Long-Term Outcome in Orbital Meningiomas: Progression-Free Survival after Targeted Resection Combined with Early or Postponed Postoperative Radiotherapy

Objective: In meningiomas involving orbit and optic canal, surgical resection is standard of care. However, radical resection is often limited to avoid functional damage so multidisciplinary treatment concepts are implemented. Data on timing and value of postoperative radiotherapy are sparse. Here, we analyzed functional outcome and tumor control in patients harboring orbital meningiomas, treated by either surgery alone or in combination with postoperative radiotherapy.

Methods: Patients that underwent resection of orbit associated meningiomas from 01/2000 to 12/2013 and presented to our outpatient department at least twice for follow-up were included. Clinical and radiological findings from our in-house database were analyzed retrospectively. We evaluated patients that were followed up with MRI alone and those that received scheduled adjuvant therapy within the first 6 months after operation.

Results: Seventy-six meningioma patients were included (WHO I: 74; WHO II: 2), median follow-up was 60 months. Most common symptoms upon presentation were visual disturbances (loss of visual acuity, visual field defects, exophthalmus), and headache. To avoid functional deficits, 75% of patients received targeted partial resection (Simpson II-III). In 14 cases, adjuvant therapy was scheduled postoperatively: 9 patients (11.8%) were treated with stereotactic radiosurgery, 5 (6.6%) received external beam radiation within 6 months of the operation; the other patients were followed up with regular MRI scans. In case of recurrence, progression free survival (PFS) was 28 months after operation (47.4%, n = 36): 3/14 patients treated with adjuvant radiosurgery or fractionated stereotactic radiotherapy and 33/62 of those that were followed up with MRI developed recurrent tumor growth so far. 22/36 patients were operated in case of recurrence, of whom 16 subsequently received radiotherapeutic treatment. 5/22 that were followed up with MRI alone after surgery for recurrence developed further symptomatic tumor growth necessitating surgery; the majority (80%) then received external beam radiation postoperatively.

Conclusion: Targeted partial resection is a reasonable treatment concept in orbital meningiomas. Our data indicate that postoperative radiation therapy early after targeted partial resection might help to postpone tumor recurrence and need for additional surgery. However, further analysis and prospective studies are needed to corroborate these findings.