Stereotactic radiosurgery for pituitary metastases

Background

We evaluated the role of Gamma Knife SRS in the multidisciplinary management of metastatic cancer to the pituitary gland.

Methods

We retrospectively reviewed records of 18 consecutive pituitary metastasis patients who underwent Gamma Knife SRS during a 21-year experience. The median patient age was 57.6 years (range, 27.0-81.1 years). There were 5 patients who had initial surgical resection of their pituitary metastasis, 5 who had fractionated radiation, and 7 who had CT before SRS. The median radiosurgery target volume was 3.5 mL (range, 0.2-18.0 mL), and the median marginal dose was 13.0 Gy (range, 9-18 Gy).

Results

The overall survival after SRS at 3, 6, and 12 months, respectively, was 66%, 36%, and 18%. The median survival after SRS was 5.2 months. The progression-free survival after SRS was 100% and 66.7% at 6 and 12 months, respectively. The only factor associated with an improved overall survival was younger age at presentation. Diabetes insipidus improved in 3 (42.9%) of 7 patients. Neurological symptoms or signs improved in 4 (50.0%) of 8 patients. Three (16.7%) patients developed new neurological deficits due to tumor progression despite SRS.

Conclusion

Development of a pituitary metastasis is an ominous finding in the context of systemic cancer. Stereotactic radiosurgery is an effective palliative approach for most patients with pituitary metastasis.