Robotic thymectomy is safe, effective for MG patients even after age 65
Surgery also cuts steroid use in late-onset myasthenia gravis: 2-decade study
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Robotic thymectomy is safe and effective in late-onset myasthenia gravis, even in patients older than 65, a study found.
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The surgery, in which the thymus gland is removed, significantly reduces corticosteroid use and improves neurological outcomes for patients.
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These findings support the use of surgery with robotic systems in people with LOMG and v-LOMG.
Robotic thymectomy — a surgical removal of the thymus gland using robotic systems — is an effective and safe treatment for people with late-onset myasthenia gravis (MG), including those who develop the rare neuromuscular disease after the age of 65, according to a two-decade-long study in China.
Rates of remission and overall favorable outcomes were similar between people with late-onset MG (LOMG) — when the condition is first seen between ages 50 and 64 — and those with very late-onset MG, or V-LOMG, typically developing after age 65, the data showed. The researchers noted that V-LOMG patients “are historically considered higher risk.”
Further, surgery led to a marked reduction in the use of corticosteroids and other MG medications, the data showed.
Given these positive outcomes, “the findings support a personalized treatment approach, including surgical intervention, for carefully selected patients likely to benefit,” the researchers wrote.
The study, “Robotic Extended Thymectomy in Late-Onset Myasthenia Gravis: A 21-Year Retrospective Cohort Study of 172 Patients,” was published in the European Journal of Neurology.
In MG, self-reactive antibodies target proteins involved in nerve-muscle communication, leading to muscle weakness. When symptoms are limited to the eye and eyelid muscles, the condition is known as ocular MG. When it’s widespread throughout the body, it’s known as generalized MG.
Abnormalities in the thymus gland, a part of the immune system, are thought to play a role in the production of the self-reactive antibodies that drive MG. As such, thymectomy, or the removal of the thymus gland, is commonly performed among people with MG to help ease symptoms.
Data from a previous appropriately-controlled clinical trial showed that a thymectomy combined with medication outperformed medical therapy alone in improving clinical outcomes in MG patients.
Analyzing outcomes of robotic thymectomy
Robotic thymectomy is a minimally invasive surgical procedure that uses robotic systems to help remove the thymus gland. A study published last year found that robotic thymectomy was a safe and effective treatment for MG, including for subgroups of patients who have historically shown poorer outcomes. Still, most of that study’s participants had early-onset MG, when the disease develops before age 50.
“High-quality, large-scale evaluations of robotic-assisted thoracic surgery (RATS) extended thymectomy in LOMG remain scarce, and its outcomes are not well defined,” the researchers wrote.
To learn more about the outcomes of this approach, the research team retrospectively analyzed data from 104 adults with LOMG and 68 with V-LOMG who underwent robotic thymectomy at the researchers’ center from 2003 to 2023. Overall, slightly more than half of the patients (55%) had ocular MG at disease onset; most of these individuals (76%) subsequently developed generalized MG.
After surgery, outcomes were measured using a composite neurological remission (CNR) scale. This noted three types of results: complete stable remission, or CSR, meaning no symptoms and no medications; pharmacologic remission, or no symptoms but still needing medication; and minimal manifestations-0, which means no symptoms, but some muscle weakness on examination, without the need for treatment in the past year.
The researchers also assessed rates of favorable outcomes, which combined CNR and minimal manifestations 1-3 — indicating absence of symptoms, some muscle weakness, and a need for one or more types of treatments in the prior year.
Results show steroid-sparing effect with surgery
During a mean follow-up of 5.1 years after surgery, the V-LOMG group had slightly higher rates of CNR (16.2% vs. 11.5%) and favorable outcomes (52.9% vs. 45.2%) than the LOMG group. Similar trends were seen for each component of CNR. Even so, the differences were not statistically significant, meaning these could be due to chance, the researchers noted.
Additionally, the median time to achieving CSR and CNR after surgery did not differ between the two groups. The 10-year outcomes were also similar between the LOMG and V-LOMG groups, both for CNR (20.1% vs. 20.4%) and for CSR (12.7% vs. 9.8%).
After surgery, there was a significant reduction in mean corticosteroid dose at the last follow-up, especially in the V-LOMG group, “confirming a steroid-sparing effect,” the team wrote. The mean dose of cholinesterase inhibitors, often used as a first-line treatment for MG, was also significantly reduced in the entire patient population.
Adjusted statistical analysis showed that immunosuppressive therapy before surgery was an independent factor associated with a significantly lower probability of achieving CNR, CSR, and favorable outcomes, “further underscoring its predictive role for unfavorable outcomes,” the team wrote.
[Robotic thymectomy] is a safe and feasible option for patients with MG onset at age [50 and older], … providing favorable neurological outcomes with a significant steroid-sparing effect.
Other independent risk factors for low favorable outcome rates included the use of additional treatments after surgery — such as plasma exchange, intravenous immunoglobulin, and other immunotherapies — and a delay of more than two years from diagnosis to thymectomy.
That last finding emphasizes “the importance of early MG diagnosis and timely surgical intervention in optimizing patient prognosis,” the researchers wrote.
MG severity before surgery was not predictive of outcomes
MG severity prior to thymectomy, as indicated by the Myasthenia Gravis Foundation of America (MGFA) classification, is widely recognized as a predictor of neurological outcomes after surgery. However, in this analysis, it was not identified as an independent predictor, the researchers noted.
The team suggested that the follow-up period may not have been long enough to fully assess the predictive value of MGFA classification in this late-onset patient group.
No patient died within 90 days after surgery, and most complications (83%) were minor, occurring at similar rates in both groups. Still, those with thymus cancer and who needed the removal of other tissues had a higher risk of adverse outcomes.
Overall, the researchers concluded that robotic thymectomy “is a safe and feasible option for patients with MG onset at age [50 and older], including those with V-LOMG, providing favorable neurological outcomes with a significant steroid-sparing effect.”
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