Subclinical myasthenia gravis in thymomas. (February 2021)

• Record Type: Journal Article
• Authors: Marcuse, Florit; Hochstenbag, Monique; Hoeijmakers, Janneke G.J.; Hamid, Myrurgia Abdul; Damoiseaux, Jan; Maessen, Jos; De Baets, Marc
• Is Part Of: Lung cancer. Volume 152(2021)
• Page Start: 143
• Page End: 148
• Publication Date: 2021-02
• Subjects: Thymomas -- Thymectomy -- Myasthenia gravis -- Anti-acetylcholinereceptor-antibodies; Lungs -- Cancer -- Periodicals; Lung Neoplasms -- Abstracts; Lung Neoplasms -- Periodicals; Poumons -- Cancer -- Périodiques; Lungs -- Cancer; Periodicals; Electronic journals; Electronic journals; 616.99424
• DOI: 10.1016/j.lungcan.2020.12.010
• Languages: English
• ISSNs: 0169-5002

Abstract

Highlights: Subclinical myasthenia gravis is not uncommon in thymomas. Transition of subclinical myasthenia to clinical myasthenia gravis is a matter of time. Positive anti-AChR-antibodies are highly significant for the presence or development of myasthenia gravis in thymomas. Positive anti-AChR-antibodies should trigger considerations of anesthetic-, oncological- and neurological treatment in thymomas. Testing anti-AChR-antibodies in suspected thymomas is part of the pre-surgical screening by the pulmonary oncologist. Therefore it is malpractice if the antibody status is unknown in suspected thymomas at the time of a thymectomy. Abstract: Background: A proportion of thymoma-patients without a history of myasthenia gravis (MG) before thymectomy, appears to have positive anti-AChR-antibodies in the serum. These subclinical MG-patients could be underdiagnosed because analyzation of anti-AChR-antibodies in thymomas is not always performed in patients who did not experience neurological symptoms. The prevalence and long-term outcomes of subclinical MG are never described in literature yet. Methods: We retrospectively analyzed 398 consecutive patients who underwent a robotic-assisted thoracoscopic surgery at the Maastricht University Medical Center+ (MUMC+) between April 2004 and December 2018. In the MUMC+, a robotic approach is the standard surgical approach in patients with thymic diseases. Inclusion criteria were thymomas, thymectomy performed in the MUMC + with a follow-up of at least one year and age above 18 years old. Exclusion criteria were patients with thymic carcinomas, refused participation, or those who were lost to follow-up. Results: Of the 102 included thymoma-patients, 87 patients (85 %) were tested for anti-AChR-antibodies before thymectomy, of which 57 patients were diagnosed with clinical MG and seven subclinical MG-patients were found. Of the 15 patients who were not tested for anti-AChR-antibodies, four more subclinical MG-patients were discovered in the years after thymectomy. The median follow-up time was 62 months. In total, 11 subclinical MG-patients were found, with a mean age of 54 years and predominantly females (64 %). Ten subclinical MG-patients (91 %) developed clinical-MG, within six years after thymectomy. Immunosuppressive drugs were prescribed in five patients. Four patients were diagnosed with a recurrence of the thymoma. No surgical mortality was reported. Two patients died due to a myasthenic crisis. Conclusions: The prevalence of subclinical MG in thymomas was found to be 10.8 %. One in four patients who experienced no neurological symptoms before thymectomy, appeared to have anti-AChR-antibodies and 91 % of these patients developed clinical MG within six years after the thymectomy. Analyzing anti-AChR-antibodies in the serum is recommended in all suspected thymomas before a thymectomy is performed.