ways, this is a good thing. It means more and more kids are surviving childhood cancer and living longer. The downside, however, is that doctors can't always predict how the life-saving treatments they perform today are going to affect children's lives next month, next year, or 10 or 20 years down the road.
What is known is that the types of effects a childhood cancer survivor might experience later appears to depend on the type of cancer the child had, where it was in the body, the type and dose of chemotherapy and radiation, and the age and general health of the child at the time of treatment.
Common Late Effects
Late side effects experienced by childhood cancer survivors include:
Learning disabilities. Cognitive and memory impairments appear to be more common in kids who were younger than 5 at the time of treatment and in those who received chemotherapy directly in the spine or radiation to the head and neck area. Some chemotherapy drugs, like methotrexate and cytarabine (Ara-C), also can interfere with learning.
Learning difficulties range from mild to severe, and may show up soon after treatment or several years later. Common learning difficulties include problems with memory, processing speed, and multitasking. Kids who are at risk of learning disabilities should be evaluated after their cancer treatment ends.
Abnormal bone growth. Kids who undergo radiation treatment may be at risk for stunted bone growth later on, especially in the area where the radiation was targeted. Chemotherapy has a similar effect, and even though there may be a period of catch-up growth after treatment, some kids won't grow past a certain height.
Growth disorders also can be caused by treatment's effect on the glands and hormones of the endocrine system, the system in the body that regulates growth and development. Children younger than 5 or those who were in puberty at the time of treatment seem to be most susceptible. They also may be at risk for developing osteoporosis (thinning of the bones) or scoliosis (a curvature of the spine).
Thyroid problems. The thyroid is a gland of the endocrine system that controls metabolism. It may be damaged by radiation to the head or neck. The result is typically hypothyroidism, an underproduction of thyroid hormone that results in fatigue, weight gain, thinning hair, and dry skin.
Hearing loss. Chemotherapy, radiation to the brain, and even certain antibiotics can lead to high-frequency hearing loss (when a person cannot hear high-pitched sounds), tinnitus (ringing in the ears), or dizziness.
Vision problems. Blurred or double vision, glaucoma, or cataracts are more likely in kids who were treated for tumors near the eye or received radiation to the brain.
Dental problems. Short dental roots, delayed teeth, or missing teeth are more common in very young children who've had radiation to the brain. All kids who have received chemotherapy are at risk for tooth decay and gum disease.
Lung, liver, or kidney problems. Childhood cancer treatments have been linked to several types of organ damage later in life, although the severity varies widely depending on the type of cancer and treatment.
Heart problems. Kids who had chemotherapy with anthracycline antibiotic drugs or underwent chest and spinal radiation are at increased risk for heart problems up to 20 years or longer after treatment. The severity of the problem depends on how much chemotherapy or radiation was given during treatment, what part of the body the radiation was delivered to, and the child's age at the time of treatment. Family genetics, weight, and cholesterol level also have an impact regarding heart problems.
Delayed sexual development and fertility issues. Both chemotherapy and radiation can cause fertility problems. These late effects may be from damage to the endocrine system (which triggers the onset of puberty) or to the sexual organs themselves.
Because of the risk, special measures are taken prior to or during treatment to preserve the reproductive organs. For example, during radiation doctors may shield the ovaries and testicles from treatment. And teens boys and girls may be able to bank their sperm and eggs prior to treatment. The good news is that despite these potential risks, many childhood cancer survivors can go on to have healthy children of their own.
Increased risk of future cancers. Childhood cancer survivors have a slightly increased risk of developing a second cancer at some point in their life — even if the original cancer doesn't recur. Many factors affect this risk, such as the type of the first cancer, the treatments given, and any genetic predisposition.
When Your Child Is in Remission
Once your child is deemed cancer-free and in remission, you may be tempted to stay as far away from doctors and hospitals as you can. But your child needs to be carefully monitored for years to come, even into adulthood. As with any disease, the sooner any potential late effects are caught, the quicker they can be managed.
After treatment ends, ask the doctor for what's called an "off-treatment summary" that includes all of the information related to your child's cancer diagnosis, treatment, and follow-up care. Follow-up appointments may include regular screenings like blood tests, hearing tests, vision tests, and heart tests (echocardiograms, or EKGs).
It's important that your child follow this schedule. The hospital may have a cancer survivorship clinic to help with this process. Survivorship clinics provide long-term medical services and follow-up care for cancer survivors. The focus is on educating you and your child about the cancer that's now in remission; long-term follow-up recommendations; and ways to live a healthy, happy, long life.
Be sure to keep all medical records in a safe place and give them to your child when he or she is old enough to manage his or her own health care.
As your child grows, emphasize the importance of regular follow-up care and also a healthy lifestyle that includes a balanced diet and regular exercise. Both can increase your child's chances of staying well in the future.
Dealing With Uncertainty
Any childhood cancer survivor has to learn to live with the thought that the cancer might come back. Some kids may even put off telling their parents about certain symptoms for fear of being sick again.
Reassure your child that no one knows what tomorrow holds and that even if a late effect should one day appear, it's better to address symptoms earlier rather than later. Many late effects are treatable with routine medical care. Also explain that the only reason the late effect exists is because his or her life was once saved.
Despite the emotional toll of having had a childhood cancer, most kids with a strong support system are not only able to move past their ordeal but also to thrive.