Q&A: Cushing’s Disease and Syndrome
CancerWise - September 2008
For the body to operate at its optimal level, it must maintain a delicate hormonal balance. If one piece of the puzzle is a bit off, as in Cushing’s syndrome and Cushing’s disease, it can set off a chain reaction of causes and effects.
Answering questions about Cushing’s syndrome and disease is Jessica Devin, M.D., assistant professor in M. D. Anderson’s Department of Endocrine Neoplasia and Hormonal Disorders.
What is Cushing’s syndrome?
Cushing’s syndrome is a condition in which the adrenal gland produces too much of the hormone cortisol. Cortisol plays a part in regulating blood pressure and the body’s reaction to stress. Too much cortisol can cause harm.
Overproduction of cortisol may be caused by:
- A tumor on the pituitary gland (most common cause)
- A tumor on the adrenal gland
- Lung, thyroid or other cancers (rare)
The pituitary is a pea-sized gland at the base of the brain that manufactures hormones that affect growth and metabolism, as well as the activities of other glands.
The adrenal glands, which are close to the kidneys, play a part in blood pressure and blood sugar levels.
What is Cushing’s disease?
In Cushing’s disease, a tumor on the pituitary gland produces too much of adrenocorticotropic hormone (ACTH). An excess of ACTH stimulates the adrenal glands to make too much cortisol, causing Cushing’s syndrome.
Tumors of the pituitary gland also are known as pituitary adenomas. They are almost always benign (noncancerous), but they often can cause serious problems in other parts of the body.
What causes Cushing’s disease?
There are no known causes of Cushing’s disease. Some rare types of Cushing’s syndrome are hereditary.
Are there any risk factors?
There are no known risk factors. Cushing’s disease tends to occur most often in women between 20 and 50 years old.
How many people are diagnosed each year?
Cushing’s syndrome is rare. About two to four new cases per 1 million people are diagnosed each year. Cushing’s disease accounts for about 70% of these cases.
Because the diagnosis of Cushing’s disease often requires specialized endocrine tests and imaging, it can be difficult to find and treat at the local level. Many people with Cushing’s disease and Cushing’s syndrome are eventually referred to larger academic medical centers.
Other conditions are similar to Cushing’s disease.
- Hypothyroidism (low thyroid hormone)
- Metabolic syndrome
- Polycystic ovary syndrome
What are the symptoms of Cushing’s disease?
A common symptom of Cushing’s is weight gain in the midsection of the body.
Other signs are:
- Muscle wasting, causing:
- Thin arms and legs
- Round face
- Frail skin that is easily bruised
- Dark red stretch marks (often in the stomach area)
- Hirsutism in women (excessive facial or body hair)
- Hypertension (high blood pressure)
In Cushing’s disease, the symptoms often appear gradually. Once they are diagnosed, patients often realize in retrospect they may have had it for several years.
If untreated, Cushing’s disease or syndrome may also cause hypertension, diabetes or osteoporosis.
How is Cushing’s disease diagnosed?
The first step is to establish if the patient has increased cortisol levels. This is done through urine or blood tests.
After a patient is diagnosed with Cushing’s syndrome, additional tests are necessary to locate what is causing the overproduction of cortisol.
If a pituitary tumor is suspected, magnetic resonance imaging (MRI) may be used to pinpoint the tumor. Since these tumors are often so small they cannot be seen on a normal MRI, special MRI technology and techniques may be necessary. These are often available only at larger academic medical centers.
What is the treatment?
Cushing’s disease usually is treated by surgical removal of the pituitary tumor. The most common procedure is known as transsphenoidal adenomectomy, and it should be performed by a skilled and experienced neurosurgeon. In the surgery, doctors make a tiny incision in the nostril or upper lip to remove the tumor.
The success rate ranges from 50% to 90%.
If surgery fails, other treatments may be used.
- Repeating the surgery
- Radiation treatment
- Medication to inhibit cortisol
- Surgery to remove the adrenal glands
What research is being done?
The Pituitary Tumor Program at M. D. Anderson will soon open a new multicenter Phase III clinical trial for patients with persistent or recurrent Cushing’s disease.
For more information, potential patients can contact Mary Jean Klein, the department’s manager of Clinical Protocol Administration at 713-792-2840.
M. D. Anderson resources:
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