Acromegaly - Treatment

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Treatment of Acromegaly

Treatment of Acromegaly
Acromegaly is treated very successfully in most cases. The aims of treatment are to reduce GH and IGF-I production to normal levels in order to reverse or improve the symptoms, and to prevent or minimize damage to the rest of the pituitary gland and surrounding brain tissue by relieving the pressure exerted by the tumor.

Surgery to remove the pituitary tumor is often the preferred treatment, as it tends to give the best results in the shortest time. If an operation is not possible in your case, then drug treatment and/or radiotherapy may be used instead. Doctors often require a combination of treatments tailored to your needs and symptoms to get the very best results.

The pituitary is located at the base of the brain, right in the middle of the skull. To reach it, and remove a tumor, the surgeon makes a small incision at the back of the nose. This is called transsphenoidal surgery and, in most patients with acromegaly, avoids more invasive surgery. From here the pituitary gland can be seen and the surgeon uses special tools to remove the tumor tissue. The operation usually takes about an hour and, in the best cases, the results can begin to be seen soon afterwards. For example, facial features may begin to improve within a few days. Most often, the soft tissue changes are the first to noticeably improve. Sometimes, although GH levels have been reduced by the operation, the acromegaly is not cured. In these instances you may be given additional treatment such as drug therapy and/or radiotherapy.

Route of transsphenoidal surgery

Head image from Microsoft Digital Library

Results depend on the size of the tumor and the skill of the surgeon. Removal of small tumors is generally more successful than large ones and it is important to make sure that your surgeon is experienced in operating on the pituitary. If the tumor is completely removed and hormone levels return to normal, then surgery may be the only treatment for acromegaly you will need.

Drug Therapy
There are three different types of drug used to treat acromegaly currently: ‘dopamine agonists’, ‘somatostatin analogs’ and ‘growth hormone receptor antagonists’. Your doctor will advise on which is best for you and this will be reviewed as treatment continues in case your condition is not improving or you are experiencing unpleasant side effects from one particular type.

Drug therapy may be chosen after surgery is determined to not completely improve your acromegaly, or in some cases, as an initial therapy without surgery.

Dopamine agonists such as bromocriptine (brand name Parlodel) and cabergoline (brand name Dostinex) inhibit GH release from the tumor. These drugs are the easiest to use as they are taken by mouth, especially cabergoline which is taken just twice weekly, whereas bromocriptine must be taken two or three times daily. However they are not always effective in treating acromegaly. Less than half of patients see a lowering of GH levels or reduction in tumor size with dopamine agonists. Additionally, side effects such constipation and dizziness when standing can be experienced. If the drug is introduced slowly and dosage built up over time these effects can usually be avoided.

Dopamine agonists are often thought of as first line medical therapy, however they are less effective than the other medications. However, dopamine agonists are easier to take and are less costly so the may be used in some cases, but other medications are more commonly used to treat acromegaly. If dopamine agonists are not working for you, your doctor may change your medication to ‘somatostatin analogs’. Dopamine agonists and somatostatin analogs have the same aim, to stop the tumor releasing growth hormone, but they act in different ways.

Two types of somatostatin analogs are available: octreotide (brand name Sandostatin) and lanreotide (brand name Somatuline). Octreotide comes in two forms, the first of which must be injected under the skin (subcutaneously) three times a day. Patients are given training to correctly inject themselves with this medication. The second form is longer-lasting (brand name Sandostatin LAR Depot) and is injected once a month deep into muscle (intramuscularly). A nurse usually performs the intramuscular injections.

Lanreotide is available as a deep subcutaneous injection (brand name Somatuline Depot) that is also long lasting. Injections are usually given once a month but can be given less frequently to some patients. The injection can be given by a nurse, and can also be given by the patient or the patient’s partner. There is little difference in the effectiveness of these two somatostatin analogs. In addition to their effects on reducing GH and IGF-I levels, somatostatin analogs decrease the size of the tumor in most patients.

Somatostatin analogs can cause side effects of the stomach or digestive system. When you start the treatment, it may cause bloating or diarrhea, although this tends to wear off after a few days. Long-term you may experience side effects such as gas or nausea, and octreotide may cause gallstones, although these rarely cause problems.

The third type of drug treatment is a growth hormone receptor antagonist, and the only drug in its class is called pegvisomant (brand name Somavert). Unlike dopamine agonists and somatostatin analogs, pegvisomant does not stop the production of GH by the tumor. Instead it stops the hormone from taking effect in the body. Pegvisomant is taken in the form of a daily injection under the skin that patients can administer themselves. The drug is well-tolerated though patients must be tested for liver abnormalities while on therapy. Also, pegvisomant does not improve headaches and does not reduce tumor size or growth.

If it is not possible for you have an operation, or if some tumor tissue remains after surgery that is not responsive to drug therapy, radiotherapy (treatment with targeted radiation) might be needed. Please rest assured, even if you are offered radiotherapy for acromegaly it does not mean that you have cancer. There are a variety of types of radiotherapy, but all work using the same principle. Depending on the type of radiotherapy, radiation beams carefully targeted at the tumor are given in small doses at a single time or daily over a month or so. Radiotherapy causes a gradual reduction in tumor size and GH release, so improvement of the acromegaly is not as quick or as noticeable as with surgery. However you may continue to see the results of radiotherapy over several years. Your doctor will monitor you for years after the radiation treatment because it is common that other pituitary functions are affected by the radiation and you may need pituitary hormone replacement therapy.

Drug treatment is usually given to reduce your GH and IGF-I levels while you wait to see results from the radiotherapy.

Monitoring Treatment
A doctor monitors the success of treatment for acromegaly carefully in each individual patient. This is done by assessing the problems acromegaly causes you and by measuring the relevant hormones. Your doctor will ask if there has been a change in hands, feet, or other areas, and discuss changes in other symptoms that you might have noticed. Blood tests to measure GH and IGF-I levels will be taken several times each year. The aim of treatment is to lower your GH level to less than 1 ng/ml and to have your IGF-I level in the normal range for your age.

What You Can Expect from Treatment
If surgery isn’t an option, or if it is not successful, it may take a little time for your doctor to find the best treatment suited to you. However, once an appropriate therapy is found, you can expect to start seeing a significant improvement in your symptoms. With treatment such as radiotherapy, changes will be gradual and can take months or even years to give full results, whereas benefits from surgery and drug therapy are often seen within days or weeks.

Once treatment is successful you can expect to notice that your hands and feet become less swollen and decrease in size – relieving any carpal tunnel syndrome – while facial features often return gradually towards normal. If you were suffering from excess sweating this should decrease and, if you had type 2 diabetes, it should improve or disappear altogether. Headaches usually improve and eyesight usually returns to normal. Life expectancy is decreased in patients with acromegaly but is restored to normal with successful treatment.