These tumors make prolactin, a hormone that stimulates a woman's breasts to make milk during and after pregnancy. They are the most common type of pituitary tumor, accounting for some 30 percent of pituitary adenomas. Prolactin-secreting microadenomas (small tumors that are less than one centimeter) are most often found in women in their 30s, while macroadenomas (tumors larger than one centimeter in size) are equally common in men and women.
Symptoms
Prolactinomas can cause the breasts to make milk and cause menstrual periods to stop when a woman is not pregnant. In men, prolactinomas can cause impotence. Large prolactinomas may cause vision disturbances by pressing on the nearby optic nerve.
Diagnosis
If your doctor suspects a prolactinoma, a blood test may be ordered to measure your prolactin levels. MRI may also be used to visualize the tumor.
Treatment
Some 80 to 90 percent of prolactinomas can be treated using medication alone. Cabergoline (Dostinex®) is a long-acting drug taken in pill form, and it typically needs to be taken once a week.
Surgery for pituitary tumors is often performed through a minimally invasive approach called transphenoidal transnasal resection, whereby the surgeon removes the tumor through an incision in the nasal passage. In cases where the tumor is too large to be removed through this approach, the surgeon performs a craniotomy, removing the tumor through an incision in the front of the skull.
Surgery is not commonly used to treat prolactinomas, but it is recommended in patients who develop significant side effects from medication or those who do not respond to medical therapy. Because Dostinex is not approved for use during pregnancy, women who are planning to conceive may also be candidates for surgery as opposed to medical treatment.
Radiation therapy may also be used to treat prolactinomas. Our experts use radiosurgery and intensity-modulated radiation treatment (IMRT) to target these tumors.
Radiosurgery, or stereotaxic radiosurgery, is a type of external radiation therapy that uses special equipment to give a single large dose of radiation to a tumor. IMRT uses radiation beams of varying intensity created to match specific tumor angles and shapes so that the tumor is targeted as precisely and uniformly as possible. This helps to reduce the damage to delicate structures in the area, such as the optic nerves.
Follow-Up
Your doctor will see you periodically and perform certain tests to ensure that your pituitary tumor has not returned. If medication is part of your treatment, you may need to take it for the rest of your life to prevent tumor recurrence.
