Thymectomy Helps Improve Strength in Myasthenia Gravis

Patients who underwent surgery also experienced lower distress levels from treatment-related symptoms.

Surgical removal of the thymus helped to reduce weakness and need for immunosuppressive drug treatment in patients with myasthenia gravis, data from a global, randomized study indicate.

While thymetomy has been a part of regular treatment in myasthenia gravis, there has been little evidence of its clinical benefits. Additionally, hospital costs for the procedure can be extensive, further complicating the risk-benefit discussion between physicians and patients.

In order to better characterize its effect on clinical outcomes, Gil I. Wolfe, MD, of the University of Buffalo Jacobs School of Medicine in New York, and colleagues from the Thymectomy Trial in Non-Thymomatous Myasthenia Gravis Patients Receiving Prednisone (MGTX) Study Group compared extended transsternal thymectomy plus alternate-day prednisone with alternate-day prednisone alone in 126 patients with myasthenia gravis. Patients were randomized from 2006 to 2012 at 36 treatment sites. Results were collected over a 3-year period.

Ultimately, 57 patients underwent thymectomy. Average Quantitative Myasthenia Gravis (QMG) scores, which measure muscle strength, were lower in both treatment groups over the 3-year follow-up, however patients who underwent thymectomy and received prednisone had QMG scores 2.84 points greater than those who received prednisone alone (6.15 vs 8.99, P<.001). Compared to the prednisone group, the thymectomy group had a lower requirement for alternate-day prednisone (44 mg vs 60 mg), and fewer required immunosuppression with azathioprine (17% vs 48%, P<.001) or were treated in a hospital for exacerbations (9% vs 37%, P<.001).

Notably, patients in the thymectomy group experienced fewer treatment-associated adverse events and in turn lower distress levels related to symptoms.

“Our results suggest surgery is a legitimate option for patients to consider,” Dr Wolfe said in a statement. “We hope that it will help doctors and patients weigh the costs and benefits of how best to reduce the disability that may impact myasthenia gravis patients on a daily basis as they go about their lives.”

The study was funded by NINDS (NS042685), the Muscular Dystrophy Association, and the Myasthenia Gravis Foundation of America.

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Wolfe GI, Kaminski HJ, Aban IB, et al. Randomized Trial of Thymectomy in Myasthenia Gravis. N Engl J Med. 2016;375(6):511-22.