LINAC-based Stereotactic Radiosurgery for Meningiomas / 대한방사선종양학회지

ABSTRACT

PURPOSE: To evaluate the role of LINAC-based stereotactic radiosurgery (SRS) in the management of meningiomas, we reviewed clinical response, image response, neurological deficits for patients treated at our institution. METHODS AND MATERIALS Between February 1995 and December 1999, twenty-six patients were treated with SRS. Seven patients had undergone prior resection. Nineteen patients received SRS as the initial treatment. There were 7 male and 19 female patients. The median age was 51 years (range, 14~67 years). At least one clinical symptom presented at the time of SRS in 17 patients and cranial neuropathy was seen in 7 patients. The median tumor volume was 4.7 cm3 (range, 0.7~16.5 cm3). The mean marginal dose was 15 Gy (range, 10~20 Gy), delivered to the 80% isodose surface (range, 46~90%). The median clinical and imaging follow-up periods were 27 months (range, 1-71 months) and 25 months (range, 1~52 months), respectively. RESULTS: Of 14 patients who had clinical follow-up of one year or longer, thirteen patients (93%) were improved clinically at follow-up examination. Clinical symptom worsened in one patient at 4 months after SRS as a result of intratumoral edema, who underwent surgical resection at 7 months. Of 14 patients who had radiologic follow-up of one year or longer, tumor volume decreased in 7 patients (50%) at a median of 11 months (range, 6~25 months), remained stable in 6 patients (43%), and increased in one patient (7%), who underwent surgical resection at 44 months. New radiation-induced neurological deficits developed in six patients (23%). Five patients (19%) had transient neurological deficits, completely resolved by conservative treatment including steroid therapy. Radiation-induced brain necrosis developed in one patient (3.8%) at 9 months after SRS who followed by surgical resection of tumor and necrotic tissue. CONCLUSIONS: LINAC-based SRS proves to be an effective and safe management strategy for small to moderate sized meningiomas, inoperable, residual, and recurrent, but long-term follow-up will be necessary to fully evaluate its efficacy. To reduce the radiation-induced neurological deficit for large size meningioma and/or in the proximity of critical and neural structure, more delicate treatment planning and optimal decision of radiation dose will be necessary.