Thymic tumors

Isolated splenic metastasis from a thymic carcinoma: A case report

Thymic carcinomas are rare tumors that arise in the anterior mediastinum. Most of these malignancies develop local metastases limited in the thorax. Splenic metastases from thymic carcinomas are extremely rare. Here we report a case of isolated splenic metastasis from a 38-year-old female patient with Stage IV thymic carcinoma, who was treated with chemoradiotherapy. At twenty-2 months follow-up, the patient was found to have an isolated spleen metastasis, which was treated by Cyberknife with a reduced size of the metastasis, representing a partial response. Although splenic metastasis is a rare phenomenon, physicians need to be aware of the possibility of such metastases.

HSP27 and 70 expression in thymic epithelial tumors and benign thymic alterations: diagnostic, prognostic and physiologic implications

Thymic Epithelial Tumors (TETs), the most common tumors in the anterior mediastinum in adults, show a unique association with autoimmune Myasthenia Gravis (MG) and represent a multidisciplinary diagnostic and therapeutic challenge. Neither risk factors nor established biomarkers for TETs exist. Predictive and diagnostic markers are urgently needed. Heat shock proteins (HSPs) are upregulated in several malignancies promoting tumor cell survival and metastases. We performed immunohistochemical staining of HSP27 and 70 in patients with TETs (n = 101) and patients with benign thymic alterations (n = 24). Further, serum HSP27 and 70 concentrations were determined in patients with TETs (n = 46), patients with benign thymic alterations (n = 33) and volunteers (n = 49) by using ELISA. HSPs were differentially expressed in histologic types and pathological tumor stages of TETs. Weak HSP tumor expression correlated with worse freedom from recurrence. Serum HSP concentrations were elevated in TETs and MG, correlated with clinical tumor stage and histologic subtype and decreased significantly after complete tumor resection. To conclude, we found HSP expression in the vast majority of TETs, in physiologic thymus and staining intensities in patients with TETs have been associated with prognosis. However, although interesting and promising the role of HSPs in TETs as diagnostic and prognostic or even therapeutic markers need to be further evaluated.

The creation of the international thymic malignancies interest group as a model for rare diseases

Similar to other orphan diseases, little progress has been made in the past decades in thymic malignancies. A determination to make a difference, despite the challenges facing a rare disease, led to the formation of the International Thymic Malignancies Interest Group (ITMIG) in 2010. This organization has brought together the majority of those focused on the management of thymic malignancies and has built a foundation for scientific collaboration, including consistent use of terms, an international database, and multidisciplinary engagement of clinicians and researchers from around the world. ITMIG has embarked on the development of novel approaches to research particularly suited to a rare condition. ITMIG has gained substantial recognition for the rapid progress that has been made and serves as a model for the advancement of knowledge in a rare disease.

Ectopic thymic carcinoma presenting as an intrathoracic mass

An asymptomatic 83-year-old man was found to have a right intrathoracic tumor. Computed tomography demonstrated a soft-tissue density mass measuring 55 × 25 × 22 mm adjacent to the right anterior chest wall. At surgery, the tumor was found to adhere to the diaphragm and right lung, contiguous with the mediastinal fat tissue. Histology of the resected specimen demonstrated proliferation of spindle and sarcomatous cells with multinucleated giant cells. Thus the tumor was diagnosed as undifferentiated thymic carcinoma and was considered to have arisen from ectopic thymic tissue. At 2 years postoperatively, the patient had no evidence of recurrence.

About thymic carcinomas: challenges in diagnosis and management

BACKGROUND

Thymic carcinomas are rare tumors with a challenging diagnosis. Our aim was to report our 17-year experience of these tumors and to highlight the challenges encountered and the main differential diagnoses ruled out.

METHODS

We studied 12 (92%) men and 1 (7.7%) woman with a mean age of 37 years (range 15-60 years). All patients were symptomatic, with chest pain representing the most frequent symptom. Radiology revealed anterior mediastinal masses in all cases, with either infiltration of the adjacent organs or pulmonary parenchymal metastases.

RESULTS

The diagnosis was made on surgical biopsies in 12 cases and a lymph node biopsy in one. Microscopic examination revealed squamous carcinoma in 3 cases, synovial sarcoma in 1, mucinous adenocarcinoma in 1, undifferentiated carcinoma in 2, clear cell carcinoma in 1, lymphoepithelioma-like carcinoma in 2, atypical carcinoid tumor in 2, and sarcomatoid carcinoma in 1. Total surgical resection was possible in one patient after neoadjuvant chemotherapy and radiotherapy. Follow-up was possible in only 6 patients, and the mean survival reached 13 months.

CONCLUSION

In spite of the lack of follow-up information, this study demonstrates the poor outcome associated with these tumors and the need for standardized treatment.

Targeted therapy for thymic epithelial tumors: a new horizon? Review of the literature and two cases reports

Surgical resection remains the cornerstone of therapy for early-stage thymic epithelial tumors (TETs), while in advanced or recurrent forms, a multimodality approach incorporating radiation and chemotherapy is required. Given the absence of effective treatment options for metastatic/refractory TETs and the poor related prognosis, there is a compelling need to identify promising 'drugable' molecular targets. Initial reports of activity from targeted agents in TETs derived from anecdotal cases have been often associated with specific activating mutations. Only in recent years, several agents have been formally investigated into prospective clinical trials, with varying success rates. We reviewed the literature on targeted therapy in TETs along with two cases of thymoma achieving striking responses to sorafenib in combination with lapatinib.

Pancreatic metastasis resulting from thymic neuroendocrine carcinoma: A case report

Thymic neuroendocrine carcinoma (NEC) is a rare type of cancer. Unlike other thymic epithelial tumors and carcinoids originating in other locations, thymic NEC possesses a more aggressive biological behavior, including invasion to proximal structures, local recurrence and distant hematogenous metastasis. Distant metastasis is often observed in the bones, lungs, spleen, liver and adrenal glands. However, pancreatic metastasis resulting from thymic NEC is extremely uncommon, and only a few cases of patients with this disease have been reported. The current study presents the case of a patient with pancreatic metastasis resulting from thymic NEC. The patient was admitted to hospital with an anterior mediastinal neoplasm, which was identified using chest enhanced computed tomography. The patient underwent a monobloc excision of the tumor with resection of involved structures. Subsequently, a pathological diagnosis of atypical thymic carcinoid was provided, according to the morphological characteristics observed and the expression of neuroendocrine markers, as identified by immunohistochemistry. Following surgery, the patient received adjuvant chemotherapy and radiotherapy. However, ~2 years after surgery, metastasis at the pancreatic head was identified. The patient underwent a total pancreatectomy and splenectomy, and did not receive any post-operative therapies; however, the patient succumbed to the disease 9 months following surgery. Overall, the results from the present study demonstrate the clinical features of thymic NEC, which may aid with the diagnosis of this rare disease in other patients.

Ectopic intrapleural thymoma: a rare location in the thoracic cavity

We present a patient with a large thymoma on the right thoracic cavity developing from the visceral pleura. This is a rare location for this tumour, and only a few had been reported to date in the literature.

Myasthenia gravis and thymic neoplasms: A brief review

Thymoma is the most common mediastinal tumor. They have varied presentation ranging from asymptomatic incidental mediastinal masses to locally extensive tumor with compressive symptoms and distant metastases. They have frequent association with various paraneoplastic syndromes (PNS). The most common PNS associated with thymoma is myasthenia gravis (MG). Patients of thymoma with MG have a favourable outcome due to early disclosure of the disease. Histologically they are classified into five subtypes and Masaoka-Koga staging system is used for staging. Surgery, chemotherapy and radiotherapy play an important role along with anti-myasthenia drugs. This review would like to highlight the association of thymoma with MG and associated clinical and therapeutic issues.

State of the art: diagnostic tools and innovative therapies for treatment of advanced thymoma and thymic carcinoma

In this review article, state-of-the-art diagnostic tools and innovative treatments of thymoma and thymic carcinoma (TC) are described with special respect to advanced tumour stages. Complete surgical resection (R0) remains the standard therapeutic approach for almost all a priori resectable mediastinal tumours as defined by preoperative standard computed tomography (CT). If lymphoma or germ-cell tumours are differential diagnostic considerations, biopsy may be indicated. Resection status is the most important prognostic factor in thymoma and TC, followed by tumour stage. Advanced (Masaoka-Koga stage III and IVa) tumours require interdisciplinary therapy decisions based on distinctive findings of preoperative CT scan and ancillary investigations [magnetic resonance imaging (MRI)] to select cases for primary surgery or neoadjuvant strategies with optional secondary resection. In neoadjuvant settings, octreotide scans and histological evaluation of pretherapeutic needle biopsies may help to choose between somatostatin agonist/prednisolone regimens and neoadjuvant chemotherapy as first-line treatment. Finally, a multimodality treatment regime is recommended for advanced and unresectable thymic tumours. In conclusion, advanced stage thymoma and TC should preferably be treated in experienced centres in order to provide all modern diagnostic tools (imaging, histology) and innovative therapy techniques. Systemic and local (hyperthermic intrathoracic chemotherapy) medical treatments together with extended surgical resections have increased the therapeutic options in patients with advanced or recurrent thymoma and TC.

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.

Radical surgical resection of advanced thymoma and thymic carcinoma infiltrating the heart or great vessels with cardiopulmonary bypass support

Background

Radical surgical resection of advanced thymic tumors invading either the heart or great vessels facing towards the heart is uncommonly performed because of the potential morbidity and mortality. To achieve a complete tumor resection, the use of cardiolpulmonary bypass (CPB) support might be necessary.

Methods

Retrospective analysis of the results in six patients, who underwent radical tumor resection with CBP support.

Results

Mean age was 46 years (27 to 66 years) and five patients were male. Tumor infiltration of the heart or the great vessels was evident in all patients. Five patients underwent induction therapy. Two patients were operated in complete cardioplegic arrest (antegrade cerebral perfusion: n = 1). Arterial cannulation of the ascending aorta (n = 5) or the femoral artery (n = 1) and venous cannulation of the right atrium (n = 4) or the femoral vein (n = 2) were performed. Resection of the left brachiocephalic vein (n = 6), resection of the superior caval vein (n = 2), the ascending aorta (n = 1) and the complete aortic arch with outgoing branches (n = 1) were performed. A macroscopic complete resection (R0/R1) was achieved in five patients, whereas one patient was resected incompletely (R2). In-hospital mortality was 0 %. Three (50 %) patients needed operative revision (hematothorax: n = 2, chylothorax: n = 1). All patients had a complicated postoperative course and developed respiratory insufficiency.

Conclusions

Locally advanced thymoma/thymic carcinoma invading the heart or great vessels can be treated with radical surgical resection alongside with increased perioperative morbidity. The usage of CBP improves the chance of complete tumor resection in selected patients and might lead to a prolonged survival.

Stage-based treatment for thymoma in due consideration of thymectomy: a single-center experience and comparison with the literature

Background

Thymomas represent an uncommon and heterogeneous group of intrathoracic malignancies which require different treatments corresponding to their individual tumor stage. The objective of this study was to review the efficacy of our applied stage-based treatment for thymoma in due consideration of thymectomy.

Methods

This is a single-center, institutional review board-approved retrospective study of 50 consecutive patients with thymoma treated at our division within 10 years.

Results

There were 29 women (58 %) and 21 men (42 %), mean age 58.3 years. Twenty nine (58 %) had clinical symptoms and 14 (28 %) had myasthenia gravis. Forty-five patients (90 %) underwent thymectomy and complete resection was done in 42 cases (93.3 %). Histologic results were 6 subtype A, 5 AB, 8 B1, 12 B2, 12 B3, and 7 C. The Masaoka staging system revealed 20 stage I, 18 stage II, 6 stage III, and 6 stage IV. Two patients had neoadjuvant therapy and 25 received postoperative treatment. Five (11.1 %) had tumor recurrence, treated with re-resection. The 5-year disease-free survival was 91.5 %. Two patients died of tumor progression and three died of other causes (10 %). The 5-year overall survival was 82.3 % and the median survival time was 92.1 months. The 5-year survival rate after thymectomy was 87.2 % and the median survival was 92.1 months.

Conclusions

Complete resection still remains the mainstay in the treatment of non-metastatic thymoma and should be performed whenever feasible. Close multidisciplinary teamwork is mandatory to optimize the neurologic outcome and to prolong postoperative survival.

Outcomes of Thymoma Treated with Multimodality Approach: A Tertiary Cancer Center Experience of 71 Patients

Aims

To explore the demographics and clinical outcome of patients with thymoma treated with a multimodality approach at our institute.

Methods

A total of 71 patients with thymoma (Masaoka stage II-IV and WHO subtype AB-B3) treated from 1999-2013 were included in this retrospective analysis. Age, stage, WHO subtypes, details of surgery, radiotherapy, and chemotherapy were noted. Progression-free survival (PFS) was estimated using Kaplan-Meier method and SPSS (version 21.0) was used for statistical analysis.

Results

Male:female ratio was 56:15 with median age at presentation of 41 years. Stage-wise distribution was 6:46:19 for stage II, stage III, and stage IV, respectively. A total of 31 patients (44%) had associated myasthenia gravis and 3 had pure red cell aplasia. A total of 57 patients (80%) underwent radical thymectomy and all of these patients received adjuvant radiotherapy. A total of 15 patients and 7 patients received adjuvant chemotherapy and neoadjuvant chemotherapy, respectively. At median follow-up of 19.3 months (range 7.9-72.3 months), 2-year and 3-year PFS rate for the entire cohort was 78.3% and 57.1%, respectively. On univariate analysis, surgery (hazard ratio [HR] 3.881; 95% confidence interval [CI] 1.784-19.220; p = 0.006) and stage (HR 5.457; 95% CI 1.567-18.996; p = 0.0001) were significant prognostic factors and association with myasthenia gravis (HR 0.404; 95% CI 0.151-1.078; p = 0.078) trended towards better PFS. Stage retained its prognostic significance (HR 5.501; 95% CI 2.076-14.573; p = 0.0006) on multivariate analysis.

Conclusions

Multimodality management of locally advanced thymoma yields decent survival outcomes. Masaoka stage is an independent prognostic factor for survival and radical surgery should be contemplated in all cases of locoregionally limited thymoma.

Successful Pregnancies after the Treatment of a Thymic Carcinoid

The present report describes the case of a woman diagnosed with an adrenocorticotropic hormone- (ACTH-) secreting thymic carcinoid associated with Cushing's syndrome. Treatment consisted of tumour resection and 131-I-meta-iodobenzylguanidine (MIBG) therapy. In spite of her iatrogenic menopausal state she twice became pregnant and delivered two healthy babies but developed recurrences during both pregnancies. The last recurrence presented as a primary breast cancer. Despite poor prognosis our patient survived for eleven years. To our knowledge this is the first report of successful pregnancy and delivery in a patient with a thymic carcinoid.

Patterns and predictors of recurrence after radical resection of thymoma

BACKGROUND

Recurrence of thymomas even after complete resection is common, but the relapse patterns remain controversial. This study aimed to define the patterns and predictors of relapse after complete resection of thymoma.

METHODS

A single-institution retrospective study was performed with 331 patients who underwent radical resection of thymoma between 1991 and 2012.

RESULTS

After a median follow-up of 59 months, the recurrence rate was 6.9% (23/331). Relapse occurred in 23 patients with the pleura (14) and tumor bed (6) as the most common sites of recurrence. According to the definitions of the International Thymic Malignancy Interest Group, 10 (43.5%) patients had local relapse, 15 (65.2%) had regional relapse, 10 (43.5%) had distant relapse. The difference in survival following relapse between lung and regional relapse was statistically significant (P=0.027) but that between lung and distant relapse was not (P=0.808). The recurrence rates correlated with the initial Masaoka stage. Further, recurrence also correlated with World Health Organization (WHO) tumor type. The recurrence-free survival rates in patients with tumor size ⩾8 cm were worse than those of patients with tumor size <8 cm (P=0.007). Tumor size was also correlated with stage (r=0.110). As tumor becomes larger, the stage is more advanced (P=0.023). Multivariate analysis showed that Masaoka stage (P=0.005), tumor size (P=0.033), and WHO histological type (P=0.046) were predictive factors of relapse.

CONCLUSION

Regional recurrence is the most common relapse pattern but local and distant relapse are also common. Advanced Masaoka stage, larger tumor size, and type B3 are risk factors of recurrence. Lung relapse should be considered distant relapse. Further, tumor size was correlated with Masaoka stage and therefore should be considered in the staging system.

Oncocytic carcinoma of the salivary gland with thymoma: A case report and review of the literature

Oncocytic carcinoma (OC) arising in the salivary gland is a very rare tumor with only 32 previously reported cases. In this report, we describe a novel case of oncocytic carcinoma with associated thymoma, which arose in the left parotid gland of a 66-year-old male with a history of a painless left parotid mass for 1 year. Oncocytes are large, polygonal cells that are characterized by marked cellular atypia, frequent mitoses, wide eosinophilic granular cytoplasm, a central nucleus and a prominent nucleolus. The follow-up data showed no evidence of recurrence and the patient is in a good health 20 months after the surgery. In the current case, the patient had not only OC but also thymoma, which is exceedingly rare and may represent the first documented case in the literature.

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.

The correlation of morphological features of chest computed tomographic scans with clinical characteristics of thymoma

OBJECTIVES

Chest computed tomography (CT) scanning has been widely utilized in thymoma identification and staging as well as in follow-up monitoring for recurrence. However, the relationship between some CT imaging features and pathological types, clinical stage, completeness of resection, or prognosis in thymoma has not been well explored.

METHODS

We retrospectively reviewed preoperative CT imaging for 238 thymoma patients, who had undergone thymectomy from October 2007 to December 2011. All CT parameters were assessed in each case based on clinical and pathological data. Survival analysis was performed by using the Kaplan-Meier and log-rank tests.

RESULTS

Tumour contours (P = 0.008), homogeneity (P = 0.009), degree of enhancement (P = 0.013), fat plane obliteration with adjacent structures (P < 0.001), the presence of mediastinal lymphadenopathy (P = 0.010), irregular infiltration into the lung (P = 0.012) and tumour shape (P = 0.007) were associated with the World Health Organization (WHO) histological classification. Lobulated or irregular tumour contours (P < 0.001), presence of calcifications (P = 0.002), infiltration of surrounding fat (P < 0.001), irregular infiltration into the lung (P < 0.001), irregular infiltration into vascular (P < 0.001), more abutment of vessels (P < 0.001) and pulmonary changes adjacent to the tumour (P < 0.001) were associated with the more advanced Masaoka-Koga clinical stage. Tumour contours (P < 0.001), infiltration of surrounding fat (P = 0.008), irregular infiltration into the lung (P < 0.001) and degree of abutment of vessel circumference (P = 0.001) were associated with completeness of resection. With multivariate analysis, no CT image features could reliably predict on the overall or disease-free survival rate.

CONCLUSIONS

CT imaging does have some features, which are significantly correlated with the WHO classification, the Masaoka-Koga clinical staging and the completeness of resection, although it has no definite role to evaluate preoperatively the survival rate of thymoma patients.

Adrenal insufficiency presenting as bilateral rigid auricles: a case report

Introduction

Stiff ears appear to be a warning sign for adrenal insufficiency. This remarkable and rare sign has not been described to present in adrenal insufficiency in the setting of critical care.

Case presentation

We present the case of a 68-year-old Caucasian male who underwent a thymoma resection and suffered from preoperative weight loss and lack of strength. The perioperative phase was characterised by hypotension and sputum stasis due to muscle weakness, which caused two readmissions to the intensive care unit. His physical examination showed two fully rigid auricles. In retrospect, our patient suffered from secondary adrenal insufficiency and hypogonadism.

Conclusions

The bilateral rigid auricles appeared to be a warning sign for adrenal insufficiency. This remarkable sign is easily checked, and should prompt a higher index of suspicion towards adrenal insufficiency and other hormonal deficiencies.

Management of thymic tumors: a European perspective

Thymic tumors are rare mediastinal tumors, which are considered as orphan diseases due to their low prevalence. The most recent histologic classification divides thymic tumors into thymomas, thymic carcinomas (TC) and neuroendocrine thymic tumors (NETT). Until recently, clinical research on thymic tumors has been primarily represented by single-institution experiences usually scattered over a long time period in order to accumulate a sufficient number of patients for clinical analysis. Europe has played a pivotal role in the advancement of the clinical research on thymus in the past years. In the last decade, there has been an increased interest in thymic malignancies in the scientific community. The European Society of Thoracic Surgeons (ESTS), the most representative society of general thoracic surgeons in the world, established a dedicated thymic working group in 2010 with the intent to provide a platform among ESTS members with a specific interest in thymic malignancies. The present review is intended to provide, through the description of the activity of the ESTS thymic working group and its published results, an overview of the European contribution to the thymic research. A brief overview of the state-of-the-art of clinical presentation, diagnosis, staging and histologic classification of thymic tumors is also provided, along with the most recent therapeutic advancements.

Therapy for thymic epithelial tumors

Thymoma is the most common tumor of the anterior mediastinum. This tumor is associated with unique paraneoplastic syndromes. The rarity of this tumor has somewhat obscured the optimal treatment for this disease. The World Health Organization classification system, which published in 1999, appears to be an advance in our understanding of thymoma. The Masaoka classification is now the most widely accepted and is an excellent predictor of the prognosis of thymoma. Now the International Thymic Malignancy Interest Group is currently engaged in the development of a validated formal TNM classification system for thymic malignancies. The optimal treatment of thymoma is performed according to its clinical stage. Surgery remains the mainstay of treatment for thymic epithelial tumors. Minimally invasive surgery including thoracoscopic surgery and robotic surgery for stage I and II thymomas is increasing now. The value of postoperative radiotherapy in completely resected stage II or III tumors is questionable. As thymomas have a moderate response rate to chemotherapy or radiotherapy, multimodality therapy involving surgery, chemotherapy and radiotherapy appears to increase the rate of complete resection and survival in the advanced (stage III and IV) thymomas.

Clinicopathological analysis of thymic malignancies with a consistent retrospective database in a single institution: from Tokyo Metropolitan Cancer Center

BACKGROUND

Thymic epithelial tumors (TETs), which comprise thymoma and thymic carcinoma, are rare cancers with specific morphological and clinical features. Their clinical characteristics and outcomes have gradually been clarified by assessing large-scale, retrospective data obtained with international cooperation.

METHODS

The study is a retrospective review of 187 Japanese patients with TETs who attended our institution from 1976 to 2012. Relevant clinical features of patients with TETs and their tumors, including histology, staging, treatment strategies, and overall survival, were investigated. Differences in survival were assessed by the Kaplan-Meier method and uni- and multi-variate Cox proportional hazards regression analyses.

RESULTS

The 187 patients included 52 patients with stage I, 37 with stage II, 22 with stage III, and 76 with stage IVa/IVb tumors according to the Masaoka-Koga Staging System. As to histological type, five patients had type A, 33 type AB, 19 type B1, 39 type B2, and 15 type B3 thymomas, whereas 68 patients had thymic carcinoma, including 11 with neuroendocrine carcinomas according to the 2004 WHO classification. Either insufficient data were available to classify the tumors of the remaining eight patients or they had rare types. Immunological abnormalities were present in 26 patients, most of whom had thymomas (21.8% of the thymoma group). Most of the patients who presented with symptoms had myasthenia gravis or extensive thymic carcinoma. Secondary cancers were present in 25 patients (13.3%). The overall 5- and 10-year survival rates for thymoma were 85.4 and 71.5%, respectively, and those for thymic carcinoma were 33.8 and 2.3%, respectively. OS differed significantly between stage IVa thymomas and thymic carcinomas. The stage and whether the tumors were thymomas or thymic carcinomas were significant determinants of survival according to multivariate analysis.

CONCLUSION

The efficacy of treatments for thymoma and thymic carcinoma should be investigated separately because these tumors differ in their clinical features and prognosis.

Thymoma patients treated in a phase I clinic at MD Anderson Cancer Center: responses to mTOR inhibitors and molecular analyses

BACKGROUND

Thymomas and thymic carcinoma are rare tumors with no approved therapies. Our purpose was to analyze the molecular features and outcomes of patients referred to the Clinical Center for Targeted Therapy (Phase I Clinic).

METHODS

We retrospectively reviewed the medical records of consecutive referred patients with advanced/metastatic thymoma or thymic carcinoma

RESULTS

Twenty-one patients were identified (median age 52 years; 10 women; median number of prior systemic therapies = 2). Six of 10 patients (60%) treated with mTOR inhibitor combination regimens achieved stable disease (SD) ≥12 months or a partial response (PR). For patients treated on mTOR inhibitor regimens (N = 10), median time to treatment failure (TTF) was 11.6 months versus 2.3 months on last conventional regimen prior to referral (p=0.024). Molecular analyses (performed by next generation sequencing in seven patients and single polymerase chain reaction (PCR)-based assays in an additional six patients) showed diverse actionable mutations: PIK3CA (1 of 12 tested; 8%); EGFR (1 of 13; 8%); RET (1 of 7; 14%); and AKT1 (1 of 7; 14%). Of two patients with PIK3CA or AKT1 mutations, one was treated with an mTOR inhibitor-based regimen and achieved 26% regression with a TTF of 17 months.

CONCLUSION

Patients with advanced/metastatic thymoma or thymic carcinoma demonstrated prolonged TTF on mTOR inhibitor-based therapy as compared to prior conventional treatment. Heterogeneity in actionable molecular aberrations was observed, suggesting that multi-assay molecular profiling and individualizing treatment merits investigation.

Recurrence after thymoma resection according to the extent of the resection

Background

Complete resection of the thymus is considered appropriate for a thymoma resection because any remaining thymic tissue can lead to local recurrence. However, there are few studies concerning the extent of thymus resection. Therefore, we conducted a retrospective study to investigate whether recurrence following thymoma resection correlated to the extent of resection.

Methods

Between 1986 and 2011, a total of 491 patients underwent resection of thymic epithelial tumors with curative intent. Of those, we excluded patients with an undetermined World Health Organization (WHO) histologic type, patients with type C thymoma, and patients who underwent incomplete resection (n = 21). The remaining 342 patients were reviewed retrospectively and compared recurrence according to the extent of resection.

Results

Extended thymectomy was performed in 239 patients (69.9%) and limited thymectomy was performed 103 patients (30.1%). In the extended thymectomy group, 29 recurrences occurred, and in the limited thymectomy group, 10 recurrences occurred.

Comparing rates of freedom from recurrence between two groups, there was no significant statistical difference in total recurrence (p =0.472) or local recurrence (p =0.798). After matching patients by stage and tumor size, there was no significant difference in freedom from recurrence between the two groups (p = 0.162). Additionally, after adjusting for histologic type and MG, there was also no significant difference (p = 0.125) between groups.

Conclusions

No difference in the rate of recurrence was observed in patients following limited thymectomy compared with extended thymectomy.

Outcome in excised thymomas: role of prognostic factors and impact of additional malignancies on survival

Background and aims:

Although the management of thymomas has been extensively evaluated, the value of prognostic factors in the outcome of these patients remains unclear.

Methods and results:

The medical records of all patients who underwent resection of thymoma between January 1985 and September 2010 at a single thoracic unit were reviewed. Patients were followed up with reference to disease recurrence and development of additional malignancies (AM). Total thymectomy was performed in all 68 cases. Mean follow-up time was four years. Mean survival was 63.9 months. Mean disease-free interval was 13 months. Factors affecting prognosis were Masaoka staging and WHO histological sub-type. Patients with thymomas had a higher risk of developing AM when compared with a control population of individuals with other tumours ( p = 0.0002). Among thymomas, the cortical subtype was associated with a higher risk of AM ( p = 0.047) and mortality ( p = 0.001).

Conclusions:

This data confirms that Masaoka staging and WHO histologic sub-type are the most important prognostic factors in patients with thymoma. Moreover, thymomas predominantly arising from the thymic cortex are associated with a higher risk of developing other malignancies and with poorer survival. The cortical origin of thymoma could therefore be considered as a significant prognostic factor.

Cixutumumab for patients with recurrent or refractory advanced thymic epithelial tumours: a multicentre, open-label, phase 2 trial

BACKGROUND

No standard treatment exists for refractory or relapsed advanced thymic epithelial tumours. We investigated the efficacy of cixutumumab, a fully human IgG1 monoclonal antibody targeting the insulin-like growth factor 1 receptor in thymic epithelial tumours after failure of previous chemotherapy.

METHODS

Between Aug 25, 2009, and March 27, 2012, we did a multicentre, open-label, phase 2 trial in patients aged 18 years or older with histologically confirmed recurrent or refractory thymic epithelial tumours. We enrolled individuals who had progressed after at least one previous regimen of platinum-containing chemotherapy, had an Eastern Cooperative Oncology Group performance status of 0 or 1, and had measurable disease and adequate organ function. Eligible patients received intravenous cixutumumab (20 mg/kg) every 3 weeks until disease progression or development of intolerable toxic effects. The primary endpoint was the frequency of response, analysed on an intention-to-treat basis. We also did pharmacodynamic studies. This trial is registered with ClinicalTrials.gov, number NCT00965250.

FINDINGS

49 patients were enrolled (37 with thymomas and 12 with thymic carcinomas) who received a median of eight cycles of cixutumumab (range 1-46). At the final actuarial analysis when follow-up data were updated (Nov 30, 2012), median potential follow-up (from on-study date to most current follow-up date) was 24·0 months (IQR 17·3-36·9). In the thymoma cohort, five (14%) of 37 patients (95% CI 5-29) achieved a partial response, 28 had stable disease, and four had progressive disease. In the thymic carcinoma cohort, none of 12 patients (95% CI 0-26) had a partial response, five had stable disease, and seven had progressive disease. The most common grade 3-4 adverse events in both cohorts combined were hyperglycaemia (five [10%]), lipase elevation (three [6%]), and weight loss, tumour pain, and hyperuricaemia (two each [4%]). Nine (24%) of 37 patients with thymoma developed autoimmune conditions during treatment (five were new-onset disorders), the most common of which was pure red-cell aplasia. Two (4%) patients died; one was attributed to disease progression and the other to disease-related complications (respiratory failure, myositis, and an acute coronary event), which could have been precipitated by treatment with cixutumumab.

INTERPRETATION

Cixutumumab monotherapy is well-tolerated and active in relapsed thymoma. Development of autoimmunity during treatment needs further investigation.

FUNDING

Division of Cancer Treatment and Diagnosis at the National Cancer Institute (National Institutes of Health), ImClone Systems.

Radiotherapy for thymic carcinoma: adjuvant, inductive, and definitive

Although historically thymoma and thymic carcinoma have been treated surgically, radiation therapy also has an important role, either as postoperative therapy to reduce the risk of mediastinal recurrence or as part of definitive treatment for patients who cannot undergo surgery. Induction chemotherapy and molecular targeted agents may also be appropriate for thymic carcinoma, the behavior of which resembles non-small-cell lung carcinoma more than that of thymoma or invasive thymoma and is increasingly being treated like lung cancer. We present here a review of current therapies for thymic malignancies and briefly discuss the potential benefits from novel technologies for such treatment.

Methylation and expression profiles of MGMT gene in thymic epithelial tumors

OBJECTIVES

A key challenge in diagnosis and treatment of thymic epithelial tumors (TET) is in improving our understanding of the genetic and epigenetic changes of these relatively rare tumors.

METHODS

Methylation specific PCR (MSP) and immunohistochemistry were applied to 66 TET to profile the methylation status of DNA repair gene O6-methylguanine DNA methyltransferase (MGMT) and its protein expression in TET to clarify the association between MGMT status and clinicopathological features, response to chemotherapy and overall survival.

RESULTS

MGMT methylation was significantly more frequent in thymic carcinoma than in thymoma (17/23, 74% versus 13/44, 29%; P<0.001). Loss of expression of MGMT protein was significantly more frequent in thymic carcinoma than in thymoma (20/23, 87% versus 10/44, 23%; P<0.0001). There is a significant correlation between of MGMT methylation and loss of its protein expression (P<0.0003). MGMT methylation and loss of expression were significantly more frequent in advanced thymic epithelial tumors (III/IV) than in early tumors (I/II).

CONCLUSION

MGMT methylation plays a soul role in development of TET, especially in thymic carcinoma. Therefore, translation of our results from basic molecular research to clinical practice may have important implication for considering MGMT methylation as a marker and a target of future therapies in TET.

Thymic neoplasms: an update on the use of chemotherapy and new targeted therapies. A literature review

Thymic malignancies represent a wide range of clinical, histological and molecular entities, with probably considerable heterogeneity even among tumors of the same histotype. Systemic chemotherapy with cisplatin-based regimens continues to represent the standard of care in metastatic or inoperable refractory/recurrent diseases and ADOC regimen (including cisplatin, doxorubicin, vincristine and cyclophosphamide) demonstrated the longer overall response rate and median survival in the first line setting, although no randomized trial is available; and there is still a lack of standard treatment after first-line failure. To date research efforts are focused on translational studies on molecular pathways involved in thymic tumors carcinogenesis, aimed to better understand and predict the efficacy of chemotherapy and targeted therapy. Recent molecular characterization includes identification of a number of oncogenes, tumor suppressor genes, chromosomal aberrations, angiogenic factors, and tumor invasion factors involved in cellular survival and proliferation and in tumor growth. The use of biologic drugs is currently not recommended in a routine practice because there are limited data on their therapeutic role in thymic epitelial tumors. Because of the lack of data from adequate-sized, prospective trials are required for validation and the enrolment of patients with advanced disease into available clinical trials has to be encouraged.

Porcine dermal collagen (permacol) for sternal reconstruction

In chest wall reconstruction after wide chest wall resection, the use of a musculocutaneous flap or prosthetic materials is inevitable for maintaining thoracic movement and a closed pleural cavity. We report a case of a 63-year-old male with a large invasive thymic carcinoma in the anterior mediastinum. The mass measured 6.8 cm and involved the sternum, left side of the parasternal area, ribs, and intercostal muscles. The patient underwent subtotal sternectomy, radical thymectomy, and reconstruction with biological mesh (Permacol). Successful chest wall reconstruction without any other complications was achieved, demonstrating the effectiveness of Permacol.