Radiotherapy, conventional or radiosurgery, has been used to control
prolactin secretion and tumour growth in
prolactinomas both as part of multimodal
therapy or rarely as primary treatment. However, considering the
radiotherapy side effects, notably
hypopituitarism, as opposed to the high efficacy and low toxicity of
dopamine agonists (DA) treatment and neurosurgery,
radiotherapy is recommended mostly for patients with aggressive or high-risk
prolactinomas or in those resistant or intolerant to medical
therapy, usually after surgical failure. We provide an overview of the published literature on the efficacy and toxicity of
radiotherapy (conventional fractionated or radiosurgery), in aggressive, high-risk, or DA resistant
prolactinomas.
Radiotherapy has shown a good efficacy and a reasonable toxicity profile in
prolactinomas where other treatment modalities failed. In aggressive and high-risk
prolactinomas, the cumulative percentage for tumour control (reduction plus stable) ranged from 68% to 100%. Most studies reported global hormonal control rates over 50%. In resistant
prolactinomas, the global secretion control rate (on, but also off DA) ranged from 28% to 89%-100%; in most studies over 80%. The 5-year rate of
hypopituitarism was around 12%-25%. To date there are no controlled study on the use of
radiotherapy as a prophylactic treatment in patients with clinical, radiological or pathological markers of aggressiveness. In conclusion, our review supports the use of
radiotherapy in patients with growing, clinically aggressive or truly DA resistant
prolactinomas. In patients with high-risk or invasive
prolactinomas or in those harboring pathological markers of aggressiveness, the prophylactic use of
radiotherapy should be individualized.