Long-Term Outcomes of Stereotactic Radiosurgery for Pineocytomas: An International Multicenter Study.

Background and objectives: Pineocytomas are grade 1 tumors arising from the pineal parenchyma. Gross total resection can potentially cure these benign lesions but can be associated with morbidity. This study was designed to provide multi-institutional data to evaluate the results of stereotactic radiosurgery (SRS) for pineocytomas.

Methods: Centers participating in the International Radiosurgery Research Foundation were asked to review their database and provide data for patients who had SRS for histology confirmed grade 1 pineocytomas, for whom clinical and imaging follow-up of at least 6 months was available.

Results: In total, 38 patients underwent SRS as part of the management of a pineocytoma. The median age at SRS was 39 years (range 8-76). SRS was performed as primary approach in 68%, adjuvant after partial resection 19%, and at recurrence in 13% of patients. The median margin dose was 15 Gy (range 11-25 Gy). The median treatment volume was 3.35 cc (range 0.1-17.9 cc). Local tumor control was achieved in 92% of patients, with a mean actuarial progression-free survival of 21.6 years (median not reached). At last follow-up, 82% were still controlled, 8% had local recurrence, and 10% had cerebrospinal fluid dissemination. Tumor control was significantly better when SRS was used as primary care compared with the adjuvant or recurrent setting (P = .016). Five patients (13%) died during follow-up, all from tumor progression. The actuarial mean survival duration was 24.3 years, with a 5-year survival rate of 91%, and an estimated rate of 76% at 29 years. Larger tumor volume at SRS was found to be correlated to increased risk of death (P = .045). Transient symptomatic adverse radiation effects were observed in 4 patients (11%).

Conclusion: SRS appears safe and effective for the management of pineocytomas. Long-term tumor control is achieved in most cases. SRS can be offered to selected patients as an alternative to surgical resection.