Brain tumors are challenging to handle and cause severe mortality and morbidity. The primary therapy for brain tumors, a combination of radiotherapy, chemotherapy (i.e temozolomide), and corticosteroids, is considered inadequate to improve patients' clinical conditions and associated with many adverse effects. There is an urgent need for new compounds or repurposing of existing therapies, which could improve brain tumor patients' prognosis. Metformin, commonly used for type 2 diabetes medication, has been examined for its protective action in cancer, reducing cancer risk and cancer-related mortality. However, its effect on cancer is still in rigorous debate. This study examines recent studies on the effects of metformin in primary brain tumor patients through systematic reviews. The literature search was performed on PubMed, ScienceDirect, and SpringerLink databases for articles published between 2013 and 2020. We selected clinical studies comparing the therapeutic outcomes of brain tumor therapy with and without metformin. The clinical benefits of the drug were assessed through the overall survival (OS) and progression-free survival (PFS) of brain tumor patients. Those studies demonstrated that the combination of metformin with temozolomide given post-radiotherapy resulted in better OS and PFS. Nonetheless, the efficacy and safety of metformin need further clinical testing in the wider population.

脑肿瘤处理起来具有挑战性，并导致严重的死亡率和发病率。脑肿瘤的主要治疗是放疗、化疗（即替莫唑胺）和皮质类固醇的组合，被认为不足以改善患者的临床状况，并且会产生许多不良反应。迫切需要新的化合物或重新利用现有疗法，以改善脑肿瘤患者的预后。二甲双胍通常用于 2 型糖尿病药物，已对其在癌症中的保护作用、降低癌症风险和癌症相关死亡率进行了检查。然而，它对癌症的影响仍然存在激烈的争论。本研究通过系统评价检验了最近关于二甲双胍对原发性脑肿瘤患者的影响的研究。在 PubMed、ScienceDirect 和 SpringerLink 数据库上对 2013 年至 2020 年发表的文章进行了文献检索。我们选择了比较使用和不使用二甲双胍的脑肿瘤治疗的治疗结果的临床研究。通过脑肿瘤患者的总生存期（OS）和无进展生存期（PFS）评估该药物的临床益处。这些研究表明，放疗后联合使用二甲双胍和替莫唑胺可带来更好的 OS 和 PFS 。尽管如此，二甲双胍的有效性和安全性需要在更广泛的人群中进行进一步的临床测试。