The Barrow Neurological Institute Experience Treating Patients with Recurrent or Residual Pituitary Adenoma using Cyberknife Stereotactic Radiosurgery

Introduction: While transsphenoidal surgery is first-line treatment in most patients with symptomatic pituitary adenomas, the treatment of patients with residual or recurrent disease is controversial. The purpose of this study was to review the outcomes of patients with pituitary adenomas following treatment with Cyberknife stereotactic radiosurgery (CK SRS).

Methods: Patients with pituitary adenomas who had previously undergone transsphenoidal surgery and presented with residual or recurrent disease from October 2004 to June 2012 were retrospectively reviewed. Patient's demographics, treatment plans, imaging, and endocrine outcomes were documented. Patients were selected for hypofractionated stereotactic radiosurgery using CK aims at improving tolerance of the surrounding structures namely optic tracts and brain stem.

Results: A total of 50 patients (24 males and 26 females) with pituitary adenoma were treated with hypofractionated stereotactic radiosurgery using (CK SRS). Of the 50 patients, 24 had nonfunctioning pituitary adenoma and 26 patients had functioning adenoma. Patient's age ranged from 29 to 83 years (median, 59 years). Overall, 49 patients had at least one surgery before CK SRS. No patients had a history of cranial radiotherapy. Planning target volumes ranged from 940 to 20,717 mL. The marginal dose ranged from 2,100 cGy/3 fractions to 4,000 cGy/5 fractions. Follow-up ranged from 12 to 100 months with a median follow-up of 40 months. Three years overall survival and progressive free survival were 100 and 98%, respectively. One patient had infield progression and had to go for salvage surgery. One patient had bitemporal homonymous hemianopsia. Two patients had temporal lobe T2 changes on posttherapy MRI after 18 and 24 months. These changes were not thought to be clinically significant and resolved spontaneously over the next 6 to 9 months. Endocrine outcomes are currently being evaluated and will be presented.

Conclusion: CK SRS is a safe and effective modality for treatment of patients with residual or recurrent pituitary adenoma following transsphenoidal surgery