gms | German Medical Science

Objective: The ultimate objective of treatment for skull base meningiomas is to achieve both tumor control and prevention of decreases in the KPS. The treatment strategy at our department since 1994 has been to prioritize the prevention of morbidity while maintaining macroscopic total resection, and to leave the tumor in place and perform combined radiosurgery in the early postoperative period in cases where resection is difficult, such as tumors located near the brain stem, cranial nerves, or perforating branches, as well as in cases of tumors located in the cavernous sinus. Here we report the long-term outcomes of the treatment strategy implemented at our department.

Methods: A total of 118 patients with skull base meningiomas have been treated at our department since 1994, including 63 cases of frontal base meningiomas, 17 cases of middle fossa meningiomas and 38 cases of posterior fossa meningiomas. The maximum tumor diameter ranged from 15 to 90 mm (mean, 38 mm), and the patients’ ages ranged from 24 to 77 years (mean, 64 years).

Results: The Simpson resection grade was II (n = 90), III (n = 12), or IV (n = 16). There were no cases of mortality, and while permanent morbidity was seen in eight patients, there were no patients with a ≥ 20 % decrease in the KPS score compared to preoperative KPS scores. Combined radiosurgery was performed during the early postoperative period in 19 patients (Simpson grade III, n = 5; grade IV, n = 14), and nine patients underwent radiosurgery at the time of recurrence or further progression. Following six to 182 months of follow-up (mean, 97 months), recurrence or further progression was observed in six patients (same site, n = 4; different site, n = 2), and additional surgery was performed on these patients. During follow-up, decreases in the KPS scores caused by other diseases were observed in six patients, but no decreases caused by tumor enlargement were seen.

Conclusions: Total resection of skull base meningioma is sometimes difficult due to factors such as adhesion to surrounding tissue and texture of the tumor. However, these findings suggest that long-term tumor control may be achieved by minimizing the residual tumor volume and combining radiosurgery at an early stage. Our data indicate that the combination of appropriate surgery and radiosurgery in patients with skull base meningiomas may result in the favorable outcomes of long-term tumor control while maintenaining the KPS scores.