A prolactinoma is a benign tumour of the pituitary gland that produces excessive amounts of the hormone prolactin. Treatment for this condition is highly effective and focuses on three primary goals: normalizing prolactin levels in the blood, shrinking the size of the tumour, and restoring normal pituitary and reproductive functions. Unlike many other types of brain or pituitary growths, the first line of treatment for a prolactinoma is typically medication rather than surgery. This medical approach is often successful in controlling the condition for many years. However, in cases where medication is not tolerated or the tumour does not respond, surgical intervention or radiotherapy may be considered.
What We’ll Discuss in This Article
- The use of dopamine agonists as the primary medical treatment.
- The specific roles of medications such as cabergoline and bromocriptine.
- Indications for transsphenoidal pituitary surgery.
- How treatment effectiveness is monitored through blood tests and imaging.
- Managing side effects and long term medication use.
- Rare instances where radiotherapy may be required.
Medical Management with Dopamine Agonists
Most people diagnosed with a prolactinoma will start their treatment journey with medication. These drugs belong to a class called dopamine agonists. In the body, dopamine is a natural chemical that acts as a “brake” on the pituitary gland, telling it to stop producing prolactin. Dopamine agonists mimic this natural action, binding to the receptors on the tumour cells and instructing them to reduce hormone production and shrink in size.
There are two main medications used in the UK for this purpose: cabergoline and bromocriptine. Cabergoline is often the preferred choice because it is long acting, usually requiring only one or two doses per week, and tends to have fewer side effects. Bromocriptine is taken daily and has a longer safety record, particularly for women who are planning to become pregnant. According to the NHS, dopamine agonists are successful in shrinking tumours and normalizing hormone levels in approximately 80 to 90 percent of patients.
Effectiveness of Medication and Tumour Shrinkage
One of the most remarkable features of dopamine agonists is their ability to physically shrink the prolactinoma. This shrinkage can be significant, often occurring within the first few months of treatment. For patients who have a large tumour (macroadenoma) pressing on their optic nerves and affecting their vision, the rapid reduction in tumour size provided by medication can often restore sight without the need for immediate surgery.
Patients undergo regular blood tests to monitor their prolactin levels and follow up MRI scans to track the size of the growth. If the prolactin levels return to a healthy range and the tumour becomes invisible on scans, some patients may be able to slowly reduce their dose or even stop medication entirely after several years, under close medical supervision. However, it is essential never to stop these medications without consulting an endocrinologist, as the tumour can regrow and hormone levels can spike quickly.
When Pituitary Surgery is Necessary
While medication is the first choice, surgery remains an important option for a specific group of patients. Surgery is typically considered if the patient cannot tolerate the side effects of dopamine agonists, if the medication fails to lower prolactin levels, or if the tumour does not shrink sufficiently to relieve pressure on the eyes. In some cases, a patient may choose surgery to potentially cure the condition and avoid lifelong medication.
The most common surgical technique is transsphenoidal surgery. This is a minimally invasive procedure where the surgeon accesses the pituitary gland through the nose and the sphenoid sinus. Because no incision is made in the skull, the recovery time is usually much faster than traditional brain surgery.
The success of surgery depends largely on the size and location of the tumour. Small microadenomas are often completely removed, leading to a permanent cure in many cases. Larger tumours that have grown into the surrounding tissue may be more difficult to remove entirely, and some patients may still require medication or further treatment after the operation.
Managing Side Effects of Treatment
Like all powerful medications, dopamine agonists can cause side effects. Common issues include nausea, dizziness, and headaches, especially when starting the treatment or increasing the dose. These can often be managed by taking the medication with food or at bedtime.
A more specific but rare side effect of dopamine agonists is the development of impulse control disorders. This can manifest as unusual urges to gamble, spend money excessively, or binge eat. It is vital that patients and their families are aware of these potential behavioural changes and report them to their doctor immediately. In such cases, the medication may need to be adjusted or changed. For surgical patients, the risks include temporary hormonal imbalances, such as diabetes insipidus, or very rarely, a leak of cerebrospinal fluid from the nose, which usually resolves with treatment.
The Role of Radiotherapy
Radiotherapy is generally reserved for rare cases where a prolactinoma is aggressive and does not respond to both medication and surgery. It involves using high energy beams to target the remaining tumour cells and prevent them from growing. In the UK, modern techniques like stereotactic radiosurgery (Gamma Knife) allow for very precise delivery of radiation, minimizing damage to the surrounding healthy brain tissue.
Because the effects of radiotherapy are very slow, it can take several years for prolactin levels to drop significantly. During this time, the patient will usually need to continue taking dopamine agonist medication. A major long term side effect of radiotherapy is the gradual loss of other pituitary hormones, meaning most patients will eventually require some form of hormone replacement therapy.
Long Term Monitoring and Quality of Life
Regardless of the treatment chosen, long term follow up is a standard part of care for anyone with a prolactinoma. This involves periodic blood tests and MRI scans to ensure the condition remains under control. For many, the goal is not just a “normal” lab result, but a restoration of their quality of life, including the return of energy levels, sex drive, and fertility.
Endocrinologists work closely with patients to tailor the treatment to their life stages, such as adjusting medication for those wishing to start a family. With the right management, most people with a prolactinoma live healthy, full lives with minimal impact from their condition. The NICE clinical knowledge summaries provide the framework for this high standard of long-term endocrine care in the UK.
Conclusion
The primary treatment for a prolactinoma is medication with dopamine agonists, which effectively lowers hormone levels and shrinks the tumour in most cases. Surgery is a vital secondary option for those who do not respond to or cannot tolerate medication, offering the possibility of a permanent cure for some. While rare, radiotherapy provides a fallback for aggressive growths. Consistent monitoring ensures that treatment remains effective and that any side effects are managed promptly. If you experience severe, sudden, or worsening symptoms such as a sudden severe headache or vision loss, call 999 immediately.
How long do I have to take medication for a prolactinoma?
Many patients take medication for several years; if the tumour disappears and prolactin stays normal, a trial period of stopping the drug may be possible under specialist guidance.
Can I get pregnant while on prolactinoma medication?
Yes, and normalizing prolactin often restores fertility; bromocriptine is frequently used in these cases due to its extensive safety record during early pregnancy.
Is the surgery for a prolactinoma dangerous?
Transsphenoidal surgery is considered a safe and common procedure, though like all surgery, it carries small risks such as infection or temporary hormonal changes.
Will my vision come back after treatment starts?
If vision loss was caused by the tumour pressing on the optic nerves, shrinking the tumour with medication or surgery often leads to a significant improvement in sight.
What happens if I forget to take my cabergoline?
You should take it as soon as you remember, but do not take a double dose to make up for a missed one; check the patient information leaflet or call your pharmacist for advice.
Can a prolactinoma come back after it’s been cured?
There is a small risk of recurrence, which is why regular blood tests and occasional scans are recommended even if the tumour has been successfully treated.
Are there any foods I should avoid while taking dopamine agonists?
There are no specific food restrictions, but taking the medication with a meal can help reduce the common side effect of nausea.
Authority Snapshot (E-E-A-T Block)
This article outlines the standard treatment pathways for prolactinoma within the UK healthcare system. It has been authored by the medical content team and reviewed by Dr. Rebecca Fernandez to ensure clinical accuracy and adherence to safety protocols. The content is strictly aligned with NHS and NICE guidance for the management of hyperprolactinaemia and pituitary adenomas.
