Stereotactic radiosurgery for convexity meningiomas

Abstract

Object Meningiomas of the cerebral convexity are often surgically curable because both the mass and involved dura mater can be removed. Stereotactic radiosurgery has become an important primary or adjuvant treatment for patients with intracranial meningiomas. The authors evaluated clinical and imaging outcomes in patients with convexity meningiomas after radiosurgery. Methods The patient cohort consisted of 125 patients with convexity meningiomas managed using radiosurgery at some point during an 18-year period. The patient series included 76 women, 55 patients who had undergone prior resection, and 6 patients with neurofibromatosis Type 2. Tumors were located in frontal (80 patients), parietal (24 patients), temporal (12 patients), and occipital (9 patients) areas. The WHO tumor grades in patients with prior resections were Grade I in 34 patients, Grade II in 15 patients, and Grade III in 6 patients. Seventy patients underwent primary radiosurgery and therefore had no prior histological tumor diagnosis. The mean tumor volume was 7.6 ml. Radiosurgery was performed using the Leksell Gamma Knife with a mean tumor margin dose of 14.2 Gy. Results Serial imaging was evaluated in 115 patients (92%). After primary radiosurgery, the tumor control rate was 92%. After adjuvant radiosurgery, the control rate was 97% for Grade I tumors. The actuarial tumor control rates at 3 and 5 years for the entire series were 86.1 ± 3.8% and 71.6 ± 8.6%, respectively. For patients with benign tumors (Grade I) and those without prior surgery, the actuarial tumor control rate was 95.3 ± 2.3% and 85.8 ± 9.3%, respectively. Delayed resection after radiosurgery was performed in 9 patients (7%) at an average of 35 months. No patient developed a subsequent radiation-induced tumor. The overall morbidity rate was 9.6%. Symptomatic peritumoral imaging changes compatible with edema or adverse radiation effects developed in 5%, at a mean of 8 months. Conclusions Stereotactic radiosurgery provides satisfactory control rates either after resection or as an alternate to resection, particularly for histologically benign meningiomas. Its role is most valuable for patients whose tumors affect critical neurological regions and who are poor candidates for resection. Both temporary and permanent morbidity are related to brain location and tumor volume.

Predictors of response to Gamma Knife radiosurgery for intracranial meningiomas

“…6,7,9,10,15,18,19,29,31,42,44,50 Therefore, the new onset of any of the aforementioned complications in each patient following SRS was documented and analyzed. The development of any new T2 or FLAIR signal changes surrounding the lesion following SRS were interpreted as edema.…”

μMLC-LINAC radiosurgery for intracranial meningiomas of complex shape

“…Kondziolka et al, reported peritumoral imaging changes in 5% either due to edema or adverse radiation effects and an overall complication rate of 9.6% in their series of convexity meningiomas [14].…”

Radiosurgical Treatment of Intracranial Meningiomas: Update 2011

“…Adopting the concept of clinical improvement as the resolution of neurological symptoms, and/or increased pre-operative performances, the vast majority of cases shows stable or improved KPS and neurological gradings at 5-7 years or longer FU. A recent review published by the Pittsburgh Gamma Knife Center (39,40) confirms in a cohort of 972 patients, with a long term follow up (for some of them up to 20 years) an overall tumor control rate up to 97% a definitively low overall morbidity rate (7.7%) slightly higher for crucial locations such as the cavernous sinus and petroclival region.…”

“…the most biologically justified -targeting dose-volume in these peculiar lesions, is still a matter of debate, with a spectrum of options: from including "only" the gross, T1 contrast enhancing tumor, plus a supposedly infiltrated margin of a few mm (39,40,50), up to the controversial inclusion either of the "dural tail", or of the hyperostotic bone. However, the former -according to extremely refined studies -has been shown to be essentially composed by hypervascular dura with surprisingly none of the expected tumor colonies (34).…”

“…(38,39,40). As regards meningiomas, routine protocols are focused on "Tumor Growth Control" (TGC) probably obtained through a combined mechanism: 1.…”