Some people who were treated for cancer during childhood may develop endocrine (hormone) problems due to changes in the function in the endocrine system.
The endocrine system is a group of glands that regulate many body functions including growth, puberty, energy level, urine production, and stress response. Glands of the endocrine system include the pituitary, hypothalamus, thyroid, adrenals, pancreas, ovaries (in females), and testes (in males). The hypothalamus and pituitary are sometimes called the “master glands” because they control many of the other glands in the endocrine system. Unfortunately, some treatments given for childhood cancer can damage the endocrine system, resulting in a variety of problems.
Hormones are chemical messengers that carry information from the endocrine glands through the bloodstream to the body’s cells. The endocrine system makes many hormones (such as growth hormone, sex hormones, adrenal and thyroid hormones) that work together to maintain specific bodily functions.
Hyperprolactinemia is a condition that occurs when there is too much of the hormone prolactin in the body. Prolactin is a hormone secreted by the pituitary gland. Its main function is to enhance breast development in females during pregnancy and to induce lactation (milk production) after childbirth. Too much prolactin can affect the reproductive system, resulting in problems with functioning of the ovaries (in females) or testicles (in males). In females, high levels of prolactin can cause galactorrhea (breast milk production by a person who is not breastfeeding) and irregular or absent menstrual periods. In males, high levels of prolactin can cause galactorrhea and decreased testosterone levels that may result in a diminished libido (sex drive). In preteens and teens, excess prolactin may interfere with normal pubertal development.
Risk Factors for Hyperprolactinemia
The risk of developing hyperprolactinemia after treatment for children’s cancer is quite low. Risk is increased in patients who have radiation to the pituitary gland in doses of 50 Gy (5000 cGy/rads) or higher, develop a second tumor (usually noncancerous) in the pituitary region, become pregnant, and who have taken certain medications and drugs (such as marijuana and alcohol). Rarely, thyroid failure (a condition in which the thyroid gland fails to secrete enough thyroid hormone) can cause hyperprolactinemia. Correcting the thyroid problem may correct the high prolactin level.
All children’s cancer survivors should have a yearly comprehensive health check-up. If hyperprolactinemia is suspected, a prolactin blood test will be done. If a problem is detected, the healthcare provider may order additional tests (such as a CT scan or MRI of the brain) and refer the patient to an endocrinologist (a doctor who specializes in the treatment of hormone problems) for further evaluation and treatment.
Endocrinologists may use medications to suppress prolactin production. If a tumor is detected, surgery or radiation is sometimes needed. The length and type of treatment varies for each patient and should be discussed with the doctor.