Endocrine System
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:
- Radiation therapy to the brain and spinal cord or head and neck.
- Total-body irradiation (TBI) as part of a stem cell transplant.
The risk also is increased in females, in survivors who were a young age at the time of treatment, and as the time since 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 of thyroid late effects depend on whether there is too little or too much thyroid hormone in the body.
These symptoms may be caused by thyroid late effects:
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.
Other conditions may cause the same symptoms. Talk to your doctor if you have 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 doctor about whether you need to have tests and procedures to check for signs of thyroid late effects. If you do, find out how often they should be done.

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