Armstrong MF, Lohse CM, Lees KA, et al. - The researchers used volumetric analyses to determine the effect of metformin on tumor growth in sporadic vestibular schwannoma (VS). Patients (n = 361) with sporadic VS who elected initial conservative treatment with at least two serial MRI scans were involved in this retrospective cohort study. Despite promising preliminary findings in several previous studies, the findings indicate that metformin use does not significantly lessen the risk of volumetric tumour growth in sporadic VS.