Treatment

There are 3 main treatment options 1) medication to control prolactin production or 2) surgery to remove the tumour and 3) radiation.

Medications

Since dopamine inhibits prolactin release, medicine that increases dopamine called dopamine agonists (DA) are used. These increase the amount of dopamine released from the hypothalamus to stop prolactin release. Two DA medicines are available, bromocriptine and cabergoline. Although both drugs are effective at reducing prolactin levels and shrinking tumour, cabergoline may be used preferentially for its faster action to decrease prolactin levels and shrink prolactinomas.

Patients are cautioned to monitor for signs of medication intolerance and adverse reactions. In rare cases, cabergoline may shrink a tumour so rapidly that it causes a tear in the sac of cerebrospinal fluid around the brain. If this occurs the patient reports a severe headache and sticky, salty tasting liquid leaking from the nose and down the back of the throat. This requires urgent surgical correction, and the patient is referred to the nearest hospital emergency department. Other rare side effects may be depression and impulsive behaviours such as gambling, impulsive purchases or other ‘out of character’ behaviours. An echocardiogram may be recommended prior to starting cabergoline and during treatment to monitor for any changes in heart valves. Prolactin levels will be monitored frequently at first then every 6 to 12 months over time. Likewise, an MRI is usually done yearly at first and then less frequently if stable.

Medication may also restore fertility once prolactin level is lowered into the normal range, so if pregnancy is not desired, birth control is recommended. If the prolactin level has been normal for several years and there is no evidence of tumour on MRI, the medication may be stopped and both prolactin level and MRI monitored for a recurrence. Likewise, after menopause dopamine agonists may be stopped.

Surgery is usually only considered for individuals with large tumors, particularly if there is loss of vision, individuals who cannot tolerate medical therapy or if there is continued tumor growth despite medication. If the entire prolactinoma cannot be removed during surgery, or if prolactin levels remain elevated after surgery, medication may need to be continued after surgery.

Radiation
If prolactin level is not controlled after medical and surgical treatment, there is residual tumour or tumour growth, radiation therapy may be recommended. However, medication may still be needed until radiation therapy becomes effective.