Thymoma and thymic carcinoma

Constitutional Factors and Irradiation as Risk Factors for Thymoma: A European Case-Control Study

Little is known about the aetiology of thymoma. This study aims to identify medical risk factors for thymoma as a systematic approach to new hypotheses on the aetiology of this disease. A European multi-centre case-control study was conducted from 1995 to 1997, including incident cases aged 35-69 years with thymoma. Altogether, we accepted 85 cases and 3350 controls, of which we interviewed 77 cases and 2071 population controls about constitutional factors, medical examinations, and former diseases. Odds ratios (ORs) with 95% confidence intervals (CI) were calculated. Medical examinations with X-ray or radiotherapy performed >20 times at least one year before the thymoma diagnosis indicated a possible risk factor for thymoma (OR 1.58, 95% CI 0.93-2.69). Having the first radiotherapy treatment at least one year before the thymoma diagnosis yielded an OR for thymoma of 2.39; 95% CI (0.96-5.99), and if it was at least five years before, the OR for thymoma was 2.81; 95% CI (1.03-7.72). Having a red/auburn hair colour was associated with thymoma, (OR 3.6, 95% CI 1.4-9.5) whereas having pigmented skin was slightly associated with thymoma (OR 1.8, 95% CI 0.8-3.8). Over twenty instances of X-ray examinations or radiotherapy were identified as potential risk factors for thymoma, along with certain constitutional factors. The observed correlations between benign tumours and thymoma could stem from an inherent predisposition to tumour development or result from detection bias. Given that this is the initial analytical study examining medical risk factors for thymoma, all of the results should be approached with caution, acknowledging the possibility that some findings might be incidental.

Postoperative radiotherapy results in 192 epithelial thymic tumours patients with 10 years of follow-up

PURPOSE

To assess the prognostic factors and patterns of failure of patients consecutively treated with surgery and postoperative radiation therapy (PORT) for thymic epithelial tumours (TET).

PATIENTS AND METHODS

Data from 192 TET patients who were operated and received PORT at a single centre from 1990 to 2019 was retrospectively analysed.

RESULTS

Most patients had thymoma (77 %, B247%), were classified Masaoka-Koga stage III (35 %) or IV (32 %) and had a R0 (75 %) resection. Radiotherapy was delivered at a median dose of 50.4 Gy (range, 42-66 Gy; ≥ 60 Gy in 17 %), 63 (33 %) patients were treated by intensity-modulated radiation therapy and elective nodal radiotherapy was used for 37 %. At a median follow-up of 10.9 years, the 10-year overall survival (OS) and progression-free survival (PFS) rates were 62 % (95 % CI: 54-70 %) and 47 % (95 % CI: 39-55 %), respectively. Locoregional recurrence (LRR) occurred in 72/192 (38 %) patients, distributed as 6 local, 45 regional and 21 both local and regional. LRR were mainly located to the pleura: 66/72 (92 %) and 16/72 (22 %; 16/192 in total, 8 %) were in-field. Distant relapse (DR) were observed in 30 patients (16 %), resulting in 10-year locoregional (LRC) and distant control rates of 58 % (95 % CI: 50-66 %) and 82 % (95 % CI: 77-88 %), respectively. In the multivariate analysis, Masaoka-Koga stage (HR [hazard ratio]: 1.9; p = 0.001), thymic carcinomas/neuroendocrine tumours (TC) (HR: 1.6; p = 0.045) and ECOG PS > 1 (HR: 1.9; p = 0.02) correlated with poorer OS. Higher Masaoka-Koga stage (HR: 2.6; p < 0.001) associated with a decreased LRC but not R1 status (HR: 1.2; p = 0.5) or WHO histology classification. TC (HR: 3.4; p < 0.001) and a younger age (HR: 2.5; p = 0.02) correlated with DR.

CONCLUSION

Approximately one-third of the TET in our study experienced a LRR, mainly to the pleura, and 8% in total were in-field. The place of radiotherapy should be better defined in higher risk thymoma patients within prospective randomized studies.

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

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

Prognostic value of preoperative chemotherapy for thymic epithelial tumors: A propensity-matched analysis based on the SEER database

Background

The aim of this study was to assess the impact of preoperative chemotherapy on long-term survival (≥1 month) in patients with thymic epithelial tumors (TETs) and conditions suitable for chemotherapy using data from surveillance, epidemiology, and end-result databases.

Methods

This retrospective study controlled for confounding factors by propensity score matching (PSM), analyzed overall survival (OS) and cancer-specific survival (CSS) by Kaplan-Meier methods, and analyzed factors affecting the prognosis of patients undergoing surgery for thymic epithelial tumors by univariate and multifactorial Cox regression.

Results

A total of 2,451 patients who underwent surgery for TETs were identified from the Surveillance, Epidemiology, and End Results database. Preoperative chemotherapy significantly improved OS and CSS in patients with stage III/IV TETs compared to patients without preoperative chemotherapy. Subgroup analysis showed that patients younger than 60 years of age with TETs, patients with thymic carcinoma, and patients with TETs with multiple cancers were more likely to benefit from preoperative chemotherapy.

Conclusion

This study found that preoperative chemotherapy is a viable option for advanced thymoma with favorable overall and cancer-specific survival rates, but patient history and physical condition should be fully considered in conjunction with diagnostic imaging findings to assess patient tolerance to chemotherapy.

Molecular profiling of rare thymoma using next-generation sequencing: meta-analysis

BACKGROUND

Thymomas belong to rare tumors giving rise to thymic epithelial tissue. There is a classification of several forms of thymoma: A, AB, B1, B2, B3, thymic carcinoma (TC) and thymic neuroendocrine thymoma. In this meta-analysis study, we have focused on thymoma using articles based on the disease's next-generation sequencing (NGS) genomic profiling.

MATERIALS AND METHODS

We conducted a systematic review and meta-analysis of the prevalence of studies that discovered the genes and variants occurring in the less aggressive forms of the thymic epithelial tumors. Studies published before 12th December 2022 were identified through PubMed, Web of Science (WoS), and SCOPUS databases. Two reviewers have searched for the bases and selected the articles for the final analysis, based on well-defined exclusion and inclusion criteria.

RESULTS

Finally, 12 publications were included in the qualitative as well as quantitative analysis. The three genes, GTF2I, TP53, and HRAS, emerged as disease-significant in the observed studies. The Odds Ratio for all three extracted genes GTF2I (OR = 1.58, CI [1.51, 1.66] p < 0.00001), TP53 (OR = 1.36, CI [1.12, 1.65], p < 0.002), and HRAS (OR = 1.02, CI [1.00, 1.04], p < 0.001).

CONCLUSIONS

According to obtained data, we noticed that the GTF2I gene exhibits a significant prevalence in the cohort of observed thymoma patients. Moreover, analyzing published articles NGS has suggested GTF2I, TP53, and HRAS genes as the most frequently mutated genes in thymoma that have pathogenic single nucleotide variants (SNV) and Insertion/Deletion (InDel), which contribute to disease development and progression. These variants could be valuable biomarkers and target points specific to thymoma.

Prognostic value of systemic inflammatory markers and the nutrition status in thymic epithelial tumors with complete resection

Background

Recent studies have shown that several systemic inflammatory markers and the nutrition status, including the neutrophil‐to‐lymphocyte ratio (NLR), monocyte‐to‐lymphocyte ratio (MLR), platelet‐to‐lymphocyte ratio (PLR), and prognostic nutritional index (PNI), are useful prognostic factors in several malignant tumors. The present study explored the prognostic value of the NLR, MLR, PLR, and PNI in thymic epithelial tumor (TET) patients who underwent complete resection.

Methods

A total of 158 TET patients who underwent complete resection were involved in the analysis. Their NLR, MLR, PLR, and PNI values were obtained from a blood examination within one month before the initiation of treatment. A receiver operating characteristic curve analysis was conducted to determine the optimal cutoff values.

Results

The enrolled patients were stratified by cutoffs of 4.35 for the NLR, 0.22 for the MLR, 130.18 for the PLR, and 44.02 for the PNI. A univariate analysis revealed that high‐grade malignant TET, including type B2 and B3 thymoma, thymic carcinoma, and thymic neuroendocrine tumor; an advanced Masaoka stage; a high NLR; a high MLR; and a low PNI were significant predictors of a poor disease‐free survival (DFS). A multivariate analysis confirmed that an advanced Masaoka stage (HR = 5.5557, p = 0.0007) and a high MLR (HR = 3.3371, p = 0.0264) were independent predictors of a poor DFS.

Conclusions

Our study demonstrated that the pretreatment MLR was an independent predictor of the DFS in patients with TETs who underwent complete resection.

Long Non-Coding RNAs in the Cell Fate Determination of Neoplastic Thymic Epithelial Cells

Thymic Epithelial Tumors (TETs) arise from epithelial cells of the thymus and are very rare neoplasms comprising Thymoma, Thymic carcinoma, and Thymic Neuroendocrine tumors that still require in-depth molecular characterization. Long non-coding RNAs (lncRNAs) are emerging as relevant gene expression modulators involved in the deregulation of several networks in almost all types of human cancer, including TETs. LncRNAs act at different control levels in the regulation of gene expression, from transcription to translation, and modulate several pathways relevant to cell fate determination under normal and pathological conditions. The activity of lncRNAs is strongly dependent on their expression, localization, and post-transcriptional modifications. Starting from our recently published studies, this review focuses on the involvement of lncRNAs in the acquisition of malignant traits by neoplastic thymic epithelial cells, and describes the possible use of these molecules as targets for the design of novel therapeutic approaches specific for TET. Furthermore, the involvement of lncRNAs in myasthenia gravis (MG)-related thymoma, which is still under investigation, is discussed.

Fluorescence Imaging-Guided Identification of Thymic Masses Using Low-Dose Indocyanine Green

BACKGROUND

Indocyanine green (ICG) fluorescence imaging has been used to detect many types of tumors during surgery; however, there are few studies on thymic masses and the dose and time of ICG injection have not been optimized.

OBJECTIVE

We aimed to evaluate the optimal ICG injection dose and timing for detecting thymic masses during surgery.

METHOD

Forty-nine consecutive patients diagnosed with thymic masses on preoperative computed tomography (CT) and scheduled to undergo thymic cystectomy or thymectomy were included. Patients were administered 1, 2, or 5 mg/kg of ICG at different times. Thymic masses were observed during and after surgery using a near-infrared fluorescence imaging system, and the fluorescence signal tumor-to-normal ratio (TNR) was analyzed.

RESULTS

Among the 49 patients, 14 patients with thymic cysts showed negative fluorescence signals, 33 patients with thymoma or thymic carcinoma showed positive fluorescence signals, and 2 patients showed insufficient fluorescence signals. The diagnosis of thymic masses based on CT was correct in 32 (65%) of 49 cases; however, the differential diagnosis of thymic masses based on NIR signals was correct in 47 of 49 cases (96%), including 14 cases of thymic cysts (100%) and 33 cases of thymomas or thymic carcinomas (94%). In addition, TNR was not affected by the time or dose of ICG injection, histological type, stage, or tumor size.

CONCLUSIONS

Low-dose intravenous injection of ICG at flexible time can detect thymic tumors. In addition, thymic cysts can be distinguished from thymomas or thymic carcinomas during surgery by the absence of ICG fluorescence signals.

Correlation Between Thymoma and Soluble Interleukin-2 Receptor Expression in a Patient with Good Syndrome

Good syndrome is a rare condition characterized by the presence of thymoma in combination with adult-onset hypogammaglobulinemia. Immunological features of Good syndrome include various immunodeficiencies accompanied with hypogammaglobulinemia. In patients with thymoma, paraneoplastic syndromes including hypogammaglobulinemia worsen the prognosis. We herein describe a patient with advanced-stage type A thymoma who was effectively treated with chemotherapy and exhibited a parallel decrease in the serum level of soluble interleukin-2 receptor (sIL-2R), which depends on cellular immunity. The present case suggests the efficacy of sIL-2R as a potential prognostic biomarker in a subset of patients with Good syndrome.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Future Perspective of Chemotherapy and Pharmacotherapy in Thymic Carcinoma

Simple Summary

Thymic carcinoma is a rare cancer, and its biology remains largely unknown. Although complete surgical resection is a standard treatment for thymic carcinoma, systemic chemotherapy is frequently administered in metastatic or recurrent cases. Given the rarity, therapeutic agents are often confirmed on the basis of the results of phase II trials or retrospective studies. Platinum-based combination chemotherapy has long been employed for treating thymic carcinoma. Recently, biomarkers have been explored, and molecular profiles and major oncogenic pathways have gradually been revealed by next-generation sequencing, resulting in the development of targeted therapies. Moreover, clinical trials assessing combination therapy with immune checkpoint inhibitors are ongoing and are expected to be efficacious for treating thymic epithelial tumors. We reviewed the current role of systemic chemotherapy, including targeted therapies and immune checkpoint inhibitors, considering recent findings regarding its biology.

Abstract

Thymic carcinoma is a rare cancer that arises from thymic epithelial cells. Its nature and pathology differ from that of benign thymoma, presenting a poorer prognosis. If surgically resectable, surgery alone or surgery followed by chemoradiotherapy or radiotherapy is recommended by the National Comprehensive Cancer Network Guidelines. Metastatic and refractory thymic carcinomas require systemic pharmacotherapy. Combined carboplatin and paclitaxel, and cisplatin and anthracycline-based regimens have been shown a fair response rate and survival to provide a de facto standard of care when compared with other drugs employed as first-line chemotherapy. Cytotoxic agents have been pivotal for treating thymic carcinoma, as little is known regarding its tumorigenesis. In addition, genetic alterations, including driver mutations, which play an important role in treatments, have not yet been discovered. However, molecular pathways and biomarker studies assessing thymic epithelial tumors have been reported recently, resulting in the development of new agents, such as molecular targeted agents and immune checkpoint inhibitors. As treatment options are currently limited and the prognosis remains poor in metastases and recurrent thymic carcinoma, genetic alterations need to be assessed. In the present review, we focused on the current role of targeted therapies and immune checkpoint inhibitors in treating thymic carcinoma.

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

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

Clinical Outcomes and Technical Approach of Thymectomy in the Veterans Health Administration

BACKGROUND

Thymectomy is traditionally performed via transsternal incision, but less invasive modalities have emerged, including transcervical, thoracoscopic, and robotic approaches. Despite the advantages of video-assisted thoracoscopic surgery(VATS) over thoracotomy, most thymectomies are performed via sternotomy. This study compared the utilization and 30-day post-operative outcomes of transsternal, transcervical, and VATS thymectomy in the Veterans Health Administration.

METHODS

This was a retrospective review of veterans that underwent thymectomy via the Veterans Affairs Surgical Quality Improvement Program. 30-day outcomes were compared between techniques, adjusting for confounding covariates. Temporal trends were analyzed using Spearman's rank correlation coefficient, rho(ρ).

RESULTS

From 2008-2019, 594 thymectomies were performed: 376(63.3%) transsternal, 113(19.0%) VATS(including robotic approaches), and 105(17.7%) transcervical cases. VATS utilization increased from 0% in 2008 to 61% of case volume in 2019. Relative to transsternal technique, VATS thymectomy was associated with decreased odds of pulmonary complications (adjusted odds ratio=0.06;p=0.028) and shorter hospital stay (2.9±0.4 days shorter;p<0.001). No difference in outcomes was detected between VATS and transcervical thymectomy. Post-operative complication rate decreased from 17.7% in 2008 to 5.6% in 2019 (ρ=-0.101;p=0.014). Length of stay decreased from median 4 days in 2008 to 3 days in 2019 (ρ=-0.093;p=0.026). In thymic cancer, VATS 5-year overall survival was non-inferior to transsternal approach(71.3% vs. 74.6%; p=0.54).

CONCLUSIONS

Transsternal approach comprised most thymectomy cases amongst veterans, while VATS thymectomy utilization increased over time and was associated with favorable outcomes. 30-day outcomes after thymectomy improved over time, which may reflect a trend towards wider utilization of less invasive approaches. Future studies should examine long-term outcomes.

Dural venous sinus tumour thrombus from metastatic thymoma

Thymomas are the most common primary tumours of the anterior mediastinum. While intrathoracic disease progression through local invasion is well described in the literature, extrathoracic extension of disease is uncommon and intracranial metastases have seldom been reported. We present a case of extensive dural venous sinus tumour thrombus in a patient with metastatic invasive thymoma.

Epidemiology of thymoma

Thymic tumours are a heterogeneous group of malignancies with a range of clinical presentations. The most common types are thymoma and thymic carcinoma, but overall it remains a rare cancer, and one without a clear aetiology. In this review of the epidemiology of the disease, the relationship between sex, age, and ethnicity is reviewed, along with limited evidence on the genetics of the condition. In terms of risk factors and potential causative factors, environmental exposures such as tobacco, radiation, alcohol, or diet, seem to be irrelevant, but there is some evidence linking the development of thymoma and thymic carcinoma with viral conditions, including Epstein Barr Virus. But data is not conclusive, and in the absence of large patient numbers, it is difficult to prove causation. There has been good research looking at the link between thymoma and other malignancies, either before or after the diagnosis. There does not appear to be a significant increased likelihood of thymoma following other malignancies. But, there is a suggestion, in several papers, that there is an increased risk of other malignancies following the diagnosis of thymoma, although the magnitude of this risk is disputed. There does appear to be an increased risk of non-Hodgkins Lymphoma after a diagnosis of thymoma, and this could be related to a disruption in T-cell function caused by either the disease process or the treatment directed at the thymoma. In summary though, it is a rare malignant process with a variety of presentations, often limited to the anterior mediastinum, and without an aggressive disease profile.

Imaging of the Anterior/Prevascular Mediastinum

Prevascular mediastinal masses include a wide range of benign and malignant entities. Localization of mediastinal masses to specific compartments together with characteristic imaging findings and demographic and clinical information allows formulation of a focused differential diagnosis. Radiologists may use these methods to distinguish between surgical and nonsurgical cases and thus inform patient management and have an impact on outcomes. Treatment of choice varies based on the pathology, ranging from no intervention or serial imaging follow-up to surgical excision, chemotherapy, and/or radiation.

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.

Surgical and Oncological Outcomes in Locally Advanced Thymoma

This study aimed at reporting the surgical management of locally advanced thymoma (Masaoka stages III and IVA) and evaluating the factors predicting the survival. This is a retrospective analysis of patients operated for locally advanced thymoma from March 2012 to December 2019 in a thoracic surgery center in India. An analysis of all perioperative variables including complications was carried out. The influence of various predictors on survival was assessed by log-rank test. Out of total 54 patients, 42 (77.8%) had stage III and 12 (22.2%) had stage IVA. Upfront surgery was done in 34 (63%) patients, and induction chemotherapy was given in 20 (37%) patients. Pericardium was the commonest structure resected (79.6%) followed by the lung (51.8%), phrenic nerve (48.1%), major vascular structures (40.7%), parietal pleura (22.2%), diaphragm (9.2%), and right atrial appendage (1.8%). Forty-seven (87%) cases had complete (R0) resection, and the remaining 7 (12.9%) cases had incomplete (R1/R2) resection. There were no perioperative deaths (< 90 days). The median follow-up was 58 months. Overall survival (OS) and disease-free survival (DFS) at 5 years were 77.8% and 75.9%. Higher age (> 60 years), incomplete surgical resection, type B histology, and "> 3" structures resected with tumor were the poor prognostic factors for survival. An aggressive surgical approach, by an experienced team of cardiac and thoracic surgeons, aimed at complete resection is vitally important and can achieve excellent surgical and oncological outcomes even in locally advanced thymomas.

Minimal Access Surgery for Thymoma

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

Superior Vena Cava Resection in Locally Advanced Thymoma-Surgical and Survival Outcomes

This study was aimed at reporting the surgical management of superior vena cava invasion in patients with locally advanced thymoma and to evaluate surgical and survival outcomes. This is a retrospective analysis of 12 patients operated for superior vena cava resection for locally advanced thymoma over 8 years in a thoracic surgery centre in India. An analysis of peri-operative variables including complications was carried out. The influence of various predictors on survival was assessed by log-rank test. Intra-operatively, superior vena cava (SVC) alone was involved in 3 (25%) cases, SVC with BCV involvement was there in 8 cases (66.7%) and in 1 patient, the SVC involvement extended into the right atrium also. In all cases, the tumour was resected en bloc with the involved part of SVC. Repair with primary closure was sufficient in 2 cases (16.6%) in view of < 1/3rd of circumferential involvement. However, in remaining 10 cases, SVC was replaced with PTFE graft (single graft in 6 cases, Y-graft in 2 cases and twin grafts in 2 cases). No peri-operative deaths. Overall survival (OS) at 1, 3 and 5 years was 100%, 91.6% and 83.3%, respectively. Myasthenia gravis and higher Masaoka stage (IV A) of the disease were poor predictors of survival. Superior vena cava resection and reconstruction is a feasible and oncologically superior option in invasive thymoma with SVC involvement. This challenging surgical procedure should only be attempted by an experienced team of thoracic and cardiac surgeons at high-volume centre to achieve best outcomes.

Comparative effectiveness and cost-efficiency of surgical approaches for thymectomy

BACKGROUND

We compared the clinical outcomes and cost-efficiency of surgical approaches (sternotomy-open, video assisted thoracoscopic surgery, and robotic assisted thoracic surgery) for thymectomy.

METHODS

This is a retrospective review of 220 consecutive patients who underwent thymectomy between January 1, 2007, and January 31, 2017. Surgical approach was determined by the surgeon, but we only included cases that could be resected using any of the 3 approaches.

RESULTS

Open approach was used in 69 patients, whereas minimally invasive technique was used in 151 (97, video assisted thoracoscopic surgery; 54, robotic assisted thoracic surgery). Open surgery was associated with greater total hospital cost ($22,847 ± $20,061 vs $14,504 ± $10,845, P < .001). Open group also revealed longer duration of intensive care unit (1.2 ± 2.8 vs 0.2 ± 1.3 days, P < .001) and hospital stay (4.3 ± 4.0 vs 2.0 ± 2.6 days, P < .001). There were no differences in major adverse clinical outcomes. Long-term recurrence-free survival after resection of thymoma was similar between the groups.

CONCLUSION

Minimally invasive techniques were equally efficacious compared with the open approach in the resection of the thymus. Additionally, their use was associated with decreased hospital duration of stay and reduced cost. Hence the use of minimally invasive approaches should be encouraged in the resection of thymus.

Deciphering tissue-based proteome signatures revealed novel subtyping and prognostic markers for thymic epithelial tumors

Thymic epithelial tumors (TETs) belong to a group of tumors that rarely occur, but have unresolved mechanisms and heterogeneous clinical behaviors. Current care of TET patients demands biomarkers of high sensitivity and specificity for accurate histological classification and prognosis management. In this study, 134 fresh‐frozen tissue samples (84 tumor, 40 tumor adjacent, and 10 normal thymus) were recruited to generate a quantitative and systematic view of proteomic landscape of TETs. Among them, 90 samples were analyzed by data‐independent acquisition mass spectrometry (DIA‐MS) leading to discovery of novel classifying molecules among different TET subtypes. The correlation between clinical outcome and the identified molecules was probed, and the prioritized proteins of interest were further validated on the remaining samples (n = 44) via parallel reaction monitoring (PRM) as well as immunohistochemical and confocal imaging analysis. In particular, two proteins, the cellular mRNA deadenylase CCR4 (carbon catabolite repressor 4)‐NOT (negative on TATA) complex subunit 2/9 (CNOT2/9) and the serine hydroxymethyltransferase that catalyzes the reversible interconversions of serine and glycine (SHMT1), were found at dramatic low levels in the thymic epithelia of more malignant subtype, thymic squamous cell carcinoma (TSCC). Interestingly, the mRNA levels of these two genes were shown to be closely correlated with prognosis of the TET patients. These results extended the existing human tissue proteome atlas and allowed us to identify several new protein classifiers for TET subtyping. Newly identified subtyping and prognosis markers, CNOT2/9 and SHMT1, will expand current diagnostic arsenal in terms of higher specificity and prognostic insights for TET diagnosis and management.

Hoarseness as an Initial Symptom of Thymic Carcinoma: A Case Report

A 65-year-old man was referred to our hospital for evaluation of hoarseness and deteriorating voice. Computed tomography revealed an area of poor contrast enhancement in soft tissue (size, 30 mm) in the inferior pole of the thyroid gland, extending to the upper margin of the sternum. No infiltration of blood vessels or bones, and no significant swelling of neck lymph nodes, was observed. These findings suggested a diagnosis of thymoma, thymic carcinoma, or thyroid tumor. Surgery was performed via median sternotomy, and complete thymectomy and tumor excision accompanied by partial thyroidectomy were performed. Histopathological examination revealed atypical polygonal tumor cells in a sheet-like arrangement, which formed a solid proliferative focus, and squamous cell carcinoma with infiltrative growth was diagnosed. Postoperatively, radiotherapy (60 Gy) was administered to the superior mediastinum. The patient is alive 22 months after surgery, without recurrence.

Comparison between thoracoscopic and open approaches in thymoma resection

Background

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

Methods

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

Results

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

Conclusions

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

Thymoma appearing 9 years after the resection of squamous cell carcinoma of the lip: A case report of triple primary tumors and literature review

The occurrence of second primary tumor (SPT)following malignancy treatment is common. In patients with head and neck (H&N) cancer, SPTs principally occur in the H&N region, lungs or esophagus. Therefore, patient follow-up after cancer treatment is important in order to detect recurrence, metastasis and new primary tumors. However, no standard guidelines on lifelong follow-up imaging are available. Herein, we report a patient who presented with three metachronous primary tumors-squamous cell carcinoma (SCC) of the tongue, SCC of the lip and type A thymoma. The third tumor was incidentally detected during follow-up using contrast-enhanced computed tomography (CT) 9 years following resection of the second tumor. To the best of our knowledge, this specific combination of metachronous tumors has not yet been reported. Based on the literature review, we observed that thymoma occurs following H&N cancer treatment. Therefore, to ensure that the presence of subsequent thymomas is not overlooked, we suggest regular lifelong follow-up using contrast-enhanced CT in patients who had previously been diagnosed with H&N cancer. The literature review revealed that thymomas occur in patients with H&N cancer and should be detected at the earliest convenience.

Long-term outcomes of advanced thymoma in patients undergoing preoperative chemotherapy or chemoradiotherapy followed by surgery: a 20-year experience

OBJECTIVES

The results of preoperative chemotherapy or chemoradiotherapy followed by surgery for locally advanced thymoma were analysed.

METHODS

Between 1997 and 2016, 29 patients with a thymoma underwent preoperative chemotherapy or chemoradiotherapy followed by surgery. These cases were retrospectively reviewed.

RESULTS

The study population included 9 men and 20 women, with a mean age of 48.8 years (range 31-68 years). The preoperative Masaoka stage was III in 12, IVa in 13 and IVb in 4 patients, whereas histological type was B3 in 11, B2 in 9 and others in 5 patients. The mean tumour size was 8.0 ± 2.5 cm (3.4-15.0 cm). The site of infiltration shown in preoperative radiological examinations was the aorta in 6 patients, the superior vena cava in 14 patients and the pulmonary artery trunk in 3 patients, with pleural dissemination detected in 14. Three patients underwent chemoradiotherapy. Chemotherapy regimens given were cisplatin + doxorubicin + vincristine + cyclophosphamide in 9 patients, carboplatin + paclitaxel in 6 patients, cisplatin + doxorubicin + methylprednisolone in 5 patients and others in 9 patients, with partial response obtained in 11 patients and stable disease noted in 18 patients. Complete resection was achieved in 24 (83%) cases. There were no perioperative mortalities, whereas 6 (21%) patients developed postoperative complications. The 5- and 10-year overall survival rates were 100% and 87%, respectively, and 5- and 10-year disease-free survival rates were 50% and 50%, respectively.

CONCLUSIONS

Preoperative chemotherapy or chemoradiotherapy followed by surgery for locally advanced thymoma can be performed with an acceptable degree of surgical risk. Such a strategy should be proactively considered, as it can lead to favourable long-term results.

A Population-Based Study of Incidence and Survival of 1588 Thymic Malignancies: Results From the California Cancer Registry

BACKGROUND

Thymic malignancies are rare and there are limited contemporary population-based epidemiological studies for this uncommon cancer.

PATIENTS AND METHODS

Adults aged 20 years and older diagnosed with thymic malignancies between 1988 and 2015 were identified from the California Cancer Registry (n = 1588). Trends in age-adjusted incidence rates were examined overall and according to race/ethnicity, and the proportion diagnosed according to stage was evaluated over time. Cox proportional hazards regression was used to estimate hazard ratios (HRs) for overall survival (OS), and Fine and Gray competing risks regression for cause-specific survival (CSS).

RESULTS

Age-adjusted incidence increased on average 2.08% per year over the study period (95% confidence interval [CI], 1.30%-2.86%; P < .0001), with an incidence of 0.277 cases per 100,000 in 2015. Incidence was highest among Asian/Pacific Islander and non-Hispanic black individuals. The proportion of unknown stage at diagnosis declined as localized diagnoses increased over time. Compared with patients with thymoma, those with thymic carcinoma had significantly worse OS (HR, 1.63; 95% CI, 1.33-2.01; P < .0001) and CSS (subdistribution HR, 2.99; 95% CI, 2.29-3.91; P < .0001). Advanced stage at diagnosis was also associated with worse survival. Surgical intervention was associated with better prognosis for patients with localized (HR, 0.08; 95% CI, 0.02-0.30; P = .0002) or regional disease (HR, 0.14; 95% CI, 0.06-0.34; P < .0001).

CONCLUSION

Thymic malignancy incidence is increasing in California. There was incidence variation across race/ethnicity, which warrants future study. These findings provide contemporary insight into the incidence and prognostic factors of thymic malignancies.

Assessment of the prognostic role of neutrophil-to-lymphocyte ratio following complete resection of thymoma

BACKGROUND

The introduction of the new TNM staging system for thymic epithelial malignancies produced a significant increase in the proportion of patients with stage I disease. The identification of new prognostic factors could help to select patients for adjuvant therapies based on their risk of recurrence. Neutrophil-to-lymphocyte ratio (NLR) has recently gained popularity as reliable prognostic biomarker in many different solid tumors. The aim of this study is to assess the utility of NLR evaluation as a prognostic marker in patients with surgically-treated thymoma.

METHODS

A retrospective analysis was conducted among patients who underwent resection for thymoma in a single center. Patients were divided in two groups, under (low-NLR-Group = 47 patients, 60%) and above (high-NLR-Group = 32 patients, 40%) a ROC-derived NLR cut-off (2.27). Associations with clinical-pathological variables were analyzed; disease-free survival (DFS) was identified as the primary endpoint.

RESULTS

Between 2007 and 2017, 79 patients had surgery for thymoma. Overall 5-year DFS was 80%. Univariate survival analysis demonstrated that NLR was significantly related to DFS when patients were stratified for TNM stage (p = 0.043). Five-year DFS in the low-NLR-Group and in the high-NLR-Group were respectively 100 and 84% in stage I-II, and 66 and 0% in stage III. TNM stage resulted as the only independent prognostic factor at multivariate analysis, with hazard ratio of 3.986 (95% CI 1.644-9.665, p = 0.002).

CONCLUSIONS

High preoperative NLR seems to be associated to a shorter DFS in patients submitted to surgery for thymoma and stratified for TNM stage.

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

Background

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

Methods

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

Results

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

Conclusions

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

Comparative study of video-assisted thoracoscopic surgery versus open thymectomy for thymoma and myasthenia gravis

Introduction

Thymectomy is the preferred standard treatment in younger non-thymoma patients with myasthenia gravis as well as in patients with early stage thymoma. Total thymectomy by median sternotomy has been the surgical approach since resection of the thymus with video-assisted thoracoscopic surgery (VATS).

Aim

To compare the clinical outcomes of VATS thymectomy with conventional open thymectomy for neoplastic and non-neoplastic thymic diseases.

Material and methods

Forty patients underwent thymectomy between October 2012 and January 2016. Fifteen patients were male and 25 patients were female. The mean age was 40.3 ±17.7 years. Seventeen (55%) patients underwent VATS thymectomy and 23 (45%) patients underwent an open procedure. We retrospectively reviewed the data of the patients and compared these two techniques.

Results

The mean tumor size was 5.17 ±3.2 cm in the thymoma group (VATS 2.5 ±2.4 cm vs. open access 4.7 ±3.7 cm). None of the patients experienced a myasthenic crisis. Conversion to thoracotomy was required in 1 patient in the VATS group due to bleeding from the right internal mammary artery; therefore, the conversion rate was 2.5% among all the patients. No mortality occurred in either group. No significant difference was found in the perioperative blood loss, operative time or pain visual analogue scale scores. On the other hand, regarding postoperative drainage, duration of chest tube drainage and length of hospital stay, VATS thymectomy yielded better results and the differences were significant.

Conclusions

Video-assisted thoracoscopic surgery thymectomy can be performed for both neoplastic and non-neoplastic thymic diseases with minimal morbidity and mortality.

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.

Epidural Metastasis in Malignant Thymoma Mimicking Epidural Abscess: Case Report and Literature Review

Thymoma and thymic carcinoma are rare epithelial tumors that originate from the thymus gland. Extrathoracic metastases occur in the liver, kidney, and bone in 1% to 15% of patients. Although thymoma and thymic carcinoma exhibit highly aggressive biological behavior, spinal metastasis is rare. We describe a 78-year-old man with left wrist and grasp weakness that occurred 7 days before admission. The patient underwent thymoma surgery 7 years ago and was cured. Magnetic resonance images showed a rim-enhanced mass in the C6-7-T1 epidural space. C6-7-T1 laminectomy was performed and the mass was removed. Histological examination was performed and patient was diagnosed with metastatic thymoma. The previous reported case occurred with involvement of the vertebral body or posterior element, but our case was mostly rim-enhanced and appeared as an abscess and intradural extramedullary tumor.

Is thymomectomy sufficient for non-myasthenic early stage thymoma patients? A retrospective, single center experience

Background

Thymic complete resection is considered the standard treatment for all thymic tumors; however, the ideal resection for non‐myasthenic early stage thymic tumors has not yet been determined. We conducted a retrospective study to examine this unique scenario.

Methods

We retrospectively analyzed the data of 118 early stage thymoma patients who underwent thymectomy (TM) or thymomectomy (TMM) with curative intent between January 2003 and December 2013 at our institution. Patients with myasthenia, thymic carcinomas, tumors with undetermined histology, and more advanced stage thymoma patients were excluded. We compared overall survival (OS) and disease‐free survival (DFS) according to the extent of thymic resection, tumor staging, and size.

Results

One hundred and eighteen patients were staged as early thymoma. TM was performed in 43 (35.6%) patients and TMM in 75 (64.4%). Forty‐nine (65.3%) patients with a tumor ≤ 3 cm underwent TMM, and 9 (20.9%) TM. Twenty‐six (34.7%) patients with a tumor > 3 cm underwent TMM, and 34 (79.1%) TM. Seventy‐four patients were categorized as stage I: 57 (76%) underwent TMM and 17 (39.5%) TM. Forty‐four patients were categorized as stage II: 18 (24%) underwent TMM and 26 (60.5%) TM. There was no statistically significant difference in recurrence between the groups (P = 0.250).

Conclusion

No difference in the rate of recurrence was observed in early stage non‐myasthenic patients following thymic resection and Masaoka–Koga staging. However, TM is considered a better option for early stage thymoma patients with tumors > 3 cm.

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.

Video-Assisted Thoracic Surgery Thymectomy Versus Sternotomy Thymectomy in Patients With Thymoma

BACKGROUND

This study was designed to evaluate the feasibility of video-assisted thoracoscopic surgery (VATS) and to compare the oncologic outcomes of VATS with those of sternotomy in patients with thymoma.

METHODS

The clinical outcomes of 2,835 patients with thymic epithelial tumors treated between 1991 and 2010 in 32 Japanese institutions were collected retrospectively. The study compared postoperative complications, positive surgical margins, location of recurrence, and survival in 140 of 142 VATS-treated patients (VATS group) matched with 140 of 1,294 sternotomy-treated patients (ST group) by using propensity scores.

RESULTS

Postoperative complications were observed in 8 patients in the VATS group. The morbidity rate in the VATS group was not different from that of the ST group (p = 0.25). Positive surgical margins were noted in 4 patients (3 in the VATS group; 1 in the ST group). There was no statistically significant difference in the recurrence rate between groups (median follow-up period: 3.7 years in the VATS group; 5.2 years in the ST group). In total the most frequent site of recurrence was pleural dissemination. In the VATS group, the 5-year recurrence-free survival rate was 93.8%, and the 5-year overall survival rate was 97.9%. There was no difference in the recurrence-free survival and overall survival rates between the VATS group and the ST group (p = 0.91 and p = 0.74, respectively).

CONCLUSIONS

VATS thymectomy was feasible and comparable to sternotomy for the treatment of patients with thymoma with regard to morbidity, incomplete resection rate, and prognosis. However, additional follow-up is required to evaluate long-term outcomes.

Long-term outcomes of 307 patients after complete thymoma resection

Background

Thymoma is an uncommon tumor without a widely accepted standard care to date. We aimed to investigate the clinicopathologic variables of patients with thymoma and identify possible predictors of survival and recurrence after initial resection.

Methods

We retrospectively selected 307 patients with thymoma who underwent complete resection at the Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (Beijing, China) between January 2003 and December 2014. The associations of patients’ clinical characteristics with prognosis were estimated using Cox regression and Kaplan–Meier survival analyses.

Results

During follow-up (median, 86 months; range, 24–160 months), the 5- and 10-year disease-free survival (DFS) rates were 84.0% and 73.0%, respectively, and the 5- and 10-year overall survival (OS) rates were 91.0% and 74.0%, respectively. Masaoka stage (P < 0.001), World Health Organization (WHO) histological classification (P < 0.001), and postoperative radiotherapy after initial resection (P = 0.006) were associated with recurrence (52/307, 16.9%). Multivariate analysis revealed that, after initial resection, WHO histological classification and Masaoka stage were independent predictors of DFS and OS. The pleura (25/52, 48.0%) were the most common site of recurrence, and locoregional recurrence (41/52, 79.0%) was the most common recurrence pattern. The recurrence pattern was an independent predictor of post-recurrence survival. Patients with recurrent thymoma who underwent repeated resection had increased post-recurrence survival rates compared with those who underwent therapies other than surgery (P = 0.017).

Conclusions

Masaoka stage and WHO histological classification were independent prognostic factors of thymoma after initial complete resection. The recurrence pattern was an independent predictor of post-recurrence survival. Locoregional recurrence and repeated resection of the recurrent tumor were associated with favorable prognosis.

Thymic Epithelial Tumors phenotype relies on miR-145-5p epigenetic regulation

BACKGROUND

Thymoma and thymic carcinoma are the most frequent subtypes of thymic epithelial tumors (TETs). A relevant advance in TET management could derive from a deeper molecular characterization of these neoplasms. We previously identified a set of microRNA (miRNAs) differentially expressed in TETs and normal thymic tissues and among the most significantly deregulated we described the down-regulation of miR-145-5p in TET. Here we describe the mRNAs diversely regulated in TETs and analyze the correlation between these and the miRNAs previously identified, focusing in particular on miR-145-5p. Then, we examine the functional role of miR-145-5p in TETs and its epigenetic transcriptional regulation.

METHODS

mRNAs expression profiling of a cohort of fresh frozen TETs and normal tissues was performed by microarray analysis. MiR-145-5p role in TETs was evaluated in vitro, modulating its expression in a Thymic Carcinoma (TC1889) cell line. Epigenetic transcriptional regulation of miR-145-5p was examined by treating the TC1889 cell line with the HDAC inhibitor Valproic Acid (VPA).

RESULTS

Starting from the identification of a 69-gene signature of miR-145-5p putative target mRNAs, whose expression was inversely correlated to that of miR-145-5p, we followed the expression of some of them in vitro upon overexpression of miR-145-5p; we observed that this resulted in the down-regulation of the target genes, impacting on TETs cancerous phenotype. We also found that VPA treatment of TC1889 cells led to miR-145-5p up-regulation and concomitant down-regulation of miR-145-5p target genes and exhibited antitumor effects, as indicated by the induction of cell cycle arrest and by the reduction of cell viability, colony forming ability and migration capability. The importance of miR-145-5p up-regulation mediated by VPA is evidenced by the fact that hampering miR-145-5p activity by a LNA inhibitor reduced the impact of VPA treatment on cell viability and colony forming ability of TET cells. Finally, we observed that VPA was also able to enhance the response of TET cells to cisplatin and erlotinib.

CONCLUSIONS

Altogether our results suggest that the epigenetic regulation of miR-145-5p expression, as well as the modulation of its functional targets, could be relevant players in tumor progression and treatment response in TETs.

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.

Ectopic Anterior Mediastinal Pathology in the Chest: Radiologic-pathologic Correlation of Unexpected Encounters with the "Terrible Ts"

The complex embryology of the anterior mediastinum makes it home to an array of primary neoplasms tied to the presence of the thyroid and thymus glands in that compartment. While the occurrence of ectopic thyroid deposits in the extramediastinal thorax has not been convincingly established, the other three “Ts” of the classic “4T” mnemonic for the differential diagnosis of an anterior mediastinal mass have occurred in the lung parenchyma, pleural space, and endobronchially as primary tumors. Finding any of the three lesions – thymoma, teratoma, or B-cell lymphoma – in the chest outside the mediastinum is very unusual, but that possibility exists. Herein, we illustrate examples of this rare phenomenon.

Circulating miR-21-5p and miR-148a-3p as emerging non-invasive biomarkers in thymic epithelial tumors

Thymic epithelial cells give rise to both thymoma and thymic carcinoma. A crucial advance in thymic epithelial tumors (TET) management may derive from the identification of novel molecular biomarkers able to improve diagnosis, prognosis and treatment planning.In a previous study, we identified microRNAs that were differentially expressed in tumor vs normal thymic tissues. Among the microRNAs resulted up-regulated in TET tissues, we evaluated miR-21-5p, miR-148a-3p, miR-141-3p, miR-34b-5p, miR-34c-5p, miR-455-5p as blood plasma circulating non-invasive biomarkers for TET management.We firstly report that the expression levels of specific onco-miRNAs, that we found upregulated in the blood plasma collected from TET patients at surgery, resulted significantly reduced in follow-up samples.This pilot study suggests that circulating miR-21-5p and miR-148a-3p could represent novel non-invasive biomarkers to evaluate the efficacy of therapy and the prognosis of TET.

Determinants of Complete Resection of Thymoma by Minimally Invasive and Open Thymectomy: Analysis of an International Registry

INTRODUCTION

Minimally invasive thymectomy (MIT) is a surgical approach to thymectomy that has more favorable short-term outcomes for myasthenia gravis than open thymectomy (OT). The oncologic outcomes of MIT performed for thymoma have not been rigorously evaluated. We analyzed determinants of complete (R0) resection among patients undergoing MIT and OT in a large international database.

METHODS

The retrospective database of the International Thymic Malignancy Interest Group was queried. Chi-square and Wilcoxon rank sum tests, multivariate logistic regression models, and propensity matching were performed.

RESULTS

A total of 2514 patients underwent thymectomy for thymoma between 1997 and 2012; 2053 of them (82%) underwent OT and 461 (18%) underwent MIT, with the use of MIT increasing significantly in recent years. The rate of R0 resection among patients undergoing OT was 86%, and among those undergoing MIT it was 94% (p < 0.0001). In propensity-matched MIT and OT groups (n = 266 in each group); however, the rate of R0 resection did not differ significantly (96% in both the MIT and OT groups, p = 0.7). Multivariate analyses were performed to identify determinants of R0 resection. Factors independently associated with R0 resection were geographical region, later time period, less advanced Masaoka stage, total thymectomy, and the absence of radiotherapy. Surgical approach, whether minimally invasive or open, was not associated with completeness of resection.

CONCLUSIONS

The use of MIT for resection of thymoma has been increasing substantially over time, and MIT can achieve rates of R0 resection for thymoma similar to those achieved with OT.

Adjuvant Therapy for Thymic Carcinoma--A Decade of Experience in a Taiwan National Teaching Hospital

Background

Thymic carcinomas are rare tumors for which surgical resection is the first treatment of choice. The role of adjuvant treatment after surgery is unknown because of limited available data. The present study evaluated the efficacy of post-surgery adjuvant chemotherapy or radiotherapy in patients with thymic carcinoma.

Methods

To evaluate the role of adjuvant therapy in patients with thymic carcinoma, we retrospectively reviewed the records of patients with thymic carcinoma who were diagnosed and treated between 2004 and 2014.

Results

Among 78 patients with thymic carcinoma, 30 patients received surgical resection. Progression-free survival (PFS) and overall survival (OS) were significantly longer among these patients than among patients who received other treatments (PFS: 88.4 months vs 9.1 months, p<0.001; OS: 134.9 months vs 60.9 months; p = 0.003). Patients with stage III thymic carcinoma who received surgery had a longer OS than patients who did not receive surgery (70.1 months vs 23.9 months; p = 0.017, n = 11). Among 47 patients with stage IV carcinoma, 12 patients who received an extended thymothymectomy had a longer PFS than 35 patients who did not receive surgery (18.9 months vs 8.7 months; p = 0.029). Among 30 patients (with stage I- IV carcinoma) who received primary lesion surgery, 19 patients received an R0 resection and 9 patients of the 19 patients received adjuvant radiotherapy. These patients had longer PFS (50.3 months) than 2 patients who received adjuvant chemotherapy (5.9 months) or 4 patients who received concurrent chemoradiotherapy (7.5 months) after surgery (p = 0.003).

Conclusions

Surgical resection should be considered for patients with thymic carcinoma, even for patients with locally advanced or stage IV carcinoma. Adjuvant radiotherapy resulted in a better PFS after R0 resection.

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.

Recurrent TERT promoter mutations identified in a large-scale study of multiple tumour types are associated with increased TERT expression and telomerase activation

BACKGROUND

Several somatic mutation hotspots were recently identified in the telomerase reverse transcriptase (TERT) promoter region in human cancers. Large scale studies of these mutations in multiple tumour types are limited, in particular in Asian populations. This study aimed to: analyse TERT promoter mutations in multiple tumour types in a large Chinese patient cohort, investigate novel tumour types and assess the functional significance of the mutations.

METHODS

TERT promoter mutation status was assessed by Sanger sequencing for 13 different tumour types and 799 tumour tissues from Chinese cancer patients. Thymic epithelial tumours, gastrointestinal leiomyoma, and gastric schwannoma were included, for which the TERT promoter has not been previously sequenced. Functional studies included TERT expression by reverse-transcriptase quantitative polymerase chain reaction (RT-qPCR), telomerase activity by the telomeric repeat amplification protocol (TRAP) assay and promoter activity by the luciferase reporter assay.

RESULTS

TERT promoter mutations were highly frequent in glioblastoma (83.9%), urothelial carcinoma (64.5%), oligodendroglioma (70.0%), medulloblastoma (33.3%) and hepatocellular carcinoma (31.4%). C228T and C250T were the most common mutations. In urothelial carcinoma, several novel rare mutations were identified. TERT promoter mutations were absent in gastrointestinal stromal tumour (GIST), thymic epithelial tumours, gastrointestinal leiomyoma, gastric schwannoma, cholangiocarcinoma, gastric and pancreatic cancer. TERT promoter mutations highly correlated with upregulated TERT mRNA expression and telomerase activity in adult gliomas. These mutations differentially enhanced the transcriptional activity of the TERT core promoter.

CONCLUSIONS

TERT promoter mutations are frequent in multiple tumour types and have similar distributions in Chinese cancer patients. The functional significance of these mutations reflect the importance to telomere maintenance and hence tumourigenesis, making them potential therapeutic targets.