RESULTS	In patients with grade 1 TBM , but not with grade 2 or grade 3 TBM , the benefit of dexamethasone treatment tended to persist over time ( five-year survival probabilities 0.69 versus 0.55 , p = 0.07 ) but there was no conclusive evidence of treatment effect heterogeneity by TBM grade ( p = 0.36 ) .\