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Gamma knife radiosurgery for prolactinomas
1Gamma Knife Center, Klinik im Park, Zürich, Switzerland. 100023.1666@compuserve.com
Object:
In this retrospective investigation the authors examined the results of gamma knife radiosurgery (GKS) for tumor remnants after unsuccessful open surgery and medical treatment in 20 patients with prolactinomas. Particular attention is paid to a possible radioprotective action of dopamine agonists similar to the action of octreotide in acromegaly.
Methods:
Twenty patients with prolactinomas were followed after GKS. Five patients were treated successfully; their prolactin (PRL) levels dropped into the normal range and dopaminergic drugs could be discontinued. Two spontaneous pregnancies were observed and 11 patients experienced improvement. Improvement was defined as normal PRL levels with the continued possibility of reduced medical treatment or a substantially reduced medical treatment dose with some degree of hyperprolactinemia maintained. The treatment failed in three patients who experienced no improvement. Patients treated with dopaminergic drugs during GKS did significantly less well in comparison with the untreated group when a cumulative distribution function (Kaplan-Meier estimate) was used.
Conclusions:
The results of GKS for prolactinomas in this investigation are better than the results published by others. This may be an effect of case selection because there were no "salvage cases" in our group of patients. Because a dopamine agonist seemed to induce radioprotection in this series, it is suggested that GKS be performed during an intermission in drug therapy when the dopamine agonist is discontinued.
Insights
Gamma knife radiosurgery (GKS) shows promising results for prolactinoma remnants. Dopamine agonists may offer radioprotection, suggesting GKS discontinuation during drug therapy for better outcomes.
Area of Science:
- Neurosurgery
- Endocrinology
- Radiation Oncology
Background:
- Prolactinomas are pituitary tumors often treated with surgery and medication.
- Tumor remnants after initial treatment pose a clinical challenge.
- Dopamine agonists are standard medical therapy for prolactinomas.
Purpose of the Study:
- To evaluate the efficacy of Gamma Knife radiosurgery (GKS) for prolactinoma remnants post-surgery.
- To investigate the potential radioprotective effect of dopamine agonists in GKS treatment for prolactinomas.
Main Methods:
- Retrospective analysis of 20 patients with prolactinoma remnants treated with GKS.
- Assessment of prolactin (PRL) levels, need for medical treatment, and pregnancy outcomes.
- Comparison of outcomes between patients treated with and without concurrent dopamine agonist therapy during GKS.
Main Results:
- Successful treatment (normal PRL, drug discontinuation) in 5 patients.
- Improvement (reduced medication or maintained PRL with reduced dose) in 11 patients.
- Patients on dopamine agonists during GKS had significantly poorer outcomes compared to untreated patients.
Conclusions:
- GKS demonstrates favorable results for prolactinoma remnants, potentially due to case selection.
- Evidence suggests dopamine agonists may have a radioprotective effect, potentially hindering GKS efficacy.
- Discontinuing dopamine agonist therapy before GKS may improve treatment outcomes.