Predictors of post-thymectomy long-term neurological remission in thymomatous myasthenia gravis: an analysis from a multi-institutional database

The impact of thymectomy in subgroups of Myasthenia gravis patients: a single center longitudinal observation

BACKGROUND

Myasthenia gravis (MG) is a rare neuromuscular disorder. Symptoms can range from ptosis only to life threatening myasthenic crisis. Thymectomy is recommended for anti-acetylcholine receptor-antibody positive patients with early-onset MG. Here, we investigated prognostic factors shaping therapeutic outcomes of thymectomy to improve patient stratification.

METHODS

We retrospectively collected single-center data from a specialized center for MG from all consecutive adult patients that underwent thymectomy from 01/2012 to 12/2020. We selected patients with thymoma-associated and non-thymomatous MG for further investigations. We analyzed the patient collective regarding perioperative parameters in relation to the surgical approach. Furthermore, we investigated the dynamics of the anti-acetylcholine receptor-antibody titers and concurrent immunosuppressive therapies, as well as the therapeutic outcomes in dependence of clinical classifications.

RESULTS

Of 137 patients 94 were included for further analysis. We used a minimally invasive approach in 73 patients, whereas 21 patients underwent sternotomy. A total of 45 patients were classified as early-onset MG (EOMG), 28 as late-onset MG (LOMG) and 21 as thymoma-associated MG (TAMG). The groups differed in terms of age at diagnosis (EOMG: 31.1 ± 12.2 years; LOMG: 59.8 ± 13.7 years; TAMG: 58.6 ± 16.7 years; p < 0.001). Patients with EOMG and TAMG were more often female than patients in the LOMG group (EOMG: 75.6%; LOMG: 42.9%; TAMG: 61.9%; p = 0.018). There were no significant differences in outcome scores (quantitative MG; MG activities of daily living; MG Quality of Live) with a median follow-up of 46 months. However, Complete Stable Remission was achieved significantly more frequently in the EOMG group than in the other two groups (p = 0.031). At the same time, symptoms seem to improve similarly in all three groups (p = 0.25).

CONCLUSION

Our study confirms the benefit of thymectomy in the therapy of MG. Both, the concentration of acetylcholine receptor antibodies and the necessary dosage of cortisone therapy show a continuous regression after thymectomy in the overall cohort. Beyond EOMG, groups of LOMG and thymomatous MG responded to thymectomy as well, but therapy success was less pronounced and delayed compared to the EOMG subgroup. Thymectomy is a mainstay of MG therapy to be considered in all subgroups of MG patients investigated.

The Duke Myasthenia Gravis Clinic Registry: II. Analysis of outcomes

INTRODUCTION/AIMS

The Duke Myasthenia Gravis (MG) Clinic Registry contains comprehensive physician-derived data on patients with MG seen in the Duke MG Clinic since 1980. The aim of this study was to report outcomes in patients seen in the clinic and treated according to the International Consensus Guidance statements.

METHODS

This is a retrospective cohort study of patients initially seen after 2000 and followed for at least 2 years in the clinic. Treatment goal (TG) was defined as achieving MGFA post-intervention status of "minimal manifestations" or better; PIS was determined by the treating neurologist. Time-to-event analysis, including Cox proportional hazards modeling, was performed to assess the effect of sex, acetylcholine receptor antibody (AChR-Ab) status, age at disease onset, distribution (ocular vs generalized), thymectomy, and thymoma on the time to achieve TG.

RESULTS

Among the 367 cohort patients, 72% achieved TG (median time less than 2 years). A greater proportion of patients with AChR-Abs and thymectomy achieved TG and they did so sooner than patients without these antibodies or thymectomy. Otherwise, there were no significant differences in these findings within the tested subgroups. The disease duration at the first Duke Clinic visit was shorter in patients who achieved TG than in those who did not.

DISCUSSION

These results demonstrate outcomes that can be achieved in patients with MG treated according to the current Consensus Guidance statements. Among other things, they can be used to determine the added value and potential role of new treatment modalities developed since 2018.

Anti-dsDNA Is Associated with Favorable Prognosis in Myasthenia Gravis: A Retrospective Study

Objectives. To investigate the presence of serum antinuclear antibody (ANA) and anti-double-stranded DNA antibody (anti-dsDNA) in patients with myasthenia gravis (MG) and analyze the clinical characteristics and prognostic factors associated with MG. Methods. We retrospectively enrolled 363 patients with MG and analyzed the clinical characteristics and follow-up data between patients positive and negative for ANA and anti-dsDNA. We defined a Myasthenia Gravis Activities of Daily Living (MG-ADL) reduction as a main prognosis predictor and used logistic regression to determine independent factors associated with prognosis. We built a nomogram to predict prognosis and evaluate the internal validity of the model. Results. Ninety-eight (27.0%) patients were positive for ANA, and 51 (14.0%) were positive for anti-dsDNA. Patients positive for ANA and anti-dsDNA antibodies tended to be female and positive for acetylcholine receptor antibody (AChR-Ab). The rate of thymoma was higher in anti-dsDNA-positive patients with MG (p-dsDNA-MG) than in patients negative for anti-dsDNA (49.0% vs. 26.0%, $p=0.001$ ), and p-dsDNA-MG was associated with reduced MG-ADL score. Regression analysis showed that except for age of onset ( $\text{OR}=0.986$ , $95\%\text{CI}=0.973–0.999$ , $p=0.037$ ), anti-dsDNA ( $\text{OR}=2.800$ , $95\%\text{CI}=1.381–5.679$ , $p=0.004$ ), ptosis ( $\text{OR}=2.930$ , $95\%\text{CI}=1.827–4.699$ , $p<0.001$ ), and eye movement disorder ( $\text{OR}=2.815$ , $95\%\text{CI}=1.672–4.741$ , $p<0.001$ ) were independent predictive factors of a favorable prognosis of MG. These predictors were used to generate a nomogram with an excellent predictive value. Conclusions. Being female and the presence of AChR-Ab were features of ANA- or anti-dsDNA-positive MG. The presence of anti-dsDNA was associated with a favorable prognosis of MG.

Identification of Potential Serum Protein Biomarkers in Thymoma with Myasthenia Gravis After Docetaxel Treatment

INTRODUCTION

Myasthenia gravis (MG) is a devastating acquired autoimmune disease that can seriously affect the patient's quality of life. It is also a common complication of thymoma. Previous studies have shown that docetaxel alleviates myasthenic symptoms in thymoma with MG (TMG). However, little is known about the protein expression profiles and biomarkers for efficacy after docetaxel treatment.

METHODS

We recruited 9 healthy controls and 30 patients with TMG for the serum proteomics study with data-independent acquisition (DIA) technology. We further recruited additional 30 patients for the key protein validation by enzyme-linked immunosorbent assay (ELISA).

RESULTS

We identified 43 proteins by trend analysis and analyzed the interaction between these proteins and MG pathogenic proteins from the DisGNET database and the correlation analysis with clinical data of patients with TMG. Among these, KRAS and SELP were screened out and validated. KRAS and SELP increased in patients with TMG and decreased significantly after docetaxel treatment.

CONCLUSIONS

Our study revealed that the serum proteins were differentially expressed after docetaxel treatment, suggesting their important role in patients with TMG, as well as the critical role of KRAS and SELP as biomarkers in evaluating the efficacy of docetaxel treatment.

Analysis of influencing factors of postoperative myasthenic crisis in 564 patients with myasthenia gravis in a single center

OBJECTIVE

To study the influencing factors of myasthenic crisis in patients with myasthenia gravis during perioperative period.

METHODS

A total of 564 myasthenia gravis (MG) patients who underwent standard expanded resection of thymoma/thymoma in the Department of Thoracic Surgery of Beijing Hospital from January 2011 to March 2022 were retrospectively included in the study. Clinical indicators such as gender, age, thymoma, American Society of Anesthesiologists (ASA) score, operation time, intraoperative blood loss, and some others were recorded.

RESULTS

Osserman-stages IIB + III + IV (odds ratio [OR] 16.091, 95% confidence interval [CI] 5.170-50.076, p value < 0.001), the dosage of pyridostigmine bromide more than 240 mg (OR 6.462, 95% CI 3.110-13.427, p value < 0.001), ASA score 2 and 3 (OR 3.203, 95% CI 1.461-7.020, p value = 0.004), low diffusion lung capacity for carbon monoxide (DLCO%) (OR 0.981, 95% CI 0.963-1.000 p value = 0.049), and blood loss greater than 1000 ml (OR 16.590, 95% CI 1.911-144.011, p value = 0.011) were independent risk factors for myasthenic crisis.

CONCLUSIONS

Patients with poor Osserman stages, higher preoperative dosage of pyridostigmine bromide, higher ASA score, poor pulmonary function (low DLCO%), and more intraoperative bleeding should be highly vigilant for the occurrence of postoperative myasthenic crisis.

Paraneoplastic Syndromes in Neuro-Ophthalmology

Paraneoplastic neurological syndromes (PNS) occur in about 1 in 300 cases of cancer. The usual mechanism is that an antigen on the cancer sets off an immune response that then cross-reacts with a nervous system antigen. The presentation is usually with a subacute progressive neurological disorder. The management of these conditions is usually of both the underlying tumor and immunomodulation to suppress the autoimmune response. There are a number of these conditions that can present to the Neuro-Ophthalmology clinic, either as a discrete condition affecting vision or eye movements or as part of a more widespread neurological disorder. This article will discuss these conditions, their management and prognosis.

Poor responses and adverse outcomes of myasthenia gravis after thymectomy: Predicting factors and immunological implications

Myasthenia gravis (MG) has been recognized as a series of heterogeneous but treatable autoimmune conditions. As one of the indispensable therapies, thymectomy can achieve favorable prognosis especially in early-onset generalized MG patients with seropositive acetylcholine receptor antibody. However, poor outcomes, including worsening or relapse of MG, postoperative myasthenic crisis and even post-thymectomy MG, are also observed in certain scenarios. The responses to thymectomy may be associated with the general characteristics of patients, disease conditions of MG, autoantibody profiles, native or ectopic thymic pathologies, surgical-related factors, pharmacotherapy and other adjuvant modalities, and the presence of comorbidities and complications. However, in addition to these variations among individuals, pathological remnants and the abnormal immunological milieu and responses potentially represent major mechanisms that underlie the detrimental neurological outcomes after thymectomy. We underscore these plausible risk factors and discuss the immunological implications therein, which may be conducive to better managing the indications for thymectomy, to avoiding modifiable risk factors of poor responses and adverse outcomes, and to developing post-thymectomy preventive and therapeutic strategies for MG.

Short-term and sustained clinical response following thymectomy in patients with myasthenia gravis

OBJECTIVE

To investigate short- and long-term outcome following thymectomy in patients with acetylcholine-receptor-antibody (AchR-Ab) positive myasthenia gravis (MG).

METHODS

Rates of clinical response (defined as minimal manifestation, pharmacological or complete stable remission) lasting for at least one year were retrospectively analyzed using Cox proportional hazard models. The occurrence of relapses was recorded during follow-up. Clinical factors associated with achieving an initial or a sustained response were analyzed.

RESULTS

94 patients with a median age of 33 years (IQR 22-51), 68% with non-thymomatous MG and 32% with thymoma-associated MG were included. An initial clinical response was reached in 72% (68/94). Neither sex, age at onset, thymus histology, delay to surgery after disease onset, surgical approach, corticosteroid treatment nor clinical severity before thymectomy were significantly associated with achieving this endpoint. During long-term follow-up (median 89.5 months; IQR 46-189.5) only half of the patients with an initial response (34/68) had a sustained response without relapses. No clinical factors predicted if the response would become sustained. In patients without immunosuppressive treatment before thymectomy (n=24), a high AChR-Ab levels reduction rate after thymectomy was associated with a higher likelihood of achieving an initial response (p=0.03).

CONCLUSION

Sustained long-term clinical response of MG patients after thymectomy is significantly lower than the initial response rates would suggest. The observation that none of the evaluated clinical factors was associated with a worse outcome supports the current clinical practice of patient selection for thymectomy. The relative decline of AchR-antibodies after surgery appears to be a promising prognostic marker.

An Overview of Surgical Treatment of Thymic Epithelial Tumors in Korea: A Retrospective Multicenter Analysis

Background

Thymic epithelial tumors (TETs) are rare, and information regarding their surgical outcomes and prognostic factors has rapidly changed in the past few decades. We analyzed surgical treatment practices for TETs and outcomes in terms of overall survival (OS) and freedom from recurrence (FFR) during a 13-year period in Korea.

Methods

In total, 1,298 patients with surgically resected TETs between 2000 and 2013 were enrolled retrospectively. OS and FFR were calculated using the Kaplan-Meier method and evaluated with the log-rank test. Prognostic factors for OS and FFR were analyzed with multivariable Cox regression.

Results

A total of 1,098 patients were diagnosed with thymoma, and 200 patients were diagnosed with thymic carcinoma. Over the study period, the total number of patients with surgically treated TETs and the proportion of patients who underwent minimally invasive thymic surgery (MITS) increased annually. The 5-year and 10-year survival rates of surgically treated TETs were 91.0% and 82.1%, respectively. The 5-year and 10-year recurrence rates were 86.3% and 80.0%, respectively. The outcomes of surgically treated TETs improved over time. Multivariable Cox hazards analysis for OS, age, tumor size, and Masaoka-Koga stage were independent predictors of prognosis. The World Health Organization classification and tumor-node-metastasis (TNM) staging were also related to the prognosis of TETs.

Conclusion

Surgical treatment of TETs achieved a good prognosis with a recent increase in MITS. The M-K stage was the most important prognostic factor for OS and FFR. The new TNM stage could also be an effective predictor of the outcomes of TETs.

Establishment of multi-center database on thymic epithelial tumors (TETs) and current situation in Korea

The Korean Association for Research on the Thymus (KART) was established in January 2014 with the following members: Asan Medical Center, Samsung Seoul hospital, Seoul national university hospital and Severance hospital, known to be the top four hospitals with the most amount of surgical cases on thymic epithelial tumor (TET). The aim of KART is to establish a multi-center TET database and present the clinical features and treatment outcomes in Korea. The KART database which was based on the International Thymic Malignancy Interest Group (ITMIG) database system included 1,462 cases of retrospectively collected thymoma and thymic carcinoma from Jan 2000 to Dec 2013. Masaoka-Koga stage I consisted of 34%, stage IIA 22% and stage IIB 17%. The overall 5- and 10-year survival rates were 90% and 76% respectively. As the Masaoka-Koga stage progressed, the survival rates decreased. Through the collaboration of ITIMG, 1,327 cases from KART were registered in the database of Cancer Research And Biostatistics (CRAB) in 2019. The Korean Association for Thoracic Surgical Oncology (KATSO) is the only organization in which all thoracic surgeons in South Korea are registered. Because KART was established with the purpose of collecting data on a national scale, KART is in collaboration to produce a nationwide database system with KATSO. The new database system is planning to collaborate with the ITMIG CRAB database and will adopt a TNM staging system developed in parallel to the Masaoka-Koga system. Data is planned on being collected retrospectively and prospectively and KART data will be the foundation of the retrospective data. Once the KATSO database is fully established, the national data of TET will be used to establish a guideline and standard of the treatment for TET in South Korea and KATSO will collaborate with ITMIG.

Thymectomy in Myasthenic Patients With Thymoma: Killing Two Birds With One Stone

BACKGROUND

Thymoma and myasthenia gravis share several pathogenetic aspects including the role of surgery as a therapeutic option. Extended thymectomy is associated with excellent survival and good local control, especially in early stages, and its role for the neurologic disease has been recently validated. The aim of this study is evaluating oncologic and neurologic outcomes of myasthenic patients with thymoma who underwent extended thymectomy.

METHODS

We retrospectively collected surgical, oncologic, and neurologic data of all myasthenic patients with thymoma who underwent extended thymectomy at our department from January 1994 to December 2016. Clinical and pathologic data, neurologic remission rate, and overall survival and disease-free interval were analyzed.

RESULTS

In all, 219 patients underwent extended thymectomy. The B2 histotype was the most represented thymoma (24.2%), and the most prevalent pathologic Masaoka stage was IIB (37.9%). The overall survival and disease-free survival were statistically different between early stage and advanced stage. During the surveillance, 33 patients (15.1%) had recurrences, treated in 21 cases with iterative surgery. Regarding neurologic outcomes, 75 patients (34.2%) reached a complete stable remission, 84 (38.4%) a pharmacologic remission, 51 (23.3%) had an improvement of their symptoms, and in 9 patients (4.1%) myasthenia was unchanged or worsened.

CONCLUSIONS

Surgery is a cornerstone in the treatment of patients with both thymoma and myasthenia gravis. Extended thymectomy, as proposed by Masaoka, offers considerable oncologic outcomes with an excellent survival and low recurrence rate of thymoma; moreover, surgery leads to remarkable neurologic results.

Prevalence and risk factors of myasthenia gravis recurrence post-thymectomy

Objectives:

To evaluate the prevalence and the factors associated with recurrence of myasthenia gravis following thymectomy.

Methods:

Six electronic databases which reported on recurrence of myasthenia gravis following thymectomy and/or its risk factors from 1985 to 2018 were searched. Summary prevalence and risk values obtained based on the random effect models were reported.

Results:

Seventy (70) papers containing 7,287 individuals with myasthenia gravis who received thymectomy as part of their management were retrieved. The patients had a mean follow-up of 4.65 years post-thymectomy. The prevalence of myasthenia gravis recurrence post-thymectomy was 18.0% (95% CI 14.7–22.0%; 1865/7287). Evident heterogeneity was observed (I²=93.6%; p<0.001). Recurrence rate was insignificantly higher in male compared with female patients (31.3 vs. 23.8%; p=0.104). Pooled recurrence rates for thymomatous (33.3%) was higher than the rate among non-thymomatous (20.8%) myasthenia gravis patients (Q=4.19, p=0.041). Risk factors for recurrence include older age, male sex, disease severity, having thymomatous myasthenia gravis, longer duration of the myasthenia gravis before surgery, and having an ectopic thymic tissue.

Conclusion:

A fifth of individuals with myasthenia gravis experience recurrence after thymectomy. Closer monitoring should be given to at-risk patients and further studies are needed to understand interventions to address these risks.

Clinical characteristics and outcomes of thymoma-associated myasthenia gravis

BACKGROUND AND PURPOSE

Prognosis of myasthenia gravis (MG) in patients with thymoma is not well established. Moreover, it is not clear whether thymoma recurrence or unresectable lesions entail a worse prognosis of MG.

METHODS

This multicenter study was based on data from a Spanish neurologist-driven MG registry. All patients were aged >18 years at onset and had anti-acetylcholine receptor antibodies. We compared the clinical data of thymomatous and nonthymomatous patients. Prognosis of patients with recurrent or nonresectable thymomas was assessed.

RESULTS

We included 964 patients from 15 hospitals; 148 (15.4%) had thymoma-associated MG. Median follow-up time was 4.6 years. At onset, thymoma-associated MG patients were younger (52.0 vs. 60.4 years, p < 0.001), had more generalized symptoms (odds ratio [OR]: 3.02, 95% confidence interval [CI]: 1.95-4.68, p < 0.001) and more severe clinical forms according to the Myasthenia Gravis Foundation of America (MGFA) scale (OR: 1.6, 95% CI: 1.15-2.21, p = 0.005). Disease severity based on MGFA postintervention status (MGFA-PIS) was higher in thymomatous patients at 1 year, 5 years, and the end of follow-up. Treatment refractoriness and mortality were also higher (OR: 2.28, 95% CI: 1.43-3.63, p = 0.001; hazard ratio: 2.46, 95% CI: 1.47-4.14, p = 0.001). Myasthenic symptoms worsened in 13 of 27 patients with recurrences, but differences in long-term severity were not significant. Fifteen thymomatous patients had nonresectable thymomas with worse MGFA-PIS and higher mortality at the end of follow-up.

CONCLUSIONS

Thymoma-associated MG patients had more severe myasthenic symptoms and worse prognosis. Thymoma recurrence was frequently associated with transient worsening of MG, but long-term prognosis did not differ from nonrecurrent thymoma. Patients with nonresectable thymoma tended to present severe forms of MG.

Thymomatous myasthenia gravis: 10-year experience of a single center

OBJECTIVES

To summarize the clinical features of thymomatous myasthenia gravis (T-MG), examine the association between MG and thymoma, and identify the related factors or predictors for long-term prognosis of T-MG.

METHODS

A retrospective, observational study was conducted on 100 patients with T-MG and 96 patients with non-T-MG (NT-MG) between January 1, 2009 and December 31, 2019. The baseline characteristics were recorded for each patient. Logistic regression was used to measure the association between all clinical variables and T-MG prognosis.

RESULTS

Between the T-MG and NT-MG groups, age at onset (45.66 ± 11.53 years vs 39.06 ± 14.39 years); age >40 years (72.0% vs. 40.6%); AChR-Ab positive rate (100.0% vs. 83.3%); Myasthenia Gravis Foundation of America (MGFA) classification at the worst condition (≥grade III, 61.0% vs. 33.0%); thyroid dysfunction (7.0% vs. 20.8%); and outcome (complete stable remission + pharmacologic remission + improvement, 74.0% vs. 93.7%) were statistically significant (P < .05). Presence of thymoma (OR = 0.196, 95%CI = 0.076-0.511, P = .001) was a risk factor for MG. Male sex, post-operative complications, higher grade of MGFA classification, and thymoma Masaoka-Koga pathological stage were risk predictors for long-term prognosis of T-MG (P < .1). Use of preoperative anticholinesterase drugs (OR = 5.504, 95%CI = 1.424-21.284, P = .013) was identified as an independent predictor for T-MG.

CONCLUSION

T-MG is clinically different from NT-MG, and thymoma is considered a risk factor for MG. Preoperative anticholinesterase drug use is a protective factor for long-term prognosis of T-MG. A comprehensive understanding of the characteristics of T-MG will likely help improve its prognosis.