Visual Outcomes and Local Control After Fractionated Stereotactic Radiation Therapy for Optic Nerve Sheath Meningioma

Purpose/Objective(s): Pituitary tumors are relatively uncommon. Primary goals of treatment include normalization of hormonal level and improving visual or neurological symptoms. Surgery, medical treatment, irradiation, or combination of these modalities is used to achieve these goals. The purpose of this analysis is to determine the clinical outcome of pituitary adenoma treated with fractionated external beam radiation therapy. Materials/Methods: This is a retrospective analysis of pituitary adenoma treated at our center between 2006 and 2014. A total of 88 patients with biopsy-proven adenomas were identified. Median age at diagnosis was 38 years (18e79 years) and 49 patients (56%) were males. Majority of tumors were marcoadenoma (87%). Presenting symptoms were mainly hormonal disturbance in 43 patients (49%), visual defects in 29 patients (33%) and headache in 21 patients (23%). Prolactinomas were the most common secretory adenoma in 22 patients (51%), followed by growth hormone secreting adenomas in 15 patients (35%) and ACTH-secreting tumors in 5 patients (12%), while one patient had TSH-secreting adenoma. The cohort follow up time reached 87 months (mean; 32 months). The primary endpoints are clinical and biochemical control. Results: Thirteen patients lost to follow up, therefore 75 patients were included in the final analysis. Surgery was the primary treatment modality in 70 patients (93%).While medical treatment was used for inoperable or hormonal secreting adenoma in 30 patients (40%). Fractionated radiation therapy was delivered to 28 patients (37%), indications for radiation were symptomatic, incompletely resected tumors (16 patients) or persistent hypersecretion (12 patients). For secretory tumors the median radiation dose was 52Gy (50-54Gy), and lower dose was delivered for non-secretory adenoma; mean 50Gy (45-52Gy). For patients received radiation therapy, the tumor control rate is 75% for non-functioning adenomas, and 69% for functioning adenomas. Conclusion: Pituitary adenoma is a slow growing benign tumor; however devastating effect can result from neurological deficits or hormonal imbalance. Our results reveal that functioning adenomas carry worse prognosis. Fractionated radiation therapy, as an adjunct to surgery and medical treatment, offers good clinical and biochemical control for pituitary adenoma. More aggressive multimodal approach and incorporation of new radiation technique may help to achieve better clinical outcome. Author Disclosure: R.A. Abu-Hijlih: None. Y. Ismael: None. H. Ghatasheh: None. A. Fawzi: None. A. Alsharbaji: None. M. Elyan: None. B. Al-Haj: None. A. Almousa: None.