Is Thymomectomy Alone Appropriate for Stage I (T1N0M0) Thymoma? Results of a Propensity-Score Analysis

Practical methods to differentiate thymic malignancies by positron-emission tomography and tumor markers

PURPOSE

An accurate diagnosis of thymic malignancies is important, but challenging due to the broad range of differential diagnoses. This study aims to evaluate the efficacy of PET/CT and tumor markers for diagnosing thymic malignancies.

METHODS

Patients admitted to our department between January 2012 and December 2021 with primary anterior mediastinal tumors were retrospectively evaluated. We evaluated the relationship between the maximum standardized uptake value (SUVmax), tumor markers, and pathological diagnosis in four groups: thymic carcinoma, thymoma, lymphoma, and others.

RESULTS

In total, 139 patients were included in this study. The SUVmax was significantly higher in lymphoma, thymic carcinoma, and thymoma, in that order. The cytokeratin 19 fragment (CYFRA 21-1) was significantly higher in thymic carcinoma than in the other groups. An ROC curve analysis indicated that the optimal cut-off values of SUVmax for thymic carcinoma plus lymphoma and CYFRA 21-1 for thymic carcinoma were 7.97 (AUC = 0.934) and 2.95 (AUC = 0.768), respectively. Using a combination of cut-off values (SUVmax = 8, CYFRA 21-1 = 3), the accuracy rate for diagnosing thymic carcinoma was 91.4%.

CONCLUSIONS

The SUVmax and CYFRA 21-1 levels are significant indicators for the diagnosis of thymic carcinoma. Combining these indicators resulted in a more accurate diagnosis of thymic malignancies, which could facilitate the decision-making process for determining the optimal treatment strategies.

Early stage thymoma and the surgical extent paradigm

The recommended treatment for early stage thymoma without myasthenia gravis is complete thymectomy (CT). Limited thymectomy (LT) (simply resecting the thymoma with safe surgical margins) is gaining popularity. In this study, we compared the surgical and oncological results of complete and limited thymectomy in non-myasthenic patients with early stage thymoma. Non-myasthenic, Masaoka stage I-II, 86 patients who underwent surgical resection for thymoma were included in the study. Complete thymectomy (n:44) included patients who had resection of the thymoma together with the entire thymus and limited thymectomy (n:42) included patients who had resection of the thymoma without remaining thymus. The surgical approach, tumor size, histological type, pathological stage, adjuvant therapy, complications, postop myasthenia gravis, recurrence and death were recorded and compared between groups. Complete thymectomy group had more WHO type B1-3 tumors, more complications and more deaths than patients in the limited thymectomy group (p = 0.03, 0.018 and 0.023 respectively). Although statistically not significant CT group had more recurrences than LT group (11.4%/4.8%, p = 0.43). The 10-year freedom from recurrence (FFR) rate in the CT group was 84.8% and in the LT group ıt was 97.6%, the difference was not statistically significant (p = 0.15). None of the factors including surgical extent analysed with univariate and multivariate analysis had a significant effect on FFR. Limited thymectomy may be a good treatment option for non-myasthenic early stage thymoma patients but randomized controlled trials with long follow-up periods, ideally comparing patients operated with minimally invasive surgery are necessary.

Long-term follow-up of non-myasthenic patients with early-stage thymoma who underwent extended thymectomy or limited resection

BACKGROUD

The standard resection for early-stage thymoma is total thymectomy and complete tumour excision with or without myasthenia gravis but the optimal surgery mode for patients with early-stage non-myasthenic thymoma is debatable. This study analysed the oncological outcomes for non-myasthenic patients with early-stage thymoma treated by thymectomy or limited resection in the long term.

METHODS

Patients who had resections of thymic neoplasms at Taipei Veteran General Hospital, Taiwan between December 1997 and March 2013 were recruited, exclusive of those combined clinical evidence of myasthenia gravis were reviewed. A total of 113 patients were retrospectively reviewed with pathologic early stage (Masaoka stage I and II) thymoma who underwent limited resection or extended thymectomy to compare their long-term oncologic and surgical outcomes.

RESULTS

The median observation time was 134.1 months [interquartile range (IQR) 90.7-176.1 months]. In our cohort, 52 patients underwent extended thymectomy and 61 patients underwent limited resection. Shorter duration of surgery (p < 0.001) and length of stay (p = 0.006) were demonstrated in limited resection group. Six patients experienced thymoma recurrence, two of which had combined myasthenia gravis development after recurrence. There was no significant difference (p = 0.851) in freedom-from-recurrence, with similar 10-year freedom-from-recurrence rates between the limited resection group (96.2 %) and the thymectomy group (93.2 %). Tumour-related survival was also not significantly different between groups (p = 0.726).result CONCLUSION: Patients with early-stage non-myasthenic thymoma who underwent limited resection without complete excision of the thymus achieved similar oncologic outcomes during the long-term follow-up and better peri-operative results compared to those who underwent thymectomy.

Long-term outcomes following surgical treatment for thymic epithelial tumor in Japan and an analysis of prognostic factors based on the Japanese Association for Research on the Thymus nationwide database

PURPOSE

Patients with a thymic epithelial tumor (TET), comprising thymoma, thymic carcinoma (TC), and thymic neuroendocrine neoplasm (TNEN), are rarely encountered. The present study was conducted to determine the recent outcomes of surgical treatment for TET in Japan and clarify the significance of prognostic factors by analyzing a nationwide database created by the Japanese Association for Research on the Thymus (JART).

METHODS

The JART database includes records of 2471 thymoma, 285 TC, and 56 TNEN cases surgically treated between 1991 and 2010. At the time of the final follow-up examination, 439 patients had died, with tumor the cause of death in 188. The disease-specific survival was examined using the Kaplan-Meier method, with Cox's proportional hazards model utilized to determine independent prognostic factors.

RESULTS

The 10-year survival rate according to TNM-based Stage I, II, IIIA, IIIB, IVA, and IVB classification was 98.7%, 76.8%, 85.0%, 68.9%, 66.2%, and 59.8%, respectively. The T factor, M factor, and tumor size were independent prognostic factors in both thymoma and thymic carcinoma cases, while the N factor had tendency to be a prognostic factor in thymoma but not in thymic carcinoma cases. The WHO histological type was an independent factor in thymoma cases.

CONCLUSION

The significance of pathology and TNM classification as prognostic factors was confirmed.

Prognosis and surgical outcomes of the total thymectomy versus thymomectomy in non-myasthenic patients with early-stage thymoma: A systematic review and meta-analysis

Whether thymectomy (TM) or thymomectomy (TMM) is better for non-myasthenic patients with early-stage thymoma. We conducted a meta-analysis to compare the clinical outcomes and prognoses of non-myasthenic patients with early-stage thymoma treated using thymectomy versus thymomectomy. PubMed, Embase, Cochrane Library and CNKI databases were systematically searched for relevant studies on the surgical treatment (TM and TMM) of non-myasthenic patients with early-stage thymoma published before March 2022. The Newcastle-Ottawa scale was used to evaluate the quality of the studies, and the data were analyzed using RevMan version 5.30. Fixed or random effect models were used for the meta-analysis depending on heterogeneity. Subgroup analyses were performed to compare short-term perioperative and long-term tumor outcomes. A total of 15 eligible studies, including 3023 patients, were identified in the electronic databases. Our analysis indicated that TMM patients might benefit from a shorter duration of surgery (p = 0.006), lower blood loss volume (p < 0.001), less postoperative drainage (p = 0.03), and a shorter hospital stay (p = 0.009). There were no significant differences in the overall survival rate (p = 0.47) or disease-free survival rate (p = 0.66) between the two surgery treatment groups. Likewise, TM and TMM were similar in the administration of adjuvant therapy (p = 0.29), resection completeness (p = 0.38), and postoperative thymoma recurrence (p = 0.99). Our study revealed that TMM might be a more appropriate option in treating non-myasthenic patients with early-stage thymoma.

Prognostic factors and role of postoperative radiotherapy in surgically resected thymomas

Objective

To investigate the prognostic factors in and role of postoperative radiotherapy (PORT) for surgically resected thymomas.

Methods

A total of 1540 patients with pathologically confirmed thymomas undergoing resection between 2000 and 2018 were identified retrospectively from the SEER (Surveillance, Epidemiology, and End Results) database. Tumors were restaged as local (limited to thymus), regional (invasion to mediastinal fat and other neighboring structures), or distant stage. Disease-specific survival (DSS) and overall survival (OS) were estimated by the Kaplan-Meier method and the log-rank test. Adjusted hazard ratios (HRs) with 95% CIs were calculated by Cox proportional hazards modeling.

Results

Tumor stage and histology were independent predictors of both DSS (regional: HR, 3.711; 95% CI, 2.006-6.864; distant: HR, 7.920; 95% CI, 4.061-15.446; type B2/B3: HR, 1.435; 95% CI, 1.008-2.044) and OS (regional: HR, 1.461; 95% CI, 1.139-1.875; distant: HR, 2.551; 95% CI, 1.855-3.509; type B2/B3: HR, 1.409; 95% CI, 1.153-1.723). For patients with regional stage and type B2/B3 thymomas, PORT was associated with better DSS after thymectomy/thymomectomy (HR, 0.268; 95% CI, 0.099-0.727), but the association was not significant after extended thymectomy (HR, 1.514; 95% CI, 0.516-4.44). Among patients with lymph node metastases, those who received PORT (HR, 0.372; 95% CI, 0.146-0.949), chemotherapy (HR, 0.843; 95% CI, 0.303-2.346), or both (HR, 0.296, 95% CI, 0.071-1.236) had a better OS.

Conclusions

The extent of invasion and tumor histology were independent predictors of worse survival following surgical resection of thymoma. Patients with regional invasion and type B2/B3 thymoma who undergo thymectomy/thymomectomy may benefit from PORT, while patients with nodal metastases may benefit from multimodal therapy, including PORT and chemotherapy.

Anterior mediastinal tumor surgery applying single-port thoracoscopy using the subxiphoid approach

Background

This study aims to investigate the effectiveness of application of single-port thoracoscopy using the subxiphoid approach in anterior mediastinal tumor surgery.

Methods

Between June 2014 and June 2016, a total of 108 patients (59 males, 49 females; mean age: 64.9±7.5 years; range, 45 to 79 years) with anterior mediastinal tumors were randomized into subxiphoid (experimental) or right chest (control) groups. Single-port thoracoscopy using the subxiphoid approach was performed in the subxiphoid group, while thoracoscopy using the right thoracic approach was performed in the control group. Preand postoperative pain stress indicators, Visual Analog Scale scores, quality of life scores, postoperative tumor recurrence, and five-year survival rates were compared between the groups.

Results

There were no mortality or serious complications in either group. The mean Visual Analog Scale pain scores on postoperative Days 1 and 7 were 6.5±0.8 and 2.9±0.8 in the subxiphoid group, respectively, compared to 7.2±0.8 and 3.4±0.8 in the control group (p<0.05 for all), respectively. The mean quality of life scores on postoperative Days 1 and 7 were 81.5±5.0 and 79.3±7.7, respectively, in the subxiphoid group compared to 72.4±4.3 and 71.3±4.8 in the control group, respectively (p<0.05 for all). Postoperative pain and pain mediator indexes were lower in the subxiphoid group (p<0.05 for all). The postoperative tumor recurrence rates were 3.70% and 20.37% in the subxiphoid and control groups, respectively (p=0.008). The five-year survival rates were 85.2% and 63.0% in the subxiphoid and control groups, respectively (p=0.008).

Conclusion

Single-port thoracoscopy using the subxiphoid approach is technically feasible, safe, and effective in performing surgery for anterior mediastinal tumors with an intact capsule and a tumor diameter of ≤5 cm.

Surgical, Radiation, and Systemic Treatments of Patients With Thymic Epithelial Tumors: A Systematic Review

INTRODUCTION

Thymic epithelial tumors are rare and are classified as thymoma, thymic carcinoma, and thymic neuroendocrine tumors. The objective of this systematic review was to evaluate the treatment options for patients with thymic epithelial tumors.

METHODS

This systematic review was developed by Ontario Health (Cancer Care Ontario)'s Program in Evidence-Based Care and by the Lung Cancer Disease Site Group. MEDLINE, EMBASE, and the Cochrane Library were searched for studies comparing surgical, radiotherapy, or systemic treatments against any combination of these treatments in patients with thymic epithelial tumors. Meta-analyses were conducted with clinically homogenous studies.

RESULTS

A total of 106 studies were included, mainly from observational studies. There was an overall survival benefit with postoperative radiotherapy for patients with thymic carcinoma (hazard ratio = 0.65, 95% confidence interval: 0.47-0.89) and for patients with thymoma (hazard ratio = 0.70, 95% confidence interval: 0.59-0.82), especially for those with a high risk for mortality. Patients with thymic carcinoma or thymoma had a response to chemotherapy. Selection bias affected the results for studies that evaluated neoadjuvant chemotherapy or minimally invasive surgical techniques. Furthermore, the overall survival benefit found for adjuvant chemotherapy may have been confounded by the administration of postoperative radiotherapy.

CONCLUSIONS

For patients with thymoma or thymic carcinoma, the literature is of low quality and subject to bias. There were overall survival benefits with postoperative radiotherapy. The results of this systematic review were used to inform treatment recommendations in a clinical practice guideline. Future large-scale prospective studies that control for confounders are needed.

Unilateral video-assisted thoracoscopic thymoma resection – Indications, early and mid-term results

Introduction. Thymoma is the most common tumour of the anterior mediastinum. Video-Assisted Thoracic Surgery technique of thymoma resection is spreading world-wide, but the thoracoscopic method is still contentious in many ways. Authors evaluate the early and mid-term results of a 17 years period of VATS unilateral approach at 2 Hungarian thoracic surgical centers. Method. Depending on the anatomical situation of the thymoma, we performed thymectomy, or partial thymectomy (thymomectomy) for the Masaoka–Koga I–II–III stage thymoma from the right or left side through 2 or 3 intercostal ports. We managed the operations with ultrasonic dissector and electrocauter. By using international standards we evaluated perioperative morbidity, mid-term oncological results and clinical symptoms of myasthenia. Results. 23 of the 54 patients were man, 31 were woman, the average age was 58 (26–79) years, 23 of them had myasthenia. The conversion rate was 11,5% (7/61). The average operation time was 84 (39–150) minutes. The average hospitalisation time was 5.5 (3–19) days. The average size of the thymomas was 46 (18–90) mm. The histology resulted thymoma type A in 2 cases, AB in 19 cases, B1/2/3 in 11/11/1 cases, mixed B in 10 cases. The examination of the resection line was R0/1/2 in 42/11/1 cases. The Masaoka–Koga stages were: I (17), IIA (28), IIB (2), III (7). There was 25 thymomectomies, and 29 thymectomies. In seven cases there were extension of the operation to the pericardium (2), to the lung (2), to the phrenic nerve (6), and to innominate vein (1). The in-hospital mortality over 30 day was in 1 case (1.85%). The morbidity was 11/54 (20.4%). The average follow-up time was 62.56 (5–198) months. In the group with myasthenia the effectivity of the operation was 18/21 (85.7%), including complete remission of 5/21 (23.8%). Post-thymectomy myasthenia gravis developed in 2/31 cases (6.5%). The average 5 years survival was 100%, tumour-free 5 years survival was 96%. Conclusions. The higher proportion of the thymomectomy in the early results, higher conversion rate and lower R0 proportion might be in connection with the attitude of the surgeons, with the learning curve and with the limitations of the unilateral method. After a longer follow-up time late results may become more real and comparable. Instead of unilateral VATS technique we have changed to the subxyphoideal approach of VATS because of its better visualisation.

Effect Evaluation of Subxiphoid and Intercostal Thymectomy: A Meta-Analysis and Systematic Review

Background

It still remains unclear whether subxiphoid video-assisted thoracoscopic surgery (SVATS) thymectomy is safe and reasonable. This meta-analysis aims at assessing the effectiveness and safety of SVATS for thymoma in comparison with that of intercostal video-assisted thoracoscopic surgery (IVATS) thymectomy.

Methods

All the relevant data systematically analyzed in this thesis were retrieved from PubMed, the Cochrane Library, web of science, EMBASE, and ClinicalTrials.gov. The time span for data retrieval was from the date of database establishment to March 2022. The outcome indicators include operation time, intraoperative blood loss, duration of postoperative drainage, postoperative hospital days, visual analogue scale (VAS) score on the day of operation, VAS score on postoperative day 3, and VAS score on postoperative day 7; postoperative complications were analyzed in our meta-analysis.

Results

In 13 studies of this paper, there were 1,198 cases included. Among them, 563 cases were treated by SVATS thymectomy and 635 cases by IVATS thymectomy. There was no significant difference in the operation time [113.38 vs. 119.91  min, 95% confidence interval (CI): -0.70-0.15, p = 0.20) and the incidence of intraoperative and postoperative complications (RR = 0.82, 95% CI: 0.58-1.15, p = 0.25) between SVATS thymectomy and IVATS thymectomy. However, SVATS thymectomy significantly reduced the amount of intraoperative blood loss (47.68 vs. 66.69  mL, SMD = -0.57, 95% CI: -0.95 to -0.18, p = 0.004), postoperative drainage days (2.12 vs. 2.72 days, SMD = -0.46, 95% CI: -0.74 to -0.18, p = 0.001), postoperative hospital stays (4.53 vs. 5.91 days, SMD = -0.64, 95% CI: -0.96 to -0.31, p = 0.0001), and VAS scores after the operation.

Discussion

SVATS thymectomy is safe and feasible, and the perioperative effect is better than IVATS thymectomy to a certain extent, which is worthy of popularization and further research.Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/.

Therapeutic options in thymomas and thymic carcinomas

INTRODUCTION

Radical surgery is the best therapeutic option for thymic malignancies. However, patients with advanced or recurrent thymic malignancies often require chemotherapy or radiotherapy. Since thymic malignancies are rare cancers, the efficacy and safety of treatments have been verified based on small Phase 2 trials or retrospective studies.

AREA COVERED

We comprehensively reviewed the treatment strategies for thymic malignancies, including surgery, radiotherapy, and pharmacotherapy, including cytotoxic chemotherapy, molecular-targeted therapy, and immunotherapy. Additionally, we reviewed specific situations, such as pleural dissemination, central nervous system metastasis, and paraneoplastic syndrome.

EXPERT OPINION

Cytotoxic chemotherapy remains the standard option in pharmacotherapy. However, multikinase inhibitors, such as sunitinib and lenvatinib, and immune checkpoint inhibitors including pembrolizumab have been developed to treat thymic carcinomas. Now, a Phase 2 study is evaluating whether lenvatinib plus pembrolizumab benefits patients with type B3 thymoma or thymic carcinoma. Phosphatidylinositol 3-kinase/AKT/ mammalian target of rapamycin inhibitors may contribute to disease control and octreotide scan is only applicable to somatostatin analogues. Although the genomic characteristics of thymic malignancies have been analyzed, few actionable mutations have been detected in general. The development of a treatment strategy using combination pharmacotherapy is anticipated.

Thymomectomy plus total thymectomy versus simple thymomectomy for early-stage thymoma without myasthenia gravis: a European Society of Thoracic Surgeons Thymic Working Group Study

OBJECTIVES

Resection of thymic tumours including the removal of both the tumour and the thymus gland (thymothymectomy; TT) is the procedure of choice and is recommended in most relevant articles in the literature. Nevertheless, in recent years, some authors have suggested that resection of the tumour (simple thymomectomy; ST) may suffice from an oncological standpoint in patients with early-stage thymoma who do not have myasthenia gravis (MG) (non-MG). The goal of our study was to compare the short- and long-term outcomes of ST versus TT in non-MG early-stage thymomas using the European Society of Thoracic Surgeons thymic database.

METHODS

A total of 498 non-MG patients with pathological stage I thymoma were included in the study. TT was performed in 466 (93.6%) of 498 patients who had surgery with curative intent; ST was done in 32 (6.4%). The completeness of resection, the rate of complications, the 30-day mortality, the overall recurrence and the freedom from recurrence were compared. We performed crude and propensity score-adjusted comparisons by surgical approach (ST vs TT).

RESULTS

TT showed the same rate of postoperative complications, 30-day mortality and postoperative length of stay as ST. The 5-year overall survival rate was 89% in the TT group and 55% in the ST group. The 5-year freedom from recurrence was 96% in the TT group and 79% in the ST group.

CONCLUSION

Patients with early-stage thymoma without MG who have a TT show significantly better freedom from recurrence than those who have an ST, without an increase in postoperative morbidity rate.

Limited resection for early-stage thymoma: minimally invasive resection does not mean limited resection

Standard resection for patients with thymoma is resection of thymoma with total thymectomy (TTx) via median sternotomy. Hence, limited resection for thymoma means a lesser extent of resection of normal thymus compared with a standard procedure, i.e. resection of thymoma with partial thymectomy (PTx). In contrast, minimally invasive resection has been defined as resection of thymoma with TTx via a less-invasive approach. However, to date, few studies have precisely evaluated the differences in surgical and oncological outcomes among these three procedures. This report summarizes the differences among these three procedures with a review of studies (January 2000 to December 2020) focusing on the difference in surgical and oncological outcomes and presents current issues in the surgical management of thymoma. In this report, 16 studies were identified; 5 compared standard resection to limited resection, 9 compared standard resection to minimally invasive resection and 2 compared limited resection to minimally invasive resection. Most studies reported that the surgical and oncological outcomes of limited resection or minimally invasive resection were similar to those of standard resection in patients with early-stage thymoma. However, they did not include a sufficient follow-up period. Both limited resection and minimally invasive resection for early-stage thymoma might be reasonable treatment options. However, they are still promising modes of resection. Further studies with a long follow-up period are needed.

Clinical features and prognostic impact of coexisting autoimmune disease other than myasthenia gravis in resected thymomas: analysis of a Japanese multi-institutional retrospective database

OBJECTIVES

The purpose of this study was to clarify the prevalence, clinical features and survival of patients with thymoma and non-myasthenia gravis autoimmune disease (NMAD) using a nationwide cohort.

METHODS

The Japanese Association for Research on the Thymus nationwide database, which includes data from 32 institutions, was examined to clarify the prevalence and characteristics of NMAD associated with thymomas and elucidate the prognostic impact of NMAD for thymoma patients.

RESULTS

Among the 2423 patients with thymomas who were surgically treated between 1991 and 2010, 114 (4.7%) were identified with NMAD. The most frequently observed NMAD was pure red cell aplasia (PRCA) in 44 (1.8%), followed by hypogammaglobulinaemia (0.5%) and rheumatic arthritis (0.5%). Twenty-eight percent of patients with NMAD had concomitant myasthenia gravis. The presence of NMAD was not an independent prognostic factor for overall survival (OS) irrespective of the type of NMAD [PRCA+: hazard ratio (HR) 1.99, 95% confidence interval 0.74-4.47; PRCA- NMAD: HR 1.28, 0.30-3.56]; however, there were more cases with advanced age and disease of the thymoma amongst PRCA+ patients and these showed a worse OS than patients with PRCA- NMAD (P < 0.001), who had an OS similar to those without NMAD (P = 0.489). The 10-year OS rates in PRCA+, PRCA- NMAD and NMAD- groups were 45.5%, 97.4% and 89.5%, respectively. The main causes of death in PRCA+ patients were the progression of thymoma and other diseases including pneumonia.

CONCLUSIONS

Although the presence of NMAD itself did not significantly affect survival after surgery for thymoma, the type of NMAD was associated with different clinical features and prognosis. The NMAD+ thymomas should be separately categorized according to the presence or absence of PRCA.

Meta-Analysis of Limited Thymectomy versus Total Thymectomy for Masaoka Stage I and II Thymoma

Background

This meta-analysis aimed to evaluate the incidence of tumor recurrence, postoperative myasthenia gravis, postoperative complications, and overall survival after limited versus total thymectomy for Masaoka stage I and II thymoma.

Methods

A systematic search of the literature was conducted using the PubMed, Embase, MEDLINE, and Cochrane databases to identify relevant studies that compared limited and total thymectomy in Masaoka stage I-II patients. The quality of the included observational studies was assessed using the Newcastle-Ottawa Scale. The results of the meta- analysis were expressed as log-transformed odds ratios (log ORs), with 95% confidence intervals (CIs).

Results

Seven observational studies with a total of 2,310 patients were included in the meta-analysis. There was an overall non-significant difference in favor of total thymectomy in terms of tumor recurrence (pooled log OR, 0.40; 95% CI, -0.07 to 0.87; p=0.10; I²=0%) and postoperative myasthenia gravis (pooled log OR, 0.12; 95% CI, -1.08 to 1.32; p=0.85; I²=22.6%). However, an overall non-significant difference was found in favor of limited thymectomy with respect to postoperative complications (pooled log OR, -0.21; 95% CI, -1.08 to 0.66; p=0.64; I²=36.1%) and overall survival (pooled log OR, -0.01; 95% CI, -0.68 to 0.66; p=0.98; I²=47.8%).

Conclusion

Based on the results of this systematic review and meta-analysis, limited thymectomy as a treatment for stage I and II thymoma shows similar oncologic outcomes to total thymectomy.

Radiotherapy for thymic epithelial tumours: a review

Thymic epithelial tumours (TETs) represent a rare disease, yet they are the most common tumours of the anterior mediastinum. Due to the rare occurrence of TETs, evidence on optimal treatment is limited. Surgery is the treatment of choice in the management of TETs, while the role of postoperative radiotherapy (PORT) remains unresolved. PORT remains debated for thymomas, especially in completely resected stage II tumours, for which PORT may be more likely to benefit in the presence of aggressive histology (WHO subtype B2, B3) or extensive transcapsular invasion (Masaoka-Koga stage IIB). For stage III thymoma, evidence suggests an overall survival (OS) benefit for PORT after complete resection. For incompletely resected thymomas stage II or higher PORT is recommended. Thymic carcinomas at any stage with positive resection margins should be offered PORT. Radiotherapy plays an important role in the management of unresectable locally advanced TETs. Induction therapy (chemotherapy or chemoradiation) followed by surgery may be useful for locally advanced thymic malignancies initially considered as unresectable. Chemotherapy only is offered in patients with unresectable, metastatic tumours in palliative intent, checkpoint inhibitors may be promising for refractory diseases. Due to the lack of high-level evidence and the importance of a multidisciplinary approach, TETs should be discussed within a multidisciplinary team and the final recommendation should reflect individual patient preferences.

Single-center evaluation of prognostic factors for thymoma treated by surgery: a retrospective study

BACKGROUND

This study aimed to retrospectively evaluate the clinical, pathological, and treatment-related factors associated with survival in patients with surgically treated thymomas.

METHODS

Sixty patients with thymomas who underwent treatment at our institution between 2004 and 2015 were included. Survival analysis was performed based on curves that were obtained using the Kaplan-Meier method. The Wilcoxon test was used for all comparisons, and p < 0.05 was considered statistically significant.

RESULTS

Forty-seven, four, three, four, and two patients presented tumor stages I, II, III, IVa, and IVb (according to the Masaoka classification), respectively, while six, 14, 11, 22, and seven patients had type A, AB, B1, B2, and B3 thymomas, respectively. Furthermore, 53 and eight patients underwent complete resection and required additional resection of adjacent organs, respectively, and no patients died from surgery-related complications. The five-year survival and recurrence-free survival (RFS) rates were 96 and 86%, respectively. The five-year survival rate for all stages was 100% except for those with stage IVb tumors (Masaoka classification); the survival rate for those patients was 0%. Separately, the five-year RFS rates for tumor stages I, II, III, IVa, and IVb were 100, 91, 91, 81, and 71%, respectively. Finally, the five-year survival rates in cases with complete and incomplete resections were 100 and 71%, respectively, indicating that the latter group had a significantly poorer prognosis (p < 0.001).

CONCLUSIONS

These findings suggest that complete resection and the Masaoka pathological stage are significant predictors of prognosis in patients with thymomas. Surgery should aim to achieve complete resection; however, advanced cases may require multimodality therapy.

Video-assisted thoracoscopic thymectomy is feasible for large thymomas: a propensity-matched comparison

OBJECTIVES

Video-assisted thoracoscopic thymectomy is becoming the preferable approach for early-stage thymoma. However, large thymomas are still recognized as a relative contraindication due to the possible risk of incomplete resection or capsular disruption. Thus, the aim of this study is to evaluate the feasibility of video-assisted thoracoscopic thymectomy for large thymomas.

METHODS

Patients diagnosed with Masaoka stage I-IV thymoma between April 2001 and December 2018 were retrospectively reviewed. All patients were divided into 2 groups: thymoma <5.0 cm (group A) and thymoma ≥5.0 cm (group B). Propensity score matching analysis was performed to compare postoperative results. Recurrence-free survival and overall survival were compared for oncological evaluation.

RESULTS

A total of 346 patients were included in this study. In the propensity score matching analysis, 126 patients were included both in group A and group B. There was no significant difference between these 2 groups in terms of the R0 resection rate (95.2% vs 94.4%, P = 1.000), conversion rate (1.6% vs 3.2%, P = 0.684), operation time (119.4 ± 48.4 vs 139.1 ± 46.6 min, P = 0.955), blood loss (93.2 ± 231.7 vs 100.5 ± 149.3 ml, P = 0.649), duration of chest drainage (2.7 ± 1.6 vs 2.8 ± 2.0 days, P = 0.184), length of hospitalization (5.0 ± 3.9 vs 5.2 ± 2.9 days, P = 0.628) or postoperative complications (5.9% vs 8.5%, P = 0.068). There was no significant difference between these 2 groups in terms of the overall survival (P = 0.271) and recurrence-free survival (P = 0.288).

CONCLUSIONS

Video-assisted thoracoscopic thymectomy is a safe and effective approach for large thymomas (≥5 cm) with comparable surgical and oncological results.

Long-Term Outcomes of Robotic Thymectomy in Patients With Thymic Epithelial Tumors

BACKGROUND

The long-term outcomes of robotic thymectomy for thymic epithelial tumors (TETs) are not well known, even though the early postoperative outcomes have improved. This study aimed to report the long-term survival and recurrence in patients with TETs who underwent robotic thymectomies.

METHODS

A total of 158 patients who underwent robotic thymectomy for TET and who were followed-up for more than 1 year were included in the study. The median follow-up time was 43 (interquartile range, 40) months, and 156 (98%) patients were followed completely until the end of the study period.

RESULTS

The mean age of the patients was 55.7 ± 12.7 years, and the mean size of the tumor was 4.6 ± 2.1 cm. There was no postoperative mortality and postoperative complications occurred in 7 (4.4%) patients. The median length of the postoperative hospital stay was 2 (interquartile range, 1-20) days. Thymoma was the most common cell type (n = 132, 84%), and thymic carcinoma (n = 24, 15%) and neuroendocrine tumors (n = 2, 1%) were the next most common types. Advanced stages more than stage III were identified in 15 patients (stage IIIA: n = 7, 4%; stage IVA: n = 5, 3%; and stage IVB: n = 3, 2%). The 5-year disease-specific survival was 100% in thymoma and 95% in thymic carcinoma. The 5-year recurrence-free survival was 94% in thymoma and 79% in thymic carcinoma.

CONCLUSIONS

Robotic thymectomy could achieve favorable long-term survival and recurrence rates, comparable to open or thoracoscopic thymectomy.

Perioperative risk factors for occurrence of myasthenia gravis after thymectomy in patients with thymoma

OBJECTIVES

The goal of this study was to identify the relationship between clinical characteristics and the occurrence of postoperative myasthenia gravis (PMG) in patients with thymomas and to further identify the relationship between PMG and prognosis.

METHODS

Thymoma patients who had surgery at the First Affiliated Hospital of Sun Yat-sen University between July 2004 and July 2016 were reviewed and those who had no previous symptoms of myasthenia gravis were selected for further investigation. In total, 229 patients were included in the study; their clinical characteristics were gathered and analysed.

RESULTS

Among the 229 patients, 19 (8.3%) had PMG. The time between the operation and the onset of myasthenia gravis was 134 days on average (range 2-730 days). Patients experiencing PMG showed a lower rate of complete thymoma resection (73.7% vs 91.4%; P = 0.014) and total thymectomy (63.2% vs 82.9%; P = 0.035) compared with those who did not. Univariable and multivariable logistic regression revealed that thymomectomy [odds ratio (OR) 2.81, 95% confidence interval (CI) 1.02-7.77; P = 0.047] and incomplete tumour resection (OR 3.79, 95% CI 1.20-11.98; P = 0.023) were associated with the occurrence of PMG. Multivariable Cox regression showed that the PMG was not related to overall survival (P = 0.087).

CONCLUSIONS

This study revealed that incomplete tumour resection and thymomectomy were independent risk factors for PMG in thymoma patients with no previous history of myasthenia gravis.

Intermediate oncologic outcomes after uniportal video-assisted thoracoscopic thymectomy for early-stage thymoma

Background

Recent years have seen a trend towards utilizing a video-assisted thoracic surgery (VATS) approach for treatment of thymoma. Although increasing in practice, intermediate- and long-term oncologic outcome data is lacking for the VATS approach. There is no oncologic data for the uniportal VATS approach. We sought to evaluate the feasibility and impact on patient survival of uniportal VATS thymectomy for early-stage thymoma.

Method

The clinical outcomes for 17 patients with Masaoka stage I to II thymomas treated between January of 2009 and July of 2014 at a single institution were collected retrospectively. Primary endpoint was overall survival (OS) and secondary endpoint was recurrence-free survival (RFS).

Results

Ten women and seven men underwent uniportal VATS thymectomy; eleven had stage I thymoma and six had stage II thymoma. There were no conversions to open surgery. Operative mortality was zero. Mean tumor size was 3.8±1.0 centimeters, with a range of 1.9 to 6.0 centimeters. All patients underwent a R0 resection. Five-year survival was 100%, and the estimated RFS was 100%.

Conclusions

Our findings suggest that uniportal VATS thymectomy for early-stage thymoma is feasible, and the intermediate-term oncologic outcomes are comparable to historic standards for open and multi-incision VATS thymectomy. However, additional follow-up is required to evaluate for long-term oncologic outcomes.

Report from the European Society of Thoracic Surgeons prospective thymic database 2017: a powerful resource for a collaborative global effort to manage thymic tumours

OBJECTIVES

We queried the European Society of Thoracic Surgeons (ESTS) prospective thymic database for descriptive analysis and for comparison with the ESTS retrospective thymic database (1990-2010).

METHODS

Data were retrieved (January 2007-November 2017) for 1122 patients from 75 ESTS institutions.

RESULTS

There were 484 (65%) thymomas, 207 (28%) thymic carcinomas and 49 (7%) neuroendocrine thymic tumours. Staging (Masaoka) included 483 (67%) stage I and II, 100 (14%) stage III and 70 (10%) stage IV tumours. The new International Association for the Study of Lung Cancer/International Thymic Malignancies Interest Group tumour, node and metastasis (TNM) classification was available for 224 patients and including 177 (85%) stage I-II, 37 (16%) stage IIIA and 10 (4%) stage IIIB tumours. Chemotherapy as induction and adjuvant treatment was used in 14% and 15% of the patients. Radiotherapy was almost exclusively used postoperatively (24%). A minimally invasive surgical approach (video-assisted thoracic surgery/robotic-assisted thoracic surgery) was used in 276 (33%) patients. The overall recurrence rate was 10.8% (N = 38). Compared to the ESTS retrospective database, the increased prevalence of thymic carcinomas (from 9% to 28%) and neuroendocrine thymic tumours (from 2% to 7%), an increase in the use of minimally invasive techniques (from 6% to 34%) and a wider use of chemotherapy as induction (from 9% to 15%) and adjuvant (from 2% to 16%) treatment were observed in the prospective database. The introduction of a set of variables considered essential for the data use ('minimum dataset') resulted in an increased average completeness rate.

CONCLUSIONS

The reported data from the ESTS prospective thymic database confirm the recent trends in the management of thymic tumours. The ESTS prospective thymic database represents a powerful resource open to all ESTS members for the global effort to manage these rare tumours.

Minimal Access Surgery for Thymoma

Thymoma is a rare epithelial tumor of the thymus gland. Despite rarity, it is the most common tumor of the anterior mediastinum. Surgical resection in the form of extended thymectomy is the gold standard operation. Conventionally and even in the current era of significant advances in the minimally invasive surgery, open transsternal extended thymectomy is considered the gold standard, particularly for advanced-stage tumors. There is however significant evidence now available for the use of minimally invasive approaches for early-stage thymomas. This article aims to discuss the various minimally invasive approaches currently being employed for thymomas.

Comparison of Subxiphoid and Intercostal Uniportal Thoracoscopic Thymectomy for Nonmyasthenic Early-Stage Thymoma: A Retrospective Single-Center Propensity-Score Matching Analysis

OBJECTIVE

The aim of this study was to compare early outcome between intercostal uniportal video-assisted thoracoscopic surgery (IU-VATS) versus subxiphoid uniportal video-assisted thoracoscopic surgery (SU-VATS) in thymectomy for non-myasthenic early-stage thymoma.

METHOD

Retrospective analysis of 76 cases completed in our hospital from May 2018 to September 2019 with subxiphoid uniportal thoracoscopic thymectomy; a single incision of ∼3 cm was made ∼1 cm under the xiphoid process. The control group included 213 patients who received intercostal uniportal thoracoscopic thymectomy from August 2015, and propensity score matching was conducted. All patients who were clinically diagnosed with thymic tumor before surgery were treated with thymectomy. Perioperative outcomes between SU-VATS (n = 76) and IU-VATS, n = 76 were compared.

RESULT

After propensity score matching, there were no statistically significant differences between the two groups in terms of age, gender, disease stage, maximal tumor size, or other baseline demographic and clinical variables. All operation was successfully completed; there were no significant differences in the operative time (88 vs. 81 minutes, p = 0.63), intraoperative blood loss (55 vs. 46 mL, p = 0.47), postoperative drainage time (2.2 vs. 2.5 days, p = 0.72), and postoperative hospital stay (3.2 vs. 3.4 days, p = 0.78) between the two groups. The visual analog scale (VAS) on postoperative days 1, 3, 7, and 30 was less in the SU-VATS group than that in the IU-VATS group. The VAS on days 60 and 180 did not differ significantly between the two groups.

CONCLUSION

Thymectomy using SU-VATS is a feasible procedure; it might reduce early postoperative pain and lead to faster recovery.

Surgical management of thymic epithelial tumors

Resection is the mainstay of treatment for thymic epithelial tumors (TETs), with complete removal of the tumor and involved organs being the ultimate aim. The choice of surgical approach plays a major role in defining treatment success, and the optimal choice of method should thus provide an adequate surgical view to achieve complete tumor resection. While median sternotomy is considered the gold standard for access to the mediastinum, several minimally invasive approaches to thymectomy have been described, including video-assisted robotic-assisted thymectomy, although the oncological outcomes of that procedure remain unclear. A multimodal approach incorporating chemotherapy or chemoradiotherapy followed by extended surgery may improve resectability and outcomes for patients with advanced TETs. Surgical debulking is also reportedly acceptable for invasive thymoma because of its potential for achieving favorable outcomes. Re-resection is an acceptable option for patients with recurrent thymoma after initial resection, and repeat resection for recurrent pleural dissemination seems effective. Here, the literature on current clinical practices in the surgical management and treatment of TETs is reviewed.

Good syndrome with cytomegalovirus hepatitis: successful resection of Thymoma: a case report

BACKGROUND

Good syndrome is a rare condition, manifesting as immunodeficiency due to hypogammaglobulinemia associated with thymoma. Herein, we present a patient with Good syndrome whose thymoma was resected after treatment of cytomegalovirus hepatitis.

CASE PRESENTATION

The patient was a 45-year-old woman presenting with fever, cough, and nasal discharge, and was diagnosed with thymoma and hypogammaglobulinemia. She subsequently developed cytomegalovirus hepatitis that was treated by immunoglobulin. After resolution of the hepatitis, she underwent thymectomy through a left anterior thoracotomy. Her postoperative course was uneventful, and while receiving ongoing immunoglobulin therapy, she has been doing well without signs of infection.

CONCLUSIONS

Management of infections is important for patients with Good syndrome. To minimize the risk of perioperative infection, we should take care while planning the surgical approach and procedure.

Development of a deep learning model for classifying thymoma as Masaoka-Koga stage I or II via preoperative CT images

Background

Accurate thymoma staging via computed tomography (CT) images is difficult even for experienced thoracic doctors. Here we developed a preoperative staging tool differentiating Masaoka-Koga (MK) stage I patients from stage II patients using CT images.

Methods

CT images of 174 thymoma patients were retrospectively selected. Two chest radiologists independently assessed the images. Variables with statistical differences in univariate analysis were adjusted for age, sex, and smoking history in multivariate logical regression to determine independent predictors of the thymoma stage. We established a deep learning (DL) 3D-DenseNet model to distinguish the MK stage I and stage II thymomas. Furthermore, we compared two different methods to label the regions of interest (ROI) in CT images.

Results

In routine CT images, there were statistical differences (P<0.05) in contour, necrosis, cystic components, and the degree of enhancement between stage I and II disease. Multivariate logical regression showed that only the degree of enhancement was an independent predictor of the thymoma stage. The area under the receiver operating characteristic curve (AUC) of routine CT images for classifying thymoma as MK stage I or II was low (AUC =0.639). The AUC of the 3D-DenseNet model showed better performance with a higher AUC (0.773). ROIs outlined by segmentation labels performed better (AUC =0.773) than those outlined by bounding box labels (AUC =0.722).

Conclusions

Our DL 3D-DenseNet may aid thymoma stage classification, which may ultimately guide surgical treatment and improve outcomes. Compared with conventional methods, this approach provides improved staging accuracy. Moreover, ROIs labeled by segmentation is more recommendable when the sample size is limited.

Robot-assisted thoracoscopic surgery for mediastinal masses: a single-institution experience

Background

The objectives of this study were to evaluate the feasibility and safety of robot-assisted thoracic surgery (RATS) using the da Vinci robotic system for mediastinal mass resection and to describe the surgical approach for masses in different mediastinal regions.

Methods

We retrospectively reviewed data from 84 patients who underwent RATS for resection of a mediastinal mass from June 2015 to April 2019. The results were analyzed with descriptive statistics.

Results

The mediastinal mass was resected successfully in all patients, with one patient requiring conversion to conventional open surgery. There were no intraoperative complications. The most common diagnoses were thymoma (n=17), bronchogenic cyst (n=16), and schwannoma (n=12). The surgical approach was determined by the location of the lesion and the planned extent of surgical resection. Resection was performed in the lateral decubitus position in 29 patients with posterior mediastinal tumor, semi-lateral decubitus position in 42 patients who only need resection of anterior mediastinal mass, and reverse Trendelenburg position in 13 patients undergoing thymectomy. The mean (± standard deviation) operation time was 91.86±56.42 min, duration of chest tube use was 1.83±0.93 days, and postoperative hospital stay was 3.62±7.52 days. Three patients (3.5%) developed postoperative complications: one chylous fistula, which required reoperation, and one case each of atrial fibrillation and pulmonary infection, which were treated conservatively.

Conclusions

Our experience demonstrated that different surgical approaches of RATS are safe and feasible for mediastinal mass resection. An appropriate approach can be selected based on the mediastinal region in which the tumor is located.

An exploratory study of CT-guided percutaneous radiofrequency ablation for stage I thymoma

Background

Thymoma is a rare tumor that originates from thymic epithelial cells and is usually associated with myasthenia gravis. Radiofrequency ablation (RFA) is a minimally invasive and curative treatment for other tumors, but RFA has not been used for the early treatment of thymoma.

Methods

The current study included 13 patients with stage I thymoma who were not candidates for surgical resection or video-assisted thoracoscopic surgery (VATS). All patients underwent first-line CT-guided percutaneous RFA. The feasibility and therapeutic effects of the intervention were thoroughly documented.

Results

All tumors were completely ablated (13 / 13, 100%). During follow-up (median 80.5 months, range, 64.6–116.9 months), only 1 of the 13 patients had recurrence of thymoma (1 / 13, 7.7%) at 35.5 months after the initial ablation. There were no surgery-related deaths after RFA treatment. The most common complications were fever (13 / 13, 100%) and pain (13 / 13, 100%). There was only one patient who occurred severe puncture-related bleeding during the procedure that needed blood transfusion and intravascular embolization of the punctured-injured vessel.

Conclusion

CT-guided percutaneous RFA for treatment of stage I thymoma is associated with minor trauma, few complications and good treatment outcomes.

Comparison between thoracoscopic and open approaches in thymoma resection

Background

To investigate the feasibility and indications of video-assisted thoracic surgery (VATS) in thymoma resection.

Methods

The clinical data of 103 patients undergoing thymoma resection via different approaches [including conventional lateral thoracotomy approach (LTA) in 41 cases, median sternotomy approach (MSA) in 40 cases, and right-sided VATS in 22 cases] were analyzed. Among them, 59, 13, 25, and 6 patients were in Masaoka stage I, II, III, and IV, respectively. Myasthenia gravis (MG) was also found in 54 cases. The patients were followed up for postoperative survival and the improvement in MG. The prognostic indicators of patients undergoing thymoma resection via different surgical approaches (i.e., LTA, MSA, and VATS) were statistically analyzed.

Results

Eight of 103 patients died. Six patients underwent unilateral sacral nerve resection, among whom 4 patients developed respiratory dysfunction, and 3 died. Two patients died of MG after surgery, 1 patient died of tumor recurrence and metastasis, 1 patient died of heart disease, and the cause of death was unknown in the remaining patient. The drainage time was shorter in VATS group than in open groups, along with smaller tumor size. The VATS group also had shorter hospital stay in the whole series and the subgroup without accompanying MG. The improvement in MG showed no significant difference among the three surgical groups. Both 5- and 10-year survival rates were 91% in the entire cohort.

Conclusions

VATS is like a conventional surgeries for improving MG in thymoma patients with accompanying MG. VATS resection can still be considered for thymoma that only invades the mediastinal pleura. For thymomas that have intact capsules and have not invaded mediastinal pleura, MSA surgery shall be performed to ensure patient safety if the anteroposterior diameters of the tumors are large and the masses have produced severe compression of the innominate vein, even if the tumors are still in the Masaoka stage II. For thymomas with large left-to-right diameters and with most parts of the tumors located in the left thoracic cavity, a left-sided approach (either VATS or an open approach) may be used in the absence of MG; if MG accompanies the condition, an MT approach or a bilateral VATS may be considered. In patients with unilateral pericardial phrenic nerve and/or local pericardial involvement, right-sided VATS thymectomy may be considered for thymomas located at the right side and bilateral VATS surgery can be performed for tumors located at the left side. In summary, VATS is feasible for the treatment of thymoma complicated by MG. VATS can be performed in patients with Masaoka stage I, II and (a certain portion of) III thymoma; for some patients with Masaoka stage II thymoma, especially those with compression of the innominate vein, the use of VATS should be cautious.

Optimal management of thymic malignancies: current perspectives

Thymic epithelial tumors (TETs) belong to orphan oncology. The incidence of TETs is about 1.3–3.2 cases per million worldwide. Following pathology, evolution and prognosis are variable. The World Health Organization classification distinguishes thymomas and thymic carcinomas. TETs are composed of thymic epithelial tumoral cells and normal lymphocytes. The mean age at diagnosis is 50–60 years-old. There are no identified risk factors. TETs are frequently associated with paraneoplastic syndromes as myasthenia gravis. The complete R₀ surgical resection is the most significant prognosis factor on survival. In 2010, the French National Institute of Cancer labeled the RYTHMIC network as a specific tumor board including thoracic surgeons, oncologist, and radiation therapist to define standard of care for the management of TETs. The aim of the review was to update knowledge to optimize the standard of care.

Radical thymectomy versus conservative thymomectomy in the surgical treatment of thymic malignancies

Background

Complete thymectomy is recommended for thymic malignancies to reduce local recurrence and the likelihood of the long-term development of myasthenia gravis (MG). Thymus-conserving surgery (thymomectomy) seems to yield similar results, but evidence is still limited. The objective of this study was to assess if the oncological outcome, in terms of overall survival (OS) and disease-free survival (DFS), are comparable between radical thymectomy vs. conservative thymomectomy patients, and to assess if the outcome of the video-assisted thoracoscopic surgery (VATS) approach was similar to open surgery approach.

Methods

We retrospectively analyzed 157 consecutive patients with either resectable thymoma or thymic carcinoma from two Italian centers (Humanitas Research Hospital, Milan, and Humanitas Gavazzeni, Bergamo) between 1997 and 2013 who underwent thymomectomy or extended thymectomy with the VATS or open approach; the patients with Miastenia Gravis underwent radical thymectomy. The patients were followed through physical examinations and phone interviews.

Results

Thymomectomy and thymectomy were performed on 86 (54.8%) and 71 (45.2%) patients, respectively. Prognostic factors and comorbidities were comparable in the two groups. The median follow-up was 77 months. Cox proportional hazards model revealed that Masaoka advanced stage and thymic carcinoma of WHO classification were independent predictive factors for overall survival, but that the extent of surgery and the approach used (minimally invasive versus open) were not. Notably, five- and ten-year survival rates were similar in the two groups.

Conclusions

In our experience, radical thymectomy and conservative thymomectomy did not differ in terms of disease-free and overall survival rates. In nonmyasthenic patients with early-stage resectable thymic malignancy, minimally invasive thymomectomy provided equivalent results to open thymectomy. Our results should be interpreted with caution due to the retrospective nature of the study. Well-designed, adequately-powered studies should be very welcome to increase the quantity and the quality of clinical evidence before incorporating this procedure in future guidelines.

Minimally invasive surgery in thymic malignances: the new standard of care

Surgery is the most important therapy for thymic malignancies. The last decade has seen increasing adoption of minimally invasive thymectomy (MIT) for thymic tumors. MIT for early stage diseases has been shown to yield similar oncological results while being helpful in minimizing surgical trauma, improving postoperative recovery, and reducing incisional pain. Similar surgical and oncological principles should be observed in both minimally invasive and open procedures so as to ensure radical resection and accurate staging of the tumor.

Comparison of surgical approach and extent of resection for Masaoka-Koga Stage I and II thymic tumours in Europe, North America and Asia: an International Thymic Malignancy Interest Group retrospective database analysis

OBJECTIVES

Surgeons at different institutions worldwide choose different types of operations for thymic tumours. It is not known whether these differences affect the outcomes of the patients.

METHODS

A total of 1430 patients with Masaoka-Koga pathological Stage I-II thymic tumours without myasthenia gravis or pre-treatment were identified from the International Thymic Malignancy Interest Group retrospective database. Outcomes of patients from 3 major continents (Europe, North America and Asia) were compared.

RESULTS

Patients from the 3 continents were comparable in gender and performance status. More European patients had more paraneoplastic syndromes; North American patients had the smallest tumour sizes and less adjuvant therapy; and Asian patients were younger and had more Stage I disease but higher grade tumours. Partial thymectomy was performed more often in Asian patients (31.7%) than in European (2.4%) and North American (5.4%; P  < 0.001) patients. The median approach (sternotomy/clamshell) was the major approach in Europe (75.3%) and North America (76.6%). In contrast, the median approach was applied significantly less frequently in Asia (45.6%, P  < 0.001); unilateral open (thoracotomy/hemi-clamshell, 23.3%) and minimally invasive approaches (video-assisted thoracoscopic surgery/robot, 31.1%) were used more often with similar rates of complete resection. The 10-year overall survival rate was 82% for Europe, 78% for North America and 90% for Asia ( P  = 0.005), respectively. The 10-year cumulative recurrence rates were similar among the geographic groups (European 0.08, North American 0.07, and Asian 0.06, P  = 0.61). Age was the only independent predictive factor for overall survival ( P  < 0.001, HR = 1.089, 95% CI 1.056-1.123) in multivariable analysis. Types B3 and thymic carcinoma ( P  = 0.003, HR = 3.932, 95% CI 1.615-9.576) were independent risk factors for increased recurrence.

CONCLUSIONS

This study shows that the selection of the surgical approach and the extent of resection for Stage I and II thymic tumours differ by geographic region. However, these differences seem to have little impact on outcomes.

Ectopic thymoma in the paratracheal region of the middle mediastinum: a rare case report and literature review

Background

Thymomas generally arise from the thymus in the anterior mediastinum. Ectopic thymomas arising in the middle mediastinum are rare. We present a case of a thymoma arising from the ectopic thymic tissue in the right paratracheal region.

Case presentation

The patient was a 67-year-old male who underwent an enhanced-computed tomography examination as preoperative staging for colon cancer. A 20-mm nodule in the right paratracheal region was found incidentally. Fluorodeoxyglucose (FDG) accumulation was detected in this solitary nodule by FDG-positron emission tomography, mimicking an enlarged, possibly malignant lymph node. The tumor was removed by thoracoscopic surgery, and a postoperative pathological diagnosis of type AB thymoma was made. Foci of ectopic thymic tissues were found adjacent to the thymoma. The patient was disease-free and without recurrence 2 years postoperatively.

Conclusions

Including the present case, 13 cases of ectopic paratracheal thymoma have been reported in the English literature, all of which were found on the right side of the paratracheal region. Although ectopic thymomas in the paratracheal region are rare, thymomas may be considered as a differential diagnosis for a paratracheal nodule.

[Minimally Invasive Surgery in Thymic Malignances]

手术是胸腺肿瘤最重要的治疗方式。近年来，胸腺肿瘤的微创手术在国内外获得迅速推广。微创手术目前主要用于早期胸腺肿瘤的外科治疗，已有证据表明，微创手术可有效减少手术创伤、有效加快患者的术后恢复以及降低术后疼痛，并且目前已有一定临床证据初步证实其肿瘤学效果与开放手术相当。同时随着外科技术的不断进步，在保证外科学和肿瘤学原则的前提下，微创手术有可能使包括局部进展期、诱导治疗后以及复发转移的患者从中获益。

Paraneoplastic Syndromes and Thymic Malignancies: An Examination of the International Thymic Malignancy Interest Group Retrospective Database

INTRODUCTION

Thymic epithelial tumors (TETs) are associated with paraneoplastic/autoimmune (PN/AI) syndromes. Myasthenia gravis is the most common PN/AI syndrome associated with TETs.

METHODS

The International Thymic Malignancy Interest Group retrospective database was examined to determine (1) baseline and treatment characteristics associated with PN/AI syndromes and (2) the prognostic role of PN/AI syndromes for patients with TETs. The competing risks model was used to estimate cumulative incidence of recurrence (CIR) and the Kaplan-Meier method was used to calculate overall survival (OS). A Cox proportional hazards model was used for multivariate analysis.

RESULTS

A total of 6670 patients with known PN/AI syndrome status from 1951 to 2012 were identified. PN/AI syndromes were associated with younger age, female sex, thymoma histologic type, earlier stage, and an increased rate of total thymectomy and complete resection status. There was a statistically significant lower CIR in the group with a PN/AI syndrome than in the group without a PN/AI syndrome (10-year CIR 17.3% versus 21.2%, respectively [p = 0.0003]). The OS was improved in the group with a PN/AI syndrome compared to the group without a PN/AI syndrome (median OS 21.6 years versus 17.0 years, respectively [hazard ratio = 0.63, 95% confidence interval: 0.54-0.74, p < 0.0001]). However, in the multivariate model for recurrence-free survival and OS, PN/AI syndrome was not an independent prognostic factor.

DISCUSSION

Previously, there have been mixed data regarding the prognostic role of PN/AI syndromes for patients with TETs. Here, using the largest data set in the world for TETs, PN/AI syndromes were associated with favorable features (i.e., earlier stage and complete resection status) but were not an independent prognostic factor for patients with TETs.

A Phase II Study of Partial and Subtotal Thymectomy for Thymoma (JART02)

BACKGROUND

We believe the merit of preservation of a part of the thymus following surgery for thymoma. We evaluated the efficacy of partial or subtotal thymectomy for early-stage thymoma in the prospective study.

METHODS

The Japanese Association for Research on the Thymus conducted a multiple institutional study of thymectomy for thymoma localized in the thymus without total thymectomy. Patients without autoimmune disease who had an anterior mediastinal tumor that had been clinically diagnosed as an early-stage thymoma were enrolled in the study. Patients who were positive for anti-acetylcholine receptor antibodies were excluded.

RESULTS

Sixty-three patients were enrolled preoperatively; 27 patients were judged as being inappropriate based on the other thymic pathologies or tumor invasion. The remaining 36 cases were diagnosed as early-staged thymoma and analyzed. The mean age of the patients was 61 years. The mean maximal tumor diameter in the resected specimens was 3.6 cm. The most common pathological types of thymoma were AB (n = 10) and B1 (n = 10). The Masaoka stages were classified as stage I (n = 22) and II (n = 14). The mean observation period was 63 months. Two patients died due to respiratory dysfunction, which was not related to thymoma. One hundred percent of the patients remained recurrence-free.

CONCLUSIONS

This prospective study suggested the efficacy of partial or subtotal thymectomy for early-stage thymoma in patients without any apparent evidence of autoimmune disease. We can preserve a part of the thymus even following surgery for thymoma to prepare the possible second malignancies or diseases in future.