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Late Effects of Treatment for Childhood Cancer (PDQ®)

  • Last Modified: 04/17/2014

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Endocrine System

Key Points for This Section



Thyroid gland

Thyroid late effects are more likely to occur after treatment for certain childhood cancers.

Treatment for these and other childhood cancers may cause thyroid late effects:

Radiation therapy to the head and neck increases the risk of thyroid late effects.

The risk of thyroid late effects may be increased in childhood cancer survivors after treatment with any of the following:

The risk also is increased in females, in survivors who were a young age at the time of treatment, in survivors who had a higher radiation dose, and as the time since diagnosis and treatment gets longer.

Late effects that affect the thyroid may cause certain health problems.

Thyroid late effects include the following:

  • Hypothyroidism (not enough thyroid hormone): The most common thyroid late effect. It usually occurs 3 to 5 years after treatment ends but may occur later. It is more common in girls than boys.
  • Hyperthyroidism (too much thyroid hormone): It usually occurs 3 to 5 years after treatment ends.
  • Goiter .
  • Lumps in the thyroid: Usually occur 10 years after treatment ends. It is more common in girls than boys.

Signs and symptoms of thyroid late effects depend on whether there is too little or too much thyroid hormone in the body.

These and other signs and symptoms may be caused by thyroid late effects or by other conditions:

Hypothyroidism (too little thyroid hormone)

  • Feeling tired or weak.
  • Being more sensitive to cold.
  • Pale, dry skin.
  • Coarse and thinning hair.
  • Brittle fingernails.
  • Hoarse voice.
  • Muscle and joint aches and stiffness.
  • Constipation.
  • Menstrual periods that are heavier than normal.
  • Depression or trouble with memory or being able to concentrate.

Hyperthyroidism (too much thyroid hormone)

  • Feeling nervous, anxious, or moody.
  • Trouble sleeping.
  • Feeling tired or weak.
  • Having shaky hands.
  • Having a fast heartbeat.
  • Having red, warm skin that may be itchy.
  • Having fine, soft hair that is falling out.
  • Having frequent or loose bowel movements.
  • Weight loss for no known reason.

Talk to your child's doctor if your child has any of these problems.

Certain tests and procedures are used to detect (find) and diagnose health problems in the thyroid.

These and other tests and procedures may be used to detect or diagnose thyroid late effects:

  • Physical exam and history : An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.

  • Blood hormone studies: A procedure in which a blood sample is checked to measure the amounts of certain hormones released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it. The blood may be checked for abnormal levels of thyroid-stimulating hormone (TSH) or free thyroxine (T4).

  • Ultrasound exam: A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. The picture can be printed to be looked at later. This procedure can show the size of the thyroid and whether there are nodules (lumps) on the thyroid.

Talk to your child's doctor about whether your child needs to have tests and procedures to check for signs of thyroid late effects. If tests are needed, find out how often they should be done.

Pituitary gland

Neuroendocrine late effects may be caused after treatment for certain childhood cancers.

The neuroendocrine system is the nervous system and the endocrine system working together. Certain nerves (the nervous system) cause hormones to be released (the endocrine system) into the blood. Treatment for these and other childhood cancers may cause neuroendocrine late effects:

Radiation therapy to the hypothalamus increases the risk of neuroendocrine system late effects.

Childhood cancer survivors are at risk for neuroendocrine late effects. These effects are caused by radiation therapy to the brain in the area of the hypothalamus. The hypothalamus controls the way hormones are made by the pituitary gland. Radiation therapy may be given to treat cancer near the hypothalamus or as total-body irradiation (TBI) before a stem cell transplant.

Childhood cancer survivors who were treated with radiation to the brain may have low levels of any of the following pituitary hormones:

Late effects that affect the hypothalamus may cause certain health problems.

Neuroendocrine late effects include the following:

  • Adrenocorticotropin deficiency : A low level of adrenocorticotropic hormone is an uncommon late effect. It may occur after low doses of radiation therapy and rarely, after chemotherapy. Symptoms of adrenocorticotropin deficiency may not be severe and may not be noticed. Symptoms include weight loss for no known reason, not feeling hungry, nausea, vomiting, low blood pressure, and feeling tired.
  • Growth hormone deficiency: A low level of growth hormone is the most common side effect of radiation to the brain in childhood cancer survivors. The higher the radiation dose and the longer the time since treatment, the greater the risk of this late effect. A low level of growth hormone in childhood results in adult height that is shorter than normal. Low growth hormone levels may be treated with growth hormone replacement therapy.
  • Hyperprolactinemia: A high level of the hormone prolactin may occur after a high dose of radiation to the brain or surgery that affects part of the pituitary gland. A high level of prolactin may cause the following:
    • Puberty at a later age than normal.
    • Flow of breast milk in a woman who is not pregnant or breast-feeding.
    • Less frequent or no menstrual periods or menstrual periods with a very light flow.
    • Hot flashes (in women).
    • Inability to become pregnant.
    • Inability to have an erection needed for sexual intercourse.
    • Lower sex drive (in men and women).
  • Hypothyroidism : A low level of thyroid hormone may develop very slowly over time. Sometimes the symptoms of hypothyroidism are not noticed. Low thyroid hormone levels may cause slow growth and delayed puberty as well as other symptoms.
  • Luteinizing hormone or follicle-stimulating hormone deficiency: Low levels of these hormones can cause different health problems. The type of problem depends on the radiation dose. A high dose of radiation may cause infertility. A low dose of radiation may cause puberty to occur at an earlier age than normal.

Certain tests and procedures are used to detect (find) and diagnose health problems in the neuroendocrine system.

These and other tests and procedures may be used to detect or diagnose thyroid late effects:

  • Physical exam and history : An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.

  • Blood chemistry study : A procedure in which a blood sample is checked to measure the amounts of certain substances, such as glucose, released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it.

  • Blood hormone studies: A procedure in which a blood sample is checked to measure the amounts of certain hormones released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it. The blood may be checked for abnormal levels of follicle-stimulating hormone, luteinizing hormone, estradiol, testosterone, or free thyroxine (T4).

  • Lipid profile studies: A procedure in which a blood sample is checked to measure the amounts of triglycerides, cholesterol, and low- and high-density lipoprotein cholesterol in the blood.

Talk to your child's doctor about whether your child needs to have tests and procedures to check for signs of neuroendocrine late effects. If tests are needed, find out how often they should be done.

Testicles and ovary

See the Reproductive System section of this summary for information about late effects in the testicles and ovaries.

Metabolic syndrome

Metabolic syndrome is more likely to occur after treatment for certain childhood cancers.

Metabolic syndrome is a group of medical conditions that includes having too much fat around the abdomen and two of the following:

  • High blood pressure.
  • High levels of triglycerides and low levels of high-density lipoprotein cholesterol in the blood.
  • High levels of glucose (sugar) in the blood.

Treatment for these and other childhood cancers may cause metabolic syndrome to occur later in life:

  • Acute lymphoblastic leukemia (ALL).
  • Cancers treated with a stem cell transplant.

Radiation therapy to the brain or abdomen and total-body irradiation (TBI) as part of a stem cell transplant increases the risk of metabolic syndrome.

Metabolic syndrome may cause the survivor to have a shorter adult height.

Childhood cancer survivors who received radiation to the brain or abdomen or had a stem cell transplant are at risk for metabolic syndrome. Metabolic syndrome may cause low levels of growth hormone, which helps promote growth and control metabolism. This may cause the survivor to be shorter than normal.

Obesity and body fat

Obesity is a late effect that is more likely to occur after treatment for certain childhood cancers.

Treatment for these and other childhood cancers may cause obesity:

  • Acute lymphoblastic leukemia (ALL).
  • Brain tumors, especially craniopharyngiomas.
  • Cancers treated with total-body irradiation (TBI) as part of a stem cell transplant.

Obesity may be measured by weight, body mass index, percent of body fat, or size of the abdomen (belly fat).

Radiation therapy to the brain increases the risk of obesity.

The risk of obesity increases after treatment with the following:

  • Radiation therapy to the brain.
  • Surgery that damages the hypothalamus or pituitary gland.

The following may also increase the risk of obesity:

  • Being diagnosed with cancer when aged 5 to 9 years.
  • Being female.
  • Not doing enough physical activity to stay at a healthy body weight.
  • Taking an antidepressant called paroxetine.

Childhood cancer survivors who get enough exercise and have a normal amount of anxiety have a lower risk of obesity.

Certain tests and procedures are used to detect (find) and diagnose obesity.

These and other tests and procedures may be used to detect or diagnose obesity:

  • Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.

  • Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances, such as glucose, released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it.

  • Lipid profile studies: A procedure in which a blood sample is checked to measure the amounts of triglycerides, cholesterol, and low- and high-density lipoprotein cholesterol in the blood.

Talk to your child's doctor about whether your child needs to have tests and procedures to check for signs of obesity. If tests are needed, find out how often they should be done.