Doctors have two main goals in treating pituitary tumors: to reduce the abnormally high levels of hormones and to shrink the tumor to prevent pressure damage to the optic nerves and brain. Treatment depends on the type of pituitary tumor:
ACTH-producing tumor — Most people with this type of pituitary tumor undergo a surgical procedure called transsphenoidal hypophysectomy. In this procedure, the surgeon removes the pituitary tumor through an incision in the upper portion of the nasal passages. After surgery, levels of glucocorticoid hormones are abnormally low, so the patient typically needs to take supplemental glucocorticoid medication for about 3 to 12 months. This medication gradually is tapered as the body slowly reestablishes a normal working relationship between the pituitary gland and the adrenal glands. If the tumor cannot be completely removed by surgery, radiation therapy may be needed.
Prolactin-producing tumor (prolactinoma) — Treatment is determined by the size of the tumor and how much prolactin is being produced. Small tumors sometimes don't need to be treated and can be monitored to see if they change. If treatment is necessary, the doctor will prescribe one of the drugs called long-acting dopamine agonists, such as bromocriptine (Parlodel) or cabergoline (Dostinex). These drugs reduce blood levels of prolactin and often shrink the size of the pituitary tumor. If a prolactinoma is large or produces high levels of prolactin, surgery may be recommended. Surgery also may be needed if medications don't help or the person can't take the medications long term because of side effects. When surgery is needed, the tumor is removed with a procedure called transsphenoidal hypophysectomy. In rare cases, radiation therapy may be needed.
Growth hormone-producing tumor — Transsphenoidal hypophysectomy is usually the first choice, often followed by medical therapy with a somatostatin analog (some form of the drug octreotide, sold as Sandostatin) to control symptoms. Radiation therapy is used in people who do not respond to surgery or medication.
Nonfunctioning pituitary tumor — Many doctors do not treat nonfunctioning pituitary tumors if the tumor is less than 10 millimeters in diameter. Instead, they monitor the growth of the tumor with periodic MRI scans. Larger tumors are removed surgically using a transsphenoidal hypophysectomy, sometimes followed by radiation therapy to eliminate any remaining tumor.
Transsphenoidal hypophysectomy is a safe and effective procedure that is popular for cosmetic reasons. However, not all pituitary tumors can be removed by using this surgical approach, either because the tumor is too large or because it is in a position that is difficult to reach through the nose. Instead, the surgeon must do a procedure called a craniotomy, which removes the tumor through an incision in the front portion of the skull.