Radiosurgery Improves Meningioma Control Over Active Surveillance

Stereotactic radiosurgery (SRS) achieved superior radiologic control of asymptomatic, skull-based meningiomas over active surveillance without increasing the risk of neurologic morbidity. The procedure should be considered for initial treatment, suggests an international study.

The study was made available as a preprint from the Journal of Neuro-Oncology on Research Square on October 27.

“If active surveillance is the initial management of choice, SRS should be recommended when radiologic tumor progression is noted and prior to clinical progression,” write researchers who were led by Georgios Mantziaris, MD, a research fellow with the University Hospital of the University of Virginia, in Charlottesville, Virginia.

“Unfortunately, active surveillance does not precisely define the time of continued tumor growth, nor…prior onset of neurological deficits in patients with asymptomatic meningiomas,” the authors write.

The greater availability of neuroimaging for nonspecific symptomatology has led to an increase in detection of asymptomatic skull-based meningiomas, which account for up to 34% of incidentally detected tumors. The natural history of incidental skull-based meningiomas is unpredictable, with estimates of progression to neurologic deterioration ranging from 2.6% to 40%.

The optimal management of these tumors is also controversial, owing to the lack of high-level evidence. Options include active surveillance, resection, fractionated radiotherapy, and SRS. The latter was reported in a small, retrospective study by Pikis and colleagues in Acta Neurochirurgica to offer long-standing tumor control and neurologic preservation.

The current study included 307 patients from 14 centers who had been incidentally diagnosed with asymptomatic, skull-base meningioma and underwent SRS. They were compared with an observational group of 110 patients assigned to active surveillance from a single neurologic center.

Patients were required to have a single intracranial, skull-based lesion on brain MRI, no history of malignancy, and no neurologic signs or symptoms. Patients with nonspecific symptoms were included.

SRS was conducted in line with the consensus definition set out by Barnett and colleagues in the Journal of Neurosurgery, using the Gamma Knife. The primary outcome was local tumor control, as defined by meningioma stability or regression at last radiologic follow-up.

The researchers performed propensity score matching for patient age, tumor location, tumor volume, and duration of radiologic and clinical follow-up. There were 110 patients in each cohort.

In the matched cohorts, tumor control was observed in 98.2% of SRS patients, vs 61.8% on active surveillance. Tumor regression occurred in 35.5% of patients treated with SRS compared with 0.9% in those assigned to active surveillance. Tumor stability was seen in 62.7% and 60.9%, respectively (P < .001 for radiologic outcomes). New neurologic deficits were reported in 2.7% of SRS-treated patients and 5.5% of those in active surveillance.

Multivariate analysis revealed that SRS treatment was the only independent predictor of tumor progression, at a hazard ratio of 0.01 (P < .001).

Factors associated with new adverse radiation effects were tumor volume >3.5 mL, at a hazard ratio of 4.5 (P = .003), and margin dose >13.5 Gy, at a hazard ratio of 2.6 (P = .02). Only increasing number of isocenters was a significant predictor of post-SRS neurologic deficits, at a hazard ratio of 1.1 (P < .001).

This was a retrospective study with several limitations, including the lack of centralized radiologic view and the nonstandardized follow-up protocols. Alongside variations in radiosurgical techniques, the authors note the lack of data on quality of life and performance status.

The study was published as a preprint and is under consideration for publication with the Journal of Neuro-Oncology. A preprint is a preliminary version of a manuscript that has not undergone peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on Research Square should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice. The research featured in this article was not financed, but co-author L. Dade Lunsford is a shareholder in Elekta AB, the manufacturer of some radiosurgical devices. Roman Liscak is a consultant for Elekta AB. No other relevant financial relationships have been disclosed.

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