What Are 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, tiredness, skin rashes, and more.

But even when the disease is in and your child has been cancer-free for years, long-term side effects may happen. These problems are called "late effects."

About 2 out of 3 cancer survivors will develop at least one late effect at some point. With early diagnosis and proper follow-up care, most late effects can be treated or cured.

What Causes Late Effects?

The cancer itself is not what usually 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 how late effects happen. Researchers think it is likely that damage to the cells at critical points in a child's development leads to late effects.

Doctors have learned that the types of effects a childhood cancer survivor might have later can depend on:

• the type of cancer the child had
• where the cancer was in the body
• the type and dose of chemotherapy and radiation
• the age and general health of the child at the time of treatment

What Are the Common Late Effects of Cancer Treatment?

Late side effects include:

Learning problems. Some chemotherapy drugs and/or radiation to the brain may interfere with learning. The problems can range from mild to severe, and may show up during treatment, soon after treatment, or several years later. Common learning problems include problems with memory, processing speed, and multi-tasking.

Abnormal bone growth. Sometimes kids do not grow in the usual timeframe and/or stop growing much earlier than normal. This may be due to radiation treatment, chemotherapy, or a brain tumor or its treatment.

Kids may also be at risk for developing osteoporosis (bone thinning) or scoliosis (a curved spine).

Thyroid problems. The thyroid is a gland of the endocrine system that controls (chemical reactions in the body's cells). It may be damaged by radiation to the head or neck. The result is typically hypothyroidism (when the thyroid doesn't make enough thyroid hormone), leading to tiredness, weight gain, thinning hair, and dry skin.

Hearing loss. Chemotherapy, radiation to the brain, and even some 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 and/or chemotherapy with a drug called vincristine. All kids who have had chemo are at risk for tooth decay and gum disease.

Lung, liver, or kidney problems. Childhood cancer treatments have been linked to several types of body organ damage later in life. How serious the organ damage is depends on the type of cancer and treatment.

Heart problems. Kids who had chest radiation and/or chemo with a class of drugs called anthracycline are at higher risk for heart problems up to 20 years or longer after treatment. The severity of the problem depends on how much chemo and/or chest radiation they got and the child's age during treatment. Family genetics, weight, and cholesterol level also play a role in in getting 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 starts the onset of puberty) or to the sexual organs themselves.

Because of the risk, special measures may be taken before or during treatment to protect the reproductive organs. For example, doctors may shield the ovaries and testicles during radiation treatment. Teen boys and girls may be able to bank their sperm and eggs before cancer treatment. The good news is that despite these 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 higher risk of developing a second cancer at some point — even if the original cancer doesn't come back. Many things affect this risk, such as the type of the first cancer, the treatments given, and any genetic risks.

What Can We Expect During Remission?

When your child is considered 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 possible late effects are caught, the quicker they can be managed.

After treatment ends, ask the doctor for what's called an "off-treatment summary." This 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.

Keep all medical records in a safe place, and help your child begin taking responsibility for managing 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.

How Can Parents Help?

Knowing that the cancer might come back can be hard for any childhood cancer survivor. Some kids might not tell their parents about any new 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 appear, it's best to pay attention to symptoms right away. Many late effects are treatable with routine medical care.