Long-term results of gamma knife radiosurgery for 100 consecutive cases of craniopharyngioma and a treatment strategy.

A new treatment strategy using the gamma knife is proposed, based on evaluation of long-term results of gamma knife radiosurgery for residual or recurrent craniopharyngioma after microsurgery. A total of 98 of 107 patients were followed up for a mean of 65.5 months after radiosurgery. The mean volume of tumor was 3.5 ml. Tumors were treated with a marginal dose of 11.5 Gy using a mean of 4.5 isocenters. Final overall results: complete response 19.4%, partial response 67.4%, tumor control rate 79.6% and progression rate 20.4%. Age (for adults) and nature of tumor (cystic or mixed) were statistically significantly favorable and unfavorable prognostic factors, respectively. Patient outcome was excellent in 45 cases, good in 23, fair in 4 and poor in 3. Sixteen patients died and deterioration of visual and endocrinological functions were found as side effects in 6 patients (6.1%). The strategy is for a small tumor between the retrochiasm and anterior stalk to be treated by gamma knife radiotherapy with 10-12 Gy, allowing cure without neuroendocrine deficits.