胸腺切除在重症肌无力治疗中的证据及争议

Evidence and controversy for thymectomy in myasthenia gravis

重症肌无力(myasthenia gravis,MG)是由自身抗体介导的获得性神经肌接头自身免疫性疾病。MG的发生与胸腺密切相关,约80%的MG合并胸腺异常,包括胸腺滤泡增生及胸腺瘤。胸腺切除已成为治疗伴胸腺瘤MG的标准方法,然而,非胸腺瘤MG能否从胸腺切除中获益这个问题争议了40余年,至今尚未达成共识。2016年新英格兰医学杂志发表了首个关于胸腺切除治疗MG的全球多中心随机对照研究,证实胸腺切除联合泼尼松能够改善非胸腺瘤乙酰胆碱受体抗体阳性全身型MG的预后长达3年,为胸腺切除在非胸腺瘤MG治疗的有效性提供了Ⅰ级证据。然而,胸腺切除在MG治疗中仍存在很多争议及未解问题,包括获益人群、手术方式的选择以及胸腺切除在其他MG亚组中的疗效等。未来仍需随机对照研究解决上述争议和问题,使胸腺切除在MG治疗中的获益最大化。

Myasthenia gravis(MG)is an acquired autoimmune disease mediated by antibodies against components expressed in the neuromuscular junction.The thymus plays an important role in the development of MG.More than 80%of patients with MG demonstrate histological abnormalities of thymus,such as follicular hyperplasia or thymoma.Although thymectomy is standard treatment for patients with MG who have thymoma,whether the procedure is of any clinical benefit in patients without thymoma has been questioned for more than 40 years.In the 2016 issue of the New England Journal of Medicine,the results of the first randomized trial to assess the role of thymectomy in the treatment of MG,the Thymectomy Trial in Non-Thymomatous Myasthenia Gravis Patients Receiving Prednisone Therapy(MGTX)was reported.The MGTX trial conclusively proved that thymectomy improved clinical outcomes over a three-year period in patients with non-thymomatous MG,which provided ClassⅠevidence supporting the use of thymectomy in patients with non thymomatous MG.However,there are still debates on the selection of patients for surgery,and surgical approaching techniques.In addition,the benefit of the thymectomy remains less clear in other subgroups of MG.In the future,randomized controlled trials are required to resolve those controversies and to maximize the benefit of thymectomy in the treatment of MG.