Download Endocrine problems after treatment for cancer

Endocrine problems
after treatment for
cancer
Abby S. Hollander, MD
Associate Professor of Pediatrics
Pediatric Endocrinology and Diabetes
Washington University School of Medicine and
St. Louis Children’s Hospital
The glands controlled by the hypothalamus
and pituitary
The hypothalamus
directs the actions of
the pituitary gland.
The pituitary produces
vasopressin, a hormone
for water balance, growth
hormone, and several other
signal hormones.
Pituitary signals
The pituitary produces
TSH which signals the
thyroid gland, ACTH
which signals the adrenal
gland, and FSH and LH
which signal the gonads
(ovaries or testes).
The hypothalamus and pituitary are at risk to be damaged by surgery or radiation.
Radiation damage is generally dose-dependent, but may not occur until several
years after the radiation was given. Deficiencies can occur in all or just some of
the hormones produced by the hypothalamus and pituitary. Below a dose of
1800 Gy, it is unusual to have deficiencies. Above a dose of 3500 Gy, there are
almost always deficiencies, and in between doses are quite variable. The most
common hormone that becomes deficient is growth hormone. The dose of radiation
that is important is the dose that touches the hypothalamus and pituitary, not
necessarily the dose directed toward the tumor bed.
Causes of growth problems after
treatment for cancer
Growth hormone deficiency
 Thyroid hormone deficiency
 Radiation of the spine
 Early timing of puberty causing growth to
end early
 Poor nutrition
 High dose steroid treatment

Thyroid deficiency or hypothyroidism
Causes: Surgical removal of thyroid (thyroid cancer), radiation of the thyroid
(spinal irradiation), chemotherapy (pazopanib),
loss of TSH due to hypothalamic/pituitary damage
Symptoms: Fatigue, feeling cold, constipation, dry skin, poor growth,
excessive menstrual bleeding, irregular menses
Treatment: levothyroxine (Synthroid, Levoxyl, Unithroid, etc)
Common blood tests: free T4, TSH
Cortisol is a stress
hormone made by the
adrenal glands when they
are signalled by pituitary
ACTH. Low cortisol levels
occur due to ACTH
deficiency after cranial
irradiation. Low cortisol
levels can also be a
temporary problem after
taking high dose steroids
for an extended period.
Symptoms of low cortisol:
fatigue, weakness,
frequent vomiting,
dizziness, risk of severe
low blood pressure
(shock)
Treatment:
hydrocortisone,
prednisone
Test: cortisol levels after
Cortrosyn stimulation
The testes will not produce
testosterone or sperm if
there are deficiencies of
FSH and LH from the
pituitary.
The ovaries can stop
functioning due to
hypothalamic/pituitary
damage, or they can be
injured directly from
radiation or chemotherapy.
Symptoms: no periods (or
no breast development), hot
flashes
Treatment: estrogen and
progesterone (pill, patch)
The testes are also very
susceptible to damage by
radiation or chemotherapy.
Sperm production is
usually affected, but
testosterone production
may remain normal.
Other endocrine-related problems
that develop after cancer treatment



Hyperlipidemia
 After some chemotherapy
 With growth hormone deficiency
Obesity
 After brain tumor treatment
 After cranial irradiation
 Due to high dose steroids
Decreased bone density
 With growth hormone deficiency
 With sex hormone deficiency
 Due to high dose steroids
Conclusions




Several hormone deficiencies are possible after treatment for
cancer.
Deficiencies due to radiation damage may not be evident until
several years after treatment is complete.
Patients who are at high risk to develop endocrine problems should
see an endocrinologist 6-12 months after completion of therapy, and
they should be monitored closely.
As children reach adulthood, they should be aware of the symptoms
that could indicate possible hormone problems (excessive fatigue,
weight gain, loss of libido, irregular periods, infertility) so they will be
evaluated by an appropriate specialist if needed.