Clinical characteristics and outcomes for patients with thymic carcinoma: evaluation of Masaoka staging

Chemotherapy versus chemotherapy plus immune checkpoint inhibitors for the first-line treatment of unresectable thymic carcinoma: A multicenter retrospective study

Thymic carcinoma (TC) is a rare malignant tumor with a poor prognosis, and there is currently limited data on the use of immunotherapy in patients with unresectable TC. In this study, data of patients with unresectable TC diagnosed from January 2017 were retrospectively collected from multiple centers. Treatment response, progression-free survival (PFS), overall survival (OS), survival-independent prognostic factor, and adverse events (AEs) were further analyzed. As a result, a total of 93 patients with unresectable TC were enrolled, of which 54 received first-line chemotherapy, and 39 received chemotherapy plus immune checkpoint inhibitors (ICIs). The objective response rate was 50% (27/54) in the chemotherapy group and 76.9% (30/39) in the chemotherapy plus ICIs group. The chemotherapy plus ICIs group achieved significant median PFS benefit (8.8 vs. 34.9 months, p < .001) and median OS benefit (41.8 months vs. not reached, p = .025). Multivariate analysis showed that ICIs and local therapy were independent prognostic factors for PFS. In addition, 17 patients developed immune-related AEs (IRAEs), of which 15 (38.5%) had Grade 1 or 2 IRAEs and 2 (5.1%) had Grade 3 IRAEs in the chemotherapy plus ICIs group. In conclusion, the efficacy of chemotherapy plus ICIs is superior to chemotherapy, and the adverse effects are manageable in patients with unresectable TC.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Evolving treatment landscape in thymic epithelial tumors: From mechanism to therapy

Thymic epithelial tumors (TETs) are rare neoplasms of the anterior mediastinum that arise from thymic epithelial cells. Although surgery is the preferred treatment for resectable TETs, the options for unresectable or recurrent advanced-stage TETs are limited beyond platinum-based chemotherapy. The evolving landscape of TET treatments is marked by significant advancements in targeted therapies and immunotherapies, particularly with anti-angiogenic agents and immune checkpoint inhibitors (ICIs). While monotherapies demonstrated certain efficacy, the development of combination strategies is vital for improving patient outcomes. This review consolidates progress in anti-angiogenic therapies and ICIs, emphasizing the evolution of combination therapies of TETs. Furtherly, we particularly discuss new first-line strategies based on these advancements and emphasizes exploring novel treatments like antibody-drug conjugates, immunomodulatory drugs and cytokine-based agents for TETs. Mechanistically, the molecular features of TETs integrated with clinical diagnosis and targeted therapy, and immunophenotyping of TETs along with its impact on the efficacy and safety of immunotherapy are discussed. Thus, this review systemizes the development in the treatment landscape of TETs, integrating the corresponding molecular and immune mechanisms, aiming to provide new references for the treatment of TETs.

Narrative review of indication and management of induction therapy for thymic epithelial tumors

Background and Objective

Thymic epithelial tumors (TETs) are rare and originate from the thymus. Thymomas and thymic carcinomas are the most common types of TETs. Of the two, thymomas tend to have a better prognosis and are typically localized, while thymic carcinomas have a worse prognosis and are more likely to spread. The Masaoka-Koga staging system is commonly used to determine the stage of TETs. Complete resection is the preferred treatment option, but treating locally advanced TETs can be challenging due to the invasion of surrounding structures. In such cases, induction therapy is administered to downstage the tumors and enable complete resection. We conducted this narrative review to evaluate the current progress in induction treatment for locally advanced TETs.

Methods

The literature search was performed using PubMed and Web of Science in June 2023. Prospective and retrospective published trials, systemic and narrative reviews, and meta-analyses were included.

Key Content and Findings

Induction chemotherapy is often used as a preoperative treatment for advanced TETs. Platinum and anthracycline-based chemotherapy regimens are commonly used for treating thymoma (response rate, 37-100%), and complete resection is highly common. Treatment with cisplatin and etoposide, carboplatin and paclitaxel, docetaxel and cisplatin have also demonstrated effectiveness, particularly in patients with thymic carcinoma or thymoma who cannot tolerate anthracycline regimens. The emergence of immunotherapy and targeted therapies may provide additional options for the treatment of TETs. Induction radiotherapy, as the sole treatment for TETs, is not widely practiced due to concerns about potential damage to surrounding tissues. However, combining modern radiation techniques with surgery has shown promising results in selected patients. Induction chemoradiotherapy, which combines chemotherapy and radiation, is an emerging approach for treating TETs. Despite the lack of randomized trials comparing chemotherapy with chemoradiotherapy, concurrent chemoradiation with radiation doses of 40-50 Gy is often considered the optimal induction therapy for thymic carcinoma patients or in more advanced special situations, such as great vessel invasion.

Conclusions

Overall, the optimal treatment for locally advanced TETs remains controversial. Induction therapy, including chemotherapy, radiotherapy, or chemoradiotherapy, is administered to downstage tumors and improve resectability. The choice of treatment depends on individual factors such as tumor stage, histology, and overall patient condition. However, further research and well-designed studies are needed to determine the most effective treatment strategies for locally advanced TETs.

China Anti-Cancer Association Guidelines for the diagnosis, treatment, and follow-up of thymic epithelial tumors (2023)

Background

Thymic epithelial tumors (TETs) are a relatively rare type of thoracic tumors with higher incidence in Asians. The diagnosis and treatment pattern has long been based mainly on clinical experience and expert consensus. In recent years, with an increasing number of TETs detected in physical examinations, there is an urgent need to develop the guidelines that apply to the Chinese population. Thus, we intend to develop a holistic integrative guideline for TETs.

Methods

Under the leadership of the Chinese Anti-Cancer Association (CACA) Mediastinal Tumor Committee, a multidisciplinary guideline development group was established. Systemic literature review and two rounds of questionnaires regarding key clinical issues were carried out. The grading of recommendations assessment, development and evaluation (GRADE) approach was used to rate the quality of evidence and the strength of recommendations.

Results

The CACA guideline provides recommendations for the clinical differential diagnosis of anterior mediastinal lesions, management of asymptomatic small anterior mediastinal nodules, pathological classification and staging systems of TETs, as well as principles of surgery, neoadjuvant and adjuvant therapies, systemic therapies for advanced TETs, and follow-up strategies after surgical resection.

Conclusions

This guideline provides holistic integrative management strategies for TETs and would be a useful tool for clinicians on decision-making.

Update on thymic epithelial tumors: a narrative review

Background and Objective

Thymoma, thymic carcinoma and thymic neuroendocrine tumors originate from the epithelial cells of the thymus and account for the thymic epithelial tumors (TETs). Although TETs are uncommon, they are the most frequent tumor type in the anterior mediastinum. Multidisciplinary approach is essential for their correct management. The aim of the present review is to summarize the update management for TETs.

Methods

For this review, we searched in Excerpta Medica database (EMBASE) and MEDLINE until 6 September 2023. The terms used in the search included thymoma, thymic carcinoma, thymic epithelial tumors, management, immunotherapy, multiple tyrosine kinases inhibitors.

Key Content and Findings

The therapeutic approach is based on histology and tumor stage and may involve surgery with or without neoadjuvant or adjuvant treatment. In the metastatic setting, platinum-based chemotherapy is the standard of care and patients who do not respond to first-line treatment have limited treatment options mainly because of the poor efficacy shown in subsequent lines of therapy.

Conclusions

Future research should focus on identifying predictive biomarkers for patients with TETs, and should implement multicenter collaborations and appropriate clinical trials tailored for rare tumor types. Immune check point inhibitors, mammalian target of rapamycin (mTOR) and antiangiogenic multikinase inhibitors have also been studied in this clinical setting.

Postoperative radiotherapy for thymic epithelial tumors: a narrative review

Background and Objective

Thymic epithelial tumors (TETs), including thymomas and thymic carcinomas, are rare mediastinal tumors. Surgical resection is the treatment strategy for resectable TETs, and postoperative radiotherapy (PORT) is administered to improve local control in patients with a high risk of recurrence. The rarity of TETs has led to a lack of randomized controlled trials, and the current indications for PORT rely largely on retrospective studies. This review analyzes the literature on TETs, highlighting PORT, to guide current research and future investigations.

Methods

Studies that focused on TETs, addressed topics on PORT, and had English abstracts accessible online were eligible for inclusion in our review. We excluded case reports or review articles, articles written in languages other than English, articles published >30 years ago, and articles concerning thymic neuroendocrine tumors.

Key Content and Findings

Masaoka or Masaoka-Koga staging, World Health Organization (WHO) histological subtype, and resection status indicate PORT in resected TETs. Current literature suggests that PORT does not improve overall survival in stage I-IIA TETs, with inconsistent results for stage IIB-III TETs. Patients with a higher risk, such as carcinomas or WHO type B, might benefit from PORT if they do not develop distant metastasis. Determining which patients will benefit most from PORT requires further investigation. For recurrent TETs, the significance of applying PORT is unclear because available data are limited. Given the long-term survival of TETs, late toxicities, including radiation pneumonitis, radiation-induced cardiotoxicities, and secondary malignancies, must be addressed. Proton beam radiotherapy might reduce toxicities by sparing organs at risk compared to conventional photon beam radiotherapy. The use of high-precision radiation therapy, along with emerging immunotherapy, targeted therapy, and minimally invasive surgery, could improve TET outcomes.

Conclusions

This review consolidates the literature on PORT for TETs, factoring in the Masaoka-Koga staging, WHO histological subtypes, and resection status. Varying results regarding PORT efficacy have led to an undefined strategy for stage IIB-III TETs. Although advanced radiotherapy techniques promise to reduce radiation-induced toxicities, further research is needed to investigate the efficacy of PORT and combination therapy.

Thymic epithelial tumours: histopathological classification and differential diagnosis

The epithelial and lymphoid compartments of the thymus can give rise to a wide variety of tumours, including thymomas, thymic carcinomas, lymphoreticular proliferations, germ cell tumours, and sarcomas. While some of these have close similarity to their counterparts in other organs, both in terms of histology and immunohistochemistry, as well as molecular features, others are unique to the thymus. The epithelial tumours, which can develop in the thymus, will be discussed in this review, with a particular emphasis on resolving differential diagnosis by means of morphology, immunohistochemical profiles, and molecular diagnostics.

Effect of open versus video-assisted thoracoscopy on perioperative outcomes and survival for cases of thymic carcinomas and thymic neuroendocrine tumors

BACKGROUND

The oncology-related indices between open and video-assisted thoracoscopic surgery (VATS) procedures for thymic carcinomas (TCs) and thymic neuroendocrine tumors (TNETs) remain unclear.

METHODS

Propensity score matching (PSM) and multivariate Cox proportional risk models were used to evaluate the perioperative outcomes and survival rates of patients undergoing open and VATS for TCs and TNETs at the Second Affiliated Hospital of Air Force Military Medical University Hospital, between 2009 and 2018.

RESULTS

Of the total 126 cases of TCs and TNETs, VATS treatment was used in 39 (30.9%). Advanced age and Masaoka-Koga staging were found to be independent prognostic factors for both TCs and TNETs, through a multifactorial Cox regression analysis. There was no significant difference in survival between the VATS and open groups before and after PSM; however, the VATS group had better perioperative-related indicators. There were no significant differences between the groups in terms of mortality at 30 days, mortality at 90 days, R0 resection rate, and 5-year survival rate (67.5% vs. 58.5% [P = 0.260] in the VATS group compared to the open group, in a PSM analysis of the 27 VATS and 27 open groups). Compared to the open group, the VATS group had a shorter length of hospital stay (13 days vs. 16 days, P = 0.015), a shorter level I care (0 days vs. 1 day, P = 0.016), and less intraoperative bleeding (50 mL vs. 300 mL, P < 0.001).

CONCLUSIONS

In this single-center retrospective study of TCs and TNETs, survival rates were comparable between the VATS group and the open group, and the VATS group showed improved perioperative-related parameters.

Thymoma and Thymic Carcinoma: Surgical Resection and Multidisciplinary Treatment

Thymoma and thymic carcinoma are the most common tumors of the anterior mediastinum and a relatively rare type of thoracic cancer. The prerequisite for surgery is clinical staging and operative evaluation, both of which are based on medical imaging. The best strategy for treating a thymic epithelial tumor is surgical resection of the organ and surrounding tissue. Thymectomy modalities vary, including open surgery and minimally invasive surgery, and surgeons have used various innovations to better meet the needs of the procedure; therefore, it is critical to select the appropriate procedure based on the patient's characteristics. Evaluation of resectability is the first step of surgical resection for thymic tumors without distant metastasis. The decision regarding unresectability should be made carefully. During subsequent chemotherapy or chemoradiotherapy, reevaluation of whether an area is resectable or not remains essential. Despite numerous technological advances in the surgical treatment of thymic tumors, several contentious issues remain, including the selection of surgical approaches for difficult cases, the selection of video-assisted thoracoscopic approaches, the evaluation of resectability, minimally invasive surgery for locally advanced thymic tumors, lymphadenectomy in thymic tumors, neoadjuvant therapy for thymic tumors, debulking surgery, and salvage surgery. In solving these problems, the surgeon's judgment, surgical experience, and surgical skills are especially important.

Chinese expert consensus on the diagnosis and treatment of thymic epithelial tumors

Thymic epithelial tumors (TETs) are a relatively rare type of thoracic tumor, accounting for less than 1% of all tumors. The incidence of TETs is about 3.93/10000 in China, slightly higher than that of European and American countries. For resectable TETs, complete surgical resection is recommended. Radiotherapy or chemotherapy may be used as postoperative adjuvant treatment. Treatment for advanced, unresectable TETs consist mainly of radiotherapy and chemotherapy, but there is a lack of standard first- and second-line treatment regimens. Recently, targeted therapies and immune checkpoint inhibitors have shown promising outcomes in TETs. Based on the currently available clinical evidences and the opinions of the national experts, the Thymic Oncology Group of Yangtze River Delta Lung Cancer Cooperation Group (East China LUng caNcer Group, ECLUNG; Youth Committee) established this Chinese expert consensus on the clinical diagnosis and treatment of TETs, covering the epidemiology, diagnosis, treatment, prognosis and follow-up of TETs.

Efficacy and safety of treatments for advanced thymic carcinoma after failure of first-line platinum-based chemotherapy: A systematic literature review and meta-analysis

Thymic carcinoma (TC) is a rare cancer and patients failing initial chemotherapy (relapse/refractory) face limited therapeutic options given no approved options or consensus standard of care. This study aimed to identify and summarize clinical outcomes of all regimens evaluated in clinical trials of relapsed or refractory patients. Interventional trials enrolling advanced TC patients who failed first-line chemotherapy and reported outcomes in this group were eligible for inclusion in our systemic literature review (SLR). Between-study heterogeneity was assessed to determine the feasibility of pooling specific studies and treatments. Objective response rate (ORR), overall survival (OS), progression-free survival (PFS), and duration of response (DOR) endpoints were of interest for meta-analysis. Nineteen trials were identified in the SLR. Three trials with one or two TC patients were removed from our assessment to reduce publication bias. Response rates among studies with at least ten TC patients varied from 9 % to 38 %. Pooled ORRs in patients receiving S-1 (46 patients), sunitinib (46 patients), or pembrolizumab (66 patients) were 28 %, 24 %, and 21 %, respectively. Prolonged duration of response with pembrolizumab was observed with a pooled median of 23.8 months (95 % confidence interval [CI]: 12, not reached). Median PFS of five months or greater was reported in patients treated with sunitinib, lenvatinib, pembrolizumab, capecitabine + gemcitabine, everolimus, or S-1. Median OS of 20 months or greater was reported in trials evaluating S-1 or pembrolizumab; this endpoint was not reached in trials evaluating lenvatinib, regorafenib, or sunitinib. Generalizability of treatment effects is challenging in the research of rare diseases and meta-analysis of clinical outcomes may help to increase precision and relevance of results to the larger TC population. Our study found limited treatment options upon relapse, demonstrating a need for further investigations into novel therapeutics and well-powered clinical trials to better inform on optimal treatments.

Good Response of Advanced Thymic Carcinoma with Low PD-L1 Expression to Chemotherapy plus Pembrolizumab as First-Line Therapy and to Pembrolizumab as Maintenance Therapy: A Case Report

Thymic carcinoma is a rare malignant tumor with a poor prognosis. No standard treatment is currently available. The present case was a 64-year-old male smoker with no symptoms referred to our hospital because of abnormal chest radiological findings. The CT study showed a tumor between the anterior mediastinum and the right lung upper lobe, multiple nodular shadows along the right pleura, and pleural effusion. A CT-guided needle biopsy revealed squamous cell carcinoma. However, the differential diagnosis between thymic carcinoma and primary lung cancer was difficult. Treatment with carboplatin, nanoparticle albumin-bound paclitaxel, and pembrolizumab was initiated. The CT scan showed tumor shrinkage and good clinical response after four treatment cycles. Therapy was switched to maintenance therapy with pembrolizumab alone. Imaging studies showed further tumor shrinkage after twelve cycles of maintenance therapy with pembrolizumab. Sixteen cycles of maintenance therapy were continued without performance status deterioration. An abnormal radiological finding was detected after a twelve-month exacerbation-free period. The diagnosis was thymic carcinoma. Treatment with lenvatinib was initiated, and tumor-size reduction was observed. This is the first report of a case showing a successful maintenance therapy with pembrolizumab after effective first-line therapy with a combination of carboplatin-based chemotherapy plus pembrolizumab in advanced thymic carcinoma.

Rare solitary splenic metastasis from a thymic carcinoma detected on fluorodeoxyglucose-positron emission tomography: A case report

BACKGROUND

Thymic carcinoma is a rare, aggressive tumor arising from the thymus. In less than 7% of patients with thymic carcinoma, extrathoracic metastases occur in the extrathoracic lymph nodes, liver, and bone. Isolated splenic metastasis can occur but is very uncommon. To date, only 2 cases of splenic metastases from thymic carcinoma have been reported.

CASE SUMMARY

A 45-year-old man presented with chronic cough, dyspnea, persistent hoarseness and unintentional weight loss 17 kgs in 6 mo. Neck magnetic resonance imaging revealed a large, lobulated, soft-tissue mass measuring 5.4 cm × 6.6 cm × 3.8 cm which involved the left superior mediastinum and supraclavicular fossa. Chest computed tomography (CT) revealed a confluent and lobulated soft tissue mass encased the right brachiocephalic artery, right and left carotid arteries, and left subclavian artery in the mediastinum. A fluorodeoxyglucose-positron emission tomography was arranged for malignancy survey. The image revealed intense fluorodeoxyglucose avidity in a soft tissue lobulated mass occupying the superior mediastinum, over the cystic lesion in the spleen and in few enlarged nodules over the left supraclavicular fossa. CT-guided biopsy of the thymic mass and the ultrasound-guided biopsy of the splenic lesion were consistent with a thymic carcinoma with splenic metastasis. The patient was diagnosed of thymic carcinoma, cT2N2M1b, stage IVb.

CONCLUSION

A fluorodeoxyglucose (FDG)-positron emission tomography (PET) scan can provide a useful diagnostic value in conjunction with pathological result in evaluating tumor staging. Our case emphasizes the utility of FDG-PET for metastasis detection in thymic carcinoma.

Thymic Carcinomas-A Concise Multidisciplinary Update on Recent Developments From the Thymic Carcinoma Working Group of the International Thymic Malignancy Interest Group

Thymic carcinomas are rare malignancies that in general arise in the prevascular (anterior) mediastinum. These tumors are usually invasive, often present at advanced stages, and typically behave aggressively. Studies are hampered by the paucity of these tumors, the large variety of carcinoma subtypes, and the lack of unique morphologic and immunophenotypic features. Despite these challenges, advances in diagnostic imaging, surgical approaches, systemic therapies, and radiation therapy techniques have been made. The WHO classification of thymic epithelial tumors has been updated in 2021, and the eighth tumor nodal metastasis staging by the American Joint Committee on Cancer/Union for International Cancer Control included thymic carcinomas in 2017. Molecular alterations that provide more insight into the pathogenesis of these tumors and that potentially permit use of novel targeted therapies are increasingly being identified. New approaches to radiation therapy, chemotherapy, and immunotherapy are under evaluation. International societies, including the International Thymic Malignancy Interest Group, European Society of Thoracic Surgeons, and Japanese, Chinese, and Korean thymic associations, have been critical in organizing and conducting multi-institutional clinical studies. Herein, we review contemporary multidisciplinary perspectives in diagnosis and management of thymic carcinoma.

Combined clinical and specific positron emission tomography/computed tomography-based radiomic features and machine-learning model in prediction of thymoma risk groups

OBJECTIVES

In this single-center study, we aimed to propose a machine-learning model and assess its ability with clinical data to classify low- and high-risk thymoma on fluorine-18 (18F) fluorodeoxyglucose (FDG) (18F-FDG) PET/computed tomography (CT) images.

METHODS

Twenty-seven patients (14 male, 13 female; mean age: 49.6 ± 10.2 years) who underwent PET/CT to evaluate the suspected anterior mediastinal mass and histopathologically diagnosed with thymoma were included. On 18F-FDG PET/CT images, the anterior mediastinal tumor was segmented. Standardized uptake value (SUV)max, SUVmean, SUVpeak, MTV and total lesion glycolysis of primary mediastinal lesions were calculated. For texture analysis first, second, and higher-order texture features were calculated. Clinical information includes gender, age, myasthenia gravis status; serum levels of lactate dehydrogenase (LDH), alkaline phosphatase, C-reactive protein, hemoglobin, white blood cell, lymphocyte and platelet counts were included in the analysis.

RESULTS

Histopathologic examination was consistent with low risk and high-risk thymoma in 15 cases and 12 cases, respectively. The age and myasthenic syndrome were statistically significant in both groups (P = 0.039 and P = 0.05, respectively). The serum LDH level was also statistically significant in both groups (450.86 ± 487.07 vs. 204.82 ± 59.04; P < 0.001). The highest AUC has been achieved with MLP Classifier (ANN) machine learning method, with a range of 0.830 then the other learning classifiers. Three features were identified to differentiate low- and high-risk thymoma for the machine learning, namely; myasthenia gravis, LDH, SHAPE_Sphericity [only for 3D ROI (nz>1)].

CONCLUSIONS

This small dataset study has proposed a machine-learning model by MLP Classifier (ANN) analysis on 18F-FDG PET/CT images, which can predict low risk and high-risk thymoma. This study also demonstrated that the combination of clinical data and specific PET/CT-based radiomic features with image variables can predict thymoma risk groups. However, these results should be supported by studies with larger dataset.

Clinical Significance of Tumor Markers for Advanced Thymic Carcinoma: A Retrospective Analysis from the NEJ023 Study

Simple Summary

Advanced thymic carcinoma (ATC) is rare. Owing to its rarity, there is limited information on the prognostic factors, and the optimal serum tumor markers are also unknown. We conducted a multi-institutional retrospective study of patients with ATC. In this study, we collected data on patient characteristics, progression-free survival (PFS), overall survival (OS), and tumor marker values, and investigated the relationship between tumor marker values and PFS/OS. We found that the neuron-specific enolase (NSE) level may be a useful prognostic tumor marker for ATC, regardless of histology. The findings of the analysis limited to squamous cell carcinoma suggested that the NSE and squamous cell carcinoma antigen levels may be useful prognostic factors.

Abstract

The optimal tumor marker for predicting the prognosis of advanced thymic carcinoma (ATC) remains unclear. We conducted a multi-institutional retrospective study of patients with ATC. A total of 286 patients were treated with chemotherapy. Clinicopathological information, including serum tumor markers, was evaluated to determine the overall survival (OS) and progression-free survival (PFS). The carcinoembryonic antigen, cytokeratin-19 fragment, squamous cell carcinoma (SCC) antigen, progastrin-releasing peptide, neuron-specific enolase (NSE), and alpha-fetoprotein levels were evaluated. In the Kaplan–Meier analysis, the OS was significantly shorter in the patients with elevated NSE levels than in those with normal NSE levels (median, 20.3 vs. 36.8 months; log-rank test p = 0.029; hazard ratio (HR), 1.55; 95% confidence interval (CI), 1.05–2.31 (Cox proportional hazard model)); a similar tendency regarding the PFS was observed (median, 6.4 vs. 11.0 months; log-rank test p = 0.001; HR, 2.04; 95% CI, 1.31–3.18). No significant differences in the OS and PFS were observed among the other tumor markers. In both univariate and multivariate analyses of the patients with SCC only, the NSE level was associated with the OS and PFS. Thus, the NSE level may be a prognostic tumor marker for thymic carcinoma, regardless of histology.

A novel risk classifier for predicting the overall survival of patients with thymic epithelial tumors based on the eighth edition of the TNM staging system: A population-based study

OBJECTIVE

Thymic epithelial tumors (TETs) are rare tumors that originated from thymic epithelial cells, with limited studies investigating their prognostic factors. This study aimed to investigate the prognostic factors of TETs and develop a new risk classifier to predict their overall survival (OS).

METHODS

This retrospective study consisted of 1224 TETs patients registered in the Surveillance, Epidemiology, and End Results (SEER) database, and 75 patients from the First Affiliated Hospital of Xi'an Jiaotong University. The univariate and multivariate Cox regression analyses were adopted to select the best prognostic variables. A nomogram was developed to predict the OS of these patients. The discriminative and calibrated abilities of the nomogram were assessed using the receiver operating characteristics curve (ROC) and calibration curve. Decision curve analysis (DCA), net reclassification index (NRI), and integrated discrimination improvement (IDI) were adopted to assess its net clinical benefit and reclassification ability.

RESULTS

The multivariate analysis revealed that age, sex, histologic type, TNM staging, tumor grade, surgery, radiation, and tumor size were independent prognostic factors of TETs, and a nomogram was developed to predict the OS of these patients based on these variables. The time-dependent ROC curves displayed that the nomogram yielded excellent performance in predicting the 12-, 36- and 60-month OS of these patients. Calibration curves presented satisfying consistencies between the actual and predicted OS. DCA illustrated that the nomogram will bring significant net clinical benefits to these patients compared to the classic TNM staging system. The estimated NRI and IDI showed that the nomogram could significantly increase the predictive ability of 12-, 36- and 60-month OS compared to the classic TNM staging system. Consistent findings were discovered in the internal and external validation cohorts.

CONCLUSION

The constructed nomogram is a reliable risk classifier to achieve personalized survival probability prediction of TETs, and could bring significant net clinical benefits to these patients.

Sphingomonas and Phenylobacterium as Major Microbiota in Thymic Epithelial Tumors

The microbiota has been reported to be closely associated with carcinogenesis and cancer progression. However, its involvement in the pathology of thymoma remains unknown. In this study, we aimed to identify thymoma-specific microbiota using resected thymoma samples. Nineteen thymoma tissue samples were analyzed through polymerase chain reaction amplification and 16S rRNA gene sequencing. The subjects were grouped according to histology, driver mutation status in the GTF2I gene, PD-L1 status, and smoking habits. To identify the taxa composition of each sample, the operational taxonomic units (OTUs) were classified on the effective tags with 97% identity. The Shannon Index of the 97% identity OTUs was calculated to evaluate the alpha diversity. The linear discriminant analysis effect size (LEfSe) method was used to compare the relative abundances of all the bacterial taxa. We identified 107 OTUs in the tumor tissues, which were classified into 26 genera. Sphingomonas and Phenylobacterium were identified as abundant genera in almost all the samples. No significant difference was determined in the alpha diversity within these groups; however, type A thymoma tended to exhibit a higher bacterial diversity than type B thymoma. Through the LEfSe analysis, we identified the following differentially abundant taxa: Bacilli, Firmicutes, and Lactobacillales in type A thymoma; Proteobacteria in type B thymoma; Gammaproteobacteria in tumors harboring the GTF2I mutation; and Alphaproteobacteria in tumors without the GTF2I mutation. In conclusion, Sphingomonas and Phenylobacterium were identified as dominant genera in thymic epithelial tumors. These genera appear to comprise the thymoma-specific microbiota.

Nomogram predict relapse-free survival of patients with thymic epithelial tumors after surgery

Background

Hematological indicators and clinical characteristics play an important role in the evaluation of the progression and prognosis of thymic epithelial tumors. Therefore, we aimed to combine these potential indicators to establish a prognostic nomogram to determine the relapse-free survival (RFS) of patients with thymic epithelial tumors undergoing thymectomy.

Methods

This retrospective study was conducted on 156 patients who underwent thymectomy between May 2004 and August 2015. Cox regression analysis were performed to determine the potential indicators related to prognosis and combine these indicators to create a nomogram for visual prediction. The prognostic predictive ability of the nomogram was evaluated using the consistency index (C-index), receiver operating characteristic (ROC) curve, and risk stratification. Decision curve analysis was used to evaluate the net benefits of the model.

Results

Preoperative albumin levels, neutrophil-to-lymphocyte ratio (NLR), T stage, and WHO histologic types were included in the nomogram. In the training cohort, the nomogram showed well prognostic ability (C index: 0.902). Calibration curves for the relapse-free survival (RFS) were in good agreement with the standard lines in training and validation cohorts.

Conclusions

Combining clinical and hematologic factors, the nomogram performed well in predicting the prognosis and the relapse-free survival of this patient population. And it has potential to identify high-risk patients at an early stage. This is a relatively novel approach for the prediction of RFS in this patient population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08585-y.

Bioinformatics analysis of the key potential ceRNA biomarkers in human thymic epithelial tumors

BACKGROUND

Thymic epithelial tumors (TETs), originating from the thymic epithelial cells, are the most common primary neoplasms of the anterior mediastinum. Emerging evidence demonstrated that the competing endogenous RNAs (ceRNAs) exerted a crucial effect on tumor development. Hence, it is urgent to understand the regulatory mechanism of ceRNAs in TETs and its impact on tumor prognosis.

METHODS

TETs datasets were harvested from the UCSC Xena as the training cohort, followed by differentially expressed mRNAs (DEmRNAs), lncRNAs (DElncRNAs), and miRNAs (DEmiRNAs) at different pathologic type (A, AB, B, and TC) identified via DESeq2 package. clusterProfiler package was utilized to carry out gene ontology and Kyoto encyclopedia of genes and genomes functional analysis on the DEmRNAs. Subsequently, the lncRNA-miRNA-mRNA regulatory network was constructed to screen the key DEmRNAs. After the key DEmRNAs were verified in the external cohort from Gene Expression Omnibus database, their associated-ceRNAs modules were used to perform the K-M and Cox regression analysis to build a prognostic significance for TETs. Lastly, the feasibility of the prognostic significance was validated by receiver operating characteristic (ROC) curves and the area under the curve.

RESULTS

Finally, a total of 463 DEmRNAs, 87 DElncRNAs, and 20 DEmiRNAs were obtained from the intersection of differentially expressed genes in different pathological types of TETs. Functional enrichment analysis showed that the DEmRNAs were closely related to cell proliferation and tumor development. After lncRNA-miRNA-mRNA network construction and external cohort validation, a total of 4 DEmRNAs DOCK11, MCAM, MYO10, and WASF3 were identified and their associated-ceRNA modules were significantly associated with prognosis, which contained 3 lncRNAs (lncRNA LINC00665, lncRNA NR2F1-AS1, and lncRNA RP11-285A1.1), 4 mRNAs (DOCK11, MCAM, MYO10, and WASF3), and 4 miRNAs (hsa-mir-143, hsa-mir-141, hsa-mir-140, and hsa-mir-3199). Meanwhile, ROC curves verified the accuracy of prediction ability of the screened ceRNA modules for prognosis of TETs.

CONCLUSION

Our study revealed that ceRNAs modules might exert a crucial role in the progression of TETs. The mRNA associated-ceRNA modules could effectively predict the prognosis of TETs, which might be the potential prognostic and therapeutic markers for TETs patients.

Mutational landscape of thymic epithelial tumors in a Chinese population: insights into potential clinical implications

BACKGROUND

Thymic epithelial tumors (TETs) are a heterogeneous group of rare malignancies which may be devastating, difficult to treat, and for which treatment options are limited. Herein, we investigated the comprehensive genomic alterations of TETs in a Chinese population for providing clinical management, especially targeted therapy.

METHODS

Comprehensive genomic profiling (CGP) was performed with DNA targeted sequencing of cancer-associated genes (CSYS) from a cohort of 40 Chinese TET patients. TMB was measured by an in-house algorithm. MSI status was inferred based on the MANTIS (Microsatellite Analysis for Normal-Tumor InStability) score. The expression status of PD-L1 was estimated by immunohistochemistry.

RESULTS

The mutational profiling of thymomas (Ts) and thymic neuroendocrine tumors (TNETs) showed scattered mutation distributions with no recurrently mutated genes. In contrast, thymic carcinomas (TCs) did show highly recurrent mutations including CDKN2A, CYLD, CDKN2B, and TP53. Among them, CDKN2A and CDKN2B mutations were the top potentially actionable alterations in TCs. PD-L1 expression was mainly present in Ts and TCs, and was predominant in males and smokers.

CONCLUSIONS

Our study provided a comprehensive genetic alteration view on the largest Chinese cohort of TETs to date. The results identified different genomic mutational profiles of Ts, TCs, and TNETs, and analyzed potential druggable biomarkers with clinical implications in Chinese TET patients, which provided the evidence for precision medicine of rare TET patients.

The safety and efficacy of Cyberknife® for thymic malignancy

PURPOSE

To evaluate the safety and efficacy of Cyberknife® (CK) for the treatment of primary or recurring thymic tumours.

MATERIALS AND METHODS

We retrospectively reviewed 12 patients (16 tumour lesions) with primary or recurring thymic tumours who were treated with CK between March 2008 and October 2017. Their data was stored in prospectively collected database. Kaplan-Meier method was used to calculate survival curves.

RESULTS

Five patients (41.7%), who had inoperable disease or refused surgery, were treated with CK initially, and 7 patients (58.3%) were treated with CK when they had recurrence diseases. The disease sites treated with CK were primary tumour site (5), regional lymph nodes (4), tumour bed (3), chest wall (2), pleura (1), and bone (1). The median target volume was 43.8 cm³ (range, 13.1-302.5cm³) for the 16 tumour lesions. The median follow-up time was 69.3 months (range, 9.7-124.8 months). The median survival time was 48.2 months, and the 5-year and 10-year OS rates were 68.2% and 45.5%, respectively. A high response rate for the tumour lesions irradiated with CK was obtained. Only one patient (8%) experienced in-field recurrence, and the 5-year local recurrence free survival was 90.9%. A case indicated that CK may induce the abscopal effect, which provides the potential to combine CK and immunotherapy. No severe radiation related toxicities were observed, and no treatment related death occurred.

CONCLUSION

CK treatment resulted in good outcomes, particularly local control, with minimal side effects, in highly selected patients with primary and recurring thymic tumours. More studies with larger sample are needed.

Clear Cell Carcinoma of the Thymus: An Improbable Enemy

Introduction

Thymic clear cell carcinoma is the most uncommon subtype of thymic carcinoma, with 20 cases reported worldwide.

Case description

We present the case of a 61-year-old female with dyspnoea and chest pain for 2 days. Computed tomography (CT) angiography showed pulmonary thromboembolism and the existence of mediastinal and bilateral hilar lymphadenopathy, the largest infracarinal with an inferior axis of 25 mm, and also, micronodules on the left pulmonary parenchyma. The patient was admitted for aetiological assessment and underwent anticoagulant therapy. After a month, she had an ischaemic stroke, the sequelae of which proved to be fatal. The autopsy showed a mass in the superior-anterior mediastinum, with dimensions of 11×8×6 cm, corresponding to a thymus signet ring cell primary carcinoma. The immunohistochemistry study revealed that this mass was positive for AE1/AE3, CK5/6 and CK7.

Conclusion

The clinical, morphological and immunophenotypic diversity of this tumour makes its diagnosis a difficult multidisciplinary challenge, which requires a high level of clinical knowledge and accurate imaging and histological investigation.

LEARNING POINTS

Thymic clear cell carcinoma is a very rare entity with an aggressive and nonspecific clinical behaviour.There are no defined diagnostic criteria, although diagnosis could be established with histologic/cytology analysis.There are no clear guidelines for treatment, which can include highly invasive surgery and chemotherapy or radiation therapy.

Thymic epithelial tumors: Do we know all the prognostic factors?

BACKGROUND

Thymic epithelial tumors constitute a morphologically and clinically diverse group of rare neoplasm of the anterior mediastinum.

METHODS

Here, we present an analysis of 188 patients diagnosed with primary thymic tumors between 1995 and 2015. The prognostic value of selected clinical and morphological factors was assessed in relation to overall survival and recurrence-free survival.

RESULTS

The risk of recurrence increased significantly in thymic carcinoma diagnosis (P = 0.0036), co-occurrence of other diseases, and weight loss (P = 0.0012 and 0.0348, respectively). Multivariate analysis showed that the most important independent risk factor for disease recurrence was clinical stage IV (P = 0.0036). A total of 63 patients (33.5%) died. In the univariate analysis, the following factors were considered as independent prognostic factors for overall survival: clinical stage (P < 0.0001), histological type (P < 0.0001), lymph node involvement (P < 0.001), WHO performance status 2 (P < 0.0001), anemia (Hb <9.5 g/dL; P = 0.0002), leucocytosis (>12.5 G/L; P = 0.0011), LDH level (>185 U/L; P < 0.0001), concomitant diseases (P = 0.0012) and weight loss (P < 0.0001).The strongest independent risk factor for death was stage IV disease (P < 0.001).

CONCLUSIONS

The results confirmed a fairly good prognosis for patients with thymic epithelial tumors. Clinical stage was the most important prognostic factor, but, some additional clinical factors may also have prognostic value.

Epidemiology of thymic epithelial tumors: 22-years experience from a single-institution

Background

To assess the correlation of WHO histological classification and Masaoka–Koga staging system of thymic epithelial tumors (TETs) with prognosis.

Methods

We retrospectively analyzed 83 patients with TETs in the Instituto Nacional de Enfermedades Neoplasicas between 1996 to 2018. We analyzed the clinical stages, histological types and treatment modalities and attempted to determine the impact on overall survival. The data was retrieved from clinical files and reviewed by a pathologist who reclassificated according to the 2004 WHO classification system. The staging was performed with the Masaoka–Koga staging system. Survival curves were constructed with Kaplan‐Meir method.

Results

There was a total of 83 patients with a median age of 55 years old included in the study. The histological type corresponded to thymoma (T) in 63.8% (n = 53) and to thymic carcinoma (TC) in 36.1%. T were type A, AB, B1, B2 and B3 in 14.4%, 18%, 12%, 3.6%, 7.4% of cases, respectively. The proportion of advanced disease (Masaoka stage III–IV) was high (65%). With a median follow‐up of 88.4 months, median overall survival (OS) was 81.6 months for T and 12.3 months for TC (P = 0.01). Univariate analysis showed that sex, histological type, clinical stage and surgery (P = 0.01) were significant independent prognostic factors. On multivariate analysis, histology type and Masaoka–Koga staging had an effect on survival.

Conclusions

The results indicates a clear association between the WHO histological classification and Masaoka–Koga staging system with survival. We found a higher proportion of TETs with advanced disease at diagnosis. Further research are required and collaboration is important to foster knowledge focused on classification and treatment.

Key points

Significant findings of the study

The WHO histological classification, the Masaoka–Koga system and surgery treatment were associated with overall survival.

What this study adds

To determine prognosis factors in TETs.

Identification of Recurrent TERT Promoter Mutations in Intrathyroid Thymic Carcinomas

Intrathyroid thymic carcinoma (ITTC) is a rare malignant neoplasm considered to be a eutopic thymic carcinoma (TC) arising ectopically in the thyroid. Histopathologically, ITTC resembles squamous cell carcinoma of the thymus with positive TC markers such as CD5 and c-KIT. Despite these similar histological findings, ITTC is clinically less aggressive than TC. In this study, we compared clinical, histological, and genetic characteristics of ITTCs and TCs. We collected 9 ITTCs and 8 TCs with their clinicopathological profiles. Immunohistochemistry for CD5, p63, CD117/c-KIT, Ki-67, p53, TTF-1, thyroglobulin, PAX8, EGFR, and PD-L1/CD274 plus in situ hybridization for EBER was performed. We further investigated mutation status of KIT, EGFR, BRAF, and TERT promoter using Sanger sequencing. In our study, ITTCs affected significantly younger patients than TCs. After a mean follow-up of 86 months, all patients with ITTC were alive, while two patients with TC had died. Immunohistochemistry showed ITTCs and TCs had a similar immunophenotype except for EGFR and p53. Genetic analysis did not identify KIT or BRAF mutations in any ITTCs or TCs. EGFR mutations were positive in 11% (1/9) of ITTCs and 25% (2/8) of TCs. Notably, TERT promoter C228T mutation was identified in 22% (2/9) of ITTCs but none of the TCs. There were no significant differences in age, tumor size, or sex between TERT-mutated and TERT-wild-type ITTCs. Collectively, ITTC and TC have similar histopathologic and immunophenotypic features but different clinical outcomes. Recurrent TERT promoter mutation may be a key event related to cancer progression in ITTCs and warrants further investigation.

Primary Driver Mutations in GTF2I Specific to the Development of Thymomas

Thymomas are rare mediastinal tumors that are difficult to treat and pose a major public health concern. Identifying mutations in target genes is vital for the development of novel therapeutic strategies. Type A thymomas possess a missense mutation in GTF2I (chromosome 7 c.74146970T>A) with high frequency. However, the molecular pathways underlying the tumorigenesis of other thymomas remain to be elucidated. We aimed to detect this missense mutation in GTF2I in other thymoma subtypes (types B). This study involved 22 patients who underwent surgery for thymomas between January 2014 and August 2019. We isolated tumor cells from formalin-fixed paraffin-embedded tissues from the primary lesions using laser-capture microdissection. Subsequently, we performed targeted sequencing to detect mutant GTF2I coupled with molecular barcoding. We used PyClone analysis to determine the fraction of tumor cells harboring mutant GTF2I. We detected the missense mutation (chromosome 7 c.74146970T>A) in GTF2I in 14 thymomas among the 22 samples (64%). This mutation was harbored in many type B thymomas as well as type A and AB thymomas. The allele fraction for the tumors containing the mutations was variable, primarily owing to the coexistence of normal lymphocytes in the tumors, especially in type B thymomas. PyClone analysis revealed a high cellular prevalence of mutant GTF2I in tumor cells. Mutant GTF2I was not detected in other carcinomas (lung, gastric, colorectal, or hepatocellular carcinoma) or lymphomas. In conclusion, the majority of thymomas harbor mutations in GTF2I that can be potentially used as a novel therapeutic target in patients with thymomas.

Clinical significance of age at diagnosis among patients with thymic epithelial tumors: a population-based study

Background: To investigate the clinicopathologic characteristics and survival outcomes of patients with thymic epithelial tumors (TET) according to age at diagnosis.

Results: A total of 4431 patients were analyzed. Gender, race, tumor histology and surgery were similar between different age groups. The 0-18 group was associated with a higher risk of distant metastasis. Compared to patients aged above 80, the hazard ratios (HR) for patients aged 0-18, 19-30, 31-40, 41-50, 51-60, 61-70, 71-80 were 1.079, 0.739, 0.614, 0.621, 0.633, 0.673, 0.861, respectively. From the subgroup analysis for the adult patients who were above 19 years old, we found that the 19-70 group had significant better cancer specific survival (CSS) and overall survival (OS) than the above 70 group.

Conclusions: Age is a strong independent prognostic factor for survival in TET. Pediatric TET has a higher risk of distant metastasis and an inferior CSS. For the adults who were above 19, patients older than 70-year-old were associated with a shorter CSS.

Methods: Information of 4431 TET patients was retrieved from the Surveillance, Epidemiology, and End Results (SEER) database. Demographic features, clinicopathologic characteristics and survival outcomes were compared between patients diagnosed at different age groups (0-18, 19-30, 31-40, 41-50, 51-60, 61-70, 71-80, above 80).

Surgery in Masaoka stage IV thymic carcinoma: a propensity-matched study based on the SEER database

BACKGROUND

Thymic carcinoma is a type of rare and highly malignant tumor. Limited information was available on prognostic factors of late-stage thymic carcinoma. The aim of this study was to identify factors that impact prognosis and to define the relationship between survival and surgical intervention in patients with Masaoka stage IV thymic carcinoma.

METHODS

From 1973 to 2015, a total of 311 consecutive patients were enrolled in this study with pathologic confirmed Masaoka stage IV thymic carcinoma from the Surveillance, Epidemiology, and End Results database. Kaplan-Meier analyses, Cox-regression analyses and propensity score matching (PSM) were performed to evaluate prognosis.

RESULTS

In the multivariate analysis, larger tumor size, distant metastasis and positive lymph node status were associated with poorer outcome. After PSM, no receipt of surgery was the prognostic factor indicating poorer survival [hazard ratio (HR) 1.985, 95% confidence interval (CI) 1.007-3.913, P=0.048 for overall survival (OS); HR 1.649, 95% CI: 1.009-2.697, P=0.046 for disease-specific survival (DSS)]. Subgroup analysis indicated that significantly improved survival with surgery was observed in patients who were <60 years (HR 0.48, 95% CI: 0.32-0.72), female (HR 0.37, 95% CI: 0.23-0.60), Caucasian (HR 0.56, 95% CI: 0.40-0.77), with larger tumor size (≥7.0 cm, HR 0.42, 95% CI: 0.25-0.69), with (HR 0.60, 95% CI: 0.39-0.90) or without distant metastasis (HR 0.46, 95% CI: 0.26-0.83), and node-positive (HR 0.56, 95% CI: 0.38-0.82).

CONCLUSIONS

Surgical treatment could be beneficial in patients with Masaoka stage IV thymic carcinoma. This SEER based analysis revealed the role of surgical resection and the favorable effect of surgery in specific thymic carcinoma subgroups.

Next-generation sequencing in thymic epithelial tumors uncovered novel genomic aberration sites and strong correlation between TMB and MSH6 single nucleotide variations

Thymic epithelial tumors (TET) including thymomas and thymic carcinomas are rare, but they are common primary tumors in the anterior mediastinum. The etiology and tumorigenesis of TET remain unclear. To better understand the novel aberrations of this rare tumor and provide more significant mutation sites for targeted therapy, we performed next-generation sequencing detection on 55 patients with TET. Our results showed that most genes in 12 core pathways harbored aberrations of indeterminate potential. In 4 genes (ARID1A, KMT2C, TGFBR2 and MAP3K1), the indel frequency was above 90%. Dozens of genes, including TGFBR2, KMT2C, PRKDC, ATR, CHD2, SDHA, KDM5A, CHEK1, MSH6 and POLE, possessed frameshift indel with different frequencies in different hotspot sites, which could be the new targets of therapy for TET. For the first time, we revealed a strong correlation between the tumor mutational burden and single nucleotide variations, but not frameshift, on DNA mismatch repair gene MSH6 in TET.

PD-L1 Expression and Tumor-Infiltrating Lymphocytes in Thymic Epithelial Neoplasms

Thymic epithelial tumors (TETs) are rare malignant mediastinal tumors that are difficult to diagnose and treat. The programmed death 1 (PD-1) receptor and its ligand (PD-L1) are expressed in various malignant tumors and have emerged as potential immunotherapeutic targets. However, the immunobiology of TETs is poorly understood. We evaluated PD-L1 expression and the presence of tumor-infiltrating lymphocytes (CD8 and CD3 expression) in surgical TET specimens from 39 patients via immunohistochemistry and determined their relation to clinicopathological parameters. Cases with membranous reactivity of the PD-L1 antibody in ≥1% of tumor cells were considered positive. Positive PD-L1 expression was observed in 53.9% of cases. Histologically, PD-L1 expression was positive in 2/6 type A, 2/6 type AB, 3/9 type B1, 4/4 type B2, 5/6 type B3, and 5/8 type C TET cases. Thus, the number of cases with PD-L1 expression and the percent expression of PD-L1 were significantly higher in more aggressive thymomas (type B2 or B3). CD3+ and CD8+ tumor-infiltrating lymphocytes were diffusely and abundantly distributed in all cases. These data suggest that a PD-1/PD-L1 blockade is a promising treatment for TETs, with more beneficial treatment effects for aggressive thymomas such as type B2 or B3.

Optimal first-line treatment for advanced thymic carcinoma

Background

Thymic carcinomas (TCs) are rare aggressive tumors with no standard first‐line treatment. This study was conducted to determine the optimal chemotherapy regimen for advanced TC.

Methods

This retrospective study included 67 patients treated for stage IV TC in 2006–2015. The primary endpoints were the objective response rate (ORR) and progression‐free survival (PFS) with different chemotherapy regimens. Multivariate Cox regression analysis was used to identify factors associated with PFS, including metastatic status, radiotherapy post‐chemotherapy, primary lesion resection before chemotherapy, and chemotherapy regimen.

Results

A total of 36 patients received a paclitaxel‐platinum regimen, 31 received a gemcitabine‐platinum regimen, 14 underwent primary lesion resection, and 33 underwent radiotherapy. ORR was 31% (11/36) and 29% (9/31) in the paclitaxel‐platinum and gemcitabine‐platinum groups, respectively (P = 0.890). Median PFS, one‐year PFS rate, and two‐year PFS rate were 7.0 months, 26%, and 6% with paclitaxel‐platinum treatment and 12 months, 48%, and 24% with gemcitabine‐platinum treatment (log‐rank P = 0.030). Median PFS, one‐year PFS rate, and two‐year PFS rate were 18.0 months, 57%, and 33% with surgical resection and 7.3 months, 31%, and 7% without resection (log‐rank P = 0.030). Median PFS, one‐year PFS rate, and two‐year PFS rate were 13.0 months, 52%, and 20% with radiotherapy and 4.3 months, 22%, and 7% without radiotherapy (log‐rank P = 0.001). In multivariate analysis, metastatic status (hazard ratio [HR], 0.33, P = 0.004), surgical resection (HR, 0.32; P = 0.004), and radiotherapy (HR, 0.32; P < 0.001) were associated with superior PFS.

Conclusions

Both gemcitabine‐platinum and paclitaxel‐platinum regimens were efficacious for advanced TC. Primary lesion resection and radiotherapy may also benefit selected patients.

Successful treatment of thymic carcinoma with dermatomyositis and interstitial pneumonia: A case report

Here, we report a rare case of thymic carcinoma (TC) associated with dermatomyositis (DM) and interstitial pneumonia (IP) in a 68-year-old man. The patient presented with the characteristic features of a skin rash with Gottron's papules and increased serum levels of muscle-associated enzymes. Computed tomography (CT) showed the presence of an anterior mediastinal soft tissue mass with IP, which was diagnosed as TC by CT-guided tumor biopsy. The patients DM and IP disappeared completely after radical resection of the tumor. After a 20-month follow-up period, the patient was in good clinical condition without disease recidivism.

Capecitabine and Celecoxib as a Promising Therapy for Thymic Neoplasms

OBJECTIVES

For patients with unresectable or metastatic thymic epithelial neoplasms, few therapy options are available and outcomes are poor. This case series demonstrates that the combination of capecitabine and celecoxib may be a promising therapeutic option for these patients.

MATERIALS AND METHODS

The current report describes the outcomes of 5 patients with thymic neoplasms treated on a drug-drug interaction study of capecitabine and celecoxib in patients with advanced solid malignancies (NCT01705106) conducted at the University of Chicago, plus a sixth patient treated with the same regimen outside of the protocol.

RESULTS

Six patients with thymic neoplasms were treated with capecitabine 1000 mg/m twice daily and celecoxib 200 mg twice daily, day 1 to day 14 on a 21-day cycle. This included 3 patients with thymic carcinoma, 1 with thymic neuroendocrine tumor, and 2 with thymomas. Objective response rates were noted in 3 of 6 patients. Two of the 3 thymic carcinoma patients had complete responses, and the third had a partial response. Best response for the other patients included stable disease for both thymoma patients and progressive disease for the thymic neuroendocrine patient. Other than grade 3 palmar-plantar erythrodysesthesia, which developed in 4 of 6 patients and required dose reductions, the regimen was well tolerated.

CONCLUSIONS

This case series suggests that capecitabine plus celecoxib may be an effective and well-tolerated treatment option for patients with thymic carcinoma. Further studies should be carried out to establish the efficacy of capecitabine plus celecoxib in thymic carcinoma, and to determine whether monotherapy with capecitabine would be similarly effective.

Effect of clinicopathologic features on survival of patients with thymic carcinomas and thymic neuroendocrine tumors: A population-based analysis

BACKGROUND

Thymic carcinomas (TCs) and thymic neuroendocrine tumors (TNETs) are aggressive cancers with poor survival outcome and limited investigation. This study is to investigate clinicopathologic features on TC and TNET patients' prognosis of a large cohort.

MATERIALS AND METHODS

The Surveillance, Epidemiology, and End Results database were used to identify a total of 362 TC and TNET patients with documented clinicopathologic features we investigated. The characteristics and overall survival of the TC and TNET patients were studied.

RESULTS

Two hundred and forty TC and 122 TNET patients were identified. For the entire cohort of TC and TNET, histologic type (P < 0.001), tumor size (P = 0.015), Masaoka-Koga stage (P = 0.008), regional node positive (P = 0.004), surgery of primary site (P < 0.001), lymph node surgery (P = 0.013), and chemotherapy (P = 0.001) were considered as significant clinicopathologic features that could affect prognosis of TC and TNET patients in univariate analysis. More importantly, histologic type (P < 0.001), regional nodes positive (P = 0.03) and surgery of primary site (P < 0.001) were able to independently predict overall survival of those patients. In addition, for the cohort of TC, we found that regional nodes positive (P = 0.034) and surgery of primary site (P = 0.001) could be independent predictors of TC patients' survival.

CONCLUSION

Regional nodes detection is essential for TC and TNET patients. Surgery of primary site is the preferred primary treatment for those patients.

Expression Patterns, Prognostic Value, and Intratumoral Heterogeneity of PD-L1 and PD-1 in Thymoma and Thymic Carcinoma

INTRODUCTION

Thymic epithelial tumors (TETs) including thymoma and thymic carcinoma are rare tumors with little data available to guide treatment. Immunotherapy with checkpoint blockade has shown promising activity, but data regarding the expression patterns and prognostic implications of programmed death 1 (PD-1) and its ligand (PD-L1) in TETs have yielded conflicting results. Intratumoral heterogeneity of PD-1/L1 expression has been shown in other cancers, but has not been described in the TET literature.

METHODS

We performed a retrospective single-center review of 35 patients with resected TET. PD-1/L1 expression was assessed by immunohistochemistry using PD-1 clone: NAT105 and PD-L1 clone: 22C3. Tumor samples from 35 patients were evaluated including 32 patients with thymoma and 3 patients with thymic carcinoma.

RESULTS

PD-L1 expression was detected in 83% (29 of 35) tumor samples, including 100% (3 of 3) of thymic carcinoma patients and 81% (26 of 32) of thymoma patients. PD-1 expression was detected in 77% (27 of 35), including 33% (1 of 3) of thymic carcinoma patients and 81% (26 of 32) thymoma patients. High PD-1 expression was associated with lower grade tumors. Unlike prior studies, PD-L1 expression was not associated with higher grade tumors or higher stage. Neither PD-L1 nor PD-1 expression was significantly associated with survival. Three patients with thymoma had multiple tumor sections evaluated for expression of PD-1/L1, with differing expression patterns of both PD-L1 and PD-1 observed in two patients.

CONCLUSIONS

This study confirms high expression of PD-L1 and PD-1 in TET and shows for the first time intratumoral heterogeneity of PD-L1 and PD-1 in thymoma patients.

A Nomogram Predicting Recurrence and Guiding Adjuvant Radiation for Thymic Carcinoma After Resection

BACKGROUND

Resection is an effective treatment for thymic carcinoma. We aimed to develop a nomogram for postoperative prediction of recurrence-free survival for patients with thymic carcinoma and guide adjuvant radiotherapy.

METHODS

A total of 198 patients who underwent surgery were divided into training cohort (n = 152) and validation cohort (n = 46). Clinicopathologic features and independent factors for postoperative recurrence were analyzed. A predictive nomogram was developed based on the prognostic factors. Discrimination and predictive accuracy of the model were measured using the concordance index (C-index), calibration curves, and validation study.

RESULTS

The overall 1-, 3-, and 5-year recurrence rate of 198 patients was 7.6%, 27.9%, and 39.9%, respectively. Independent predictors of recurrence-free survival on multivariate analysis were incorporated into the nomogram. Calibration curves for the probability of 1-, 3-, and 5-year recurrence-free survival fitted well. The C-index of the nomogram for predicting recurrence-free survival was 0.862 (95% confidence interval: 0.804 to 0.919). Internal validation supported the results optimally. Adjuvant radiotherapy was effective for patients with a total score greater than 208.

CONCLUSIONS

Our nomogram for predicting recurrence-free survival had good performance. Adjuvant radiotherapy should be recommended for patients with a total score greater than 208.

Treatment and prognostic factors of patients with thymic epithelial tumors at first recurrence or progression

AIM

The treatment of patients with recurrent or progressive thymic epithelial tumors remains uncertain due to limited data in this rare disease.

MATERIALS & METHODS

A retrospective 10-year monoinstitutional analysis was conducted on 25 patients with first recurrence or disease progression following primary treatment.

RESULTS

Twenty patients had thymoma, five thymic carcinomas. Ten patients (40%) received surgery, four (40%) following chemotherapy; 17 (68%) had chemotherapy, with a combination regimen in 16 of them (94%). Surgery had a significant effect both on overall survival and progression-free survival-2 by univariate analysis (p = 0.04), combination chemotherapy only on progression-free survival-2 (p = 0.03).

CONCLUSION

Combination chemotherapy and surgery at first recurrence/progression of thymic epithelial tumors were associated with improved survival.

DISCUSSION

Although several limitations may have affected this retrospective study on a relatively small number of patients with this rare entity of recurrent thymic malignancies, we suggest the use of combination chemotherapy and surgery at their first recurrence may have contributed to the high overall and progression-free survival observed with adequate follow-up and deserve further investigations in broader retrospective and comparative studies.

A rare highly aggressive tumour: lymphoepithelioma-like thymic carcinoma

Lymphoepithelioma-likethymic carcinoma is a rare neoplasm that presents with compressive symptoms or as an incidental radiological finding of an anterior mediastinal mass. It is an aggressive carcinoma with a high rate of invasion, metastasis and recurrence. Its diagnosis usually carries a poor prognosis largely due to propensity for late diagnosis. To date, guidance for treatment remains limited. This is a case of lymphoepithelioma-like thymic carcinoma in a young male adult who presented initially with back pain. Despite prompt initiation of chemotherapy with cisplatin, doxorubicin and cyclophosphamide, he had a complicated hospital course leading to demise within 2 months of diagnosis.

Expression of PD-L1 and other immunotherapeutic targets in thymic epithelial tumors

Introduction

The thymus is a critical organ for the development of the adaptive immune system and thymic epithelial tumors (TETs; thymomas and thymic carcinomas) are often associated with auto-immune paraneoplastic conditions. However, the immunobiology of TETs is not well described. An evaluation of the tumor microenvironment, with particular focus on expression of immunotherapeutic targets, may facilitate and prioritize development of immunotherapy strategies for patients with TETs.

Methods

Tumor tissues from 23 patients with WHO Type B2/B3 thymoma (n = 12) and thymic carcinoma (n = 11) were identified and clinical outcomes were annotated. The expression of membranous PD-L1 on tumor cells, CD3+ and CD8+ tumor infiltrating lymphocytes (TILs), co-stimulatory (CD137, GITR, ICOS), and co-inhibitory immune checkpoint molecules (PD-1, CTLA-4, TIM-3) were assessed semi-quantitatively using immunohistochemistry.

Results

PD-L1 positivity (≥ 25% of tumor membrane expression) was frequent in TETs (15/23, 65%), more common in thymomas compared to thymic carcinomas (p<0.01), and was associated with longer overall survival (p = 0.02). TIM-3 and GITR were expressed in all TETs, including 18/23 and 12/23 with at least moderate/high expression, respectively. Moderate/high CD137 expression correlated with CD8+ (p = 0.01) and moderate/high GITR expression co-associated with PD-1 (p = 0.043).

Conclusions

TETs are characterized by frequent PD-L1 expression and PD-L1 is associated with improved survival, suggesting PD-L1 signaling may be biologically important in TETs. Robust expression of markers of immune activation and immunotherapeutic target molecules in TETs emphasizes the potential for development of anti-PD-1/PD-L1 therapies.

Multimodality treatment of stage II thymic tumours

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Stage IVb thymic carcinoma: patients with lymph node metastases have better prognoses than those with hematogenous metastases

Background

This study aimed to analyze the pattern of lymphogenous and hematogenous metastases in patients with stage IVb thymic carcinomas and identify prognostic factors for their survivals.

Methods

Between September 1978 and October 2014, 68 patients with pathologically confirmed stage IVb thymic carcinomas were treated at Fudan University Shanghai Cancer Center. Forty-three patients had lymph node involvement without distant metastases, and the remaining 25 patients had hematogenous metastases. Clinical-pathological characteristics, including age, sex, histologic subtype, tumor size, metastasis, treatment modalities, such as surgical resection, radiotherapy, and chemotherapy, and clinical outcomes, such as overall survival (OS) and progression free survival (PFS), were analyzed.

Results

The median follow-up time was 22 months (range, 1–126 months). The median OS of all patients with stage IVb thymic carcinomas was 30 months, and the 5-year overall survival rate was 25.1%. The median PFS was 11 months, and the 5-year PFS was 17.9%. Stage IVb patients with lymph node involvement had a better survival than those with distant metastasis (40 vs. 20 months, p = 0.002). Patients with myasthenia gravis had a worse prognosis (p = 0.033). Multivariate analysis identified metastatic status as an independent prognostic factor for OS in patients with stage IVb thymic carcinomas.

Conclusions

Patients with lymph node involvement had a better survival than those with distant metastases. Much work remains to investigate the prognosis of patients with stage IVb thymic carcinomas and to explore different treatment strategies for patients with lymph node involvement and distant metastases.

A Single-Institution Analysis of Thymic Carcinoma Treated with Multi-Modality Therapy

PURPOSE

Review of our experience in treating thymic carcinoma patients using a combination of surgery, chemotherapy and radiation therapy.

METHODS

An institutional review of thymic carcinoma patients treated between 2007 and 2014 was performed analyzing clinical characteristics, treatment intent, surgical margin status, and radiation treatment dose. Survival curves were generated using the Kaplan-Meier method.

RESULTS

Nine individuals were treated for newly diagnosed thymic carcinoma. Three patients had unresectable disease at presentation; two of these were treated with definitive chemoradiation therapy while another received neoadjuvant chemotherapy. Seven subjects underwent surgical resection (one after neoadjuvant chemotherapy) with pathological staging ranging from IIa - IVb disease. Patients were planned for adjuvant radiotherapy followed by chemotherapy; however, one developed liver metastases prior to initiating radiotherapy and was therefore treated with palliative chemotherapy alone. A second patient was non-compliant with radiation treatments and was considered as treated with palliative chemotherapy alone. Of the seven patients who completed definitive treatment, median time to progression and overall survival has yet to be reached. Only one of these patients developed progressive disease 10 months after completing treatment and eventually succumbed to disease 41 months after completing definitive therapy. With a median follow up of 30 months, two year overall survival is 67% for all patients.

CONCLUSION

Resection with an emphasis on best possible oncologic margins, followed by radiation and chemotherapy remains an effective treatment strategy for advanced stage thymic carcinoma. In patients who present with unresectable tumors, neoadjuvant chemotherapy or definitive chemoradiation therapy may also be considered as viable treatment strategies.

Efficacy and safety of the combination of paclitaxel and platinum in advanced thymic carcinoma

This study aimed to assess the efficacy and safety of a combination of paclitaxel and cisplatin/carboplatin for the treatment of advanced thymic carcinoma. Thirty‐seven patients (23 men and 14 women, median age 47 years, performance status score ≤2) with pathologically or cytologically diagnosed advanced thymic carcinoma were recruited. Patients received 175 mg/m² paclitaxel on day 1 and 75 mg/m² cisplatin or 300 mg/m² carboplatin on day 2 of a 21 day cycle for at least two cycles to evaluate efficacy and adverse events. No complete response (CR) was observed; 11 patients had a partial response (PR), 16 patients had no change (NC), and 10 had progressive disease, resulting in an overall response rate of 29.7%, a stable rate of 43.2%, and a disease control rate (CR + PR + NC) of 72.9%. Grade I/II and III/IV neutropenia were observed in 21 (56.7%) and 13 (35.1%) patients, respectively. Four (10.8%) patients developed grade I/II thrombocytopenia. Grade I/II and III/IV nausea and vomiting were observed in 19 (51.2%) and five (13.5%) patients, respectively. Grade I/II liver dysfunction was observed in seven (18.9%) patients. Two patients with grade III liver dysfunction recovered after hepatoprotective treatment. The combination of paclitaxel and platinum was effective and well tolerated in patients with advanced thymic carcinoma.