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Some childhood cancer treatments, particularly radiation to the head or brain, may cause problems in the endocrine system. This complex network of glands controls body functions such as growth, puberty, energy level, urine production, and stress response. One endocrine condition caused by childhood cancer treatment is central precocious puberty.
Precocious puberty means having signs of puberty at a younger than expected age (8 years in girls, 9 years in boys). It is caused by an early release of sex hormones.
Central precocious puberty happens when the cause that triggers puberty is in the hypothalamus or pituitary, which are the areas of the brain that normally control the ovaries and testes.
Glands in the endocrine system include the pituitary, hypothalamus, thyroid, adrenals, pancreas, ovaries (in females), and testes (in males). Located in the brain, the hypothalamus and pituitary are sometimes called “the master glands” because they control many of the other glands in the endocrine system.
These glands manufacture hormones. Hormones are chemical messengers that carry information through the bloodstream to maintain bodily functions such as puberty.
Puberty is the time of life when a child experiences physical and hormonal changes that mark the transition into adulthood. These changes result from the production of sex hormones and the maturing of the reproductive organs such as testes in males and ovaries in females. Changes include being able to have children and developing pubic and armpit hair, facial hair growth in males, and breasts in females.
Puberty normally begins between the ages of 8-13 in girls and ages 9-14 in boys. The timing of puberty is influenced by a person’s genetic background. The onset of puberty at a young age may run in families.
Most girls begin puberty by developing breast buds. Menstrual periods usually start around 2 years later.
Boys typically begin puberty with increase in size of the testes.
Most doctors agree precocious puberty has occurred in girls if sexual traits develop before age 8 and in boys if sexual traits appear before age 9.
Precocious puberty is not only an early form of puberty, it is also a type of puberty that advances very quickly. It may shorten the period of time during which growth is possible. Children with precocious puberty who do not get treated may have a final adult height that is much shorter than expected.
Risk factors include:
Tumor growth, radiation treatments and changes in intracranial pressure may change the signals in the hypothalamus and pituitary gland and trigger puberty sooner than normal.
Tests can be done to confirm that the cause of precocious puberty is in the brain (central precocious puberty) and not because of a problem in the ovaries, testicles or other organs.
All childhood cancer survivors should have a physical examination at least once a year. They should share a copy of their survivorship care plan with their health care provider.
The yearly check-up should include measurement of height and weight and evaluation of puberty progress in preteens and teens. If there are signs of accelerated growth or early puberty, a blood test to check sex hormones produced in the brain (FSH - follicle-stimulating hormone, LH - luteinizing hormone), testes (testosterone) or ovaries (estradiol) may be done. Sometimes, an X-ray that measures the developmental age or maturation of bone (bone age) may also be done.
If a problem is detected, the provider may refer the survivor to an endocrinologist (doctor who specializes in hormone problems). Medications may be used to temporarily stop puberty and to decrease the rate of bone maturation.
It is also important to evaluate and manage the psychological effects of beginning puberty too early. Although children with precocious puberty may have a mature physical appearance, their thoughts, emotions, and behaviors are still that of their actual (chronological) age.
Reviewed: June 2018