My doctor thinks I have acromegaly, what steps are next?
If a person begins to develop the physical features of acromegaly (enlarged hands and feet, changes in facial features, etc.) they will likely do two different things to help make the diagnosis.
The first thing is some blood work. Acromegaly is caused by elevated levels of growth hormone (GH). Because levels of growth hormone fluctuate in every person, taking blood at one random time is not enough to make a diagnosis. Therefore, in order to get a more accurate result, a glucose tolerance test is used. This test has a person drink 75-100mg of glucose (essentially sugar water). In people without acromegaly, the GH level should drop to a very low level. In people with acromegaly, this lowering does not occur.
The second step is some imaging of the brain to look at the pituitary gland located deep in the center of the brain. This is because most people who develop acromegaly do so because of a benign (non-cancerous) tumor that is growing on the pituitary gland. MRI scans are preferred to look at the pituitary, but CT scans can also be used. If a tumor is not found on the pituitary, them more imaging of the body needs to be done. This is because about 5% of the time, people with acromegaly develop a tumor in other places of their body that can also cause acromegaly.
Once the diagnosis is confirmed and the location of the tumor is identified, then treatment can begin. Ideally, surgery is recommended to remove the pituitary tumor, if possible. The size and location of the tumor will depend on whether or not it can be removed through surgery. Usually, tumors under 10 millimeters in a good location in the pituitary can be removed.
If surgery is not an option or not successful, then medical therapy can be used. This can also be used prior to a surgery to see if they are able to shrink the tumor. There are three different groups of medications that can be used. The first are somatostatin analogs (SSAs). These drugs shut off GH production and are effective in about 50-70% of patients. They also reduce the size of the tumor somewhat in up to 50% of patients. The second group of medications are the GH receptor antagonists (GHRAs). These interfere with the action of the GH. These normalize the IGF-I levels in more than 90% if of patients. The IGF-I becomes elevated in those with acromegaly due to the high GR. It is what is actually causing the enlargement of hands and feet. The third group of medications are dopamine agonist. These are least effective in lowering GH and/or IGF-I levels.
Lastly is radiation therapy. This is usually used only when patients are not able to have surgery (or have tumor remaining after surgery_ and do not respond to medication. Radiation therapy is given in small doses over a period of 4 to 6 weeks. As the effects of radiation therapy take time, medications are often still used in the interim while the treatment is still ongoing.
No one treatment is effective for all patients. The options are individualized based upon hormone levels, patient age, tumor size and location.
"Acromegaly" National Institute of Diabetes and Digestive and Kidney Diseases. April 2012. https://www.niddk.nih.gov/health-information/health-topics/endocrine/acromegaly/Pages/fact-sheet.aspx#common