Pineal tumours present management dilemmas. This reflects their varied histology, and the hazards of surgical approaches.

     These issues prompted a systematic review of our radiosurgical experience of pineal tumors to rationalize future therapeutic choices.

     From 1987-2009, 44 patients (66% male) underwent 50 Gamma Knife radiosurgical treatments. Mean(±SD) age at first radiosurgery was 34±16 years.

     Twenty-four patients had definitive histology (11 pineal parenchymal tumours(PPT), including 2 pineoblastomas, 6 pineocytomas and 3 of intermediate differentiation; 6 astrocytomas, 3 ependymomas, 2 papillary epithelial tumours, 2 germ cell tumours(GCT)). Eleven patients had undergone surgery without a definitive tissue diagnosis: nine had not undergone surgery. Ten patients had received radiotherapy (5 PPT, 3 astrocytomas, 2 without tissue diagnosis). At treatment, mean tumour volume was 3.7±3.5cm3. Mean marginal dose was 18±4Gy. Mean follow-up was 62±53months (range 6-240). Radiological features were assessed blindly by two radiologists.

     Of 44 patients, five died 36±37 months after radiosurgery. Five further individuals showed radiological disease progression. Seven of these 10 patients had received radiosurgery as salvage therapy. Malignant tumour histology (p=0.04), previous radiotherapy (p=0.002) and radiological evidence of necrosis (p=0.03) were associated with poor outcomes. Patients with none of these features had a 5 year progression free survival of 91% (80% at 10 years). If any of these features were present, the 5 year progression free survival fell to 48%. No complications were identified due to radiosurgery.

     This was a retrospective study.

     Patients referred for radiosurgery are clearly super-selected. GCTs are under-represented in this series reflecting their established and effective treatment paradigms, and clearly they need to be identified with blood/CSF markers and biopsy as appropriate.

     The finding that a quarter of this series did not have a tissue diagnosis despite undergoing surgery, raises the question of how far it is mandatory to pursue tissue diagnoses. The high control rate if no worrying features are present, combined with the lack of complications, suggests that primary radiosurgery without a tissue diagnosis is justifiable. Once there are concerns of malignancy, necrosis or failed radiotherapy, we suspect that a tissue diagnosis is essential, as these patients are often young and their response to radiosurgery less certain.