Outcome of surgical treatment for recurrent thymic epithelial tumors with reference to world health organization histologic classification system

Updated outcomes of surgical treatment for recurrent thymic tumour: a report from the Japanese nationwide database

OBJECTIVES

This study aimed to analyse the surgical outcomes for recurrent thymic epithelial tumours and identify the factors associated with post-recurrence survival, using an updated Japanese nationwide database.

METHODS

The cohort that developed recurrence after the initial resection was extracted from an updated database of patients whose thymic epithelial tumours were treated surgically between 1991 and 2010. Furthermore, we reviewed clinicopathological and prognostic factors of re-resected cases. Post-recurrence survival outcomes and cause-specific deaths in non-re-resected cases were also reviewed.

RESULTS

We enrolled 191 patients who underwent re-resection and 259 patients who did not. In the surgery group, more patients with early stage disease, less aggressive World Health Organization (WHO) histological classification, initial complete resection and shorter recurrence-free intervals were included. Non-thymic carcinoma, absence of preoperative treatment, longer recurrent-free interval, single-site recurrence and R0-1 re-resection were all significantly favourable prognostic factors for post-recurrence survival in the surgery group, according to univariable analyses. Non-thymic carcinoma histology, longer recurrence-free interval and R0-1 re-resection were identified as independent prognostic factors according to multivariable analysis. The post-recurrence survival of the entire cohort with R2 re-resection was significantly better than that of the non-surgery group, although it was not demonstrated that patients with thymoma who underwent R2 re-resection had significantly better post-recurrence and lower cause-specific death.

CONCLUSIONS

R0-1 re-resection was newly identified as a prognostic factor after re-resection, in addition to non-thymic carcinoma histological classification and longer recurrence-free intervals, as documented in the initial report.

Salvage surgery for recurrent transdiaphragmatic thymoma in a patient not eligible for chemotherapy

The recurrence rate following thymoma surgery has been reported to be as high as 29%. In cases of localized recurrence, complete resection can result in prolonged patient survival. However, surgery is rarely considered in cases of invasive recurrent thymomas with high disease burden. Here, we present the case of a woman with type B2 thymoma (Masaoka-Koga stage IVa) treated with surgery, chemotherapy, and radiotherapy. The disease recurred 6 years later, with invasion of the left lung and the 12th thoracic vertebra, as well as extension into the retroperitoneum. Due to the development of chemotherapy-associated toxicity, she underwent surgery with complete tumor resection and has remained free of disease at a 12-months follow-up. Radical surgery for recurrent invasive thymoma extending through the diaphragm is a feasible and safe therapeutic option in highly selected patients who are not eligible for systemic treatments.

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.

Open redo thymectomy for a large recurrent thymoma in a patient with myasthenia gravis: a case report

Thoracoscopic and robotic approaches are becoming increasingly popular for thymoma surgery. Yet open thymectomy must still be mastered today, as it may be the only viable option in challenging cases. In this study, we report a case of an extended local recurrence of myasthenia gravis associated thymoma and a history of previous sternotomy. The mediastinal mass infiltrated the left upper lobe of the lung, the pericardium, and presumably the aortic arch. Although the standard for thymoma resection at our institution is the robotic approach, we performed primary open redo thymectomy in standby of cardiopulmonary bypass in this case. Intraoperatively, bleeding from the aortic arch occurred, which was promptly controlled due to the open approach and due to immediate availability of cardiopulmonary bypass. The patient was transferred to the normal ward on the first postoperative day, was treated according to fast-track principles and recovered well. The pathology revealed a WHO B2:B1 thymoma with negative resection margins. Thymectomy is recommended as the principal treatment for thymoma and is also advised in the case of recurrence. However, there is no evidence regarding the optimal surgical approach. Our case indicates that in the era of minimally invasive thymectomy, the decision to conduct open surgery is wise when the risk of serious bleeding is anticipated or adherence to oncologic principles is challenged by tumor size or growth pattern.

Percutaneous Image-Guided Ablation of Lung Tumors

Tumors of the lung, including primary cancer and metastases, are notoriously common and difficult to treat. Although surgical resection of lung lesions is often indicated, many conditions disqualify patients from being surgical candidates. Percutaneous image-guided lung ablation is a relatively new set of techniques that offers a promising treatment option for a variety of lung tumors. Although there have been no clinical trials to definitively compare its efficacy to those of traditional treatments, lung ablation is widely practiced and generally accepted to be safe and effective. Especially encouraging results have recently emerged for cryoablation, one of the newer ablative techniques. This article reviews the indications, techniques, contraindications, and complications of percutaneous image-guided ablation of lung tumors with special attention to cryoablation and its recent developments in protocol optimization.

Quantitative Histogram Analysis of T2-Weighted and Diffusion-Weighted Magnetic Resonance Images for Prediction of Malignant Thymic Epithelial Tumors

PURPOSE

To assess the value of histogram analysis for differentiating a high-risk thymic epithelial tumor (TET) from a low-risk TET using T2-weighted images and the apparent diffusion coefficient (ADC).

METHODS

Forty-nine patients with histopathologically proven TET after thymectomy were enrolled in this study and retrospectively classified as having low-risk TET (low-risk thymoma) or high-risk TET (high-risk thymoma or thymic carcinoma). Twelve parameters were obtained from the quantitative histogram analysis. The histogram parameters were compared using the Mann-Whitney U test. Diagnostic efficacy was estimated by receiver-operating characteristic curve analysis.

RESULTS

Twenty-five patients were classified as having low-risk TET and 24 as having high-risk TET. The mean ADC value showed diagnostic efficacy for differentiating high-risk TET from low-risk TET, with an area under the curve of 0.7, and was better than when using conventional methods alone.

CONCLUSION

The ADC-based histogram analysis could help to differentiate between high-risk and low-risk TETs.

Type A thymoma with simultaneous solitary intrapulmonary metastasis: A case report

A 79‐year‐old woman was referred to our facility because of an abnormal chest shadow. Chest computed tomography (CT) showed a solitary right middle lung nodule with a maximum diameter of 3 mm and anterior mediastinal nodule with a maximum diameter of 21 mm. The lung nodule was suspected of being a primary lung cancer rather than a metastatic tumor because there were no primary malignant tumors, apart from an anterior mediastinal tumor visible on diagnostic imaging, including F¹⁸ fluorodeoxyglucose‐positron emission tomography, and a solitary lung nodule. Partial lung resection by video‐assisted thoracoscopic surgery (VATS) was performed, and the intraoperative frozen section of the tumor tissue resulted in a diagnosis of carcinoid tumor. As a result, right middle lobectomy by VATS was performed. The final histological diagnosis of the permanent specimen was intrapulmonary type A thymoma. VATS thymectomy was performed three months later. The histological diagnosis was type A thymoma with intrapulmonary metastasis (Masaoka stage IVb). Additional therapy was not performed because complete resection was achieved. Follow‐up CT was performed once every six months after the operation. The patient has been followed up for one year without any further recurrence.

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.

Which Is the Best Treatment in Recurrent Thymoma? A Systematic Review and Meta-Analysis

Simple Summary

Thymomas are rare tumors developing in the anterior mediastinum. Despite their usually indolent behavior, recurrence might occur in 5–15% of cases. Considering their rarity, the optimal recurrence treatment is still unclear even if surgical treatment seems to ensure a remarkable long-term survival compared to chemo- or radiotherapy. However, the major part of studies report low patient numbers, and it is difficult to plan prospective studies due to tumor characteristics, long follow-up and rarity of cases. For these reasons, we planned a systematic review and meta-analysis comparing surgical treatment with other therapies, in order to identify the best treatment for these patients. Our meta-analysis included more than 700 patients showing that surgical treatment seems to be associated with a better survival compared to other treatments and should be considered where feasible.

Abstract

Background: Optimal recurrent thymoma management remains arguable because of limited patient numbers, and relatively late and variable recurrence patterns. Given the absence of high-quality evidence and relatively small study cohorts, we performed a quantitative meta-analysis to determine the outcome of surgical and non-surgical approaches assessing the five-year overall survival (5y overall survival (OS)) in patients with recurrent thymoma. Methods: We performed a comprehensive literature search and analysis according to PRISMA guidelines of studies published from 1 January 1980 until 18 June 2020 from PubMed/MEDLINE, EMBASE, and Scopus. We included studies with the cohorts’ superior to 30 patients describing recurrent thymoma treatment, comparing surgical and non-surgical approaches reporting survival data. Results: Literature search revealed 3017 articles. Nine studies met all inclusion criteria and were selected for the meta-analysis. The recurrences were local/regional in 73–98% of cases and multiple in 49–72%. After treatment, 5y OS ranged from 48–77% and 10y OS from 37–51%. The quantitative meta-analysis showed a better outcome comparing surgical vs other treatments. Two studies showed statistically significant risk differences in the 5y OS favoring complete resection. After pooling results of seven studies using the random model, the combined 5y OS risk difference was 0.39, with lower and upper limits of 0.16 and 0.62, respectively (p = 0.001), and a moderate heterogeneity among studies (p = 0.098, I2 = 43.9%). Definitive conclusions could not be drawn regarding the prognostic impact of myasthenia gravis, histology, and patterns of relapse reported in literature. Conclusions: Surgical treatment after thymoma recurrence is associated with a significant better 5y OS; therefore, surgical resection should be preferred in all technically feasible cases.

The treatment and survival of patients with postoperative recurrent thymic carcinoma and neuroendocrine carcinoma: a multicenter retrospective study

PURPOSE

There are few data available on the outcomes of postoperative recurrent thymic carcinoma (TC) and thymic neuroendocrine carcinoma (TNEC). The aim of this study is to evaluate the treatment and survival in patients with recurrent TC and TNEC after undergoing surgical resection.

METHODS

A retrospective chart review was performed using our multicenter database to identify patients with a postoperative recurrence of TC and TNEC from 1995 to 2018. The clinicopathological factors were reviewed and the survival outcomes were analyzed.

RESULTS

Sixty patients were identified among 152 patients who underwent resection of TC and TNEC. The median follow-up period from the first recurrence was 14.8 months (range 0-144). The 5-year post-recurrence survival was 23% for the whole cohort. According to a univariable analysis, advanced stage [hazard ratio (HR) 2.81, 95% confidence interval (CI) 1.09-9.54], interval between primary surgery and recurrence (HR 0.97, 95% CI 0.95-0.99), any treatment for recurrence (HR: 0.27, 95% CI 0.13-0.58) and chemotherapy for recurrence (HR: 0.46, 95% CI 0.22-0.95) were significant factors related to post-recurrence survival.

CONCLUSIONS

Chemotherapy rather than surgery appears to be the mainstay treatment for managing patients with postoperative recurrent TC and TNEC and it may also be considered in multidisciplinary management. Further studies with a larger sample size are required to confirm our findings.

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.

[Treatment of Recurrent Thymoma]

胸腺瘤是一种具有恶性潜能的疾病，完整切除后的复发率为10%-30%。复发性胸腺瘤的治疗策略及标准未达成一致，治疗方式包括再次手术治疗、化疗、放疗、靶向治疗及免疫治疗等，至今存在着争议。在这篇综述中，通过回顾既往的文献，总结了复发性胸腺瘤的不同治疗方法的适应证、疗效以及预后，以期给复发性胸腺瘤治疗标准的制定提供一些参考。

A nomogram for predicting recurrence after complete resection for thymic epithelial tumors based on the TNM classification: A multi-institutional retrospective analysis

OBJECTIVES

This study aimed to compare the predictive ability between the Masaoka-Koga (M-K) staging system and the 8th TNM staging system for the recurrence of thymic epithelial tumors (TETs). In addition, a nomogram was developed on the basis of the proposed TNM classification to predict individual recurrence rate.

METHODS

A retrospective study was performed on 445 patients who underwent complete resection (R0) of TETs between January 2000 and February 2013. Concordance index (C-index) was used as a statistical indicator to quantify the prediction power of the prediction models.

RESULTS

In multivariate analysis, tumor stage and WHO classification were independent recurrence factors in a predictive model on the basis of M-K and TNM stage. The TNM model showed higher C-index than the M-K model (0.837 vs 0.817). The nomogram, on the basis of the TNM model, revealed a highly predictive performance, with a bootstrap-corrected C-index of 0.85 (95% CI, 0.76 to 0.93).

CONCLUSIONS

A predictive model based on the 8th TNM stage was slightly better than that based on M-K stage with respect to recurrence after R0 of TETs. The proposed nomogram could be applied to estimate the individual recurrence rate and make decisions for proper surveillance.

Long-Term Outcomes After Surgical Resection for Pleural Dissemination of Thymoma

BACKGROUND

Cases of thymoma with pleural dissemination are occasionally encountered, and their management is difficult. Some reports have noted that surgical treatment for dissemination is effective, although the long-term results and clinical course details remain unclear. The current study investigated the short- and long-term outcomes of surgical resection of pleural dissemination.

METHODS

A retrospective review examined the medical records for 38 patients who underwent surgical resection for pleural dissemination occurring synchronously with a primary thymoma or metachronously after complete surgical resection of a primary thymoma between 1996 and 2017 at the authors' institution. Clinical characteristics and prognostic factors were analyzed.

RESULTS

The patients were classified into synchronous (n = 21) and metachronous (n = 17) groups. The 10-year overall survival rate was 59% for the synchronous group and 88% for the metachronous group. The median follow-up period for all the patients was 61 months (range 4-225 months). No perioperative deaths occurred. For all the patients, the 5- and 10-year overall survival rates were respectively 91% and 82%, and the 5- and 10-year relapse-free survival rates were respectively 29% and 19%. A significantly worse prognosis was observed for patients 50 years of age or older than for those younger than 50 years (p = 0.02). For 13 patients who underwent repeat resection for pleural dissemination, the prognosis was better than for those without repeat resection (p < 0.01).

CONCLUSION

Surgical resection of thymoma with pleural disseminated nodules can be safely performed and provides a favorable long-term outcome. Repeat resection is considered to be effective for achieving a good prognosis.

Different pattern of PD-L1, IDO, and FOXP3 Tregs expression with survival in thymoma and thymic carcinoma

OBJECTIVES

The expression of immune checkpoint ligand PD-L1 has been reported in various tumors. The expression of IDO and FOXP3 Tregs are considered to be associated with tumor-induced tolerance and poor outcome. Their prognostic role in surgically treated thymoma and thymic carcinoma, however, has not been investigated.

MATERIALS AND METHODS

Tissue microarray (TMA) blocks comprised of 100 surgically treated thymomas and 69 surgically treated thymic carcinomas were conducted. Tissue sections were incubated with primary antibodies against PD-L1 (clone E1L3N, 1:100), IDO (clone 10.1, 1:50), and FOXP3 (clone 236 A/E7, 1:50). Comparisons for categorical variables were performed using χ² test and Fisher's exact test. Survival analysis was established using Kaplan-Meier method and log-rank test. Univariate and multivariate analyses were performed using Cox regression model.

RESULTS AND CONCLUSIONS

High expression of PD-L1, IDO, and FOXP3 Tregs were identified in 36 (36%), 13 (13%), and 16 (16%) thymoma patients, respectively. High expression of PD-L1, IDO, and FOXP3 Tregs was associated with higher grade of tumor histology (P <  0.001, P =  0.007, and 0.014, respectively). High expression of PD-L1 was also associated with advanced Masaoka staging (P <  0.001). In patients with thymic carcinoma, high expression of PD-L1, IDO, and FOXP3 Tregs were identified in 25 (36%), 10 (14%), and 20 (29%) patients, respectively. Complete resection, low expression of IDO, and high expression of FOXP3 Tregs were associated with better overall survival (P =  0.001, 0.004, and 0.032, respectively), and progression-free survival (P <  0.001, P =  0.026, and 0.047, respectively) in multivariate analysis. In surgically treated thymoma, high PD-L1 expression was associated with advanced Masaoka staging. High PD-L1, IDO, and FOXP3 Tregs expression was associated with high grade histology. In surgically treated thymic carcinoma, significant survival benefit was noted in patients with complete resection, low IDO expression, and high FOXP3 Tregs expression.

Focal adhesion kinase is overexpressed in thymic epithelial tumors and may serve as an independent prognostic biomarker

Focal adhesion kinase (FAK) has long been considered to be a key regulator of growth factor receptor- and integrin-mediated signals, with pivotal roles in tumor cells through its kinase activity and scaffolding function. Increased FAK expression and activity has been observed in tumors of various origins and is often associated with a poor prognosis. However, there have been no studies on the aberrant expression of FAK in thymic epithelial tumors to date. The aim of the present study was to evaluate FAK expression in thymic epithelial tumors and to explore the prognostic significance of FAK. FAK expression was investigated in 100 formalin-fixed, paraffin-embedded human thymic epithelial tumor (TET) specimens using immunohistochemical analysis with FAK-specific monoclonal antibody 4.47, and the associations between FAK expression and clinicopathological parameters (including sex, age, tumor size, myasthenia gravis, World Health Organization classification and Masaoka-Koga stage) were analyzed. FAK was significantly overexpressed in TETs compared with in normal thymus tissues (P<0.001). Additionally, FAK overexpression was significantly associated with advanced tumor stages (stages III or IV; P<0.001) and highly aggressive TET subtypes (type B2 and B3 thymomas and thymic carcinomas; P<0.001). Furthermore, FAK overexpression was significantly associated with a worse 10-year overall survival, as determined by univariate analysis (P<0.001). Multivariate analysis revealed that FAK overexpression was an independent prognostic factor for patients with TETs (P=0.034). The results of the present study suggest that FAK serves an important role in the tumorigenesis and progression of TETs. Therefore, FAK may serve as a prognostic biomarker and is a potential therapeutic target for the treatment of TETs.

Metastatic Thymoma-Associated Myasthenia Gravis: Favorable Response to Steroid Pulse Therapy Plus Immunosuppressive Agent

BACKGROUND Our study retrospectively reviewed the therapeutic effect of steroid pulse therapy in combination with an immunosuppressive agent in myasthenia gravis (MG) patients with metastatic thymoma. MATERIAL AND METHODS MG patients with metastatic thymoma that underwent methylprednisolone pulse therapy plus cyclophosphamide were retrospectively analyzed. Patients initially received methylprednisolone pulse therapy followed by oral methylprednisolone. Cyclophosphamide was prescribed simultaneously at the beginning of treatment. Clinical outcomes, including therapeutic efficacy and adverse effects of MG and thymoma, were assessed. RESULTS Twelve patients were recruited. According to histological classification, 4 cases were type B2 thymoma, 3 were type B3, 2 were type B1, and 1 was type AB. After combined treatment for 15 days, both the thymoma and MG responded dramatically to high-dose methylprednisolone plus cyclophosphamide. The symptoms of MG were improved in all patients, with marked improvement in 6 patients and basic remission in 4. Interestingly, complete remission of thymoma was achieved in 5 patients and partial remission in 7 patients. Myasthenic crisis was observed in 1 patient and was relieved after intubation and ventilation. Adverse reactions were observed in 7 patients (58.3%), most commonly infections, and all were resolved without discontinuation of therapy. During the follow-up, all patients were stabilized except for 1 with pleural metastasis who received further treatment and another 1 who died from myasthenic crisis. CONCLUSIONS The present study in a series of MG patients with metastatic thymoma indicated that steroid pulse therapy in combination with immunosuppressive agents was an effective and well-tolerated for treatment of both metastatic thymoma and MG. Glucocorticoid pulse therapy plus immunosuppressive agents should therefore be considered in MG patients with metastatic thymoma.

The clinical features, diagnosis and management of recurrent thymoma

Thymoma is a disease with malignant potential, which has a recurrence rate after complete resection ranging from 5 to 50 %. Multiple studies on the risk factors, treatment or prognosis have been reported. Many of them are controversial, however. In this review, we summarized some accepted risk factors, means of diagnosis and different treatments of recurrent thymoma. The risk factors of recurrent thymoma haven’t been well-studied, and its management remains controversial. We reviewed the literatures and found some key points which should be noticed during the surgery of initial thymoma. Although reoperation should be taken into account preferentially, multimodal treatments are also available. The prognosis are also been discussed.

Pretreatment biopsy for histological diagnosis and induction therapy in thymic tumors

BACKGROUND

This study was to investigate the value of pretreatment biopsy for histological diagnosis and induction therapies in the management of locally advanced thymic malignancies.

METHODS

The clinical pathological data of patients with thymic tumors in the Chinese Alliance for Research in Thymomas (ChART) who underwent biopsy before treatment from 1994 to December 2012 were retrospectively reviewed. The application trend of preoperative histological diagnosis and its influence on treatment outcome were analyzed.

RESULTS

Of 1,902 cases of thymic tumors, 336 (17.1%) had undergone biopsy for histological diagnosis before therapeutic decision was decided. In recent years, percentage of pretreatment histological diagnosis significantly increased in the later ten years than the former during the study period (P=0.008). There was also a significant increase in thoracoscopy/mediastinoscopy/E-BUS biopsy as compared to open biopsy (P=0.029). Survival in Patients with preoperative biopsy for histology had significantly higher stage lesions (P=0.000) and higher grade malignancy (P=0.000), thus a significantly lower complete resection rate (P=0.000) and therefore a significantly worse survival than those without preoperative biopsy (P=0.000). In the biopsied 336 patients, those who received upfront surgery had significantly better survival than those received surgery after induction therapy (P=0.000). In stage III and IVa diseases, the R0 resection rate after induction therapies increased significantly as compared to the surgery upfront cases (65.5% vs. 46.2%, P=0.025). Tumors downstaged after induction had similar outcomes as those having upfront surgery (92.3% vs. 84.2%, P=0.51). However, tumors not downstaged by induction had significantly worse prognosis than those downstaged (P=0.004), and fared even worse than those having definitive chemoradiation without surgery (37.2% vs. 62.4%, P=0.216).

CONCLUSIONS

It is crucial to get histological diagnosis for thymoma before surgery or adjuvant treatment and minimally invasive biopsy should be undertaken. Although in our study we could not find the benefit of induction chemotherapy before surgery in survival and recurrence rate, it could increase the R0 resection rate compared with direct surgery in late stage (III and IVa).

Superior vena cava syndrome from an invasive thymoma with transcaval invasion to the right atrium

Invasive thymoma with transcaval extension to the right atrium is a rare cause of superior vena cava syndrome. We present a case on a 74-year-old female presenting with dyspnea on exertion, and facial and upper extremity swelling. Physical examination revealed mild facial swelling, non-pitting edema involving the upper extremities and distention of superficial veins of the anterior chest wall and jugular veins. An echocardiogram showed moderate right atrial dilation with a mobile mass in the atrial cavity prolapsing through the tricuspid valve. Cardiac magnetic resonance imaging revealed a 9.9 × 4.3 cm heterogeneous mass in the anterior mediastinum compressing the superior vena cava and endovenously extending into the right atrium. Tissue biopsy of the mediastinal mass revealed a type B1 thymoma, further staged as a Masaoka IVa invasive thymoma that underwent successful en bloc resection followed by removal of intracaval and right atrial mass.

Video assisted thoracic surgery (VATS) for recurrent thymoma

Between 10-30% of patients that undergo a radical operation for thymoma develop a recurrence in a variable range of time. The surgical treatment of thymoma relapses is an established and effective therapeutic approach, particularly for a single intrathoracic recurrence; however, no agreement has been reached on the best surgical approach and the extent of surgical resection, particularly in the most common event of pleural relapses. In the era of minimally invasive approach for most thoracic pathologies, the role of the video assisted thoracic surgery (VATS) approach for thymoma recurrence resection is still unclear and controversial: to date, only few authors have reported in their series a thoracoscopic resection of pleuro-pulmonary relapses, mostly when a single lesion was present. Furthermore, a thoracoscopic approach for mediastinal recurrence has been rarely reported after a previous sternotomy to resect the primary tumor. It is likely that in the future, the role of VATS for thymic recurrence resection will be better defined and extensively studied.

Behind and Beyond the Masaoka Staging: A 25-Year Follow-up Study of Tumor Recurrence in Completely Resected Thymic Epithelial Tumors in a Single Institution

We analyzed prognosticators for recurrence and post-recurrence survival in completely resected thymic epithelial tumors for the past 25 years in a single institution.Between June 1988 and December 2013, 238 patients undergoing intent-to-treat surgery for thymic epithelial tumors were reviewed. Sex, age, myasthenia gravis (MG), tumor histology, Masaoka staging, characteristic of locoregional invasion and recurrence, and the treatment for recurrence were collected. Comparison between groups was conducted using the Student t test and χ test. Survival analysis was performed using the Kaplan-Meier method and log-rank test. The Cox proportional hazards model was used for univariate and multivariate analyses of prognostic factors.One hundred sixteen of 135 patients with completely resected thymoma and 35 of 56 patients with thymic carcinoma remained free of recurrence. In patients with completely resected thymoma, Masaoka staging, MG, tumor invasion into the lung, pericardium, and innominate vein or superior vena cava (SVC) invasion were associated with recurrence-free survival in univariate analysis (P = 0.004, 0.003, 0.001, 0.007, and 0.039, respectively). In multivariate analysis, MG was the positive independent prognosticator (P = 0.039). In patients with completely resected thymic carcinoma, Masaoka staging and innominate vein or SVC invasion were associated with recurrence-free survival in univariate analysis (P = 0.045 and 0.005, respectively), whereas innominate vein or SVC invasion was the negative independent prognosticator (P = 0.012). In patients with recurrent thymoma, those treated with surgery followed by chemotherapy had a significantly better post-recurrence survival than those undergoing chemoradiotherapy (P = 0.029) and those without treatment (P = 0.007). Patients with recurrent thymic carcinoma undergoing surgery followed by chemotherapy had a significantly better post-recurrence survival than those without treatment (P = 0.004), but not significantly better than those undergoing chemoradiotherapy (P = 0.252).In patients with completely resected thymoma, MG was the positive independent prognosticators of recurrence-free survival. Surgery should be attempted for recurrent disease for better post-recurrence survival. In patients with completely resected thymic carcinoma, innominate vein or SVC invasion was the negative independent prognosticator. Surgery for recurrence could be considered since it provided benefit for post-recurrence survival as chemoradiotherapy did.

Long-term results after treatment for recurrent thymoma: a multicenter analysis

OBJECTIVES

The treatment for recurrent thymoma remains a very controversial issue. This study aims to investigate the long-term outcomes in patients with relapse according to treatment strategies and clinicopathological features.

METHODS

We retrospectively analyzed the database of three tertiary centers of thoracic surgery with the aim of reviewing the clinical records of 81 patients who experienced a recurrent thymoma after radical thymectomy, in the period between January 2001 and June 2013. The staging of both primitive and recurrent thymomas were based on the surgical and pathological criteria described by Masaoka. Experienced pathologists reassessed independently the histology of the initial thymoma and its relapse, according to the WHO classification. To the purposes of this study R+ resection or thymic carcinoma were considered as exclusion criteria. The overall outcome for long-term (5 years and 10 years) survival and disease-free survival after initial thymectomy and after treatment of recurrent thymoma were analyzed using standard statistics.

RESULTS

The population was gender balanced (41 M, 40 F), mean age: 46.4 ± 12.3 years. Fifty-four patients (66.7%) were affected by myasthenia gravis, while the other 14 by other paraneoplastic conditions. Surgery was performed in 61 patients (75.3%,), and radiotherapy and/or chemotherapy in 14 patients (17.3%). The mean follow-up duration after recurrence onset was 66.3 ± 56.4 months. Adjuvant therapy had no effect on prolonging the disease-free survival: no differences were found when investigating the administration of adjuvant chemotherapy (no CHT = 91.5 ± 76.4 months versus yes CHT=64.0 ± 41.3) and radiotherapy (no RT=86.2 ± 72.8 months versus yes RT= 93.0 ± 62.3; p = 0.8). Relapses were mostly local (mediastinum: 15 cases, pleura: 44 cases); hematogenous distant recurrences were observed in 15 cases (lung: 12; liver: 1; bone: 2 cases). An upgrade in the WHO class (defined as the "migration" of WHO class at initial thymectomy to more aggressive WHO class assigned at thymic recurrence resection) was found in 25/61 cases (40.9%), but this phenomenon apparently did not influence patient's prognosis. Overall, the 5- and 10-year survival rates after the initial thymectomy were 94.8% and 71.7%, respectively, while the 5- and 10-year survival rates after the treatment of the recurrence at the thymic level were 73.6% and 48.3%, respectively (82.4% at 5 years and 65.4% at 10 years when a R0-re-resection was obtained). The analysis on the trends of disease-free survival indicated that the site of recurrence (hematogenous diffusion) seems to be associated to a higher risk of re-relapse (p = 0.01).

CONCLUSIONS

Even following a thymectomy performed with radical intent, thymoma may recur several years later, usually as a locoregional relapse. A rewarding long-term survival may be expected after treatment, especially when a re-resection (radical) is performed (82.4% at 5 years). An histopathological "WHO upgrade" (from "low-risk" WHO classes at thymectomy to "high-risk classes" at relapse) may be observed in a remarkable percentage of patients (nearly 40% in this series), but this phenomenon seems to be not correlated with any worsening of the prognosis.

Surgical management of recurrent thymic epithelial tumors: a retrospective analysis based on the Japanese nationwide database

BACKGROUND

There is no standard treatment for recurrent thymic epithelial tumors. Although the efficacy has not been validated based on the large series studies, surgical resection is sometimes employed for patients with recurrent thymic tumors. The aim of this study is to evaluate the surgical outcomes for recurrent thymic epithelial tumors based on the Japanese nationwide database.

METHODS

From the database of patients whose thymic epithelial tumors were treated surgically from 1991 through 2010, the cohort who developed recurrence after the initial resection was extracted. Clinicopathological factors were reviewed, and the prognostic factors of re-resected cases were examined.

RESULTS

Twenty-eight hundred thirty-five patients who underwent surgical resection of thymic epithelial tumors were registered to the database. Among these patients, 420 (14.8%) experienced recurrence. One hundred sixty-two patients were treated surgically and 243 were treated nonsurgically for recurrent disease. The 5- and 10-year postrecurrence survival rates were 82.7% and 68.2%, respectively, in the surgery group and 43.5% and 25.4%, respectively, in the nonsurgery group (p < 0.001). According to univariate analyses, female sex and the pathological Masaoka I-II stage, nonthymic carcinoma, absence of preoperative treatment and longer recurrent-free interval (RFI) were significantly favorable factors for survival in the surgery group. According to the multivariate analysis, nonthymic carcinoma histology and longer RFI were identified to be independent prognostic factors.

CONCLUSIONS

The surgical outcomes of recurrent thymic epithelial tumors are favorable in selected patients. The role of re-resection may be limited in the setting of thymic carcinoma and/or a short RFI.

Is it valuable and safe to perform reoperation for recurrent thymoma?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was whether it is valuable and safe to perform reoperation for recurrent thymoma. Altogether, more than 500 papers were found using the reported search, of which 15 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. This paper includes 1 level 1a study and 15 level 2b studies. The operative mortality was reported in six studies, ranging from 0 to 13.3%, and the operative morbidity in five studies, ranging from 0 to 32.1%. Most patients suffering from operative mortality (5/5) and morbidity (16/19) had myasthenia gravis. One meta-analysis demonstrated improved rates of long-term overall survival in patients with recurrent thymoma who were treated surgically compared with those treated non-surgically. Ten studies showed better survival after surgical treatment than after non-surgical treatment with the difference being statistically significant in 4 of them. Two studies reported that the prognosis in patients with complete reresection was comparable with that of patients without recurrence. One study found that patients with a thymus-related syndrome improved after re-resection. Another two studies revealed that debulking surgery for recurrent thymoma was associated with poorer survival and worse outcomes than both complete resection and non-surgical therapy. From the papers identified in our search, we can conclude that reoperation can be performed with acceptable morbidity and low mortality in appropriately selected patients with locally and/or regionally recurrent thymoma. Both survival and thymus-related syndromes are improved if the recurrence is surgically resected when compared with other medical treatments. Debulking surgery should be limited to those few selected patients in whom other treatment options are not available. In addition, morbidity and mortality most commonly occur in association with myasthenia gravis, and hence medical control of this should be optimized prior to reoperation.

ITMIG consensus statement on the use of the WHO histological classification of thymoma and thymic carcinoma: refined definitions, histological criteria, and reporting

INTRODUCTION

The 2004 version of the World Health Organization classification subdivides thymic epithelial tumors into A, AB, B1, B2, and B3 (and rare other) thymomas and thymic carcinomas (TC). Due to a morphological continuum between some thymoma subtypes and some morphological overlap between thymomas and TC, a variable proportion of cases may pose problems in classification, contributing to the poor interobserver reproducibility in some studies.

METHODS

To overcome this problem, hematoxylin-eosin-stained and immunohistochemically processed sections of prototypic, "borderland," and "combined" thymomas and TC (n = 72) were studied by 18 pathologists at an international consensus slide workshop supported by the International Thymic Malignancy Interest Group.

RESULTS

Consensus was achieved on refined criteria for decision making at the A/AB borderland, the distinction between B1, B2, and B3 thymomas and the separation of B3 thymomas from TCs. "Atypical type A thymoma" is tentatively proposed as a new type A thymoma variant. New reporting strategies for tumors with more than one histological pattern are proposed.

CONCLUSION

These guidelines can set the stage for reproducibility studies and the design of a clinically meaningful grading system for thymic epithelial tumors.

Undifferentiated pleiomorphic sarcoma simultaneously occuring with thymoma

We report here a case of thymoma simultaneously associated with neuroendocrine tumor. A 65-year-old male, presented with cough. Radiographic studies showed a mediastinal mass. On fine needle aspiration cytology and histopathological examination, a diagnosis of thymoma with coexisting undifferentiated pleomorphic sarcoma was made. Although thymoma is associated with many extrathymic malignancies, its association with neuroendocrine tumor is rare. This case is being reported on to reinforce that clinicians should bear in mind the possibility of extrathymic malignancies in patients with thymoma.

Recurrent thymoma with stiff-person syndrome and pure red blood cell aplasia

Stiff-person syndrome (formerly known as stiff-man syndrome) is a very rare autoimmune and neurogenic disorder, thought to present as a paraneoplastic variant in association with thymoma. Pure red blood cell aplasia is also a paraneoplastic disorder associated with thymoma. Although separate cases of stiff-person syndrome and pure red blood cell aplasia have been reported, we describe here what is to our knowledge the first case of recurrent thymoma with both stiff-person syndrome and pure red blood cell aplasia. We describe the successful treatment of the neurogenic symptoms of stiff-person syndrome and the progressive anemia associated with pure red blood cell aplasia by tumor excision.

Advances in thymic carcinoma diagnosis and treatment: a review of literature

Thymomas account for up to 50 % of anterior mediastinal neoplasms with an incidence of 0.13 per 100,000 person-years in the USA. Thymic carcinoma is a rare malignancy of the thymus gland distinguished from thymomas as it has a more invasive and metastasizing potential conferring poor prognosis. Due to the rarity of thymic carcinoma and the great variety of its histological subtypes, there is no solid evidence on optimal staging, imaging and treatment guidelines. Herein, we systematically review the literature on current clinical practice with regard to diagnostic evaluation, histopathological assessment, management and treatment of squamous thymic carcinoma.

Invasive thymoma disseminated into the pleural cavity: mid-term results of surgical resection

OBJECTIVES

The optimal strategy for pleural dissemination of advanced thymoma remains controversial, while a potential benefit from macroscopic clearance of disseminations has been reported. In this study, we review our mid-term results of surgical resection of pleural disseminations of invasive thymoma.

METHODS

Data from patients with pleural dissemination synchronously or metachronously to primary invasive thymoma who underwent surgical resection from 1991 to 2012 at our institute were retrospectively reviewed.

RESULTS

Of 136 thymoma patients who underwent surgery during the study period, 13 consecutive patients with pleural dissemination (synchronous: 7, metachronous: 6) with a median age of 49 years (range: 27-78 years) at the time of dissemination resection were identified. No patients presented with haematogenous metastases. Operative procedures included the thorough resection of visible disseminated nodules in 11 patients and extrapleural pneumonectomy (EPP) in 2 patients. The median number of resected nodules was 6 (range: 1-52). The median follow-up was 948 days (range: 38-4025 days). One patient died of postoperative bleeding, but there were no tumour-related deaths during the study period. Pleural recurrence was found in 9 cases, including 2 EPP cases, and among them, 3 underwent repeated resection. The overall survival and the recurrence-free survival ratio at 5 years was 92.3 and 33.3%, respectively. Five patients, including 2 repeated resection cases, remained tumour-free at the final observation.

CONCLUSIONS

Resection of pleural dissemination of invasive thymoma can be performed in selected patients and may offer optimal local control as part of a multimodal strategy.

Thymic neoplasm: a rare disease with a complex clinical presentation

Thymic neoplasms constitute a broad category of rare lesions with a wide spectrum of pathologic characteristics and clinical presentations which therefore require a high index of suspicion to diagnose. The natural history of the disease is seldom predictable, anywhere from an indolent to an aggressively malignant course. Although the classification and staging of these lesions are complex and controversial, complete radical surgical resection remains the gold standard of therapy. Radiation and chemotherapy are important elements of the multimodality approach to treating these patients and it is important for thoracic surgeons to work closely with their colleagues in other disciplines in the management of and future research endeavors in thymic neoplasm. In this review, we discuss the evaluation of the patient with an anterior mediastinal mass, the classification and staging of thymic neoplasms, the role of surgery, radiation and chemotherapy in treating this disease, as well as future directions in research for novel targeted therapies.

Pulmonary metastasis from encapsulated cervical ectopic type a thymoma

A 39-year-old woman underwent tumor resection for an encapsulated cervical ectopic thymoma (type A). However 7 years after complete resection, computed tomography (CT) screening detected a 9-mm pulmonary nodule, which was completely resected and was diagnosed as a metastasis from the ectopic thymoma. There have been few reports on cervical ectopic thymoma metastasizing to a distant site and, to the best of our knowledge, this is the first case report of a cervical ectopic type A thymoma with distant metastasis.

WHO types A and AB thymomas: not always benign

The 2004 WHO classification of thymic tumors recognizes five major subtypes of thymomas and thymic carcinoma. Subtypes A and AB thymomas are purported to be benign neoplasms, although prior studies have suggested a potential for malignant behavior. The purpose of this study was to assess the clinical behavior of A and AB thymomas identified from a large institutional pathologic database. A retrospective slide review of 500 thymic epithelial tumors identified 71 (∼ 14%) cases of types A and AB thymomas. Clinical history and follow-up information were obtained through retrospective chart review. There were 38 and 33 cases of types A and AB thymomas, respectively. Complete follow-up data were available in 37 (52%) cases. Eighteen (49%) patients (type A, n=9 and type AB, n=9) had evidence of recurrent/metastatic disease at an average of 62 months (range from 6 to 244 months) after initial diagnosis. Survival curves for patients with types A and AB thymomas, with and without recurrences, show a statistically significant difference (P=0.001 and 0.005, respectively). Analysis of this large cohort confirms the potential for subtypes A and AB thymomas to show malignant behavior. Long-term clinical monitoring, therefore, appears to be justified in these cases. This study also shows the poor correlation between the WHO classification and tumor behavior.

Tumors of the mediastinum and chest wall

Primary tumors of the mediastinum and chest wall comprise a diverse group of conditions with a wide range of presentations. A thorough knowledge of thoracic anatomy is essential for appropriate diagnosis and treatment. Given their proximity to critical structures, treatment of these tumors is often challenging. Although surgery is the mainstay of therapy for most mediastinal and chest wall tumors, a multidisciplinary approach is valuable in many cases.

Comparison of patterns of relapse in thymic carcinoma and thymoma

OBJECTIVE

Thymic carcinomas are considered to be more aggressive than thymomas and carry a worse prognosis. We reviewed our recent experience with the surgical management of thymic tumors and compared the outcomes and patterns of relapse between patients with thymic carcinoma and those with thymoma.

METHODS

We performed a single-institution retrospective cohort study. Data included patient demographics, stage, treatment, pathologic findings, and postoperative outcomes.

RESULTS

During the period 1995-2006, 120 patients with thymic tumors underwent surgical intervention, including 23 patients with thymic carcinoma and 97 patients with thymoma, as classified according to the World Health Organization 2004 histologic classification. The overall 5-year survival was significantly different between patients with thymic carcinoma and those with thymoma (thymic carcinoma, 53%; thymoma, 89%; P = .01). Data on relapse were available for 112 patients. The progression-free 5-year survival was also significantly different between patients with thymic carcinoma and those with thymoma (thymic carcinoma, 36%; thymoma, 75%; P < .01). Using multivariate analysis, thymic carcinoma and incomplete resection were found to be independent predictors of progression-free survival. Relapses in patients with thymic carcinoma tended to occur earlier, and occurred significantly more frequently at distant sites than in patients with thymoma (60% vs 13%, P = .01).

CONCLUSIONS

Patterns of relapse differ significantly between patients with thymic carcinoma and those with thymoma, with lower progression-free survival, earlier onset, and more distant relapses in patients with thymic carcinoma. Given the greater propensity for distant failures, the inclusion of systemic therapy in the treatment of thymic carcinoma might take on greater importance. Despite significantly higher rates of distant relapse, good overall survival in patients with thymic carcinoma can be achieved.

The Correlation of the World Health Organization Histologic Classification of Thymic Epithelial Tumors and Its Prognosis: A Clinicopathologic Study of 108 Patients From China

This study retrospectively reviewed the clinicopathological features of thymic epithelial tumors in 108 patients, and evaluated World Health Organization (WHO) histologic classification of thymic tumors. Other prognostic factors, including age, gender, clinical stage, and completeness of tumor resection were also analyzed. Seven type A tumors, 19 type AB, 23 type B1, 19 type B2, 27 type B3, and 13 thymic carcinomas were studied. The 5-year and 10-year survival rates were 100% after resection of tumor types A and AB; 93% and 81% for B1; 83% and 70% for B2; and 43% and 33% for B3. The overall 5-year and 10-year survival rates were 72.0% and 63.0%, respectively. Tumor classification was highly significant in predicting survival ( P .001) and also reflected the clinical behavior of tumors. The Masaoka stage was the most important independent prognostic index in thymomas. The WHO histologic subtype and completeness of resection were also important prognostic factors.