Long-Term Outcomes of Stereotactic Radiosurgery for Papillary Tumors of the Pineal Region: A Multicenter...

Papillary tumors of the pineal region (PTPR) are rare neuroepithelial tumors that are at high risk of local recurrence even after gross total resection. Their optimal management, including the potential role of stereotactic radiosurgery (SRS), remains a matter of debate. Only a few retrospective outcome studies have been reported. This study was designed to provide multi-institutional data to strengthen the evidence related to the use of SRS for PTPR.

Centers participating in the International Radiosurgery Research Foundation were asked to provide data for patients who had SRS and at least 6 months of follow-up for a histology-confirmed PTPR.

In total, 19 patients (12 male and 7 female) underwent SRS for PTPR in 6 institutions: 7 patients had primary SRS after biopsy, 9 had adjuvant SRS, and 3 had SRS for recurrent tumor. The median margin dose used was 16 Gy, and median treatment volume was 1.73 cc. Initial local control was achieved in all patients after SRS, with a median progression-free survival of 5 years. A total of 6 patients had local recurrence, managed by repeat SRS in 4 patients, surgical resection in 1, and both interventions in the other. The cumulative actuarial local control at 20 years, considering additional SRS procedures as needed, was 69%. One patient had ventricular and leptomeningeal dissemination which led to death. The mean survival duration was 15.8 years, with an estimated survival rate of 83% at 10 years and 69% after 20 years. Adverse radiation effects were observed in 5 cases, 4 of which were symptomatic, but eventually resolved in all patients.

SRS for PTPR is safe and enables local tumor control in most cases. SRS can be considered as primary management after diagnosis of PTPR.