The Role of Gamma Knife Stereotactic Radiosurgery in the Management of Pineal Region Tumors

Introduction: High risk of surgical morbidity prompts consideration of alternative neurosurgical approaches for pineal tumors. The objective of this study is to report institutional outcomes for patients with pineal tumors after SRS.

Methods: Thirty-three patients (13 female) with pineal tumors (31 pineocytoma, 2 papillary tumors) were identified from 1987 to 2022. Seventeen patients had a pre-SRS biopsy, and 8 patients had pre-SRS craniotomy. Twenty-six patients had pre-SRS hydrocephalus: 15 had a shunt, 10 underwent endoscopic third ventriculostomy, and 1 received pre-SRS steroid therapy. Patients presented with headache (n=21), ocular movement impairments (n=11), gait disturbances (n=7) and vision loss (n=4). The median age at time of SRS was 27 years (range, 4-77). The median tumor volume was 2.97 cc (range, 0.22-14.2) and the median margin dose was 14.5 Gy (range, 12-20 Gy).

Results: Overall survival rates at 1-, 5-, and 10-years were 94.03%, 77.53%, 61.71%, respectively; 9 patients expired secondary to pineal tumor complications. Fifteen patients had tumor regression, 7 had stable tumor response, 6 had tumor progression, and 5 had tumor disappearance. Median time from SRS to progression was 4.67 years (range, 1.08 – 28.58). Local tumor control rates at 1-, 5, and 10-years were 100.00%, 85.06%, 76.55%, respectively. Fifteen patients had improved symptoms, 10 remained stable, and 8 worsened. Four patients were managed with additional fractionated radiotherapy, 3 had a new shunt placement, and 2 had repeat SRS. Two patients were managed with corticosteroids for symptomatic adverse radiation effects: one patient improved while the other experienced ongoing neurological deterioration and opted against further intervention.

Conclusion : SRS can be effectively used in patients with tumors of the pineal region to provide long-term tumor control and symptom management. Utilizing primary SRS for tumors of the pineal region can achieve durable tumor control and minimize need for additional invasive interventions.