Treatment focuses on lowering your production of GH, as well as reducing the negative effects of the tumor on the pituitary gland and surrounding tissues. You may need more than one type of treatment.
Doctors can remove most pituitary tumors using a method called transsphenoidal surgery. In this procedure, your surgeon works through your nose to extract the pituitary tumor.
Removing the tumor can normalize GH production and eliminate the pressure on the tissues surrounding your pituitary gland to relieve associated signs and symptoms. In some cases, your surgeon may not be able to remove the entire tumor. This may result in persistently elevated GH levels after surgery, requiring further medical or radiation treatments.
Drugs used to lower the production or block the action of GH include:
- Somatostatin analogues. The drugs octreotide (Sandostatin) and lanreotide (Somatuline Depot) are synthetic versions of the brain hormone somatostatin. They can interfere with the excessive secretion of GH by the pituitary gland, and thus can produce rapid declines in GH levels. When starting octreotide treatment, you initially inject yourself with a short-acting preparation under your skin (subcutaneously) three times a day to determine if you have any side effects from the medication and if it's effective. Then, if it's tolerated and effective, you can take a long-acting form that requires an injection into the muscles of your buttocks (gluteal muscles) by a health care professional, administered once a month. Lanreotide is administered as a subcutaneous injection once a month.
- Dopamine agonists. The medications cabergoline and bromocriptine (Parlodel) are taken as pills. In some people, these drugs can lower levels of GH and IGF-I. The tumor may decrease in size in some people taking a dopamine agonist or somatostatin analogues. Some people may develop compulsive behaviors, such as gambling, while taking these medications.
- Growth hormone antagonist. The medication pegvisomant (Somavert), a growth hormone antagonist, acts to block the effect of GH on body tissues. Pegvisomant may be particularly helpful for people who haven't had good success with other forms of treatment. You administer this medication yourself daily by subcutaneous injection. This medication can normalize IGF-I levels and relieve symptoms in most people with acromegaly, but doesn't lower GH levels or reduce the tumor size.
Your doctor may recommend radiation treatment when tumor cells remain after surgery. Radiation therapy destroys any lingering tumor cells and slowly reduces GH levels. It may take years for this treatment to noticeably improve acromegaly symptoms.
You receive radiation treatment in one of three ways:
- Conventional radiation therapy. This type of radiation therapy is usually given every weekday over a period of four to six weeks. You may not realize the full effect of conventional radiation therapy for 10 or more years after treatment.
- Proton beam therapy. Proton beam therapy delivers a targeted, high dose of radiation to the tumor, sparing radiation exposure to normal tissues. Proton beam therapy is provided in fractions over time, but treatment times are generally less than conventional radiation.
- Stereotactic radiosurgery. Also known as Gamma Knife radiosurgery, stereotactic radiosurgery can deliver a high dose of radiation to the tumor cells in a single dose while limiting the amount of radiation to the normal surrounding tissues. This type of radiation may bring GH levels back to normal within three to five years.
Stereotactic radiosurgery is available at only a few U.S. medical centers and is not recommended for all people undergoing radiation for acromegaly. Your doctor will determine which type of radiation therapy is right for you based on:
- The size and location of your remaining tumor cells
- Your levels of insulin-like growth factor-I (IGF-I)
Even after initial treatment, acromegaly requires periodic monitoring by your doctor to make sure that your pituitary gland is functioning properly. This follow-up care may last for the rest of your life.