Thymectomy in ocular myasthenia gravis before generalization results in a higher remission rate

Abstract

OBJECTIVES This study aimed to compare the outcomes of patients with ocular myasthenia gravis (OMG) who underwent thymectomy before generalization with the outcomes of those who underwent thymectomy after generalization. METHODS We retrospectively reviewed patients who underwent robotic thymectomy for myasthenia gravis between January 2003 and February 2018. Patients who presented with purely ocular symptoms at myasthenia gravis onset were eligible for inclusion. Exclusion criteria were patients who were lost to follow-up and patients who underwent re-thymectomy. Patients with OMG who developed generalization before thymectomy were categorized into gOMG group and those who did not were categorized into OMG group. The primary outcome was complete stable remission according to the Myasthenia Gravis Foundation of America Post-Intervention Status (MGFA-PIS). RESULTS One hundred and sixty-five (66 males and 99 females) out of 596 patients with myasthenia gravis were eligible for inclusion. Of these, there were 73 and 92 patients undergoing thymectomy before and after the generalization of OMG, respectively. After propensity score matching, a data set of 130 patients (65 per group) was formed and evaluating results showed no statistical differences between the 2 groups. The estimated cumulative probabilities of complete stable remission at 5 years were 49.5% [95% confidence interval (CI) 0.345–0.611] in the OMG group and 33.4% (95% CI 0.176–0.462) in the gOMG group (P = 0.0053). Similar results were also found in patients with non-thymomatous subgroup [55 patients per group, OMG vs gOMG, 53.5% (95% CI 0.370–0.656) vs 28.9% (95% CI 0.131–0.419), P = 0.0041]. CONCLUSIONS Thymectomy in OMG before generalization might result in a higher rate of complete stable remission than thymectomy after generalization.

Controversies in Ocular Myasthenia Gravis

“…As available evidence comes from retrospective heterogeneous studies, no firm conclusions can be drawn on the efficacy of thymectomy in OMG. Some investigations reported no clear benefit (102)(103)(104), while others found early thymectomy to be associated with an increased probability of remission and improvement (105)(106)(107)(108). In a metanalysis, the pooled remission rate after surgery was 50% with a better outcome in pediatric patients (108).…”

Der Stellenwert der Thymektomie ohne Thymom in der Therapie der Myasthenia gravis

“…Die aktuellen Therapieempfehlungen begründen sich ausschließlich auf die vorhandene retrospektive Datenlage [ 4 , 47 ]. Dennoch scheint die Thymektomie die Generalisierungswahrscheinlichkeit zu reduzieren und damit einen signifikanten Einfluss auf die Entwicklung der Erkrankung dieser Patienten zu nehmen [ 36 , 68 ]. Vor allem das Alter der Patienten bei Krankheitsbeginn, die dem operativen Eingriff unterzogen werden, und der Zeitraum von Krankheitsbeginn bis zur Thymektomie sind prognostisch hinweisgebend [ 26 , 40 , 47 ].…”

“…Aufgrund der starken visuellen Vergrößerung sowie der ausgeprägten Flexibilität in der Ausrichtung der Operationsarme scheint die roboterassistierte Thymektomie der transsternalen Thymektomie im Hinblick auf die Radikalität in nichts nachzustehen und die der anderen videoassistierten Versionen sogar zu übersteigen [ 52 ]. Mittlerweile ist die roboterassistierte chirurgische Resektion nicht mehr ein experimentelles Verfahren, sondern ist im Begriff selbst für die Sonderformen der Myasthenia gravis als Mittel der Wahl anerkannt zu werden [ 36 , 38 ].…”

Prediction of the generalization of myasthenia gravis with purely ocular symptoms at onset: a multivariable model development and validation

“…Moreover, our previous study suggests that thymectomy before the generalization of OoMG might improve clinical outcomes compared with thymectomy only after generalization. 13 Thus, minimally invasive thymectomy might also be a treatment option for well-defined patients with OoMG, given the side effects of long-term treatment with prednisone. 14 However, since not all patients with OoMG will progress to gMG, a wait-and-see strategy appears to be justified hoping to achieve spontaneous remission and avoiding the ‘aggressive’ treatment with thymectomy only potentially improving the clinical outcome.…”