Acromegaly Treatment Options

There are three main types of Acromegaly treatment options available: surgery, medication, and radiation. Learn more about the various treatment options available for controlling the symptoms of Acromegaly, how, and why they are used.

Individual Acromegaly treatment plans are determined by your doctor based on:

  • age
  • overall health
  • medical history
  • extent of the progression of signs and symptoms
  • tolerance for certain therapies, procedures, or medications
  • expectations
  • personal preference

Treatment of Acromegaly depends on the cause of the disease. More than 95 percent of Acromegaly cases are caused by benign tumors on the pituitary gland. Because the tumor is compressing the pituitary gland, the hormone production of growth hormone (GH) as well as other hormones can be affected. In rare cases, Acromegaly is caused by tumors outside of the brain in places such as: the pancreas, lungs, and adrenal glands.

The goal of treatment is to restore the normal function of the pituitary gland  function resulting in normal levels of GH. Treatment may include removal of the tumor, radiation therapy, and injection of growth hormone blocking drugs. Left untreated, Acromegaly can lead to other complications including worsening diabetes mellitus and hypertension. The condition also increases a patient’s risk for cardiovascular disease and colon polyps that could lead to cancer.

Surgery

Surgical removal of the growth hormone-secreting tumor.

Medication

Medications designed to regulate hormone levels and treat symptoms.

Radiation

Radiotherapy destroys the cells of the hormone secreting tumor.

In cases where Acromegaly is caused by a benign tumor inside the pituitary gland (pituitary adenoma), surgery offers the chance of a cure. If the pituitary adenoma is small enough that it does not extend outside of the normal boundaries of the pituitary gland and can be completely removed, surgery is considered to be the best option for treating Acromegaly.

Some people discover they have a pituitary adenoma when they experience vision loss. In these cases, the pituitary adenoma becomes so large that it threatens a person’s vision by putting pressure on their optic nerves. If the tumor is impossible to remove completely, additional treatments may be required to treat the symptoms of acromegaly.

Since most acromegaly is caused by pituitary adenomas the pituitary gland, special tools such as an endoscope are used so that the neurosurgeon can see inside and perform a less invasive surgery by creating a small incision in the back of the nose. This type of surgery is called a transsphenoidal procedure as it is done via the sphenoid sinus. When considering surgery, it is wise to find out how many times this specific type of surgery has been performed by your surgeon.

How well does surgery work?

Surgery is usually effective in reducing growth hormone levels, although not always to normal. The chance that the growth hormone levels will be normal after surgery is directly related to the size of the adenoma before surgery, as well as the experience of the surgeon. The levels of growth hormone and insulin-like growth factor-1 (IGF-1) will return to normal in about 80 percent of people with small adenomas (less than 1 cm [0.5 inch]). On the other hand, IGF-1 levels will return to normal in fewer than 40 percent of patients who have adenomas that extend beyond the pituitary area.

If the adenoma is completely removed, the blood growth hormone level falls to normal within hours after surgery and the blood IGF-1 level returns to normal within weeks to months.

Even when a pituitary adenoma is successfully and completely removed, it can be possible to be cured of the symptoms of Acromegaly, however, it is also possible that you will require additional treatment and/or ongoing symptom management.

There are several medication options available for treating the symptoms of Acromegaly. These drugs are designed to regulate the growth hormone and insulin growth factor one (IGF-1) levels at normal levels. This keeps the symptoms and signs of the elevated levels of these hormones under control.

Three classes of medications are used to treat Acromegaly. They work by lowering blood levels of growth hormone or blocking the effects of growth hormone: somatostatin analogs (octreotide, lanreotide, or pasireotide), growth hormone receptor antagonists (pegvisomant), and dopamine antagonists (cabergoline.)

Somatostatin analogs

Somatostatin analogs block the release of growth hormone from tumor cells in the pituitary gland and tumor.

  • Octreotide (brand name: Sandostatin LAR) is a long-acting release (LAR) form given every four weeks by injection
  • Lanreotide (brand name: Somatuline Depot) is available in a long-acting form given every four to six weeks by injection
  • Pasireotide (brand name: Signifor LAR) is a long-acting form given every four weeks by injection.

Somatostatin analog medications can be used as an initial treatment, especially when an adenoma is too large to be removed completely with surgery. They can also be used as a secondary treatment for people who have remaining adenoma tissue and an elevated IGF-1 level after surgery.

Results – Somatostatin analogs reduce blood concentrations of GH and IGF-1 to some degree in most patients with Acromegaly, although levels return to normal in approximately 30 to 40 percent of patients. Somatostatin analogs may also stabilize or even reduce adenoma size.

Side effects – Somatostatin analogs are usually well-tolerated, but there are possible side effects. Here are some of the most common side effects. These symptoms often occur after the first dose, less often after the second, and uncommonly thereafter.

  • Abdominal cramps
  • Abdominal discomfort
  • Bloating, and loose stools during the first month of treatment
  • Gallstones
  • Elevated blood glucose

Growth hormone receptor antagonist

The one growth hormone receptor antagonist available (pegvisomant; brand name: Somavert) blocks the effects of growth hormone by binding to its receptor, decreasing liver IGF-1 production and therefore, IGF-1, levels. This leads to an improvement in the signs and symptoms.

Results – Approximately 65 percent of subjects who are treated with pegvisomant have a lowering of IGF-1 to normal.

Side effects – Reversible liver function abnormalities occur occasionally, so liver tests should be measured periodically. As adenoma size may continue to increase during pegvisomant use in some patients, magnetic resonance imaging (MRI) is recommended once per year to monitor adenoma size.

Dopamine agonists

Dopamine agonists may decrease growth hormone secretion and, therefore, may decrease IGF-1 levels to normal, although not as often as the medications described above. Because they can be taken orally and are less expensive than the other medications, they are more convenient than other forms of treatment.

Results – Some studies report that cabergoline reduces the level of growth hormone and IGF-1 to normal in one-third of patients, although most endocrinologists have not found cabergoline to be this successful. Bromocriptine (brand name: Parlodel) is another dopamine agonist, although it is even less effective and not recommended, especially as very high doses are required.

Side effects – The most common side effects of dopamine agents, especially at the higher doses used for Acromegaly, are:

  • Nausea
  • Lightheadedness
  • Mental fogginess or mood disturbances
  • Fatigue
  • Sinus congestion
  • Bad dreams
  • Constipation

Side effects, especially nausea, can be minimized by taking the medication with meals or at bedtime and beginning with the lowest dose and increasing gradually.

Radiation therapy has been used for many years for the treatment of pituitary adenomas, including those that make growth hormone. Radiation can be delivered in one of several ways:

  • Linear Accelerator delivers x-radiation in multiple small doses over the course of a month or in one or a few large doses
  • Cobalt Source (gamma knife) gamma radiation as a single large dose.
  • CyberKnife delivers a single or a few large doses of gamma radiation.
  • Cyclotron (proton beam), which delivers protons in multiple small doses or a single large dose

Single large dose of radiation is used only if the adenoma tissue is located far enough away from the optic chiasm (nerves to the eyes) that the radiation will not cause damage. Multiple small fractions of radiation can be used when the adenoma is close to the optic chiasm, and could lengthen treatment time.

Results — Radiation therapy is usually effective in stopping or even reversing adenoma growth and in decreasing growth hormone and IGF-1 production. However, the decline in GH secretion (and clinical improvement) is very slow. Even 10 to 15 years after radiation, only a small percentage of patients achieve a normal blood growth hormone level.

Side effects — Side effects that occur during or shortly after treatment include fatigue, nausea, loss of scalp hair, and loss of taste and smell. These problems usually resolve within weeks to months after treatment. Damage to the nerve that controls vision (called optic neuritis) can result in blindness, usually in one eye; blindness generally develops between 6 and 24 months after radiation therapy. This occurs very rarely, but it is permanent.

Within 10 years after radiation treatment, approximately 50 percent of patients develop a deficiency of one or more pituitary hormones, including the hormones that control the thyroid gland, adrenal glands, and ovaries or testicles.

References:

The Mayo Clinic (2019, November 17) Acromegaly Diagnosis and Treatment [Website]. Retrieved January 2020.

The Pituitary Society (2000, October 18) Treatment of Acromegaly What is Acromegaly? [Website]. Retrieved January 2020.

Stanford Health Care (2014, July 23) Medical Therapy for Acromegaly Stanford Health Care [Website]. Retrieved January 2020.

NCBI (1996 October, 18) Pharmacological management of Acromegaly: a current perspective [Website]. Retrieved January 2020.

NCBI (1996 October, 18) Pharmacological management of Acromegaly: a current perspective [Website]. Retrieved January 2020.