Recently, the prognosis of
myasthenia gravis (MG) has improved considerably because the commercial measurement of
acetylcholine receptor (AChR) antibody has been introduced and early treatment with
steroid at large quantities has been utilized. On the other hand, the efficacy and the safety of
thymectomy for MG patients without
thymoma are still controversial. A meta-analysis of
thymectomy for MG patients without
thymoma revealed an uncertain effect. Since 2005, a controlled randomized study for
thymectomy in patients with MG has been in progress at 66 centers in 16 countries. This study compares the efficacy and safety of
steroid combined with
thymectomy versus those of
steroid alone. The total number of study patients is 150. When patients are randomized into the group of
steroid plus
thymectomy, they receive extended trans-sternal
thymectomy prior to receiving
steroid. In both groups, patients receive oral
steroid on alternate days. The dose of
steroid increases relatively rapidly, and is then maintained at 1.5mg/kg BW or 100mg on alternate days. After 4 months, the maintained dose of
steroid is decreased according to the protocol. This study, initially planned and conducted by Dr. John Newsom-Davis, should provide solid evidence on the efficacy and safety of extended trans-sternal
thymectomy for MG without
thymoma.