Stereotactic radiosurgery for pineal tumours

Pineal tumours continue to present considerable clinical dilemmas and challenges. We were, therefore, interested to review our cumulative experience with a view to formulating a potential treatment strategy.

A retrospective analysis of all patients treated with Stereotactic radiosurgery (SRS) for pineal tumours in one centre between 1987 and 2009. Forty-four patients (66% male) were treated radiosurgically with a mean age(± 1 sd) of 33.6 (16.4) years. Eleven had biopsy-proven pineal parenchymal tumours (PPT), six astrocytomas, three ependymomas, two papillary epithelial tumours and two germ cell tumours. Twenty (45%) patients had no definitive histology despite attempted surgical biopsy in 11. Prior to radiosurgery, 17 had undergone craniotomy, 10 radiotherapy and four chemotherapy. Nine patients were referred for primary SRS.

Fifty Gamma knife treatments were performed on 44 patients prescribing 18.1 (4.2) Gy with a treatment volume of 3.8 (3.8) cm( 3 ). Routine clinical and MRI assessments were reviewed to calculate control rates. Mean follow up was 62.5 (52.9) months. Five patients (two ependymomas and three PPT) died at 36.2 (36.7) months after initial radiosurgical treatment. Overall progression-free survival (PFS) results were 93% at 1 year, 77% at 5 years, 67% at 10 and 20 years. Log-rank analysis revealed that higher initial tumour grade (P = 0.04), previous radiotherapy (P = 0.002) and radiological evidence of necrosis (P = 0.03) were associated with worse outcomes. The 5-year PFS for patients who possessed these 'aggressive' features was 47.1% compared with 91% for those patients who did not have these features. No persistent complications were attributed to SRS.

These results further demonstrate the increasingly significant role played by STRS in the treatment of pineal tumours. Based on our findings, we believe a re-examination of the role of more established therapies for this patient group may be warranted.