Myasthenia gravis in patients with thymoma affects survival rate following extended thymectomy

Surgical and Neurological Outcomes in Robotic Thymectomy for Myasthenic Patients with Thymoma

BACKGROUND

While the safety and feasibility of robotic thymectomy have been well documented through several studies, the surgical and long-term neurological outcomes in patients with thymomatous myasthenia gravis (MG), particularly in advanced stages, remain scarce. This study aims to evaluate the surgical outcomes in patients undergoing robotic-assisted thymectomy (RATS) for thymoma and to analyze neurological outcomes in patients with myasthenia.

MATERIAL AND METHODS

Out of 128 robotic thymectomies performed at our institution between October 2013 and January 2022, clinical and pathological data from 55 patients diagnosed with thymoma were reviewed. Of these, thirty (54.5%) patients had concomitant acetylcholine-receptor-antibody-associated MG. Neurological outcomes were assessed using the Myasthenia Gravis Foundation of America post-intervention score (MGFA-PIS).

RESULTS

Thirty-nine (70.9%) procedures were performed using the left-sided approach. The mean operative time was 196.9 ± 79.9 min in patients with MG compared to 175.8 ± 61.6 min in non-MG patients (p = 0.285). Additionally, patients with MG had a longer in-hospital stay (4.8 ± 2.6 vs. 3.3 ± 2.2 days, p = 0.01) and a significantly higher need for intensive care unit admission (p < 0.01). No deaths were reported. The rates of conversions (3.3% vs. 4.0%, p = 0.895) and complications (p = 0.813) were comparable between the myasthenic and non-myasthenic thymomas. A multivariable analysis identified lung involvement (p = 0.023), vascular involvement (p = 0.04), and extended resection (p = 0.019) as significant risk factors for conversion and complications. The mean age of surgery for patients with MG was 54.5 ± 15.9 years. After a mean follow-up period of 35.6 ± 25.7 months, 18 (60%) patients with myasthenia showed clinical improvement of their condition. Specifically, 2 patients (6.6%) achieved complete stable remission (CSR), 2 (6.6%) experienced pharmacological remission (PR), 12 (40.0%) demonstrated minimal manifestation (MM), and 4 (13.3%) exhibited a combination of PR and MM. Twelve patients (40%) exhibited no changes, maintaining a stable clinical condition. No clinical worsening was observed. The overall improvement rates at 2 years and 5 years were 38% and 83%, respectively.

CONCLUSIONS

RATS thymectomy is a safe and feasible approach for patients with thymoma. Patients with coexisting MG may benefit through a good rate of neurological improvement.

Thymoma With Myasthenia Gravis: A Study of Two Cases

Thymoma is a rare, primary neoplasm of the thymus gland, commonly presenting in adults and associated with autoimmune diseases, most commonly myasthenia gravis (MG). Despite its generally indolent behavior, the variability in clinical presentation and potential for malignancy necessitates detailed evaluation and management. In this report, we present two cases: a 41-year-old male and a 39-year-old female, both of whom presented with a mediastinal mass with symptoms of myasthenia. Further investigation, including imaging and histopathological examination, confirmed the diagnosis of a type B2 thymoma and type B1 thymoma for the male and female patients, respectively. The patients underwent successful complete surgical resection of the masses, with the postoperative recovery being uneventful. They were monitored for signs of disease recurrence and associated autoimmune conditions during follow-up visits. This report underscores the importance of early detection and thorough clinical evaluation of thymoma, particularly in patients with associated paraneoplastic syndromes. Complete surgical resection remains the cornerstone of treatment, with adjuvant therapy tailored based on individual risk factors. Ongoing surveillance is crucial for identifying potential recurrences and associated conditions.

Long-term prognosis in patients with thymoma combined with myasthenia gravis: a propensity score-matching analysis

Introduction

We aimed to assess the impact of myasthenia gravis (MG) on the long-term prognosis in patients with thymoma after surgery and identify related prognostic factors or predictors.

Methods

This retrospective observational study included 509 patients with thymoma (thymoma combined with MG [MG group] and thymoma alone [non-MG group]). Propensity score matching was performed to obtain comparable subsets of 96 patients in each group. A comparative analysis was conducted on various parameters.

Results

Before matching, the 10-year survival and recurrence-free survival rates in both groups were 93.8 and 98.4%, and 85.9 and 93.4%, respectively, with no statistically significant difference observed in the survival curves between the groups (p > 0.05). After propensity score matching, 96 matched pairs of patients from both groups were created. The 10-year survival and recurrence-free survival rates in these matched pairs were 96.9 and 97.7%, and 86.9 and 91.1%, respectively, with no statistical significance in the survival curves between the groups (p > 0.05). Univariate analysis of patients with thymoma postoperatively revealed that the World Health Organization histopathological classification, Masaoka-Koga stage, Tumor Node Metastasis stage, resection status, and postoperative adjuvant therapy were potentially associated with tumor recurrence after thymoma surgery. Multivariate analysis demonstrated that the Masaoka-Koga stage and postoperative adjuvant therapy independently predicted the risk of recurrence in patients with thymoma after surgery.

Conclusion

There was no difference in prognosis in patients with thymoma with or without MG. The Masaoka-Koga stage has emerged as an independent prognostic factor affecting recurrence-free survival in patients with thymoma, while postoperative adjuvant therapy represents a poor prognostic factor.

Diagnosis and therapy of myasthenia gravis-the patients' perspective: a cross-sectional study

The survey aimed to explore patients' perspectives with myasthenia gravis (MG) toward the diagnosis made and the therapy used to treat MG. The survey was conducted with a quantitative method, using the CAWI technique. A total of 321 people participated in the survey. More than half of the respondents (56.4%) had suffered from MG for less than 10 years. In three out of 10 cases (30.9%), the diagnosis of MG lasted 3 years or longer. The diagnostic delay was significantly longer in female respondents than in the males (p = 0.029). Cholinergic drugs were used in 92.9% of cases initially, and as maintenance therapy in 84.3% of cases. Corticosteroids were used in initiating therapy (45.8%) and as maintenance therapy (46.4%). One in four respondents (25.5%) reported experiencing very strong and strong side effects after using steroids. The side effects from steroid therapy very strong or strong affected overall physical health in 55.9% of respondents, very strong or strong affected self-acceptance in 52%, to a very large or large extent on mental health in 47.1%, and to a very strong or strong extent influenced the performance of daily activities in 28.2%. More than half of the respondents (57.0%) had had a thymectomy. Seven out of 10 respondents (72.0%) declared that the therapy they were on at the time of the survey allowed them (to varying degrees) to control their course of MG. Low therapy acceptance and less well controlled MG was associated with a preference for non-tablet therapies (p = 0.045). Regular follow-up and cooperation with the specialist health care system should improve MG symptoms, activities of daily living, and quality of life.

COVID-19-associated AMPA-R and CRMP-5 autoimmune encephalitis in a patient with thymoma and myasthenia gravis

Thymomas are associated with autoimmune disease, most commonly myasthenia gravis, and rarely with autoimmune encephalitis. More recently, viral triggers including COVID-19 have also been implicated in autoimmunity. We present a case of antibody-positive autoimmune encephalitis that developed in the setting of COVID-19 in a patient with thymomatous myasthenia gravis.

Clinical characteristics, prognostic factors, and long-term outcomes associated with epithelial malignancies of the thymus: A 20-year single-institution experience

BACKGROUND

Thymic epithelial tumors are rare and include thymomas and thymic carcinomas. There is scarce literature characterizing prognostic factors and long-term outcomes in these tumors.

AIMS

This review aims to describe disease features of thymomas and thymic carcinomas and to report clinical differences among thymoma histological subtypes.

METHODS AND RESULTS

A retrospective chart review was performed at the University of Florida Shands Hospital, a tertiary care academic medical center in Gainesville, Florida, USA. The review included clinical data of adults with thymic epithelial tumors diagnosed between 2001 and 2021. Significant associations among demographics, histology, stage, and outcomes were investigated. Thymoma subgroup analysis was performed using histological subtype and sex. Forty patients with thymoma and seven patients with thymic carcinoma were included in the final analysis. Among those with thymomas, patients with subtype B1, B2, or B3 tumors were younger, had larger tumors, and presented with higher stage disease when compared to those with subtypes A or AB. Tumor recurrence was most common in subtype B2 and B3 tumors (50.0% and 16.7% vs. 0%; p < .01). However, there was no significant difference in overall survival between histologic subtypes. Compared to females, males with thymomas had superior overall survival (103.0 vs. 62.9 months; p = .021) despite presenting with larger tumors (9.8 vs. 5.8 cm; p = .041). Concomitant myasthenia gravis was associated with increased recurrence but not worsened mortality. Compared to thymomas, patients with thymic carcinoma presented with higher-stage disease and had poorer 5-year survival (50.0% vs. 93.1%; p < .01).

CONCLUSION

This study affirmed pathologic stage and resectability as prognostic factors for thymic epithelial tumors. New findings include inferior overall survival in female patients and higher recurrence rates in those with thymomas and concomitant myasthenia gravis.

Prognostic factors and genetic markers in thymic epithelial tumors: A narrative review

Thymic epithelial tumors (TET) are a group of rare neoplasms of the anterior mediastinum comprising thymomas and thymic carcinomas. The carcinogenesis of TET is mostly unknown. Many studies, mostly retrospective case series, have tried to establish prognostic factors in TET. TET is a very heterogeneous group of tumors with many subtypes for which diagnosis and treatment remains a very challenging task. Despite the disparities among retrospective studies, there are some prognostic factors that are more pertinent such as the completeness of resection, TNM stage and the Masaoka-Koga classification. On the other hand, the identification of different genetic pathways that result in the pathogenesis of TET represents a fascinating field of study that could possibly lead to the development of new targeted therapies. The aim of this review is to discuss the different prognostic factors and genetic markers of TET. The meticulous use of national and international databases could provide sufficient number of patients in order to draw more valid conclusions.

The Studies of Prognostic Factors and the Genetic Polymorphism of Methylenetetrahydrofolate Reductase C667T in Thymic Epithelial Tumors

Objective

To describe the clinical features of a cohort of patients with thymic epithelial tumors (TETs) and to analyze their prognostic factors. In particular, we investigated the correlation between the genetic polymorphism of methylenetetrahydrofolate reductase (MTHFR) C667T and the incidence of TETs.

Methods

Pathological records were reviewed from the database of the Second Affiliated Hospital of Jiaxing University, from January 2010 to December 2020, and 84 patients with TETs were recruited for this study. Univariate and multivariate analyses were performed to determine the prognostic factors. The genetic polymorphism of MTHFR C667T was examined in the patients with TETs and in a group of healthy individuals. The correlation between MTHFR transcriptional levels and methylation was analyzed using The Cancer Genome Atlas (TCGA) thymoma dataset from the cBioPortal platform.

Results

Kaplan–Meier univariate survival analysis showed that sex, age, the maximum tumor diameter, surgery, chemotherapy, radiotherapy, WHO histological classification, Masaoka–Koga stage, and 8th UICC/AJCC TNM staging, were statistically significantly correlated with the prognosis of patients with TETs. The Masaoka–Koga stage and 8th UICC/AJCC TNM staging were strongly correlated with each other in this study (r=0.925, P<0.001). Cox multivariate survival analysis showed that the maximum tumor diameter, Masaoka–Koga stage, and 8th UICC/AJCC TNM staging were independent prognostic factors affecting the overall survival (OS) of patients with TETs (P<0.05). The MTHFR C667T genotype (χ^{2 =} 7.987, P=0.018) and allele distribution (χ^{2 =} 5.750, P=0.016) were significantly different between the patients and healthy controls. CT heterozygous and TT homozygous genotypes at this MTHFR polymorphism significantly increased the risk of TETs (odds ratio [OR] =4.721, P=0.008). Kaplan–Meier univariate survival analysis showed that there was no correlation between different genotypes and the prognosis of TETs (CC versus CT + TT, χ^{2 =}0.003, P=0.959). Finally, a negative correlation between the transcriptional and methylation levels of MTHFR was observed in the TCGA thymoma dataset (r=-0.24, P=0.010).

Conclusions

The Masaoka–Koga stage, 8th UICC/AJCC TNM staging, and maximum tumor diameter were independent prognostic factors for TETs. Reduced methylation levels of MTHFR and particular polymorphic variants may contribute to the susceptibility to developing TETs.

A case of uniportal VATS thymectomy for Thymoma associated with myasthenia gravis and toxic multinodular goiter

BACKGROUND

Thymoma is a rare neoplasm, which may be associated with autoimmune disorders, the occurrence of hyperthyroidism in the patients with thymoma is rare.

CLINICAL PRESENTATION

Here we present an extremely rare case of a 56-year-old female patient who was discovered to have malignant thymoma with associated myasthenia gravis and hyperthyroidism due to toxic multinodular goiter. Our patient started to complain of difficulty breathing and swallowing, Chest CT scan was done and revealed an anterior mediastinal mass, measures about 4.1 × 3.1 × 2.2 cm with enlarged lymph node mostly representing thymoma. Complete thymectomy was performed via uniportal video-assisted thoracoscopic surgery, and the patient's postoperative recovery was uneventful. Microscopic histopathology findings corresponded to thymoma type B1.

CONCLUSION

The coexistence of thymoma, MG and toxic multinodular goiter is extremely rare. MG should always be suspected in a patient with thymoma. VATS thymectomy has been increasingly used to treat thymoma as it has several advantages over open surgery.

Intrapericardial Thymoma Presented as Pericardial Tamponade with Post-Operative Myasthenia Gravis

Background: Thymoma is an epithelial mass arising from the thymus. Most thymomas are located in the anterior mediastinum. Ectopic intrapericardial thymoma is very unusual; to date, only eight cases of pericardial thymoma have been reported. Among thymoma patients, 20% to 25% are associated with myasthenia gravis. However, postoperative myasthenia gravis occurs in less than 1% of cases. Here, we share a rare case of ectopic intrapericardial thymoma that developed postoperative myasthenia gravis six months after surgery. Case presentation: A 66-year-old woman visited the outpatient department due to productive cough and chest pain. Chest radiography showed increased soft tissue opacity over the mediastinum. A soft tissue mass in the pericardium and a ground glass nodule in right upper lung were noted using chest computed tomography. The diagnosis of thymoma, type B2, pT3N0M0, and stage IIIA and synchronous adenocarcinoma in situ of the right upper lung was confirmed after surgical removal. Six months later, the patient developed postoperative myasthenia gravis. Conclusions: Thymoma is rarely considered a differential diagnosis in pericardial tumors. Surgical removal with adjuvant radiation therapy should be performed considering the malignancy potential of thymomas and cardiac complications. In patients without myasthenia gravis, a small chance of postoperative myasthenia gravis remains. Patients should be carefully monitored for myasthenia gravis after surgery.

Long Non-Coding RNAs in the Cell Fate Determination of Neoplastic Thymic Epithelial Cells

Thymic Epithelial Tumors (TETs) arise from epithelial cells of the thymus and are very rare neoplasms comprising Thymoma, Thymic carcinoma, and Thymic Neuroendocrine tumors that still require in-depth molecular characterization. Long non-coding RNAs (lncRNAs) are emerging as relevant gene expression modulators involved in the deregulation of several networks in almost all types of human cancer, including TETs. LncRNAs act at different control levels in the regulation of gene expression, from transcription to translation, and modulate several pathways relevant to cell fate determination under normal and pathological conditions. The activity of lncRNAs is strongly dependent on their expression, localization, and post-transcriptional modifications. Starting from our recently published studies, this review focuses on the involvement of lncRNAs in the acquisition of malignant traits by neoplastic thymic epithelial cells, and describes the possible use of these molecules as targets for the design of novel therapeutic approaches specific for TET. Furthermore, the involvement of lncRNAs in myasthenia gravis (MG)-related thymoma, which is still under investigation, is discussed.

Utilization of Decision Tree Algorithms for Supporting the Prediction of Intensive Care Unit Admission of Myasthenia Gravis: A Machine Learning-Based Approach

Myasthenia gravis (MG), an acquired autoimmune-related neuromuscular disorder that causes muscle weakness, presents with varying severity, including myasthenic crisis (MC). Although MC can cause significant morbidity and mortality, specialized neuro-intensive care can produce a good long-term prognosis. Considering the outcomes of MG during hospitalization, it is critical to conduct risk assessments to predict the need for intensive care. Evidence and valid tools for the screening of critical patients with MG are lacking. We used three machine learning-based decision tree algorithms, including a classification and regression tree, C4.5, and C5.0, for predicting intensive care unit (ICU) admission of patients with MG. We included 228 MG patients admitted between 2015 and 2018. Among them, 88.2% were anti-acetylcholine receptors antibody positive and 4.7% were anti-muscle-specific kinase antibody positive. Twenty clinical variables were used as predictive variables. The C5.0 decision tree outperformed the other two decision tree and logistic regression models. The decision rules constructed by the best C5.0 model showed that the Myasthenia Gravis Foundation of America clinical classification at admission, thymoma history, azathioprine treatment history, disease duration, sex, and onset age were significant risk factors for the development of decision rules for ICU admission prediction. The developed machine learning-based decision tree can be a supportive tool for alerting clinicians regarding patients with MG who require intensive care, thereby improving the quality of care.

Pure Red Cell Aplasia and Other Haematological Diseases Associated With Thymoma: A Case Series and Systematic Review

Background: Thymoma-associated haematological diseases (HDs), such as pure red cell aplasia (PRCA) and Good's syndrome, are extremely rare, and due to the paucity of large-scale studies, the characteristics, remission after thymectomy, and long-term evaluation remain undetermined.

Methods: We retrospectively assessed patients with thymoma and associated HDs from Jan 2005 to Dec 2020. All patients received thymectomy and/or additional treatments for HDs. A comparison with thymoma-associated myasthenic gravis (MG), and a systematic review from PubMed/MEDLINE and Embase were conducted.

Results: In the median follow-up of 56 months, 130 patients were enrolled. Patients with thymoma-associated MG (n = 46) and HDs [n = 8; PRCA (n = 5), PRCA and Good's syndrome (n = 2) and autoimmune haemolytic anaemia (n = 1)] were evaluated. Patients with MG had a significantly higher remission rate after thymectomy (50 vs. 17%; p = 0.0378) as compared to those with other autoimmune diseases. Two of seven patients with PRCA experienced remission with thymectomy alone, and an additional two patients achieved remission with thymectomy plus immunosuppressive therapy (IST). In the systematic review, 60 studies (case reports, n = 46; case series including the present study, n = 14) were evaluated. Forty-four percent of patients were diagnosed with PRCA after thymoma, and 61% achieved remission with thymectomy plus IST; however, Good's syndrome was unaffected.

Conclusions: Our study indicates that patients with thymoma-associated autoimmune diseases other than MG have a lower remission rate than those with MG. Remission of thymoma-associated PRCA can be achieved by thymectomy and IST. This study provides insight into extremely rare but puzzling autoimmune manifestations.

Robotic thymectomy for thymomas: a retrospective follow-up study in the Netherlands

BACKGROUND

The Maastricht University Medical Center+ (MUMC+) is a Dutch center of expertise, appointed by the Netherlands Federation of University Medical Centres (NFU), for the treatment of thymomas. The aim of this study was to investigate the long-term oncological-, surgical-, and neurological outcomes of all patients who underwent a robotic thymectomy for a thymoma at the MUMC+.

METHODS

We retrospectively analyzed the clinical-pathological data of all consecutive patients with a thymoma who underwent robotic thymectomy using the DaVinci® Robotic System at the MUMC+ between April 2004 and December 2018. Follow-up data were collected from 60 referring Dutch hospitals.

RESULTS

In total, 398 robotic thymectomies were performed and 130 thymomas (32.7%) were found. Median follow-up time, procedure time and hospitalization were 46 months, 116 minutes and 3 days, respectively. In 8.4% of the patients a conversion was performed and in 20.8% a complication was registered. The majority of myasthenic patients with a thymoma went into remission, mostly within 12 to 24 months after thymectomy (81.0%). No statistical difference was found in the number of complications, conversions, incomplete resections or deaths between patients with myasthenia gravis and nonmyasthenic patients. Thirty-six patients (27.7%) underwent postoperative radiotherapy. The recurrence rate was 9.1% and the five-year thymoma-related survival rate was 96.6% .

CONCLUSIONS

Robotic thymectomy was found to be safe and feasible in early-stage thymomas, most advanced-stage thymomas and thymomatous myasthenia gravis. A national guideline could contribute to the improvement of the oncological follow-up of thymic epithelial tumors in the Netherlands.

Clinical Predictors of Prolonged Hospital Stay in Patients with Myasthenia Gravis: A Study Using Machine Learning Algorithms

Myasthenia gravis (MG) is an autoimmune disorder that causes muscle weakness. Although the management is well established, some patients are refractory and require prolonged hospitalization. Our study is aimed to identify the important factors that predict the duration of hospitalization in patients with MG by using machine learning methods. A total of 21 factors were chosen for machine learning analyses. We retrospectively reviewed the data of patients with MG who were admitted to hospital. Five machine learning methods, including stochastic gradient boosting (SGB), least absolute shrinkage and selection operator (Lasso), ridge regression (Ridge), eXtreme gradient boosting (XGboost), and gradient boosting with categorical features support (Catboost), were used to construct models for identify the important factors affecting the duration of hospital stay. A total of 232 data points of 204 hospitalized MG patients admitted were enrolled into the study. The MGFA classification, treatment of high-dose intravenous corticosteroid, age at admission, treatment with intravenous immunoglobulins, and thymoma were the top five significant variables affecting prolonged hospitalization. Our findings from machine learning will provide physicians with information to evaluate the potential risk of MG patients having prolonged hospital stay. The use of high-dose corticosteroids is associated with prolonged hospital stay and to be used cautiously in MG patients.

Myasthenia gravis affects overall survival in patients with thymoma: an analysis of multicentre database using propensity score matching

OBJECTIVES

About one-third of patients with thymoma have myasthenia gravis (MG). It remains controversial whether MG affects the prognosis of patients with thymoma. The aim of this study was to evaluate the effect of MG on the prognosis of patients with thymoma in a multicentre database.

METHODS

Patients with thymoma who underwent thymectomy were identified from 2 prospectively collected databases in 2 medical centres from 2010 to 2018. Kaplan-Meier curves and the log-rank test were used to assess overall survival and recurrence-free survival, and a Cox proportional hazards model was used to determine significant contributors to survival. Propensity score matching was performed to eliminate selection bias.

RESULTS

A total of 514 patients with thymoma were included in this study, of whom 320 patients were MG-free and 194 had MG. Patients with MG were younger (median age 50 vs 54 years, P = 0.001) and had smaller tumours (4.4 ± 2.0 vs 4.9 ± 2.3 cm, P = 0.020). Pathological analysis showed that type B tumours especially B2-B3 (B2 + B3 + mix B tumours, 55.2%) are more common in patients with MG, while type AB (37.2%) was the most common in patients without MG. A larger proportion of Masaoka III-IV stage tumour (25.7% vs 11.0%, P < 0.001) was seen in patients with thymoma and MG. Multivariable Cox regression analysis demonstrated that MG (hazard ratio [HR] = 3.729, 95% confidence interval [CI]: 1.398-9.947, P = 0.009), incomplete resection (HR = 5.441, 95% CI: 1.500-19.731, P = 0.010) and Masaoka stage III + IV (HR = 3.390, 95% CI: 1.196-9.612, P = 0.022) were negative prognostic factors of overall survival. Meanwhile, MG (HR =3.489, 95% CI: 1.403-8.680, P = 0.007) and Masaoka stage III + IV (HR = 6.582, 95% CI: 2.575-16.828, P < 0.001) were negative prognostic factors of recurrence-free survival. Propensity-matched analysis compared 148 patient pairs. K-M survival analysis demonstrated that MG was associated with worse overall survival and recurrence-free survival in propensity score-matched patients (log-rank, P = 0.034 and 0.017, respectively).

CONCLUSIONS

Thymoma patients with MG have smaller tumours and a higher percentage of late-stage tumours, which are mainly of WHO B types, especially B2-B3 types. In addition, MG is significantly associated with worse overall survival and recurrence-free survival in thymoma.

Characteristics and outcomes of thymomas in Latin America: Results from over 10 years of experience (CLICaP-LATimus)

BACKGROUND

Thymomas are a group of rare neoplasms of the anterior mediastinum. The objective of this study was to describe the demographics, clinical characteristics and treatment approaches in Latin America.

METHODS

This was a retrospective multicenter cohort study including patients with histologically proven thymomas diagnosed between 1997 and 2018. Demographics, clinicopathological characteristics and therapeutic outcomes were collected locally and analyzed in a centralized manner.

RESULTS

A total of 135 patients were included. Median age at diagnosis was 53 years old (19-84), 53.3% (n = 72) of patients were female and 87.4% had an ECOG performance score ranging from 0-1. A total of 47 patients (34.8%) had metastatic disease at diagnosis. Concurrent myasthenia gravis occurred in 21.5% of patients. Surgery was performed in 74 patients (54.8%), comprising 27 (20%) tumorectomies and 47 (34.8%) thymectomies. According to the Masaoka-Koga system, overall survival (OS) at five-years was 73.4%, 63.8% and 51%, at stages I-II, III-IVA and IVB, respectively (p = 0.005). Furthermore, patients with low lactate dehydrogenase (LDH) (≤373 IU/L) at baseline and myasthenia gravis concurrence showed significantly better OS (p = 0.001 and p = 0.008, respectively). In multivariate analysis, high LDH levels (HR 2.8 [95% confidence interval [CI]: 1.1-7.8]; p = 0.036) at baseline and not performing a surgical resection (HR 4.1 [95% CI: 1.3-12.7]; p = 0.016) were significantly associated with increased risk of death.

CONCLUSIONS

Our data provides the largest insight into the clinical characteristics and outcomes of patients with thymomas in Latin America. Survival in patients with thymomas continues to be very favorable, especially when subjected to adequate local control.

Myasthenia Gravis Is Not an Independent Prognostic Factor of Thymoma: Results of a Propensity Score Matching Trial of 470 Patients

Objective

The association between the prognosis of thymoma and MG remains controversial. Differences in clinical characteristics and treatments between patients with and without MG may affect the findings of those studies. We designed this propensity score matching trial to investigate whether MG is an independent prognostic predictor in thymoma.

Methods

Patients with pathologically diagnosed thymoma and MG were enrolled in the MG group. Moreover, the propensity score matching method was used to select patients who were diagnosed with thymoma without MG from the database of two participating centers. Matched factors included sex, age, Masaoka stage, pathological subtypes, and treatments. Matched patients were enrolled in the non-MG group. Chi-squared test was used to compare the characteristics of the two groups. Overall survival, local-regional relapse-free survival, distant metastasis-free survival, progression-free survival, and cancer-specific survival were calculated from the diagnosis of thymoma using the Kaplan–Meier method.

Results

Between April 1992 and October 2018, 235 patients each were enrolled in the MG and non-MG groups (1:1 ratio). The median ages of patients in the MG and non-MG groups were 46 years old. The World Health Organization pathological subtypes were well balanced between the two groups (B2 + B3: MG vs. non-MG group, 63.0 vs. 63.4%, p = 0.924). Most patients in both groups had Masaoka stages I–III (MG vs. non-MG group, 90.2 vs. 91.5%, p = 0.631). R0 resections were performed in 86.8 and 90.2% of the MG and non-MG groups, respectively (p = 0.247). The median follow-up time of the two groups was 70.00 months (MG vs. non-MG group, 73.63 months vs. 68.00 months). Five-year overall survivals were 92.5 and 90.3%, 8-year overall survivals were 84.2 and 84.2%, and 10-year overall survivals were 80.2 and 81.4% (p = 0.632) in the MG and non-MG groups, respectively. No differences were found in the progression-free survival, distant metastasis-free survival, and local-regional relapse-free survival between the two groups.

Conclusion

MG is not an independent or direct prognostic factor of thymoma, although it might be helpful in diagnosis thymoma at an early stage, leading indirectly to better prognosis.

Role of thymus on prognosis of myasthenia gravis in Turkish population

OBJECTIVE:

Myasthenia gravis (MG) is an autoimmune disease that may cause a disorder in transmission at the neuromuscular junction. Antibodies directed against acetylcholine receptors are responsible. The thymus is the place that that production of these antibodies mainly occurs. The thymus gland abnormalities and abnormal production of these antibodies are associated with MG. Consequently, thymectomy is a common treatment for MG. The nature of the disease makes it difficult to plan prospective, controlled trials; therefore, there is no current consensus among clinicians on a single algorithm of treatment, and the approach is frequently based on the observations and experiences of experts. The contributions to the literature largely consist of retrospective studies examining an approach to treatment and the effects of thymectomy on prognosis. In this retrospective study, evaluation of Turkish patients with myasthenia gravis was carried out for the importance of thymectomy and effects on prognosis.

METHODS:

In this study, 93 patients with myasthenia gravis whose followed up at Neuromuscular outpatient clinic between 1998–2018 were evaluated retrospectively. Type of disease, antibody status, treatment, thymectomy, thymus pathology and prognosis were assessed.

RESULTS:

Thymectomy had been a positive effect on the prognosis of the disease independent of the duration of disease and thymic pathology. The best results had been obtained with early thymectomy with short disease duration, younger age and patients with thymic hyperplasia. Success of therapy was limited with thymoma. With advanced age need for thymectomy was decreased.

CONCLUSION:

In the present study, evaluation of 93 patients with myasthenia gravis was done retrospectively and it was concluded that thymectomy had a positive effect on prognosis, especially in young patients when performed as early as possible. The most successful results were obtained in cases with thymic hyperplasia.

Surgical outcomes of 215 patients with thymic epithelial tumors: A single-center experience

Objectives

To evaluate the oncological prognosis and neurological outcomes for patients with thymic epithelial tumors (TETs) after thymectomy.

Methods

Consecutive patients with TETs who underwent thymectomy at Beijing Hospital from January 2011 to December 2018 were retrospectively enrolled into the study. Clinical, pathological, and perioperative data was collected. Patients were followed‐up by telephone interview and outpatient records. Statistical analyses were performed using SPSS version 19.0.

Results

A total of 215 patients (115 men and 100 women) were included in this study of which 133 patients (61.9%) had TETs associated with myasthenia gravis (MG), and 82 patients (38.1%) had thymic tumors without MG. A total of 194 (90.2%) patients were successfully followed‐up. The median follow‐up period was 42 months. The five‐year overall survival (OS) rate was 88.6%. MG was the first cause of death for patients with MG (6/10). Prognosis in MG patients was similar to those without MG. Multivariate Cox regression analysis demonstrated that TNM stage III + IV was an independent risk factor for OS. Incomplete resection and younger age were risk factors for tumor recurrence. For patients with MG, the cumulative complete stable remission (CSR) rate increased with the postoperative follow‐up period, and the five‐year CSR rate was 44.7%. Univariate Cox analysis indicated that age, preoperative MG duration and preoperative medication might correlate with CSR. Multivariate Cox analysis only indicated older age as a negative factor of achieving CSR.

Conclusions

MG had little influence on OS and tumor recurrence of thymic tumors. The new TNM staging system was an independent prognostic factor. Incomplete resection and younger age were risk factors for tumor recurrence. Older age was a negative factor of achieving CSR for thymoma patients with MG after extended thymectomy.

Key points

Surgical effect and prognostic factors of myasthenia gravis with thymomas

Background

To evaluate the surgical effect and prognostic factors of extended thymectomy for myasthenia gravis (MG) patients with thymomas.

Methods

Patients with MG with thymomas who underwent extended thymectomy at Peking University People's Hospital and Beijing Hospital between January 2010 and December 2018 were retrospectively enrolled. Patients were followed up by telephone or outpatient record review . Statistical analyses were performed using SPSS version 19.0.

Results

A total of 194 patients were included in this study. According to the Osserman classification, there were 56 type I, 52 type IIa, 67 type IIb, 14 type III, and five type IV. Video‐assisted thoracoscopic surgery (VATS) thymectomies were performed in 137 patients, and transthymectomies in 57 patients. The average operation time was 136.6 ± 46.5 minutes, average blood loss was 129.3 ± 287.4 mL, and average postoperative stay was 8.3 ± 7.4 days. A total of 170 patients (87.6%) were successfully followed up. The median follow‐up period was 45 months, and the five‐year overall survival (OS) rate was 81.9%. Cox regression analysis demonstrated that age, Masaoka stage, and recurrence were prognostic factors of OS. Tumor recurrence tended to occur in patients with Masaoka stage III + IV, and age was a protective factor. A total of 20 patients experienced postoperative myasthenic crisis (POMC). Univariate analysis indicated that presence of bulbar symptoms, surgical procedure, and blood loss were risk factors for POMC, but multivariate analysis only indicated the presence of bulbar symptoms as an independent risk factor. A total of 162 patients were evaluated for post intervention MG status. A total of 55 patients achieved complete stable remission; the overall effective rate was 84.5%. Older patients and those with B‐type thymomas had a lower probability of achieving complete stable remission. Efficacy was similar in patients who underwent VATS or the transsternal procedure.

Conclusions

Age, Masaoka stage, and recurrence were prognostic factors of OS. Presence of bulbar symptoms was an independent risk factor for POMC. Age and World Health Organization classification influence the postoperative effect of MG.

Key points

Significant findings of the study

Age, Masaoka stage, and recurrence were prognostic factors of OS for MG with thymomas. The presence of bulbar symptoms was an independent risk factor for POMC. Age and World Health Organization classification may influence the postoperative effect of MG.

What this study adds

Our study had a relatively large sample size of MG patients with thymomas only. We emphasize the analysis of the postoperative effect of MG and overall survival for these patients, which is a complement to previous studies.

Thymic epithelial tumor complicated by immunological abnormalities: results from a single-center retrospective study in China

Background

To describe the clinical manifestations, immunological features, treatments, and outcomes of patients with thymic epithelial tumor (TET) complicated by immunological abnormalities, and to improve knowledge on immunological abnormalities in this rare disease.

Methods

Patients with pathologically confirmed TET at Beijing Chaoyang Hospital between January 2013 and May 2018 were included in this study, and clinical data were analyzed retrospectively. Immunological abnormalities were classified into two groups as follows: Good syndrome (GS) and autoimmune disease (AD).

Results

Fifty-nine TET patients were enrolled; twenty-two patients (37.3%) had immune dysfunction. There were no gender, age, or histological type differences between groups with or without immunological abnormalities. Six patients had GS, of whom four patients were diagnosed after thymectomy. Recurrent respiratory infections, particularly opportunistic infections, were the most common manifestation. Three GS patients developed a second cancer (50%; P=0.011). Anti-infective therapy and immunoglobulin supplements effectively treated GS. Seventeen patients developed ADs, including myasthenia gravis (MG) (n=13), Hashimoto's thyroiditis (n=4), Sjogren's syndrome (n=1), rheumatoid arthritis (n=1), pemphigus (n=1), and Evans syndrome (n=1). One patient developed both MG and GS and 4 patients presented with two ADs. Three AD cases occurred after thymectomy. Pemphigus and 80% (8/10) of MG cases were resolved following thymectomy.

Conclusions

There is a strong association between immunological abnormalities and TET, which may present at any time point during the disease, even after thymectomy. In addition to infection, GS patients are more likely to develop a second cancer. Thymectomy may produce favorable outcomes for MG in this study, while surgery does not improve immunodeficiency in GS patients.

Acquired neuromyotonia in thymoma-associated myasthenia gravis: a clinical and serological study

Background and purpose

Acquired neuromyotonia can occur in patients with thymoma, alone or in association with myasthenia gravis (MG), but the clinical prognostic significance of such comorbidity is largely unknown. The clinico‐pathological features were investigated along with the occurrence of neuromyotonia as predictors of tumour recurrence in patients with thymoma‐associated myasthenia.

Methods

A total number of 268 patients with thymomatous MG were studied retrospectively. Patients with symptoms of spontaneous muscle overactivity were selected for autoantibody testing using immunohistology for neuronal cell‐surface proteins and cell‐based assays for contactin‐associated protein 2 (CASPR2), leucine‐rich glioma inactivated 1 (LGI1), glycine receptor and Netrin‐1 receptor antibodies. Neuromyotonia was diagnosed according to the presence of typical electromyography abnormalities and/or autoantibodies against LGI1/CASPR2.

Results

Overall, 33/268 (12%) MG patients had a thymoma recurrence. Five/268 (2%) had neuromyotonia, four with typical autoantibodies, including LGI1 (n = 1), CASPR2 (n = 1) or both (n = 2). Three patients had Netrin‐1 receptor antibodies, two with neuromyotonia and concomitant CASPR2+LGI1 antibodies and one with spontaneous muscle overactivity without electromyography evidence of neuromyotonia. Thymoma recurrence was more frequent in those with (4/5, 80%) than in those without (28/263, 10%, P < 0.001) neuromyotonia. Neuromyotonia preceded the recurrence in 4/5 patients. In univariate analysis, predictors of thymoma recurrence were age at thymectomy [odds ratio (OR) 0.95, 95% confidence interval (CI) 0.93–0.97], Masaoka stage ≥IIb (OR 10.73, 95% CI 2.38–48.36) and neuromyotonia (OR 41.78, 95% CI 4.71–370.58).

Conclusions

De novo occurrence of neuromyotonia in MG patients with previous thymomas is a rare event and may herald tumour recurrence. Neuronal autoantibodies can be helpful to assess the diagnosis. These observations provide pragmatic risk stratification for tumour vigilance in patients with thymomatous MG.

Myasthenia gravis as a prognostic marker in patients with thymoma

Background

Thymoma is the most common mediastinal tumor, representing <1% of all cancers. It is usually associated with paraneoplastic disorders, mainly myasthenia gravis (MG). The aim of the present study was to describe patients with thymoma and the differences between those with MG and those without it.

Methods

A retrospective 10-year database of the patients with thymoma treated at a single cancer referral hospital (National Institute of Cancer, Mexico City), was analyzed.

Results

Sixty-four files from patients with thymoma were analyzed, 18 of them had MG. The symptoms that occurred most frequently in patients with MG were ptosis, diplopia, appendicular weakness, dysphonia and dysphagia. The most frequent Myasthenia Gravis Foundation of America (MGFA) stage was IIIb followed by stage I. Almost all the patients with MG had positive Acetylcholine Receptor antibodies (P<0.001), with not specified antibodies in four patients. The median overall survival showed a trend to be higher among the patients with MG, but there were no significant differences.

Conclusions

In patients with thymoma MG manifests with different clinical and autoimmune traits, but not survival differences. A larger multi-centric study should be encouraged to evaluate the prognostic implications of having MG in patients with thymoma.

The effect of myasthenia gravis as a prognostic factor in thymoma treatment

OBJECTIVE:

Thymoma is a standard epithelial tumor. Though it is rare, it constitutes 50% of anterior mediastinal masses. Variety of immunological diseases may accompany thymoma; however, myasthenia gravis (MG) is the most frequently associated paraneoplastic syndrome. Most effective treatment for thymoma is complete surgical resection. In this study, impact of MG on prognosis of thymoma cases was examined.

METHODS:

Records of 61 patients who underwent surgery with diagnosis of thymoma between January 2003 and September 2016 were retrospectively reviewed. All cases were analyzed for data related to age, gender, complaint, localization of lesion, surgical procedure, histopathological diagnosis, stage, MG, and long-term follow-up results.

RESULTS:

Total of 58 cases were included in the study. Of those, 37 patients were male and 21 were female. Mean age was 48 years. While 24 cases of thymoma were accompanied by MG, 34 cases were not. Duration of follow-up ranged from 1 month to 155 months.

CONCLUSION:

It was found that in group with MG, 5-year survival rate was 87.5% while it was 82.4% in group without MG. Despite longer duration of survival in group of thymoma associated with MG, there was no significant statistical difference between groups (p=0.311).