gms | German Medical Science

Nonacoustic neuromas are rare tumors in contrast to the most common ones of the cranial nerve VIII. Until now microsurgical resection is the treatment of choice in those cases. But there is a high risk of postoperative complications, especially in cavernous sinus invading tumors. In addition, complete tumor removal cannot be reached in many of these cases, therefore recurrences are still more probable. Radiosurgery (RS) and Stereotactic radiotherapy (SRT) offer an alternate treatment option for those patients.

76 intracranial neuromas were treated from May 2000 till May 2004, among them 9 patients with nonacoustic tumors of cranial nerves V (7 cases) and IX (2 cases). The results with a mean follow-up of 36 months (10-54 mo.) and the preferred modalities were studied. RS was applied in only 1 case with a small tumor volume of 0.9 ccm. The other 8 patients (irregular tumor volume ranging from 2.2 to 13.5 ccm) were treated with SRT - 6 cases with 2 Gy per fraction up to 54 Gy total dose. Hypofractionation with 6 x 5 Gy was applied in 2 cases.

A tumor regression was proved in all cases (tumor shrinkage of more than 50% in 5 cases and between 20% and 40% in 4 cases). Only within the first 6 months 2 patients had developed a temporary increased cystic tumor volume as a well known reaction of irradiation - in one of these both cases there were mild side effects according to CTC grade I. No patient got a new or increased neurological deficit. The mostly moderate trigeminal pain decreased slowly.

SRT is a low risk and effective treatment option for intracranial neuromas – particulary in case of sinus cavernosus invading trigeminal neuromas and in glossopharyngeal tumors SRT should be the treatment of choice. Concerning tumor regression SRT is as effective as RS. In cases of irregular tumors >4 ccm and those near critical structures we recommend to use SRT.