Numerous retrospective studies, however, have suggested strongly that the addition of postoperative radiation to incomplete resections improves both progression-free survival (i.e. prevents tumor recurrence) and improves overall survival.In the case of a  grade III meningioma, the current standard of care involves postoperative radiation treatment regardless of the degree of surgical resection. This is due to the proportionally higher rate of local recurrence for these higher-grade tumors. Grade II tumors may behave variably and there is no standard of whether to give radiotherapy following a gross total resection. Subtotally resected grade II tumors should be radiated. Chemotherapy
Likely, current chemotherapies are not effective. Antiprogestin agents have been used, but with variable results. A 2007 study of whether hydroxyurea has the capacity to shrink unresectable or recurrent meningiomata is being further evaluated. Epidemiology
Many individuals have meningiomata, but remain asymptomatic, so the meningiomata are discovered during an autopsy. One to two percent of all autopsies reveal meningiomata that were unknown to the individuals during their lifetime, since there were never any symptoms. In the 1970s, tumors causing symptoms were discovered in 2 out of 100,000 people, while tumors discovered without causing symptoms occurred in 5.7 out of 100,000, for a total incidence of 7.7/100,000. With the advent of modern sophisticated imaging systems such as CT scans, the discovery of asymptomatic meningiomata has tripled.Meningiomata are more likely to appear in women than men, though when they appear in men, they are more likely to be malignant.
Larger tumors may cause symptoms, depending on the size and location. Focal seizures may be caused by meningiomata that overlie the cerebrum. Progressive spastic weakness in legs and incontinence may be caused by tumors that overlie the parasagittal frontoparietal region. Tumors of the Sylvian aqueduct may cause myriad motor, sensory, aphasic, and seizure symptoms, depending on the location. Increased intracranial pressure eventually occurs, but is less frequent than in gliomas. Diplopia (Double vision) or uneven pupil size may be symptoms if related pressure causes a third and/or sixth nerve palsy. Causes
The causes of meningiomata are not well understood. Most cases are sporadic, appearing randomly, while some are familial. Persons who have undergone radiation, especially to the scalp, are more at risk for developing meningiomata, as are those who have had a brain injury. Atomic bomb survivors from Hiroshima had a higher than typical frequency of developing meningiomata, with the incidence increasing the closer that they were to the site of the explosion. Dental X-rays are correlated with an increased risk of meningioma, in particular for people who had frequent dental X-rays in the past, when the X-ray dose of a dental X-ray was higher than in the present.Having excess body fat increases the risk.A 2012 review found that mobile telephone use was unrelated to meningioma.People with neurofibromatosis type 2 (NF-2) have a 50% chance of developing one or more meningiomata.Ninety-two percent of meningiomata are benign. Eight percent are either atypical or malignant.