[Radiosurgical treatment of meningioma with the Leksell gamma knife].

BACKGROUND

Up to the present time radical microsurgery of the tumour was considered the most satisfactory treatment. Now an ever more important part in the treatment of these tumours is played by radiosurgery. It involves minimal surgical stress, a minimal rate of complications and minimal change of lifestyle during the postoperative period. The objective of the submitted work was to evaluate the authors' results with the use of Leksell's gamma knife.

METHODS AND RESULTS

In 1992-1994 48 patients with meningiomas were indicated for treatment with a gamma knife. The group comprised 12 men (25%) and 36 women (75%) aged 18-73 years (mean age 52.8 years which did not differ significantly in the two groups). In 19 patients (39.6%) one or more neurosurgical operations were carried out previously, in 4 patients (8.3%) fractionated radiotherapy. Karnofski's score, as an indicator of the general condition, varied between 30-90%, the mean value for the whole group being 71%. The calculated volume of the meningioma was between 0.7 and 25.8 cm3, the average being 7.4 cm3. Collateral oedema in the adjacent area of the tumour was found in 6 patients (12.5%). In 19 patients (39.6%) the tumour was at the base of the skull, in 29 patients (60.4%) at other sites. The radiosurgically administered dose was within the range of 6.5-24 Gy, on average 14,2 Gy, on the isodose on average 50.7% (range 40-75%). The dose below the maximum was within the range of 13-45 Gy), on average 28.3 Gy. Only in two patients fractionated administration of the dose was used. After a 6-month interval following operation 30 patients were examined. In 7 patients (23.3%) partial wrinkling of the meningioma occurred (range 6-18 months), Karnofski's score improved by 10% in 8 (26.6%) and deteriorated in 3 patients (10%). The neurodeficit improved in 7 (23.3%) and deteriorated in 4 patients (13.3%). Collateral oedema developed in 5 patients (16.6%) 5-7 months after operation, in about half the patients it was symptom free. During the follow up period 2 patients died (8 and 5 months following surgery): in one the cause of death was not associated with the basic disease, in the second patient (where radiotherapy was the third neurosurgical operation) the radiosurgical operation could not reverse tha fatal course of the disease.

CONCLUSIONS

Radiosurgery of meningiomas is a safe therapeutic method with zero mortality, minimal surgical stress, a minimal rate of complications and a minimal morbidity. It is indicated in meningiomas and possibly their residues after subtotal neurosurgery up to a maximal volume of 30 cm3. It is primary treatment suitable in particular in old.patients, patients with a high per- and postoperative risk and in patients refusing open neurosurgery.