Published September 1, 2016
Surgical removal of the thymus provides significant benefits to myasthenia gravis (MG) patients without a chest tumor, according to a new study authored by Gil I. Wolfe, MD, professor and Irvin and Rosemary Smith Chair of neurology.
Randomized Trial of Thymectomy in Myasthenia Gravis, published Aug. 11 in the New England Journal of Medicine, addresses a question doctors have sought to clarify for decades: whether a mainstay in the treatment of MG for 75 years actually benefits patients.
Wolfe is first author and clinical chair of the worldwide study that found a thymectomy provides benefits to patients without a chest tumor who have MG, a rare autoimmune disease that affects neuromuscular function.
“These findings solidly confirm the early use of thymectomy in managing myasthenia gravis,” he says. “These findings tell patients they can be even more assured that thymectomy is a positive step to take in the management of their condition.”
Since the 1940s, thymectomy has been used in MG patients — both in patients with a chest tumor called thymoma and those without.
Wolfe says it is widely accepted that patients with a thymoma need to have it surgically removed, but the data have not been as clear in MG patients who do not present with a tumor.
“Until this study, the only evidence was from non-randomized studies that contained significant bias issues,” says Wolfe, an expert on neuromuscular disorders with a special focus on MG, who was awarded the 2015 Doctor of the Year award from the Myasthenia Gravis Foundation of America.
While he was at the University of Texas Southwestern, Wolfe worked with colleagues John Newsom-Davis, MD; Henry J. Kaminski, MD; Alfred Jaretzki III, MD; and Gary R. Cutter, PhD, to develop a study that would provide the data neurologists needed to correctly assess the value of thymectomy.
The global study is the longest and one of the largest randomized studies in the history of MG. It ran from 2006 until 2012 with 126 patients with MG who participated in 36 sites across the world.
It judged the effectiveness of thymectomy by comparing disease status of patients and how much of the corticosteroid prednisone they needed after the surgery compared to patients who did not have surgery.
The study found that thymectomy patients needed approximately one-third less prednisone to control their disease than did those who did not have the surgery. Their need for steroid-sparing immunosuppressants, such as azathioprine, was reduced by nearly two-thirds.
“We were quite satisfied to see that thymectomy conferred benefits on disease status measures by the Quantitative Myasthenia Gravis (QMG) score, reduced the need for corticosteroids and other immunosuppressants, reduced hospitalization needs, and also, according to most measures, reduced the side effect burden,” Wolfe says.
MG results from an immune-mediated disruption of communication between nerve and muscle. Symptoms may include droopy eyelids; blurred or double vision; difficulty speaking, swallowing and breathing; and muscle weakness.
The disease affects as many as 60,000 Americans, and its incidence has been increasing, in part as a result of improved diagnostic techniques and an aging population.
Only a few decades ago, approximately a third of all patients with MG died from it, but new diagnostic techniques and treatments have dramatically improved both the quality of life and longevity of patients.
Today, the lifespan for MG patients matches that of the general population.