Many pituitary tumors don't require treatment. Treatment for those that do depends on the type of tumor, its size and how far it has grown into your brain. Your age and overall health also are factors.
Treatment involves a team of medical experts, possibly including a brain surgeon (neurosurgeon), endocrine system specialist (endocrinologist) and a radiation oncologist. Doctors generally use surgery, radiation therapy and medications, either alone or in combination, to treat a pituitary tumor and return hormone production to normal levels.
Surgical removal of a pituitary tumor usually is necessary if the tumor is pressing on the optic nerves or if the tumor is overproducing certain hormones. The success of surgery depends on the tumor type, its location, its size and whether the tumor has invaded surrounding tissues. The two main surgical techniques for treating pituitary tumors are:
- Endoscopic transnasal transsphenoidal approach. This usually enables your doctor to remove the tumor through your nose and sinuses without an external incision. No other part of your brain is affected, and there's no visible scar. Large tumors may be difficult to remove this way, especially if a tumor has invaded nearby nerves or brain tissue.
- Transcranial approach (craniotomy). The tumor is removed through the upper part of your skull via an incision in your scalp. It's easier to reach large or more complicated tumors using this procedure.
Radiation therapy uses high-energy X-rays to destroy tumors. It can be used after surgery or alone if surgery isn't an option. Radiation therapy can be beneficial if a tumor persists or returns after surgery and causes signs and symptoms that medications don't relieve. Methods of radiation therapy include:
- Gamma Knife stereotactic radiosurgery. Often delivered as a single high dose, this focuses radiation beams on the tumor without an incision. It delivers radiation beams the size and shape of the tumor into the tumor with the aid of special brain-imaging techniques. Minimal radiation comes in contact with healthy tissue surrounding the tumor, decreasing the risk of damage to normal tissue.
- External beam radiation. This delivers radiation in small increments over time. A series of treatments, usually five times a week over a four- to six-week period, is performed on an outpatient basis. While this therapy is often effective, it may take years to fully control the tumor growth and hormone production. Radiation therapy may also damage remaining normal pituitary cells and normal brain tissue, particularly near the pituitary gland.
Proton beam therapy. Another radiation option, this type uses positively charged ions (protons) rather than X-rays. Unlike X-rays, proton beams stop after releasing their energy within their target. The beams can be finely controlled and can be used on tumors with less risk to healthy tissues. This type of therapy requires special equipment and isn't widely available.
The benefits of these forms of radiation therapy often aren't immediate and may take months or years to be fully effective. A radiation oncologist will evaluate your condition and discuss the pros and cons of each option with you.
Treatment with medications may help to block excess hormone secretion and sometimes shrink certain types of pituitary tumors:
- Prolactin-secreting tumors (prolactinomas). The drugs cabergoline and bromocriptine (Parlodel) decrease prolactin secretion and often reduce tumor size. Possible side effects include drowsiness, dizziness, nausea, vomiting, diarrhea or constipation, confusion, and depression. Some people develop compulsive behaviors, such as gambling, while taking these medications.
Growth hormone-secreting tumors. Two types of drugs are available for these types of pituitary tumors and are especially useful if surgery has been unsuccessful in normalizing growth hormone production. One type of drugs known as somatostatin analogs (Sandostatin, Somatuline Depot, others) causes a decrease in growth hormone production and may shrink the tumor. These are given by injections, usually every 4 weeks.
These drugs can cause side effects such as nausea, vomiting, diarrhea, stomach pain, dizziness, headache and pain at the site of injection. Many of these side effects improve or even go away with time. They can also cause gallstones and may worsen diabetes mellitus.
The second type of drugs, pegvisomant (Somavert), blocks the effect of excess growth hormone on the body. This drug, given by daily injections, may cause liver damage in some people.
Replacement of pituitary hormones
If a pituitary tumor or surgery to remove it decreases hormone production, you'll likely need to take replacement hormones to maintain normal hormone levels. Some people who have radiation treatment also need pituitary hormone replacement.
In watchful waiting — also known as observation, expectant therapy or deferred therapy — you might need regular follow-up tests to determine if your tumor grows. This might be an option if your tumor isn't causing signs or symptoms.
Many people with pituitary tumors function normally without treatment if the tumor isn't causing other problems. If you're younger, watchful waiting can be an option as long as you accept the possibility of your tumor changing or growing during the observation period, possibly requiring treatment. You and your doctor can weigh the risk of symptoms developing versus treatment.