Treatments

The treatment of acromegaly has significantly progressed in recent years. Several medical expert groups from around the world have developed guidelines to manage this disease.

General treatment goals

  • Completely remove the causative tumour, if possible; if not possible, control its growth and related mass effects over nearby structures
  • Normalize GH and IGF-1 and relieve symptoms of acromegaly
  • Preserve normal pituitary function
  • Restore life expectancy to normal

Some signs and symptoms may improve or disappear with treatment (i.e., with normalization of GH and IGF-1), such as headaches, visual disturbances, cranial nerve palsies, hypopituitarism, soft tissue swelling, deepening of the voice, tongue thickness, snoring, excessive sweating, thickening and oily skin, acne and skin tags, joint pain/arthritis, and Carpal Tunnel Syndrome. In addition, complications may be avoided if the treatment is begun early.

Treatment Options

Treatment options depend on the characteristics of the lesion causing acromegaly. The following treatment options are available:

1. Surgery

  • Transsphenoidal surgery
  • Endoscopic endonasal surgery

2. Medical Therapy (Drugs)

  • Somatostatin analogue (lanreotide, octreotide)
  • Dopamine agonist (cabergoline, bromocriptine)
  • GH-receptor antagonist (pegvisomant)

3. Radiotherapy

  • Conventional
  • Stereotactic: fractionated, Gamma knife or CyberKnife

1. Surgery

Surgery is the first choice for microadenomas or enclosed (not invasive) macroadenomas as long as there is no contraindication for general anesthesia. In the case of microadenoma, the remission rate (correction of GH overproduction) is very good – around 80%. Debulking surgery (aimed to reduce the bulk of the tumour) is also indicated in cases of macroadenomas with compression of nerve structures, such as visual pathways. In cases of macroadenomas, the remission rate is less (20-40%)* even with an experienced neurosurgeon. Surgery is generally not indicated as initial therapy in cases of large non-resectable tumours without compression of neural structures. Your doctor will discuss surgery with you and which treatment is the most appropriate depending on your condition.

The neurosurgeon alone or with the assistance of an Ear-Nose and Throat (ENT) surgeon (for endoscopic endonasal surgery) will enter through your nose, which sometimes requires making a small cut in your nose or mouth. A special microscope and endoscope will be used to allow the surgeon direct access to where the tumour lies, so they can attempt to remove as much tumour as safely possible. Ideally, the entire tumour is removed. Doing the operation this way means there is no visible scarring and your stay in the hospital is shorter. The operation will normally take 2-4 hours and you will be in the hospital for about 4-6 days. Very seldom an operation through the skull (transcranial) may be needed instead. The surgeon will explain all surgical procedures to you, its complications and will require your informed consent.

Your care and the surgical procedures may vary depending on which hospital or specialist you see. Ask if the neurosurgery department at your institution has an informational booklet on surgery and post-op care. 

*Varies among clinical studies consulted

Frequently asked questions about surgery

What are the risks of surgery?

The risks of pituitary neurosurgery are rare. They can include hemorrhage, infection, fistula and damage to the normal pituitary gland, which can occur even if the operation is performed by an expert pituitary surgeon. This means that new hormone replacement might be required after the surgery, possibly including thyroid hormones, glucocorticoids, growth hormone, estrogen or testosterone. Damage to the posterior or back portion of the pituitary gland may produce a condition known as diabetes insipidus, which is characterized by frequent urination and excessive thirst, since the kidneys will no longer adequately concentrate the urine. This can be controlled with either a nasal spray or pill form of a medication called DDAVP®. Ask your neurosurgeon for a detailed review of surgical complications.

How long does the operation take?

The procedure itself usually takes about 2-4 hours. Patients go to the recovery room for 2-3 hours after the surgery and are then admitted to the hospital floor. There is usually no need to stay in an Intensive Care Unit. Most patients are discharged from the hospital in just 4-6 days.

How will I feel after the surgery?

You will have a sinus headache and nasal congestion. This will gradually improve over a few weeks. You should speak to your surgeon about medications that might help these symptoms. It is common to feel fatigued for 2-3 weeks after the surgery, but this will gradually improve. Depending on the type of surgery, you may have a decrease in smell or taste, but this may improve with time.

How long will I be out of work?

That depends on what you do. The average time would be about 1-2 months.

 

2. Medical Therapies 

Medical treatment of acromegaly may be considered when surgical removal of the tumour is unsuccessful, when the tumour is an invasive and non-resectable (inoperable) macrodenoma, or when surgery could not be performed because of medical counter indications. Under these circumstances, medical treatment should be initiated as soon as possible. In some cases, medical therapy may be given before surgery in order to induce tumour shrinkage and hence improve the chances of surgical cure. If re-growth occurs after successful surgical removal, medical therapy should be re-initiated as well.

The following are the medical therapies available at present. Others are currently being developed as well.

Somatostatin Analogues (SSA)

SSAs are molecules that resemble the naturally occurring hormone somatostatin, which inhibits GH secretion from the normal or tumoural pituitary cells. SSAs may induce tumour shrinkage. These drugs should be used as first line therapy in acromegaly. They have to be given as injections at 28 day intervals, either intramuscularly by a healthcare professional in the case of Sandostatin® LAR®-octreotide or subcutaneously with Somatuline®Autogel®-lanreotide. The efficacy of this treatment is assessed by symptoms improvement, plasma GH and IGF-1 measurements and tumour shrinkage. Somatuline® Autogel® can also be used in an extended dosing interval (EDI) of up to 8 weeks (instead of 4) in some patients.

SSAs are:

  • Octreotide:
  • Octreotide SQ
  • Sandostatin® LAR®1
  • Lanreotide:
  • Somatuline® Autogel® (Lanreotide)2

Most patients tolerate this treatment extremely well. However, some experience side effects. They are usually mild and as the treatment progresses, they likely would disappear.

Most common side effects:

They are mostly gastro-intestinal such as: diarrhea, loose stools, constipation, loss of appetite, nausea, feeling bloated, flatulence, stomach pain and gallstones. Pain, redness, swelling and irritation at the site of the injection can also occur. A low heart rate and fatigue are sometimes reported. Blood glucose may have to be monitored. 

Dopamine Agonists

Dopamine agonists (DA) prevent the GH release from the somatotroph adenoma by another mechanism than SSAs. Cabergoline (Dostinex®)3 is the most often used DA but is generally less effective than SSAs (10-30%). It may be used in people with mild or moderately elevated IGF-1 levels. DA is also used to treat co-secreting tumours. This medication is given orally 1-3 times a week.

Most common side effects:

Nausea, hypotension (low blood pressure), mental fogginess or mood disturbances.

GH-Receptor Antagonists

In cases of resistance to SSAs and DA, pegvisomant (Somavert®)4 may be used when other medicines have not been successful in controlling acromegaly. Although it does not have a direct effect on the tumour or on the release of GH, it is effective in treating the symptoms of acromegaly. This medication is given as a daily subcutaneous injection and can be given by the patient or a family member.

Most common side effects:

Side effects are often mild to moderate in intensity and of limited duration. They include pain, redness, itching at the injection site, weight gain, diarrhea, nausea, and flu-like symptoms.

For all of these medications, there may be side effects other than those listed. It’s important to discuss with your doctor the potential risks associated with each treatment.

3. Radiotherapy

Pituitary radiotherapy is indicated when surgery and medical therapy fail to control acromegaly. There are several different types of radiotherapy: conventional, fractionated, with Gamma knife, and CyberKnife. The availability varies among hospitals and the most appropriate is also chosen based on the individual case.

Radiotherapy involves the use of external beam radiation and is planned and carried out with extreme care. The radiation beam is aimed with great precision from several directions at the tumour. Patients do not feel any discomfort or pain during this treatment, but may feel tired. Some people continue to work, while this may not be possible for others.

Radiotherapy is effective, but the irradiated tumour cells die slowly over a period of months, even years. In the meantime, medical treatments have to be pursued. Potential side effects include: hypopituitarism, secondary brain tumours, CVA, and it may interfere with fertility. In cases of permanent hypopituitarism, you might have to take additional medications for life, such as Synthroid® (Abbott Canada), Cortef® (Pfizer Canada) testosterone, and DDAVP®.

Ask your radiotherapy specialist for more details on the procedure chosen, its risks and side effects.

References:

  1. Sandostatin® (octreotide acetate injection) and Sandostatin® LAR® octreotide (as acetate) for Injectable Suspension. Product Monograph. Novartis Pharmaceuticals Canada Inc. September 3, 2009.
  2. Somatuline® Autogel® (lanreotide injection). Product Monograph. EMD Serono. February 23, 2012.
  3. Dostinex®  (carbegoline). Product Monograph. Pfizer Canada Inc. July 23, 2013.
  4. Somavert® (pegvisomant for injection). Product Monograph. Pfizer Canada Inc. November 17, 2011.

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Check out the true-2-me guest editorial on treatment Considerations for Acromegaly


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