Evaluation and Treatment of Stage I and II Thymoma

Survival Outcome After Surgery in Patients With Thymoma Distant Recurrence

OBJECTIVE

The aim of this study is to describe characteristics and survival outcome of patients who underwent surgical treatment for distant thymoma relapse according to the definition of the International Thymic Malignancy Interest Group.

METHODS

Data of patients affected by thymoma recurrence from four different institutions were collected and retrospectively reviewed. Patients with locoregional metastases who underwent nonsurgical therapies and with incomplete data on follow-up were excluded. According to the International Thymic Malignancy Interest Group distant recurrence definition, patients with recurrence due to hematogenic localization were included. Clinical and pathologic characteristics were described using descriptive statistics, whereas survival outcome was calculated using Kaplan-Meier curves and Cox regression analysis.

RESULTS

The analysis was conducted on 40 patients. A single localization was present in 13 patients, the relapse was intrathoracic in 28 cases (70%), and lung involvement was found in 26 cases. The liver was operated in seven cases, whereas other kinds of abdominal involvement were detected in eight cases. Adjuvant treatment was administered in 22 cases (55%).Five- and 10-year overall survival (OS) were 67% and 30%, respectively. Univariable analysis identified as significant favorable factor a low-grade histology (A, B1, B2): five-year OS at 92.3% versus 53.3% in high-grade (B3-C) (p = 0.035). Site of recurrence and number of localization did not influence the prognosis, but in patients with adjuvant therapy administration, there was a survival advantage also if not statistically significant: five-year OS 84.8% versus 54.5% in patients without adjuvant therapy (p = 0.101).Multivariable analysis confirmed as independent prognostic factor low-grade histology: hazard ratio = 0.176, 95% confidence interval 0.042-0.744, p = 0.018.

CONCLUSIONS

Our study revealed a good survival outcome in patients who underwent surgery for distant thymoma recurrence, independently from the number and site of the relapse localization. Patients with A, B1, or B2 histology presented a significantly better survival than patients with B3-C.

CT-guided pretreatment biopsy diagnosis in patients with thymic epithelial tumours: diagnostic accuracy and risk of seeding

AIM

To investigate the diagnostic performance of computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) for thymic epithelial tumours (TETs) and the complication rate after PTNB including seeding after PTNB.

MATERIALS AND METHODS

This retrospective study identified PTNBs for anterior mediastinal lesions between May 2007 and September 2021. The diagnostic performance for TETs and complications were investigated. The concordance of the histological grades of TETs between PTNB and surgery was evaluated. The factors associated with pleural seeding after PTNB were determined using Cox regression analysis.

RESULTS

Of 387 PTNBs, 235 PTNBs from 225 patients diagnosed as TETs (124 thymomas and 101 thymic carcinomas) and 150 PTNBs from 133 patients diagnosed as other than TETs were included. The sensitivity, specificity, and accuracy for TETs were 89.4% (210/235), 100% (210/210), and 93.5% (360/385), respectively, with an immediate complication rate of 4.4% (17/385). The concordance rate of the histological grades between PTNB and surgery was 73.3% (77/105) after excluding uncategorised types of thymomas. During follow-up after PTNB (median duration, 38.8 months; range, 0.3-164.6 months), no tract seeding was observed. Pleural seeding was observed in 26 patients. Thymic carcinoma (hazard ratio [HR], 5.94; 95% confidence interval [CI], 2.07-17.08; p=0.001) and incomplete resection (HR, 3.29; 95% CI, 1.20-9.02; p=0.02) were associated with pleural seeding, while the biopsy approach type (transpleural versus parasternal) was not associated (p=0.12).

CONCLUSIONS

Pretreatment biopsy for TETs was accurate and safe and may be considered for diagnosing TETs, particularly when the diagnosis is challenging and histological diagnosis is mandatory.

A diagnostic model based on 18F-FDG PET/CT parameters in improving the differential diagnosis of invasive thymic epithelial tumors and anterior mediastinal lymphomas

BACKGROUND

Accurately distinguishing between invasive thymic epithelial tumors (TETs) and anterior mediastinal lymphoma before surgery is crucial for subsequent treatment choices. But currently, the diagnosis of invasive TET is sometimes difficult to distinguish from anterior mediastinal lymphoma.

OBJECTIVE

To assess the application of fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography/computer tomography (PET/CT) in the differential diagnosis of TETs and anterior mediastinal lymphomas.

METHODS

18F-FDG PET/CT images of 133 invasive TETs and anterior mediastinal lymphomas patients were retrospectively analyzed. In particular, the tumor's longest diameter and maximum standardized uptake value (SUVmax) were evaluated. The SUVmax and longest diameter values of the two groups were analyzed by using the receiver operating characteristic (ROC) curve to determine the optimal threshold and diagnostic efficiency.

RESULTS

Age, myasthenia gravis, SUVmax and tumor longest diameter differed significantly between invasive TETs and anterior mediastinal lymphomas patients. The tumor location, calcification, relationship with adjacent vessels and distant metastasis differed significantly between the groups. The ROC analysis showed an AUC for SUVmax and tumor longest diameter of 0.841 and 0.737. Respectively, the cutoff values with the best diagnostic performance were 9.65 (sensitivity: 77.78%, specificity: 81.97%) and 6.65 (sensitivity: 80.56%, specificity: 62.30%) for SUVmax and tumor longest diameter. The diagnostic model of SUVmax, calcification, relationship with surrounding blood vessels, lymph node metastasis and lung metastasis in the highest AUC of 0.935 (sensitivity: 90.16%, specificity: 88.89%). In addition, we incorporated splenic involvement and metastatic sub-diaphragmatic lymph node into Model 2 as a new predictive model 3 for differential diagnosis and found a significant improvement in the diagnostic performance of Model 3.

CONCLUSION

The diagnostic model composed of 18F-FDG PET parameters is improving the differential diagnosis of invasive TETs and anterior mediastinal lymphomas.

Case Reports: A role of postoperative radiation therapy in completely resected early stage intrathyroid thymic carcinoma: a case report and literature review of the diagnosis and treatment

Background

Intrathyroid thymic carcinoma (ITTC) is a rare malignant tumor of the thyroid, probably arising from ectopic thymus or branchial pouch remnants. Most of the literature recommended radical resection as the fundamental treatment for ITTC, and postoperative radiation appears to be able to reduce the recurrence rate in patients with advanced ITTC. However, the issue of adjuvant radiotherapy in completely resected early-stage ITTC has been controversial.

Case presentation

Here, we reported a new case of early-stage ITTC that treated with total thyroidectomy and the right central neck dissection. Postoperative external beam radiation therapy (50.0 Gy/25 fractions) was given to the thyroid bed and bilateral cervical lymph node area since the tumor involved part of the sternal thyroid muscle. At 4-year follow-up after completion of radiotherapy, she is without evidence of locally recurrent or distant disease.

Conclusion

Since there are no current guidelines for early-stage ITTC, in combination with this case and previous literature, we may suggest routine adjuvant radiotherapy should be considered in patients with incompletely resected tumors and extraparenchymal extension of ITTC. Moreover, we summarized comprehensive and advanced diagnosis, treatment, prognosis of ITTC and comparison between ITTC, primary squamous cell carcinoma of thyroid gland, differentiated thyroid cancer, and anaplastic thyroid cancer.

Conventional and radiomic features to predict pathology in the preoperative assessment of anterior mediastinal masses

OBJECTIVES

The aim of this study was to differentiate benign from malignant tumors in the anterior mediastinum based on computed tomography (CT) imaging characteristics, which could be useful in preoperative planning. Additionally, our secondary aim was to differentiate thymoma from thymic carcinoma, which could guide the use of neoadjuvant therapy.

MATERIALS AND METHODS

Patients referred for thymectomy were retrospectively selected from our database. Twenty-five conventional characteristics were evaluated by visual analysis, and 101 radiomic features were extracted from each CT. In the step of model training, we applied support vector machines to train classification models. Model performance was assessed using the area under the receiver operating curves (AUC).

RESULTS

Our final study sample comprised 239 patients, 59 (24.7 %) with benign mediastinal lesions and 180 (75.3 %) with malignant thymic tumors. Among the malignant masses, there were 140 (58.6 %) thymomas, 23 (9.6 %) thymic carcinomas, and 17 (7.1 %) non-thymic lesions. For the benign versus malignant differentiation, the model that integrated both conventional and radiomic features achieved the highest diagnostic performance (AUC = 0.715), in comparison to the conventional (AUC = 0.605) and radiomic-only (AUC = 0.678) models. Similarly, regarding thymoma versus thymic carcinoma differentiation, the model that integrated both conventional and radiomic features also achieved the highest diagnostic performance (AUC = 0.810), in comparison to the conventional (AUC = 0.558) and radiomic-only (AUC = 0.774) models.

CONCLUSION

CT-based conventional and radiomic features with machine learning analysis could be useful for predicting pathologic diagnoses of anterior mediastinal masses. The diagnostic performance was moderate for differentiating benign from malignant lesions and good for differentiating thymomas from thymic carcinomas. The best diagnostic performance was achieved when both conventional and radiomic features were integrated in the machine learning algorithms.

SEOM-GECP-GETTHI Clinical Guidelines for the treatment of patients with thymic epithelial tumours (2021)

Thymic epithelial tumours (TET) represent a heterogeneous group of rare malignancies that include thymomas and thymic carcinoma. Treatment of TET is based on the resectability of the tumour. If this is considered achievable upfront, surgical resection is the cornerstone of treatment. Platinum-based chemotherapy is the standard regimen for advanced TET. Due to the rarity of this disease, treatment decisions should be discussed in specific multidisciplinary tumour boards, and there are few prospective clinical studies with new strategies. However, several pathways involved in TET have been explored as potential targets for new therapies in previously treated patients, such as multi-tyrosine kinase inhibitors with antiangiogenic properties and immune checkpoint inhibitors (ICI). One third of patient with thymoma present an autoimmune disorders, increasing the risk of immune-related adverse events and autoimmune flares under ICIs. In these guidelines, we summarize the current evidence for the therapeutic approach in patients with TET and define levels of evidence for these decisions.

Outcomes of thymoma after multimodal therapy and determinants of survival: A 16-year experience of a tertiary cancer center

Background

In this study, we aimed to evaluate the factors that contribute to survival outcomes in patients with thymoma treated with multimodal approaches.

Methods

A total of 203 patients (105 males, 98 females; median age: 49 years; range, 17 to 77 years) with Masaoka-Koga Stage II-IV thymoma between January 2002 and December 2018 were retrospectively analyzed. Data including diagnosis of myasthenia gravis, diagnosis of diabetes mellitus, disease stage, histological type of tumor, capsule invasion and surgical margin status, lymphadenectomy, adjuvant radiotherapy or chemotherapy, time from surgery to the first day of adjuvant treatment, length of hospital stay, and overall and disease-free survival rates were recorded.

Results

Of the patients, 91 had Stage II, 67 had Stage III, and 45 had Stage IV disease. A total of 123 patients (61%) had myasthenia gravis. Seventy-six patients received adjuvant radiotherapy and 48 patients received either neoadjuvant (n=35) or adjuvant (n=25) chemotherapy. Higher disease stage, presence of R1 resection, and treatment with chemotherapy were significant factors for decreased disease-free survival time. Older age, higher disease stage, longer postoperative hospital stay, chemotherapy, and disease recurrence were effective contributors to decreased overall survival time. Adjuvant radiotherapy had a statistically significant positive effect on overall survival only in patients with completely resected Stage IV disease (five-year overall survival: 94.7% vs. 79.1%, respectively; p=0.015). In the multivariate analysis, older age (hazard ratio: 4.26), higher disease stage (hazard ratio: 2.95), and longer hospitalization time (hazard ratio: 3.81) were significant prognostic factors for overall survival. Patients with local recurrence who underwent complete resection had a survival time comparable to non-recurrent patients (p=0.753).

Conclusion

For patients with thymoma, higher disease stage, age ≥50 years, longer hospitalization, and need for chemotherapy are associated with worse survival rates. Adjuvant chemotherapy has a positive impact on Stage IV disease. Resection of recurrent lesions has a valuable impact on survival.

The International Thymic Malignancy Interest Group Classification of Thymoma Recurrence: Survival Analysis and Perspectives

INTRODUCTION

The International Thymic Malignancy Interest Group (ITMIG) classifies thymoma recurrences on the basis of the topographic location, but its effectiveness in prognosis prediction has not been well investigated yet. Aims of this study are to analyze survival outcome of patients surgically treated for thymoma recurrence according to the ITMIG recurrence classification and to investigate possible alternatives.

METHODS

From January 1, 1990, to January 7, 2017, data on 135 surgically treated patients for thymoma recurrence from three high-volume centers were collected and retrospectively analyzed. Patients were classified according to the ITMIG classification as local, regional, and distant. The ITMIG classification and alternative classifications were correlated to overall survival (OS).

RESULTS

According to the ITMIG classification, recurrence was local in 17 (12.5%), regional in 97 (71.8%), and distant in 21 (15.7%) patients, with single localization in 38 (28.2%) and multiple localizations in 97 (71.8%). The 5- and 10-year OS were 79.9% and 49.7% in local, 68.3% and 52.6% in regional, and 66.3% and 35.4% in distant recurrences, respectively, but differences were not statistically significant (p = 0.625). A significant difference in survival was present considering single versus multiple localizations: 5- and 10-year OS of 86.2% and 81.2% versus 61.3% and 31.5% (p = 0.005, hazard ratio = 7.22, 95% confidence interval: 0.147-0.740), respectively. Combining the localization number with the recurrence site, ITMIG locoregional single recurrence had a statistically significant better survival compared with patients with ITMIG locoregional multiple recurrence or ITMIG distant recurrence (p = 0.028). Similarly, a significant difference was present considering intrathoracic single versus intrathoracic multiple versus distant recurrence (p = 0.024).

CONCLUSIONS

The ITMIG classification for thymoma recurrence did not have significant survival differences comparing local, regional, and distant recurrences. Integrating this classification with the number of the localizations may improve its effectiveness in prognosis prediction.

Thymoma with osseous metaplasia; a case report with a brief literature review

INTRODUCTION AND IMPORTANCE

The thymus is a primary lymphatic organ within the mediastinum that plays an essential role in developing and maintaining cell-mediated immunity. The current study aims to report a case of intra-tumoral osseous metaplasia of the thymus gland, which is an infrequent phenomenon.

CASE PRESENTATION

A 43-year-old male presented with weakness and easy fatigability for 2 months. The patient had an elevated anti-acetylcholinesterase antibody (19.5 nmole/L). Magnetic resonance imaging showed a round, capsulated, enhanced mass in the anterior mediastinum measuring 5.5 × 3.5 cm, suspecting thymoma. The patient underwent plasmapheresis three times in one week, under general anesthesia, in a supine position, sternotomy was performed, and the thymoma was totally resected.

DISCUSSION

Thymomas are known to occur in all age groups with the peak of nearly between 35 and 70 years with the median age of 54 years. The sex distribution of thymoma is approximately equal with slight predilection of women in old age groups. However, among all reported cases of thymomas with osseous metaplasia, the majorities are female. The significance of this ossification is still to be clarified.

CONCLUSION

Although it is rare, secondary changes in thymoma may occur including calcification and ossification.

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.

The role of postoperative radiotherapy in stage II and III thymoma: a Korean multicenter database study

Background

Complete resection is a standard treatment for patients with Masaoka-Koga stages II and III thymoma, however the role of postoperative radiotherapy (PORT) is controversial. We analyzed data collected from 4 Korean hospitals to determine the effectiveness of PORT in stage II and III thymoma patients.

Methods

Between January 2000 and December 2013, 1,663 patients underwent surgery for thymic tumors at the 4 hospitals. Among them, 668 patients (527 with stage II and 141 with stage III) were investigated, among whom, 443 received PORT (335 with stage II and 108 with stage III). Propensity score matching (PSM) was performed, and 404 patients (346 with stage II and 58 with stage III) were selected.

Results

Perioperative characteristics were similar in the PORT and non-PORT groups after PSM. On survival analysis of stage II patients, the PORT and non-PORT groups showed no difference in either 5-year recurrence-free survival (RFS) (96.3% vs. 96.6%, P=0.622) or 5-year overall survival (OS) (94.6% vs. 93.8%, P=0.839). However, among stage III patients, the PORT group showed significantly better 5-year RFS (75.7% vs. 50.1%, P=0.040) and 5-year OS (86.5% vs. 54.7%, P=0.001). On multivariate Cox regression analysis, PORT was a significant positive prognostic factor in terms of both RFS (P=0.005) and OS (P=0.004) in patients with stage III thymomas, but not in those with stage II disease (P=0.987 and 0.968, respectively).

Conclusions

PORT improved the RFS and OS in stage III thymoma patients, but showed no survival benefit in stage II patients.

Octreotide in the treatment of malignant thymoma - Case report

Thymomas are the most common mediastinal tumors. Systemic therapy for patients with unresectable or recurrent thymomas is a challenging field in the current oncology research. There is some evidence that somatostatin analogs combined with corticosteroids may have a role in the treatment of advanced malignant thymoma; however, the role of these agents have not been fully evaluated.

Case report

A 39-year-old man with metastatic thymoma was administered long-acting depot injection form of octreotide. Octreotide scan before the treatment initiation revealed low uptake. CT control after three months of the treatment revealed marked regression of pleural metastases, while the primary tumor mass remained stable. The treatment response was lasting for 9 months.

Conclusion

We describe an interesting case of marked clinical and radiological response of advanced malignant thymoma to the treatment with octreotide in a heavily pre-treated patient, even though octreotide scan revealed low uptake.

Safety and efficacy of INTRABEAM intraoperative radiotherapy for invasive thymoma

Intraoperative radiotherapy (IORT) has been used to treat different residual solid tumors after tumor removal and has shown many advantages over other treatment methods. However, the use of IORT for invasive thymoma has not been reported. Therefore, in this study, we tried to determine the safety and efficacy of INTRABEAM IORT for the treatment of invasive thymoma.Among the patients admitted to our hospital from September to December 2016 who were diagnosed with invasive thymoma, 14 were selected as study subjects. With medical histories taken beforehand, 8 of these patients were diagnosed with Masaoka stage IIA and 6 with Masaoka stage IIB; furthermore, 5 of the patients were diagnosed with myasthenia gravis (MG). INTRABEAM radiation (8-10 Gy, low energy) was delivered to the postoperative tumor bed of each patient during surgery. The intra- and postoperative complications were observed and evaluated, and the improvement in symptoms was assessed. An additional 23 patients with stage II thymoma undergoing radical surgery from April to August 2016 were chosen as the control group.One month after the operation, only 1 patient in the IORT group had cough, increased levels of leucocytes and neutrophils, and pulmonary inflammation on chest computed tomography. Reactive inflammation and pleural effusion in the 2 groups were similar (P > .05). There was no significant difference between the 2 groups in the improvement of myasthenia gravis (P > .05). Postoperative chest computed tomography and routine blood examination at 3 and 12 months showed that all the patients recovered, with normal hemogram levels and no pulmonary fibrosis around the radiation field. In addition, ultrasonic cardiography and electrocardiography demonstrated no significant difference before or after surgery within the IORT group. At the end of the follow-up, all the patients were alive, no relapse or remote metastasis was observed in the IORT group, and 2 inpatients in the control group had experienced relapse at 24 and 26 months. There was a significant difference in disease-free survival between the 2 groups (P = .00).It is safe to administer low-energy INTRABEAM IORT at a dose of approximately 10 Gy in patients with stage II invasive thymoma. INTRABEAM IORT does not significantly increase operation- or radiation-related complications and has no significant effect on vital organs such as the lungs and heart. Its long-term efficacy is worth expecting.

Heat shock protein 90α in thymic epithelial tumors and non-thymomatous myasthenia gravis

Background

Thymic epithelial tumors (TETs) are rare malignancies with unique association to the autoimmune disease myasthenia gravis (MG). Heat shock proteins (HSPs) harbor great potential as cancer biomarkers and HSP inhibitors approach clinical cancer therapy.

Methods

To explore HSP pathophysiology, we assessed sera (immunoassays) and tissues (immunohistochemistry) of TETs (and thymic tissues) for HSP27, phosphorylated (p)HSP27, HSP70 and HSP90α expression in 114 TETs and 26 non-thymomatous MG patients undergoing extended thymectomy.

Results

Serum concentrations of HSP90α were significantly increased in patients with thymic carcinomas, thymomas, thymic neuroendocrine tumors and non-thymomatous MG compared to patients who underwent thymectomy revealing regular thymic morphology or controls. In thymoma patients, high serum HSP90α represented a significantly worse prognostic factor for free-from-recurrence, and complete tumor resection led to decreased levels. The expression of HSP90 in nuclei and cytoplasm of tumor cells and non-neoplastic lymphocytes varied with WHO histological subtype. HSP90 was expressed in centroblasts of thymic germinal centers in MG patients. Higher pHSP27 serum concentrations were observed in seropositive MG and those not treated with steroids.

Conclusions

HSP data suggest high potential for HSPs as TET cancer biomarkers or as candidates for targeted therapy. Caution is warranted in TET patients with associated MG overexpressing HSPs.

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.

A Rare Complication of Thymoma: Pure White Cell Aplasia in Good's Syndrome

Pure white cell aplasia (PWCA) is a rare manifestation of thymoma. It is characterized by agranulocytosis with absent myeloid precursors in the bone marrow and normal hematopoiesis for other cell lines. Here we describe a 65-year-old female patient who presented with three days of fever and night sweat. Chest CT revealed an anterior mediastinal mass. A biopsy of the mass confirmed a diagnosis of thymoma mixed type A and B2. The patient developed a severe neutropenia, and her bone marrow revealed significantly decreased neutrophil-lineage cells, rare to absent B cells, and defective T cells, consistent with PWCA. Following thymectomy, a complete resolution of PWCA was achieved via multimodality therapy of intravenous immunoglobulins, granulocyte colony-stimulating factor, and immunosuppressant. This report highlights the care complexity regarding treatment choices and decision to perform thymectomy in patients presenting with PWCA.

[Clinical Study on the Prognosis of Patients with Thymoma with Myasthenia Gravis]

背景与目的

胸腺瘤常伴发重症肌无力（myasthenia gravis, MG），但是这些患者行胸腺切除的预后与MG的关系尚不明确。本研究旨在探讨影响胸腺瘤合并MG患者预后的因素。

方法

回顾性分析中国胸腺瘤协作组（Chinese Alliance for Research of Thymoma, ChART）数据库1992年-2012年875例随访20年资料完整的胸腺瘤病例，分析世界卫生组织（World Health Organization, WHO）组织学分型、Masaoka分期、术后辅助治疗与MG及预后的关系。

结果

胸腺瘤WHO组织学分型与MG有相关性，差异有统计学意义（χ²=24.908, P < 0.001）。MG发生率为22.7%，其中B2型（58/178, 32.58%） > B3型（65/239, 27.20%） > B1型（27/132, 20.45%） > AB型（43/267, 16.10%） > A型（6/59, 10.17%），Masaoka分期与MG无相关性（χ²=1.365, P=0.714）。生存分析表明WHO分型、Masaoka分期与预后有关（P < 0.05），而是否合并MG（χ²=0.113, P=0.736）、是否行胸腺扩大切除（χ²=1.548, P=0.213）、术后辅助放疗（χ²=0.380, P=0.538）与预后无相关，术后辅助化疗与差的预后相关（χ²=14.417, P < 0.001）。是否行胸腺扩大切除与MG的疗效有相关性（χ²=24.695, P < 0.001）。

结论

胸腺瘤患者是否合并MG和是否行胸腺扩大切除与预后无相关性，胸腺扩大切除可改善MG患者的疗效。

Wnt4 overexpression promotes thymoma development through a JNK-mediated planar cell polarity-like pathway

Thymoma is the most common neoplasm of the anterosuperior mediastinum. Activation of the Wnt signaling pathway has a role in a variety of human cancers. The present objective was to examine c-Jun N-terminal kinase (JNK) mRNA and protein expression in thymoma cells undergoing apoptosis subsequent to downregulation of Wnt4. Wnt4 and JNK mRNA and protein expression was analyzed by reverse transcription-quantitative polymerase chain reaction and immunohistochemistry, respectively, in 15 thymoma tissues and 6 thymus cyst tissues. Thymoma cells were cultured and transfected with shRNA plasmids targeting the Wnt4 gene. Wnt4 and JNK protein expression was detected by western blot analysis. Apoptosis was analyzed using Wright-Giemsa staining, Hoechst-33342/propidium iodine double staining and flow cytometry. The results showed that Wnt4 and JNK mRNA and protein expression were significantly increased in thymoma compared with normal thymus tissue. Subsequent to transfection, thymoma Wnt4 and JNK mRNA and protein expression were significantly decreased in shRNA-treated groups, with the strongest inhibition being 52.37%. Characteristic apoptotic morphological changes were observed and apoptosis increased. Overall, the present concluded that Wnt4 has an important role in thymoma development, which appears to be activated through a JNK mediated planar cell polarity-like pathway.

Multimodality treatment of stage II thymic tumours

BACKGROUND

Complete resection for stage II thymic tumors can be easily accomplished even if the capsula and adjacent mediastinal tissue are macroscopically involved; however, also at this stage, recurrence may occur, particularly for B2, B3 and thymic carcinoma. The criteria for the administration of adjuvant therapy remain controversial and it is unclear whether patients at this stage may benefit from it. We reviewed a series of patients at this stage receiving adjuvant chemo-radiotherapy (chemo-RT) based on histology.

METHODS

Eighty-eight consecutive patients with stage II thymic tumors were reviewed; 59 patients (67%) with B thymoma or thymic carcinoma received adjuvant treatment with mediastinal irradiation (40-55 Gy), chemotherapy (CH) (PAC regimen) or a combination of both.

RESULTS

Complete resection was achieved in all patients. Fifty-four patients (61%) received post-operative chemo-RT, 2 (2%) patients received adjuvant CH only and 3 (3%) post-operative RT only; they all had B2, B3 histology or thymic carcinoma. The median follow up was 107±83 months. 5-year and 10-year survival were 96%±2% and 83.4%±5%. Recurrence was observed in 5 patients (5.7%). Disease-free 5 and 10-year survival was 94%±2% and 92%±3% respectively. Five patients (5.7%) had recurrence.

CONCLUSIONS

The administration of adjuvant chemo-RT to patients with stage II type B thymoma and thymic carcinoma contributes to reduce the recurrence rate and to increase long-term survival.

Surgical approach in thymectomy: Our experience and review of the literature

Aim

Thymectomy is the main treatment for thymoma and patients with myasthenia gravis (MG). The traditional approach is through a median sternotomy, but, recently, thymectomy through minimally invasive approaches is increasingly performed. Our purpose is an analysis and discussion of the clinical presentation, the diagnostic procedures and the surgical technique. We also consider post-operative complications and results, over a period of 5 years (May 2011–June 2016), in thymic masses admitted in our Thoracic Surgery Unit.

Methods

We analyzed 8 patients who underwent surgical treatment for thymic masses over a period of 5 years. 6 patients (75%) had thymoma, 2 patients (25%) had thymic carcinomas. 2 patients with thymoma (33%) had myasthenia gravis. We performed a complete surgical resection with median sternotomy as standard approach.

Results

One patient (12%) died in the postoperative period. The histological study revealed 6 (75%) thymoma and 2 (25%) thymic carcinomas. Post-operative morbidity occurred in 2 patients (25%) and were: pneumonia in 1 case (12%), atrial fibrillation and pleural effusion in 2 patients (25%). One patient with thymoma type A recurred at skeletal muscle 2-years after surgery.

Conclusions

Thymic malignancies are rare tumors. Surgical resection is the main treatment, but a multimodal approach is useful for many patients. Radical thymectomy is completed removing all the soft tissue in the anterior mediastinum between the two phrenic nerves and this is the most important factor in controlling myasthenia and influencing survival in patients with thymoma. Open (median sternotomy) approach has been the standard approach for thymectomy for the better visualization of the anatomical structures. Actually, video-assisted thoracoscopic surgery (VATS) thymectomy and robotic video-assisted thoracoscopic (R-VATS) approach versus open surgery has an equal if not superior oncological efficacy, better perioperative complications and survival outcomes.

Long term oncological outcome of thymoma and thymic carcinoma - an analysis of 235 cases from a single institution

BACKGROUND AND OBJECTIVES

Thymoma has a variable long-term oncological outcome after surgical resection. Survival and tumor recurrence were analyzed to determine the predisposing factors for tumor recurrence.

METHODS

A total of 235 patients who underwent surgery for thymoma or thymic carcinoma from December 1997 to March 2013 were analyzed using Masaoka staging system and World Health Organization (WHO) histological classification. Surgical intervention included extended thymothymectomy via median sternotomy and thymomectomy via thoracotomy/ video-assisted thoracoscopic surgery (VATS).

RESULTS

The median duration of follow-up was 105 months (12-198 months). Among these 235 patients, recurrence was observed in 25 patients (10.7%). according to Masaoka stage I, IIA, IIB, III, IVA, IVB, recurrence rates were 1/65(1.5%), 8/106(7.5%), 1/32(3.1%), 6/20(30.0%), 8/10(80.0%), 1/1(100.0%), respectively. Disease or treatment-related mortality was observed in 13 patients. Overall survival rate was 94.4%. After univariate analysis, predisposing factors for tumor recurrence included Masaoka stage, WHO histologic type, tumor size, adjuvant therapy and margin status.

CONCLUSIONS

Due to the indolent behavior of thymoma, tumor recurrence appears to be a better assessment of oncological outcome rather than survival. Factors associated with tumor recurrence include Masaoka stage, WHO histologic type, tumor size, adjuvant therapy and margin status.

Associations between computed tomography features of thymomas and their pathological classification

Background Thymoma exhibits a range of histological and biological features and their imaging findings varies. Purpose To evaluate the associations between CT findings of thymomas and their classification according to the Masaoka staging system and World Health Organization (WHO) classification. Material and Methods Eighty-four patients with thymoma were evaluated. Comparisons between the CT findings of Masaoka stage I/II and III/IV lesions, and the WHO type A-B1 (low risk) and B2/B3 (high risk) lesions were performed. Results Stage III/IV thymomas (mean size, 60 mm) were significantly larger than stage I/II (45 mm) lesions and had more irregular shape and contour. Necrosis and calcification were observed in 16 (59%) and nine (33%) stage III/IV thymomas, and 16 (28%) and seven (12%) stage I/II lesions, respectively. Regarding the WHO classification, the high-risk thymomas displayed irregular shape and contour more often than low-risk lesions. There were significant differences between the patterns of mediastinal invasion seen in high- and low-risk groups; 21 (68%) vs. six (12%) lesions demonstrated mediastinal fat invasion, seven (23%) vs. two (4%) lesions exhibited great vessel invasion, five (16%) vs. 0 (0%) lesions displayed pericardial invasion, and 18 (58%) vs. 10 (20%) lesions invaded the lungs, respectively. Conclusion Masaoka stage III/IV thymomas were larger in size, had more irregular shape and contour, and exhibited necrosis and calcification more often than the stage I/II lesions. In the WHO classification, high-risk thymomas demonstrated more irregular shape and contour than low-risk thymomas.

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

Thymomas are the most common adult tumors in the anterior mediastinal compartment, and a significant amount of thymomas are complicated by myasthenia gravis (MG). Extended thymectomy (ET) is the primary treatment method for thymomas and is used to completely resect possible ectopic thymus to avoid recurrence. Studies on the effect of MG in thymoma patients following ET are limited. The aim of the present study was to determine whether the presence of MG affects the prognosis of patients with thymoma. The present study consisted of 104 patients with thymoma that underwent ET; 61 men (58.7%) and 43 women (41.3%) (mean age, 54.6 years). In total, 38 patients had MG (36.5%). MG was most frequently observed in World Health Organization (WHO) classification type B2 thymoma compared with other types of thymoma. During the 5-year follow-up period, 11 patients succumbed to a recurrence of thymoma or respiratory failure due to MG. The overall 5-year survival rate in patients without MG or with MG was 89.1 and 76.0%, respectively. The overall survival (OS) rate in patients with Masaoka stages I + II and III + IV was 90.0 and 68.0%, respectively. The OS rate in patients with WHO type A + AB + B1 and type B2 + B3 was 96.9 and 76.8%, respectively. The patients with MG (P=0.026), Masaoka stages III + IV (P=0.008) and WHO type B2 + B3 (P=0.032) had a poorer prognosis compared with patients without these characteristics. Furthermore, multivariate analysis by Cox regression revealed that age [P=0.032; relative risk (RR)=1.097; 95% confidence interval (CI)=1.097-1.192] and MG (P=0.042; RR=0.167; 95% CI=0.037-0.940) significantly affected OS rate. In summary, ET is a reliable method for the treatment of thymoma. Long-term survival is expected for patients at early Masaoka stages, and for patients without MG. The prognosis of patients with thymomas with MG is poorer compared with patients without MG. The present findings provide useful information for the future management of patients with thymomas.

[Thymus cancers: A clinical observation]

INTRODUCTION

Thymic tumors including thymomas, thymic carcinomas, and thymic carcinoid tumors are rare tumors with an incidence of 0.13/100,000.

MATERIALS AND METHODS

A literature search was performed to identify recent findings on epidemiology, classification, and various therapeutic approaches.

RESULTS

These tumors with a wide spectrum of histologic and biologic features may be clinically unapparent for a long time or show a very aggressive behavior with local invasion and distant metastases. Surgical resection is the mainstay in stage I and II thymomas, whereas in stage III thymomas and in thymomas with pleural dissemination surgery in context of a multimodal treatment should be discussed. Thymic tumors are chemoreactive. Targeted therapies show poor results and should only be considered in the palliative situation after failure of chemotherapy.

CONCLUSION

The new TNM (T: tumor, N: node, M: metastasis) classification of thymic tumors will help to identify the best treatment options.

Thymoma and thymic carcinomas

Thymomas (Ts) and thymic carcinomas (TCs) are rare tumours of the mediastinum with an incidence rate of 1.7/million per year in Europe. Histological classification is based on rate of non-malignant-appearing thymic epithelial cells and proportions of lymphocytes (A, AB, B1, B2, B3, and C), while staging system concerns localisation of the involved areas. Surgery is the mainstay of treatment with a 10-year survival of 80%, 78%, 75%, and 42% for stages I, II, III and IV, respectively, with an R0 resection. Radiotherapy has a role in selected cases (stage III patients or R1-2 residual) and platinum-based chemotherapy remains the standard of care for patients with advanced disease. A multimodality approach would be advisable when surgery is not recommended. Since molecular aberrations are poorly understood and few responses are reported, targeted therapies are yet being studied. In this review, we describe key aspects of clinical management for Ts and TCs.

Recurrent Thymoma in the Retroperitoneal Space: A Rare Case Report

Thymoma is an epithelial neoplasm of the thymus, which commonly lies in the anterior mediastinum and recurrences of thymoma generally are locally, and retroperitoneal recurrence is considered to be rare. A 46-year old Asian woman with invasive thymoma had undergone thymectomy 10 years ago. Computed tomography demonstrated a well-circumscribed mass in the left retroperitoneal space. The patient had not any symptom including myasthenia gravis. Because on the anterior mediastinum area shows no sign of tumor recurrence and the mass adjacent to the vertebral body, neurogenic tumor was suspected. Surgical resection was performed using a retroperitoneal approach, which revealed the tumor adhering neighboring diaphragm. The tumor was histologically diagnosed to be type B1 thymoma according to the World Health Organization classification. The retroperitoneal mass was an unusual local recurrence after thymectomy. The patients whose had under invasive thymectomy should be evaluated carefully when finding retroperitoneal mass during follow-up.

Postoperative radiotherapy is effective for thymic carcinoma but not for thymoma in stage II and III thymic epithelial tumors: the Japanese Association for Research on the Thymus Database Study

BACKGROUND

The efficacy of postoperative radiotherapy (PORT) for thymic epithelial tumors is still controversial. Using the Japanese Association for Research on the Thymus (JART) database, this study was aimed at clarifying the efficacy of PORT for Masaoka stage II and III thymic carcinoma and thymoma.

METHODS

The JART database registered the records of 2835 patients collected from 32 Japanese institutions from 1991 to 2010. Thymic carcinoma and thymoma at stage II or III were extracted. The efficacy of PORT with respect to relapse-free survival (RFS) and overall survival (OS) was evaluated with the Kaplan-Meier method and Cox regression analysis.

RESULTS

There were 1265 patients in all: 155 thymic carcinoma cases (12.3%) and 1110 thymoma cases (87.7%). Eight hundred ninety-five (70.8%) were at stage II, and 370 (29.2%) were at stage III. Four hundred three cases (31.9%) underwent PORT. PORT for stage II and III thymic carcinoma was associated with increasing RFS (hazard ratio, 0.48; 95% confidence interval, 0.30-0.78; P = .003) but was not associated with OS (hazard ratio, 0.94; 95% confidence interval, 0.51-1.75; P = .536). PORT for stage II and III thymoma was not associated with RFS or OS (P = .350). A subgroup analysis of stage III thymoma showed no factor associated with the efficacy of PORT.

CONCLUSIONS

In this study, PORT did not increase RFS or OS for stage II or III thymoma but increased RFS for stage II and III thymic carcinoma.

Mediastinal mass in a 25-year-old man

A 25-year-old black man presented with left-sided chest pain and cough for 3 days. His pain was pressure-like and nonradiating and was aggravated with movement and relieved when the patient lay at a 45° angle. The patient denied fevers, chills, night sweats, and swelling but reported gaining 4 to 6 kg (10 to 15 lbs) in the past few months. His cough had started 2 weeks prior with yellow mucus production but he denied facial swelling or tenderness. He had no chronic medical conditions and was not taking medications. He had no known exposure to chemicals, fumes, or dust and no history of tobacco or alcohol abuse.

Comparative study of video-assisted thoracic surgery versus open thymectomy for thymoma in one single center

BACKGROUND

Due to the popularity of video-assisted thoracic surgery (VATS) techniques in clinical, thymoma patients via VATS thymectomy are increasing rapidly. However, compared with open thymectomy, the potential superiorities and defects of VATS thymectomy remain controversial.

METHODS

A number of 129 patients who underwent thymectomy of early stage thymoma (Masaoka stage I and stage II) in one single center from January 2007 to September 2013 were selected in this retrospective study. Of those patients, 38 thymoma patients underwent VATS thymectomy (VATS group) and 91 underwent open thymectomy (open group) via either transsternal [44] or transthoracic approach [47] in the same period. The postoperative variables, which included postoperative hospital length of stay (LOS), the intensive care unit (ICU) LOS, the entire resection ratio, the number of thoracic drainage tubes, the quantity of output and duration of drainage, were analyzed. Meanwhile, the operation time and blood loss were considered as intraoperative variables.

RESULTS

All thymoma patients in the analysis included 19 thymoma patients with myasthenia gravis, among which five patients via VATS thymectomy and 14 patients via open thymectomy respectively. There was no death or morbidity due to the surgical procedures perioperatively. The ICU LOS, operation time, entire resection ratio, and the number of chest tubes were not significantly different in two groups. The postoperative hospital LOS of VATS thymectomy was shorter than that of open thymectomy (5.26 versus 8.32 days, P<0.001). The blood loss of VATS thymectomy was less than open thymectomy (114.74 versus 194.51 mL, P=0.002). Postoperatively, the quantity of chest tubes output in VATS group was less than that in open thymectomy group (617.86 versus 850.08 mL, P=0.007) and duration of drainage in VATS group was shorter than that in open thymectomy group (3.87 versus 5.22 days, P<0.001).

CONCLUSIONS

VATS thymectomy is a safe and practicable treatment for early-stage thymoma patients. Thymoma according with Masaoka staging I-II without evident invading seems to be performed through VATS approach appropriately, which has shorter postoperative hospital LOS, less blood loss and less restrictions to activities, hence patients will recover sooner.

Predictors of recurrence after thymoma resection

PURPOSE

Recurrence rate is considered a better measure of clinical outcomes after thymoma resection than overall survival due to the indolent behavior of thymomas. This study was designed to determine predictors of recurrence after thymoma resection.

MATERIALS AND METHODS

A single-institution, retrospective study was performed, including 305 patients who had undergone thymoma resection between 1986 and 2009.

RESULTS

Among 305 patients, recurrence was observed in 41 patients (13.4%). The recurrence rates were 0% (0/19), 6.3% (4/63), 4.2% (2/48), 18.6% (11/59) and 20.7% (24/116) for type A, AB, B1, B2 and B3 tumors, respectively. The recurrence rate according to Masaoka stage was 6.1% (8/132), 11.4% (13/114), 26.8% (11/41) and 50.0% (9/18) for stages I, II, III and IV, respectively. After univariate analysis, completeness of resection (R0 versus R1), World Health Organization (WHO) histologic type (A, AB, B1 versus B2, B3), Masaoka stage, and size of tumor (<8 cm versus ≥8 cm) demonstrated significant differences with freedom from recurrence. Upon multivariate analysis, Masaoka stage was the only independent predictor of recurrence.

CONCLUSION

WHO histologic type, Masaoka stage, and size of tumor were associated with recurrence. Particularly, Masaoka stage was the only independent predictor of recurrence after thymoma resection.

Is There a Role of Postoperative Radiation Therapy in Completely Resected Stage I/II Thymic Epithelial Tumor?

PURPOSE

Retrospective analyses of patients with stage I-II thymic epithelial tumors (TET) who were treated with either surgery alone (S) or surgery plus postoperative radiation therapy (SRT) were conducted to evaluate the role of adjuvant radiation therapy (RT).

MATERIALS AND METHODS

A total of 110 stage I-II TET patients following complete resection were included in this study. Postoperative radiation therapy was recommended for those with aggressive histologic type and/or invasive features according to the surgeons' judgment during the operation. A median dose of 54.0 Gy (range, 44 to 60 Gy) focused on the primary tumor bed was administered to 57 patients (51.8%).

RESULTS

In all patients, the rates of overall survival, disease-specific survival, and disease-free survival at 10 years were 91.7%, 97.1%, and 95.8%, respectively. No significant differences in disease-specific survival (100% in the S group and 93.5% in the SRT group at 10 years, p=0.12) and disease-free survival (98.1% in the S group and 94.5% in the SRT group at 10 years, p=0.41) were observed between the treatment groups, although a significantly larger number of World Health Organization (WHO)-type B2-C (p<0.001) and Masaoka stage II (p=0.03) tumors were observed in the SRT group than in the S group. No local recurrence was observed in the SRT group. No grade 2 or greater RT-related toxicities were observed in the SRT group.

CONCLUSION

Excellent outcomes were achieved in patients with stage I-II TET who underwent complete resection. Considering excellent local control and low morbidity, adjuvant RT may be considered in high risk patients with WHO-type B2-C histology and Masaoka stage II.