[pubmed] Risk factors for developing post-thymectomy myasthenia gravis in patients with thymoma

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Muscle Nerve. 2021 Jan 12. doi: 10.1002/mus.27169. Online ahead of print.

ABSTRACT

INTRODUCTION: Thymectomy is required for the treatment of thymoma-associated myasthenia gravis (MG). However, MG may develop only after thymectomy, a condition known as post-thymectomy MG. This study aimed to investigate the risk factors for post-thymectomy MG in patients with thymoma.

METHODS: We retrospectively identified 235 patients with thymoma who underwent thymectomy at a single hospital from January 2008 to December 2017. Forty-four with preoperatively diagnosed MG were excluded, leaving 191 patients in the final analysis. Univariable survival analyses using Cox proportional hazards regression model and Kaplan-Meier estimate were conducted to identify risk factors for post-thymectomy MG.

RESULTS: Post-thymectomy MG developed in 4.2% (8/191) of the patients with thymoma between 18 days and 108 months after surgery. Hazard ratios (HR) of pre- and postoperative anti-acetylcholine receptor antibody (AchR-Ab) titers were 2.267 (p = 0.002) and 1.506 (p < 0.001), respectively. Patients with extended thymectomy had a low chance of post-thymectomy MG (HR 0.035, p = 0.007). Larger thymoma (HR 1.359, p = 0.005) and type A or AB thymoma according to World Health Organization histological classification (HR 11.92, p = 0.021) were associated with higher chances of post-thymectomy MG. Within the subgroup of preoperatively AchR-Ab seropositive patients, post-thymectomy MG developed in 22.2% (6/27).

DISCUSSION: Pre- and postoperative AchR-Ab levels should be measured in patients with thymoma. A large thymoma and partial thymectomy appear to be associated with a higher probability of post-thymectomy MG.

PMID:33434360 | DOI:10.1002/mus.27169


Source: https://pubmed.ncbi.nlm.nih.gov/3343436 ... 2&v=2.14.2