Postoperative Radiation Therapy Is Associated with Longer Overall Survival in Completely Resected Stage II and III Thymoma-An Analysis of the International Thymic Malignancies Interest Group Retrospective Database

Postoperative radiotherapy for completely resected thymoma and thymic carcinoma: A systematic review and meta-analysis

BACKGROUND

The role of postoperative radiotherapy (PORT) after complete tumor resection in patients with thymoma or thymic carcinoma remains controversial. We performed a meta-analysis to identify groups that would benefit from PORT.

METHODS

Multiple scientific databases were systematically searched for studies comparing overall survival (OS) and/or disease-free survival (DFS) between PORT and surgery alone in patients with completely resected thymomas or thymic carcinomas until April 10, 2024. A random-effects model was used for the statistical analysis.

RESULTS

A total of 31 studies with 10543 patients were included (17 studies involving 4763 patients with thymoma, seven studies involving 1045 patients with thymic carcinoma, and seven studies involving 4735 patients with mixed histological types). Notably, PORT significantly prolonged OS (hazard ratio [HR] = 0.73, 95% confidence interval [CI]: 0.59-0.91) and DFS (HR = 0.62, 95% CI: 0.43-0.89). Similar results were also observed when the multivariate-adjusted HRs were used as the measure of effect (OS: HR = 0.60, 95% CI: 0.43-0.83; DFS: HR = 0.48, 95% CI: 0.29-0.79). In subgroup analyses, PORT was associated with a longer OS and DFS for thymoma (HR = 0.73, 95% CI: 0.56-0.96 and HR = 0.65, 95% CI: 0.46-0.93), thymic carcinoma (HR = 0.72, 95% CI: 0.49-1.07 and HR = 0.38, 95% CI: 0.19-0.77), and stage 3-4 disease (HR = 0.50, 95% CI: 0.34-0.74 and HR = 0.44, 95% CI: 0.27-0.70), but not for stage 2 disease (HR = 0.81, 95% CI: 0.55-1.19 and HR = 0.97, 95% CI: 0.51-1.83).

CONCLUSIONS

PORT is likely to improve OS and DFS in patients with completely resected stage 3-4 thymoma or thymic carcinoma; however, the value of PORT for stage 2 disease requires further evaluation in large-scale studies.

Recommendations for Post-Operative RadioTherapy After Complete Resection of Thymoma-a French DELPHI Consensus Initiative

INTRODUCTION

Thymomas are rare intrathoracic malignancies that can relapse after surgery. Whether or not Post-Operative RadioTherapy (PORT) should be delivered after surgery remains a major issue. RADIORYTHMIC is an ongoing, multicenter, randomized phase 3 trial addressing this question in patients with completely R0 resected Masaoka-Koga stage IIb/III thymoma. Experts in the field met to develop recommendations for PORT.

METHODS

A scientific committee from the RYTHMIC network identified key issues regarding the modalities of PORT in completely resected thymoma. A DELPHI method was used to question 24 national experts, with 115 questions regarding the following: (1) imaging techniques, (2) clinical target volume (CTV) and margins, (3) dose constraints to organs at risk, (4) dose and fractionation, and (5) follow-up and records. Consensus was defined when opinions reached more than or equal to 80% agreement.

RESULTS

We established the following recommendations: preoperative contrast-enhanced computed tomography (CT) scan is recommended (94% agreement); optimization of radiation delivery includes either a four-dimensional CT-based planning (82% agreement), a breath-holding inspiration breath-hold-based planning, or daily control CT imaging (81% agreement); imaging fusion based on cardiovascular structures of preoperative and planning CT scan is recommended (82% agreement); right coronary and left anterior descending coronary arteries should be delineated as cardiac substructures (88% agreement); rotational RCMI/volumetric modulated arc therapy is recommended (88% agreement); total dose is 50 Gy (81% agreement) with 1.8 to 2 Gy per fraction (94% agreement); cardiac evaluation and follow-up for patients with history of cardiovascular disease are recommended (88% agreement) with electrocardiogram and evaluation of left ventricular ejection fraction at 5 years and 10 years.

CONCLUSION

This is the first consensus for PORT in thymoma. Implementation will help to harmonize practices.

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.

A Re-Examination of Neoadjuvant Therapy for Thymic Tumors: A Long and Winding Road

For most patients with advanced thymic epithelial tumors (TETs), a complete resection is a strong indicator of a better prognosis. But sometimes, primary surgery is unsatisfactory, and preoperative therapy is needed to facilitate complete resection. Neoadjuvant chemotherapy is the most used form of preoperative therapy. But studies on neoadjuvant chemotherapy have included mainly patients with thymoma; its efficacy in patients with thymic carcinoma is less known. Neoadjuvant chemoradiation has also been explored in a few studies. Novel therapies such as immunotherapy and targeted therapy have shown efficacy in patients with recurrent/metastatic TETs as a second-line option; their role as preoperative therapy is still under investigation. In this review, we discuss the existing evidence on preoperative therapy and the insight it provides for current clinical practice and future studies.

Impact of adjuvant radiotherapy and chemotherapy on thymoma

PURPOSE

Thymoma is a rare tumour. The most common treatment for thymoma is surgical resection, while the use of radiotherapy and chemotherapy remains controversial.

PATIENTS AND METHODS

We conducted a monocentric observational study of 31 patients diagnosed with thymoma from June 2004 to July 2020 at cancer centre in Strasbourg, France. We analysed the outcomes of the patients.

RESULTS

The 2- and 5- year locoregional relapse-free survival rates were 96.3% (95% confidence interval [CI]: 76.5-99.5%) and 68.0% (95% CI: 43.8-83.5%), respectively. Radiotherapy and chemotherapy significantly improved local tumour control (P=0.0008 and 0.04, respectively), while a larger initial tumour size significantly worsened local control rates (P=0.04). The 5- and 10-year overall survival rates were 87.1% (95% CI: 69.2-95%) and 81.7% (95% CI: 60.3-92.2%), respectively. The median overall survival was not reached, and no favourable factor was retrieved. For relapsed patients, the median overall survival after relapse was 115 months.

CONCLUSION

Despite the inherent limitations of retrospective studies with a limited patient sample size, we demonstrated that chemotherapy and radiotherapy in addition to surgery were effective in achieving local control and contributed to improving patient outcomes in thymoma. Notably, an aggressive treatment strategy at the time of relapse resulted in favourable outcomes for retreated patients.

Postoperative Radiation Therapy for Thymic Carcinoma: An Analysis of the International Thymic Malignancy Interest Group/European Society of Thoracic Surgeons Database

INTRODUCTION

R0 resection and radiation therapy have been associated with improved overall survival (OS) in patients with thymic carcinoma (TC). Here, we analyzed which subgroups of patients derive the greatest benefit from postoperative radiation therapy (PORT).

METHODS

Clinical, pathologic, treatment, and survival information of 462 patients with TC from the International Thymic Malignancy Interest Group/European Society of Thoracic Surgeons database were analyzed. Variables included age, sex, continent of treatment, paraneoplastic syndrome, carcinoma subtype, tumor size, pathologic Masaoka stage, resection status, and use of chemotherapy. OS was the primary end point using the Kaplan-Meier method. Time to recurrence (TTR) was the secondary end point using a competing risk analysis. A 3-month landmark analysis was performed.

RESULTS

PORT was associated with a significant OS benefit (5-y OS 68% versus 53%, p = 0.002). In patients with R0 resection, PORT was associated with increased OS for advanced (stages III-IV, p = 0.04), but not early (stages I-II, p = 0.14) stage TC. In patients with an R1/2 resection of advanced-stage TC, PORT was associated with significantly longer OS (5-y OS 53% versus 38%; p < 0.001). Subset analyses did not reveal clear associations of PORT with TTR. On multivariable analysis, lower pathologic stage, PORT, and R0 resection status were associated with an OS benefit, whereas only higher age and lower pathologic stage had an association with longer TTR.

CONCLUSIONS

In the largest individual patient data set on patients with TC reported to date, PORT was associated with a meaningful OS benefit in patients with advanced-stage TC after an R0 or R1/2 resection.

Comparison of radiotherapy techniques in patients with thymic epithelial tumor who underwent postoperative radiotherapy

PURPOSE

This retrospective study aimed to compare clinical outcomes and dosimetric parameters between radiation therapy (RT) techniques in patients with thymic epithelial tumor (TET).

MATERIALS AND METHODS

From January 2016 to December 2020, 101 patients with TET received adjuvant RT (median, 52.8 Gy; range, 48.4 to 66.0). Three different RT techniques were compared: three-dimensional conformal RT (3D-CRT; n = 59, 58.4%), intensity-modulated RT (IMRT; n = 23, 22.8%), and proton beam therapy (PBT; n = 19, 18.8%).

RESULTS

The median age of the patients and the follow-up period were 55 years (range, 28 to 79) and 43.4 months (range, 7.7 to 77.2). Patients in the PBT group were of the youngest age (mean age, 45.4 years), while those in IMRT group had the largest clinical target volume (mean volume, 149.6 mL). Patients in the PBT group had a lower mean lung dose (4.4 Gy vs. 7.6 Gy vs. 10.9 Gy, respectively; p < 0.001), lower mean heart dose (5.4 Gy vs. 10.0 Gy vs. 13.1 Gy, respectively; p = 0.003), and lower mean esophageal dose than patients in the 3D-CRT and IMRT groups (6.3 Gy vs. 9.8 Gy vs. 13.5 Gy, respectively; p = 0.011). Twenty patients (19.8%) showed disease recurrence, and seven patients (6.9%) died. The differences in the survival rates between RT groups were not statistically significant.

CONCLUSION

In patients with TET who underwent adjuvant RT, PBT resulted in a lower dose of exposure to adjacent organs at risk. Survival outcomes for patients in PBT group were not significantly different from those in other groups.

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.

Long-term outcomes following surgical treatment for thymic epithelial tumor in Japan and an analysis of prognostic factors based on the Japanese Association for Research on the Thymus nationwide database

PURPOSE

Patients with a thymic epithelial tumor (TET), comprising thymoma, thymic carcinoma (TC), and thymic neuroendocrine neoplasm (TNEN), are rarely encountered. The present study was conducted to determine the recent outcomes of surgical treatment for TET in Japan and clarify the significance of prognostic factors by analyzing a nationwide database created by the Japanese Association for Research on the Thymus (JART).

METHODS

The JART database includes records of 2471 thymoma, 285 TC, and 56 TNEN cases surgically treated between 1991 and 2010. At the time of the final follow-up examination, 439 patients had died, with tumor the cause of death in 188. The disease-specific survival was examined using the Kaplan-Meier method, with Cox's proportional hazards model utilized to determine independent prognostic factors.

RESULTS

The 10-year survival rate according to TNM-based Stage I, II, IIIA, IIIB, IVA, and IVB classification was 98.7%, 76.8%, 85.0%, 68.9%, 66.2%, and 59.8%, respectively. The T factor, M factor, and tumor size were independent prognostic factors in both thymoma and thymic carcinoma cases, while the N factor had tendency to be a prognostic factor in thymoma but not in thymic carcinoma cases. The WHO histological type was an independent factor in thymoma cases.

CONCLUSION

The significance of pathology and TNM classification as prognostic factors was confirmed.

Prognostic factors and role of postoperative radiotherapy in surgically resected thymomas

Objective

To investigate the prognostic factors in and role of postoperative radiotherapy (PORT) for surgically resected thymomas.

Methods

A total of 1540 patients with pathologically confirmed thymomas undergoing resection between 2000 and 2018 were identified retrospectively from the SEER (Surveillance, Epidemiology, and End Results) database. Tumors were restaged as local (limited to thymus), regional (invasion to mediastinal fat and other neighboring structures), or distant stage. Disease-specific survival (DSS) and overall survival (OS) were estimated by the Kaplan-Meier method and the log-rank test. Adjusted hazard ratios (HRs) with 95% CIs were calculated by Cox proportional hazards modeling.

Results

Tumor stage and histology were independent predictors of both DSS (regional: HR, 3.711; 95% CI, 2.006-6.864; distant: HR, 7.920; 95% CI, 4.061-15.446; type B2/B3: HR, 1.435; 95% CI, 1.008-2.044) and OS (regional: HR, 1.461; 95% CI, 1.139-1.875; distant: HR, 2.551; 95% CI, 1.855-3.509; type B2/B3: HR, 1.409; 95% CI, 1.153-1.723). For patients with regional stage and type B2/B3 thymomas, PORT was associated with better DSS after thymectomy/thymomectomy (HR, 0.268; 95% CI, 0.099-0.727), but the association was not significant after extended thymectomy (HR, 1.514; 95% CI, 0.516-4.44). Among patients with lymph node metastases, those who received PORT (HR, 0.372; 95% CI, 0.146-0.949), chemotherapy (HR, 0.843; 95% CI, 0.303-2.346), or both (HR, 0.296, 95% CI, 0.071-1.236) had a better OS.

Conclusions

The extent of invasion and tumor histology were independent predictors of worse survival following surgical resection of thymoma. Patients with regional invasion and type B2/B3 thymoma who undergo thymectomy/thymomectomy may benefit from PORT, while patients with nodal metastases may benefit from multimodal therapy, including PORT and chemotherapy.

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.

Surgical, Radiation, and Systemic Treatments of Patients With Thymic Epithelial Tumors: A Systematic Review

INTRODUCTION

Thymic epithelial tumors are rare and are classified as thymoma, thymic carcinoma, and thymic neuroendocrine tumors. The objective of this systematic review was to evaluate the treatment options for patients with thymic epithelial tumors.

METHODS

This systematic review was developed by Ontario Health (Cancer Care Ontario)'s Program in Evidence-Based Care and by the Lung Cancer Disease Site Group. MEDLINE, EMBASE, and the Cochrane Library were searched for studies comparing surgical, radiotherapy, or systemic treatments against any combination of these treatments in patients with thymic epithelial tumors. Meta-analyses were conducted with clinically homogenous studies.

RESULTS

A total of 106 studies were included, mainly from observational studies. There was an overall survival benefit with postoperative radiotherapy for patients with thymic carcinoma (hazard ratio = 0.65, 95% confidence interval: 0.47-0.89) and for patients with thymoma (hazard ratio = 0.70, 95% confidence interval: 0.59-0.82), especially for those with a high risk for mortality. Patients with thymic carcinoma or thymoma had a response to chemotherapy. Selection bias affected the results for studies that evaluated neoadjuvant chemotherapy or minimally invasive surgical techniques. Furthermore, the overall survival benefit found for adjuvant chemotherapy may have been confounded by the administration of postoperative radiotherapy.

CONCLUSIONS

For patients with thymoma or thymic carcinoma, the literature is of low quality and subject to bias. There were overall survival benefits with postoperative radiotherapy. The results of this systematic review were used to inform treatment recommendations in a clinical practice guideline. Future large-scale prospective studies that control for confounders are needed.

Clinical characteristics, prognostic factors, and long-term outcomes associated with epithelial malignancies of the thymus: A 20-year single-institution experience

BACKGROUND

Thymic epithelial tumors are rare and include thymomas and thymic carcinomas. There is scarce literature characterizing prognostic factors and long-term outcomes in these tumors.

AIMS

This review aims to describe disease features of thymomas and thymic carcinomas and to report clinical differences among thymoma histological subtypes.

METHODS AND RESULTS

A retrospective chart review was performed at the University of Florida Shands Hospital, a tertiary care academic medical center in Gainesville, Florida, USA. The review included clinical data of adults with thymic epithelial tumors diagnosed between 2001 and 2021. Significant associations among demographics, histology, stage, and outcomes were investigated. Thymoma subgroup analysis was performed using histological subtype and sex. Forty patients with thymoma and seven patients with thymic carcinoma were included in the final analysis. Among those with thymomas, patients with subtype B1, B2, or B3 tumors were younger, had larger tumors, and presented with higher stage disease when compared to those with subtypes A or AB. Tumor recurrence was most common in subtype B2 and B3 tumors (50.0% and 16.7% vs. 0%; p < .01). However, there was no significant difference in overall survival between histologic subtypes. Compared to females, males with thymomas had superior overall survival (103.0 vs. 62.9 months; p = .021) despite presenting with larger tumors (9.8 vs. 5.8 cm; p = .041). Concomitant myasthenia gravis was associated with increased recurrence but not worsened mortality. Compared to thymomas, patients with thymic carcinoma presented with higher-stage disease and had poorer 5-year survival (50.0% vs. 93.1%; p < .01).

CONCLUSION

This study affirmed pathologic stage and resectability as prognostic factors for thymic epithelial tumors. New findings include inferior overall survival in female patients and higher recurrence rates in those with thymomas and concomitant myasthenia gravis.

The Value of Postoperative Radiotherapy in Thymoma Patients with Myasthenia Gravis

INTRODUCTION

Surgery is the first-line treatment for patients with thymoma associated with myasthenia gravis (MG); however, the value of radiotherapy among these patients remains debatable. Herein, we examined the impact of postoperative radiotherapy (PORT) on the efficacy and prognosis of patients with thymoma and MG.

METHODS

This retrospective cohort study included 126 patients with thymoma and MG who were enrolled in the Xiangya Hospital clinical database between 2011 and 2021. Demographic and clinical data were collected including sex, age, histologic subtype, Masaoka-Koga staging, primary tumor, lymph node, metastasis (TNM) staging, and therapeutic modalities. To evaluate short-term MG symptom improvement following PORT, we examined changes in the quantitative myasthenia gravis (QMG) scores within 3 months post-treatment. Minimal manifestation status (MMS) was the main endpoint for assessing long-term improvement in MG symptoms. Overall survival (OS) and disease-free survival (DFS) were primary endpoints to determine the impact of PORT on prognosis.

RESULTS

Effects of PORT on MG symptoms: QMG scores significantly differed between the non-PORT and PORT groups (χ2= 6.300, p = 0.012). The median time to achieve MMS was significantly shorter in the PORT group than that in the non-PORT group (2.0 years vs. 4.4 years; p = 0.031). Multivariate analysis revealed that radiotherapy was associated with a reduced time to achieve MMS (hazard ratio [HR] 1.971, 95% confidence interval [CI]:1.102-3.525, p = 0.022). Effects of PORT on DFS and OS: The 10-year OS rate of the entire cohort was 90.5%, whereas OS rates for the PORT and non-PORT groups were 94.4 and 85.1%, respectively. The 5-year DFS rates for the whole cohort, PORT group, and non-PORT group were 89.7, 95.8, and 81.5%, respectively. PORT was associated with improved DFS (HR 0.139, 95% CI: 0.037-0.533, p = 0.004). In the high-risk histologic subgroup (type B2, B3), patients who received PORT had better OS (p = 0.015) and DFS (p = 0.0053) than those who did not receive PORT. PORT was associated with improved DFS (HR 0.232, 95% CI: 0.069-0.782, p = 0.018) in Masaoka-Koga stages II, III, and IV disease.

CONCLUSIONS

Overall, our findings indicate that PORT positively impacts thymoma patients with MG, particularly those with a higher histologic subtype and Masaoka-Koga staging.

Evaluation of the role of postoperative radiotherapy in locally invasive thymoma: A propensity-matched study based on the SEER database

OBJECTIVES

No consensus was reached on the efficacy of postoperative radiotherapy (PORT) in locally invasive thymomas because of the rarity of the thymic epithelial and the variations of study results. Therefore, we aimed to explore the efficacy of PORT in locally invasive thymomas using the Surveillance, Epidemiology, and End Results (SEER) database.

METHODS

Patients diagnosed with thymomas from 2004 to 2016 were identified using the SEER database. Prognostic factors of cancer-specific survival (CSS) and overall survival (OS) were identified using univariate and multivariate Cox regression analyses.Propensity score matching (PSM) was performed to balance the baseline characteristics.

RESULTS

A total of 700 eligible patients were identified. After PSM, 262 paired patients were selected from the two groups, those who received or did not receive PORT. Receiving PORT improved CSS and OS before and after PSM. In the matched population, the multivariate analyses showed that tumour invasion into adjacent organs/structures and non-utilisation of PORT were independent poor prognostic factors for CSS, whereas age ≥62 years,tumour invasion into adjacent organs/structures, and non-utilisation of PORT were independently associated with poorer OS. The subgroup analysis revealed that PORT improved CSS and OS in Masaoka-Koga stage III thymoma, but showed no OS benefit in Masaoka-Koga stage IIB thymoma.

CONCLUSION

Based on the SEER database, we found that PORT provides a significant survival benefit in Masaoka-Koga stage III thymoma with complete or incomplete resection. The role of PORT in thymoma requires further evaluation.

An Updated Review on Radiation Treatment Management in Thymus Cancers

This narrative review aims to summarize the currently available evidence for the role of radiation in the treatment of thymus cancers. Thymus cancers are rare, heterogeneous tumors with limited evidence to guide their clinical management. There remains some controversy over the role of radiation in the adjuvant and induction/definitive setting. We performed a systematic search of the MEDLINE/PubMed database, focusing on studies published within the last 30 years. Our search queried "thymoma [OR] thymic carcinoma [AND] radiation" and was limited only to prospective and retrospective studies and metanalyses, omitting books, documents, and reviews. Our search resulted in 174 total references, of which only 31 references were within the scope of interest ranging from 1988 to 2021. For resectable disease, there is prospective evidence to support the avoidance of postoperative radiation (PORT) in completely resected Masaoka stage I thymoma, but there is a lack of prospective evidence guiding the use of PORT in other situations. Several retrospective studies and metanalyses have suggested a benefit with PORT for positive margins and advanced stage disease, although it remains controversial whether PORT is beneficial for all completely resected Masaoka stage II thymoma. For unresectable disease, induction chemotherapy followed by reassessment of resectability is the preferred management. Prospective evidence exists to support the use of induction chemoradiation for patients unable to tolerate anthracycline-based chemotherapy and the use of definitive chemoradiation for those unable to undergo surgery. An effective multidisciplinary approach is the optimal strategy for achieving the best outcomes in patients with thymus cancers.

The Studies of Prognostic Factors and the Genetic Polymorphism of Methylenetetrahydrofolate Reductase C667T in Thymic Epithelial Tumors

Objective

To describe the clinical features of a cohort of patients with thymic epithelial tumors (TETs) and to analyze their prognostic factors. In particular, we investigated the correlation between the genetic polymorphism of methylenetetrahydrofolate reductase (MTHFR) C667T and the incidence of TETs.

Methods

Pathological records were reviewed from the database of the Second Affiliated Hospital of Jiaxing University, from January 2010 to December 2020, and 84 patients with TETs were recruited for this study. Univariate and multivariate analyses were performed to determine the prognostic factors. The genetic polymorphism of MTHFR C667T was examined in the patients with TETs and in a group of healthy individuals. The correlation between MTHFR transcriptional levels and methylation was analyzed using The Cancer Genome Atlas (TCGA) thymoma dataset from the cBioPortal platform.

Results

Kaplan–Meier univariate survival analysis showed that sex, age, the maximum tumor diameter, surgery, chemotherapy, radiotherapy, WHO histological classification, Masaoka–Koga stage, and 8th UICC/AJCC TNM staging, were statistically significantly correlated with the prognosis of patients with TETs. The Masaoka–Koga stage and 8th UICC/AJCC TNM staging were strongly correlated with each other in this study (r=0.925, P<0.001). Cox multivariate survival analysis showed that the maximum tumor diameter, Masaoka–Koga stage, and 8th UICC/AJCC TNM staging were independent prognostic factors affecting the overall survival (OS) of patients with TETs (P<0.05). The MTHFR C667T genotype (χ^{2 =} 7.987, P=0.018) and allele distribution (χ^{2 =} 5.750, P=0.016) were significantly different between the patients and healthy controls. CT heterozygous and TT homozygous genotypes at this MTHFR polymorphism significantly increased the risk of TETs (odds ratio [OR] =4.721, P=0.008). Kaplan–Meier univariate survival analysis showed that there was no correlation between different genotypes and the prognosis of TETs (CC versus CT + TT, χ^{2 =}0.003, P=0.959). Finally, a negative correlation between the transcriptional and methylation levels of MTHFR was observed in the TCGA thymoma dataset (r=-0.24, P=0.010).

Conclusions

The Masaoka–Koga stage, 8th UICC/AJCC TNM staging, and maximum tumor diameter were independent prognostic factors for TETs. Reduced methylation levels of MTHFR and particular polymorphic variants may contribute to the susceptibility to developing TETs.

Type A thymoma: a rare cause of neoplastic cardiac tamponade with long-term survival

Background

The prognosis of thymoma with cardiac tamponade is generally poor. Most of the reported thymomas with cardiac tamponade were type B or type AB (mixed thymoma), and cardiac tamponade due to type A thymoma, which has a better prognosis compared to type B thymoma, is extremely rare.

Case presentation

We encountered a case of cardiac tamponade in a 71-year-old male. He visited our emergency department due to exacerbation of fatigue and dyspnea on exertion that lasted for two weeks. Chest imaging revealed a large amount of pericardial fluid and a contrast-enhanced tumor with calcification in the anterior mediastinum. The patient underwent thoracoscopic tumor biopsy and pathological examinations revealed type A thymoma. In this case, long-term disease-free survival (7.5 years) was achieved by multidisciplinary treatment (preoperative chemotherapy, surgical excision, and postoperative radiation therapy), in accordance with the histological type.

Conclusions

This case indicates that neoplastic cardiac tamponade, even in elderly patients, should not necessarily be regarded as a terminal cancer and requires a systematic investigation for underlying causes.

"Radiotherapy for thymic epithelial tumors: What is the optimal dose? A systematic review."

Thymic epithelial tumors (TETs) are rare thoracic tumors, often requiring multimodal approaches. Surgery represents the first step of the treatment, possibly followed by adjuvant radiotherapy (RT) and, less frequently, chemotherapy. For unresectable tumors, a combination of chemotherapy and RT is often used. Currently, the optimal dose for patients undergoing radiation is not clearly defined. Current guidelines on RT are based on studies with a low level of evidence, where 2D RT was widely used. We aim to shed light on the optimal radiation dose for patients with TETs undergoing RT through a systematic review of the recent literature, including reports using modern RT techniques such as 3D-CRT, IMRT/VMAT, or proton-therapy. A comprehensive literature search of four databases was conducted following the PRISMA guidelines. Two investigators independently screened and reviewed the retrieved references. Reports with < 20 patients, 2D-RT use only, median follow-up time < 5 years, and reviews were excluded. Two studies fulfilled all the criteria and therefore were included. Loosening the follow-up time criteria to > 3 years, three additional studies could be evaluated. A total of 193 patients were analyzed, stratified for prognostic factors (histology, stage, and completeness of resection), and synthesized according to the synthesis without meta-analysis (SWIM) method. The paucity and heterogeneity of eligible studies led to controversial results. The optimal RT dose neither for postoperative, nor primary RT in the era of modern RT univocally emerged. Conversely, this overview can spark new evidence to define the optimal RT dose for each TETs category.

Therapeutic options in thymomas and thymic carcinomas

INTRODUCTION

Radical surgery is the best therapeutic option for thymic malignancies. However, patients with advanced or recurrent thymic malignancies often require chemotherapy or radiotherapy. Since thymic malignancies are rare cancers, the efficacy and safety of treatments have been verified based on small Phase 2 trials or retrospective studies.

AREA COVERED

We comprehensively reviewed the treatment strategies for thymic malignancies, including surgery, radiotherapy, and pharmacotherapy, including cytotoxic chemotherapy, molecular-targeted therapy, and immunotherapy. Additionally, we reviewed specific situations, such as pleural dissemination, central nervous system metastasis, and paraneoplastic syndrome.

EXPERT OPINION

Cytotoxic chemotherapy remains the standard option in pharmacotherapy. However, multikinase inhibitors, such as sunitinib and lenvatinib, and immune checkpoint inhibitors including pembrolizumab have been developed to treat thymic carcinomas. Now, a Phase 2 study is evaluating whether lenvatinib plus pembrolizumab benefits patients with type B3 thymoma or thymic carcinoma. Phosphatidylinositol 3-kinase/AKT/ mammalian target of rapamycin inhibitors may contribute to disease control and octreotide scan is only applicable to somatostatin analogues. Although the genomic characteristics of thymic malignancies have been analyzed, few actionable mutations have been detected in general. The development of a treatment strategy using combination pharmacotherapy is anticipated.

Pathological Features and Prognosis of Thymoma With or Without Myasthenia Gravis

INTRODUCTION

To evaluate the different pathological and clinical characters of thymoma with and without myasthenia gravis (MG) and to determine whether the presence of MG influences the prognosis in patients with thymoma.

METHODS

Four hundred and twenty-five consecutive patients operated was analyzed. A median sternotomy was used in 189 cases, and video-assisted thoracoscopic thymectomy was used in 236 cases. These patients with thymoma were subdivided into two groups: thymoma with myasthenia gravis MG (n = 220) and thymoma without MG (n = 205). All thymic epithelial tumors were classified according to the WHO histologic classification and the Masaoka clinical staging system. The result was evaluated according to the Myasthenia Gravis Foundation of America's criterion. The clinical features of the 2 test were compared between the two groups, and the survival analysis of Cox treatment effects was compared between the two groups.

RESULTS

There were no perioperative deaths. The proportions of type A and thymic carcinoma were 0% in the group with MG and 10.7% (22/205) and 11.2% (23/205), respectively, in the group without MG. Thymic hyperplasia around the thymoma was 29.1% (64/220) in patients with MG and only 6.3% (13/205) in patients without MG (χ2 = 23.63, P = 0.000). The overall survival curve showed that the 5- and 10-year survival rates in the group without MG were 89.2 and 77.4%, respectively, while those in the MG group were 91.1 and 80.5%.

CONCLUSIONS

The existence of MG has little influence on the prognosis of thymomas, but it is suitable for early diagnosis and treatment. Extended thymectomy should be performed on all patients with thymoma, whether they have MG or not.

Development of a competing risk nomogram for the prediction of cause-specific mortality in patients with thymoma: a population-based analysis

Background

This study was developed to assess the odds of cause-specific mortality and other types of mortality in thymoma patients. In addition, these analyses were leveraged to develop a comprehensive competing risk model-based nomogram capable of predicting cause-specific mortality as a result of thymoma.

Methods

Thymoma patients included within the Surveillance, Epidemiology, and End Results (SEER) database from 2004–2016 were identified, and the odds of cause-specific mortality due to thymoma and other forms of mortality for these patients were estimated. In addition, Fine and Gray’s proportional subdistribution hazard model was constructed, and a competing risk nomogram was developed using this model that was capable of predicting the odds of 3-, 5-, and 10-year cause-specific mortality in thymoma patients.

Results

In total, 1,591 relevant cases in the SEER database were selected for analysis. In this patient cohort, the respective 5-year cumulative incidence rates for cause-specific mortality and mortality attributable to other causes were 12.4% and 8.2%. Variables significantly associated with cause-specific mortality included age, chemotherapy, surgery, and Masaoka stage. Additionally, the odds of other-cause-specific mortality rose with increasing patient age, and chemotherapy was correlated with other-cause-specific mortality. The competing risk nomogram that was developed exhibited good discriminative ability as a means of predicting cause-specific mortality, as evidenced by a concordance index (C-index) value of 0.84. Calibration curves further revealed excellent consistency between predicted and actual mortality when using this nomogram.

Conclusions

In summary, we herein assessed the odds of cause-specific and other-cause-specific mortality among thymoma patients, and we designed a novel nomogram capable of predicting cause-specific mortality for thymoma, providing a promising tool that may be of value in the context of individualized patient prognostic evaluation.

The Prognostic Value of Preoperative Serum D-dimer Levels After Surgical Resection of Thymic Epithelial Tumors

Introduction

Thymic epithelial tumors are the most common mediastinal tumors. Despite the high survival rate after surgery, some patients still require postoperative adjuvant therapy and closer follow-up. Hematological indicators such as biochemical routines and coagulation indicators have been reported to be independently associated with the prognosis of various malignancies. Therefore, we included hematological indicators in the analysis.

Methods

The data of 105 patients with thymic epithelial tumors were retrospectively collected from Sun Yat-sen University Cancer Center, and the patients with missing preoperative hematological indicators were excluded. X-tile software was used to obtain the best cutoff value of each preoperative hematological indicator, and COX regression analysis and Kaplan-Meier survival curves were used to demonstrate statistically significant results.

Results

COX univariate regression analysis of all patients showed that Masaoka stage, T stage, WHO histologic types, D-dimer, albumin-fibrinogen ratio (AFR), Fibrinogen (Fbg) were associated with postoperative overall survival ( P < .05). T stage, WHO histologic types, D-dimer, and AFR were associated with postoperative recurrence-free survival ( P < .05). Finally, multivariate regression analysis showed that T stage, D-dimer levels were independently associated with postoperative overall survival (OS) and recurrence-free survival (RFS) in patients with thymic epithelial tumors.

Conclusions

For thymic epithelial tumors, higher preoperative D-dimer levels predict poorer survival and shorter recurrence-free survival. This may help guide postoperative adjuvant therapy and follow-up patterns in patients with thymic epithelial tumors.

Thymic tumours and their special features

Thymic tumours are rare thoracic malignancies, that may be aggressive and difficult to treat. The pillars of the management include pathological review, consideration of differential diagnoses, staging and multidisciplinary discussion. Assessment of resectability is key to drive the treatment sequencing. Association with autoimmune diseases, especially myasthenia gravis, is observed, which impacts the oncological management. Networks are being built at the national and international levels. This article provides an overview of the most recent findings in the diagnosis, staging, histology, and management strategies of thymic tumours.

Thymic tumours are rare and heterogeneous tumours. Management is based on multidisciplinary discussion and networking.https://bit.ly/3kYAZ7u

Dosimetric analysis of postoperative radiotherapy for thymoma

PURPOSE

To compare the dosimetric differences between intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) in the treatment of male and female thymoma.

MATERIAL AND METHODS

This single-institutional analysis included 20 patients with thymoma treated with RT between January 2017 and December 2020. Twenty patients were retrospectively planned for IMRT (IMRT1 with an average field angle of 216°, 288°, 0°, 72°,and 144°; IMRT2 with fan-shaped field angles of 280°, 320°, 0°, 40°, and 80°) and VMAT (VMAT1 with two arcs ranging form 280° to 80°,clockwise and then counterclockwise; VMAT2 with two 360° arcs). The plans for all investigated RT modalities were optimized for a prescriptional dose of 50Gy and fractional dose of 2.0Gy. Planning target volume (PTV) and organs-at-risk (OARs: heart, breasts, lungs, spinal cord, and esophagus) dosimetric parameters were compared.

RESULTS

All plans met the preparation aims for all the included metrics. There was little difference in the median values of PTV parameters (D_2%, D_98%, D_mean, homogeneity index[HI], and conformity index [CI]). The CI of the VMAT2 plan was the closest to 1 in both therapy groups. The monitor unit (MU) of IMRT2 and the estimated total delivery time of VMAT1 were the lowest in both therapy groups and were statistically significant. In the male group, the lung parameters (D_mean, V_5Gy, V_10Gy, and V_20Gy) for VMAT1 were the lowest and showed statistical significance. In the female group, the lung parameters (D_mean, V_5Gy, V_10Gy, and V_20Gy) and bilateral breast parameters (Dmean, V_5Gy, V_10Gy, and V_20Gy) of IMRT2 were the lowest and showed statistical significance.

CONCLUSIONS

In male thymoma patients undergoing postoperative RT (PORT) treatment, the choice of fan-shaped VMAT may be a better option for protecting the lungs. For female thymoma patients receiving PORT, fan-shaped IMRT can better protect the lungs and breasts. The fan-shaped field performed better than the average and the full arc fields in PORT for thymoma.

Invasive thymoma - Which patients benefit from post-operative radiotherapy?

BACKGROUND

The aim of this study is to identify patients with thymoma who should receive post-operative radiotherapy.

METHODS

The Surveillance, Epidemiology, and End Results database was queried for stage IIB-IV thymoma patients diagnosed during 1988-2015. We analyzed the prognostic implications of various clinical-pathological factors by comparing the outcomes of those who received surgery with and without post-operative radiotherapy.

RESULTS

A total of 1120 patients were identified; 62% received post-operative radiotherapy and 38% underwent surgery alone. In a propensity-matched cohort of 812 patients, no survival difference was seen in World Health Organization A, AB, B1, B2, or B3 tumors with the addition of post-operative radiotherapy to surgery (p>0.05). Post-operative radiotherapy also did not improve survival over surgery alone for tumors ≥ or < less than the 4 cm, 7 cm, 10 cm, and 13 cm cutoffs, all p>0.05. Post-operative radiotherapy was an independent, positive prognostic indicator only in the subgroup with stage III disease and in those receiving chemotherapy in addition to post-operative radiotherapy, both p<0.05.

CONCLUSIONS

Patients with stage III thymoma are most likely to benefit from the addition of post-operative radiotherapy to surgical treatments. Tumor size or World Health Organization histology alone should not be criteria for determining the need for post-operative radiotherapy in locally advanced thymoma. Masaoka-Koga stage, which has traditionally been used to help make such decisions, appears to be the most reliable determinant of the use of post-operative radiotherapy.

GOECP/SEOR radiotherapy guidelines for thymic epithelial tumours

Thymic epithelial tumours (TET) are rare, heterogeneous neoplasms that range from resectable indolent tumours to aggressive thymic carcinomas with a strong tendency to metastasize. The pathological diagnosis is complex, in part due to the existence of several different classification systems. The evidence base for the management of TETs is scant and mainly based on non-randomised studies and retrospective series. Consequently, the clinical management of TETs tends to be highly heterogenous, which makes it difficult to improve the evidence level. The role of technological advances in the field of radiotherapy and new systemic therapies in the treatment of TETs has received little attention to date. In the present clinical guidelines, developed by the GOECP/SEOR, we review recent developments in the diagnosis and classification of TETs. We also present a consensus-based therapeutic strategy for each disease stage that takes into consideration the best available evidence. These guidelines focus primarily on the role of radiotherapy, including recent advances, in the management of TETs. The main aim of this document is to promote the standardisation of clinical practice and lay the foundations for future studies to clarify the main unresolved questions related to the optimal management of TET.

Radiotherapy for thymic epithelial tumours: a review

Thymic epithelial tumours (TETs) represent a rare disease, yet they are the most common tumours of the anterior mediastinum. Due to the rare occurrence of TETs, evidence on optimal treatment is limited. Surgery is the treatment of choice in the management of TETs, while the role of postoperative radiotherapy (PORT) remains unresolved. PORT remains debated for thymomas, especially in completely resected stage II tumours, for which PORT may be more likely to benefit in the presence of aggressive histology (WHO subtype B2, B3) or extensive transcapsular invasion (Masaoka-Koga stage IIB). For stage III thymoma, evidence suggests an overall survival (OS) benefit for PORT after complete resection. For incompletely resected thymomas stage II or higher PORT is recommended. Thymic carcinomas at any stage with positive resection margins should be offered PORT. Radiotherapy plays an important role in the management of unresectable locally advanced TETs. Induction therapy (chemotherapy or chemoradiation) followed by surgery may be useful for locally advanced thymic malignancies initially considered as unresectable. Chemotherapy only is offered in patients with unresectable, metastatic tumours in palliative intent, checkpoint inhibitors may be promising for refractory diseases. Due to the lack of high-level evidence and the importance of a multidisciplinary approach, TETs should be discussed within a multidisciplinary team and the final recommendation should reflect individual patient preferences.

RADIORYTHMIC: Phase III, Opened, Randomized Study of Postoperative Radiotherapy Versus Surveillance in Stage IIb/III of Masaoka Koga Thymoma after Complete Surgical Resection

INTRODUCTION

Thymomas are rare intrathoracic malignancies that may be aggressive and difficult to treat. Knowledge and level of evidence for treatment strategies are mainly based on retrospective studies or expert opinion. Currently there is no strong evidence that postoperative radiotherapy after complete resection of localized thymoma is associated with survival benefit in patients. RADIORYTHMIC is a phase III, randomized trial aiming at comparing postoperative radiotherapy versus surveillance after complete resection of Masaoka-Koga stage IIb/III thymoma. Systematic central pathologic review will be performed before patient enrollment as per the RYTHMIC network pathway.

PATIENTS AND METHODS

Three hundred fourteen patients will be included; randomization 1:1 will attribute either postoperative radiotherapy (50-54 Gy to the mediastinum using intensity-modulated radiation therapy or proton beam therapy) or surveillance. Stratification criteria include histologic grading (thymoma type A, AB, B1 vs B2, B3), stage, and delivery of preoperative chemotherapy. Patient recruitment will be mainly made through the French RYTHMIC network of 15 expert centers participating in a nationwide multidisciplinary tumor board. Follow-up will last 7 years. The primary endpoint is recurrence-free survival. Secondary objectives include overall survival, assessment of acute and late toxicities, and analysis of prognostic and predictive biomarkers.

RESULTS

The first patient will be enrolled in January 2021, with results expected in 2028.

Postoperative Radiotherapy for Completely Resected Masaoka/Masaoka-Koga Stage II/III Thymoma Improves Overall Survival: An Updated Meta-Analysis of 4746 Patients

INTRODUCTION

Our systematic review and meta-analysis aimed to evaluate the effect of postoperative radiotherapy (PORT) on completely resected Masaoka/Masaoka-Koga (M/MK) stage II/III thymomas.

METHODS

We systematically searched four online databases and included studies that compared surgery alone versus surgery plus a PORT for completely resected M/MK stage II/III thymoma. The multivariate-adjusted hazard ratios (HRs) of overall survival (OS) and disease-free survival were evaluated as the primary and secondary end points, respectively. We performed a subgroup analysis for OS with respect to M/MK stage II, III, and inseparable II/III cases. A generic inverse variance meta-analysis using a random model was conducted.

RESULTS

Five studies including 4746 patients (among them, 2408 patients received PORT) met our selection criteria. A meta-analysis of these five studies revealed that PORT was associated with a significantly better OS (HR = 0.68, 95% confidence interval [CI]: 0.57-0.83, p < 0.001, I² = 0%, p for heterogeneity = 0.97). Subgroup analyses for M/MK stage II disease (HR = 0.63, 95% CI: 0.44-0.91, p = 0.01, I² = 0%, p for heterogeneity = 0.80) and M/MK stage III disease (HR = 0.72, 95% CI: 0.55-0.95, p = 0.02, I² = 0%, p for heterogeneity = 0.84) revealed similar results. PORT was not associated with an improved disease-free survival (HR = 0.96, 95% CI: 0.70-1.33, p = 0.83, I² = 0%, p for heterogeneity = 0.72).

CONCLUSIONS

Currently available evidence from observational studies suggests PORT for patients with completely resected M/MK stage II/III thymoma. A randomized trial is warranted.

Multimodality approach in treatment of thymic tumors

Thymic tumors are rare neoplasms showing important clinical and pathologic polymorphisms ranging from low-mitotic encapsulated tumors to a highly aggressive and disseminating one. Complete resection of the tumor with surrounding fatty and mediastinal tissue is of paramount importance and provides good prognosis. Diagnosis of the tumor, radiologic evaluation and implementation of multimodal treatment including preoperative chemotherapy, radiotherapy, postoperative radiotherapy, adjuvant chemotherapy or radiotherapy are important components of the treatment strategy. Some of the stage III tumors can be resected without additional treatment, however, there is a good evidence to support administering preoperative and postoperative chemotherapy and postoperative radiotherapy in these patients providing higher complete resection rate and better survival. For stage IVA thymomas, surgery alone should not be considered as an effective approach and these tumors are considered as unresectable. Chemo/radiotherapy can be administered to those patients. Of those, postoperative chemotherapy and radiotherapy should be considered if these patients who were deemed to be previously unresectable become resectable. The combined modality treatment should provide prevention of locoregional and intrathoracic recurrence and eventually long-term survival with cure. New targeted therapies including agents against PI3K, CDK, and immune checkpoint PD-1/PD-L1 may lead to higher response rates with less toxicity.

The role of postoperative radiotherapy for thymomas: a multicentric retrospective evaluation from three Italian centers and review of the literature

Background

Thymoma is a rare mediastinal neoplasia. Surgery is the backbone of the treatment, but the role of postoperative radiotherapy (PORT) remains controversial. We aimed to obtain data on survival and safety in patients treated with PORT in three different Italian institutions.

Methods

We retrospectively analyzed 183 consecutive patients who underwent surgery from 1981 to 2015. According to the Masaoka-Koga staging system, 39.3%, 32.7%, 18.6% and 9.8% patients were in stage I, II, III and IV of disease, respectively. PORT was indicated in 114 patients (62.3%), while 69 subjects underwent surgery alone. Complete resection was obtained in 68 patients who underwent PORT. Adverse events (AEs) were graded according to CTCAE v4.0. We analyzed the recent literature to describe the current reports on PORT for resected thymoma.

Results

Mean follow-up was 130 months (range, 3–417 months). Overall survival (OS) at 1-, 5- and 10-year from surgery was 98.3%, 90.2% and 69.7% respectively. One-, 5- and 10-year disease specific survival (DSS) was 98.9%, 92.3% and 89.8% respectively. Disease free survival (DFS) at 1, 5 and 10 years from surgery was 96.7%, 88.3% and 82.8% respectively. Univariate analysis showed that complete resection, cell histology A-AB-B1 and stages I–II were significant predictors of better DSS and DFS. Multivariate analysis showed that sex, R0 margins and WHO histology was independent prognostic factors. Among patients treated with PORT, a trend towards better OS was evident with Masaoka stage I–II (P=0.09). Patients with R0 margins treated with PORT showed better OS and DSS (P=0.05). No differences in DSS for performance status (P=0.70), WHO histology (P=0.19), paraneoplastic syndrome (P=0.23) and surgical procedure (P=0.53) were evident. Patients treated with PORT had a higher level of acute AEs compared to surgery alone, but none of these was graded ≥3.

Conclusions

Our results confirmed that patients with incompletely resected thymoma had the worst OS and DSS. High grade acute toxicity was not different between PORT and surgery alone. Other trials reported a significant benefit in OS, DSS and DFS in stage IIb–IV thymoma treated with PORT.

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

Background

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

Methods

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

Results

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

Conclusions

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

Prognostic Factor of Completely Resected and Pathologic T3 N0 M0 Thymic Epithelial Tumor

BACKGROUND

A multiinstitutional study was conducted to analyze prognosticators of completely resected and pathologic T3 N0 M0 (pT3 N0 M0) stage thymic epithelial tumors.

METHODS

A total of 607 patients with surgically treated thymic epithelial tumors between June 1988 and December 2017 were enrolled. A Cox proportional hazards model and an inverse probability of treatment weighting-adjusted analysis using the propensity score were performed.

RESULTS

A total of 394 patients with thymoma and 130 patients with thymic carcinoma underwent complete tumor resections. Forty-one thymomas and 49 thymic carcinomas were confirmed as pT3 N0 M0 stage tumors. Postoperative adjuvant radiotherapy was associated with improved disease-free and overall survival in patients with thymoma (hazard ratio [HR], 0.40; 95% confidence interval [CI], 0.23 to 0.69; and HR, 0.24; 95% CI, 0.11 to 0.52, respectively) and in patients with thymic carcinoma (HR, 0.15; 95% CI, 0.07 to 0.33; and HR, 0.12; 95% CI, 0.05 to 0.31, respectively). Although lung invasion was associated with poor disease-free survival (HR, 3.28; 95% CI, 1.90 to 5.89) and overall survival (HR, 2.60; 95% CI, 1.21 to 6.07), male sex (HR, 1.88; 95% CI, 1.10 to 3.18), older age (HR, 2.77; 95% CI, 1.29 to 5.70), and advanced histologic features (HR, 3.84; 95% CI, 1.42 to 14.51) were associated with poor overall survival in patients with pT3 N0 M0 thymoma. Adjuvant chemotherapy was associated with improved disease-free survival (HR, 0.11; 95% CI, 0.03 to 0.41) and overall survival (HR, 0.11; 95% CI, 0.06 to 0.20) in patients with pT3 N0 M0 thymic carcinoma with superior vena cava or innominate vein invasion.

CONCLUSIONS

Postoperative radiotherapy was associated with improved survival in patients with pT3 N0 M0 thymic epithelial tumors. Lung invasion was associated with poor survival in patients with pT3 N0 M0 thymoma. Adjuvant chemotherapy was associated with improved survival in patients with pT3 N0 M0 thymic carcinoma with superior vena cava or innominate vein invasion.

Thymic Malignancy-Updates in Staging and Management

Thymomas are relatively indolent tumors that present with locally advanced disease in 30% of the patients. Thymic carcinoma is a more aggressive histology with shorter disease-free and overall survival. Early-stage tumors are managed best with complete resection. Multimodal therapy is the standard of care for locally advanced tumors and neoadjuvant therapy may help improve respectability. Stage and complete resection are the strongest prognostic factors for long-term survival. Based on early experience, targeted and immunotherapies have shown limited promise in advanced disease.

Management and Long-Term Outcomes of Advanced Stage Thymoma in the United States

BACKGROUND

Thymomas are rare tumors, with limited data regarding treatment of advanced stage disease. Although surgical resection is the mainstay of treatment, the role of additional therapy remains controversial. Our objectives were to describe treatment strategies for stage III/IV thymoma in the United States and compare survival outcomes among treatment approaches.

METHODS

We identified Masaoka stage III/IV thymoma reported in the National Cancer Database between 2004 and 2016. Frequencies of treatment with surgery, chemotherapy, radiation, and combinations were calculated. Five-year overall survival was compared using the Kaplan-Meier method and log-rank test. Risk-adjusted proportional hazards modeling compared mortality between treatment regimens.

RESULTS

A total of 1849 patients were identified (1108 stage III, 741 stage IV). Among stage III patients, 83.8% underwent resection (± other modalities) compared with 60.2% of stage IV. Surgery plus radiation was the most common regimen for stage III (32.6%), and nonsurgical treatment (definitive chemotherapy and/or radiation) was the most common for stage IV (36.4%). Overall 5-year survival was 70.3% for stage III and 58.5% for stage IV. In risk-adjusted analysis, surgery plus radiation had the lowest mortality (hazard ratio 0.41, 95% confidence interval 0.30-0.55). Patient age, tumor size, metastases, and non-academic treating hospital were associated with mortality.

CONCLUSIONS

Current treatment regimens for advanced stage thymoma vary significantly. Regimens that include surgical resection are most common and are associated with superior outcomes. Patients selected to have surgery as primary treatment had the best survival. Adjuvant radiation treatment is associated with better survival and should be considered in patients who undergo resection.

Impact of Definitive Radiotherapy and Surgical Debulking on Treatment Outcome and Prognosis for Locally Advanced Masaoka-Koga stage III Thymoma

The role of definitive radiotherapy (dRT) and debulking surgery (DS) for patients with locally advanced, unresectable, Masaoka-Koga stage III thymomas was not well studied. Unresectable tumor refers to tumor that could not be completely resected because of invasion of surrounding organs. Consecutive patients with unresectable stage III thymomas between 2000 and 2017 were reviewed. According to the treatment intent and radiation dose, patients were categorized into a dRT group and a non-dRT group. The former group included patients who received radiotherapy at doses ≥ 54 Gy after DS or biopsy. The latter group included patients who did not receive radiotherapy and those who received a radiation dose < 54 Gy. A total of 82 patients were included. Compared with non-dRT, dRT significantly improved 5-year overall survival (OS, P = 0.003), progression-free survival (PFS, P = 0.008), and freedom from locoregional failure (FFLF, P < 0.001). Compared with biopsy alone, DS did not improve OS, PFS, FFLF. On multivariate analysis, dRT was an independent prognostic factor for OS (hazard ratio [HR]: 2.37, P = 0.024), PFS (HR: 2.40, P = 0.004), and FFLF (HR: 3.83, P = 0.001). In conclusion, dRT was an effective and beneficial treatment for patients with unresectable Masaoka-Koga stage III thymoma.

The Role of Adjuvant Therapy in Advanced Thymic Carcinoma: A National Cancer Database Analysis

BACKGROUND

There is area of controversy and variability in the recommendation for the role of adjuvant therapy after R0 resection of a Masaoka stage IIB and III thymic carcinoma. This study investigated the role of adjuvant therapy in patients who had complete surgical resection for thymic carcinoma.

METHODS

Patients with stage IIB and III thymic carcinoma who underwent curative resection were queried and categorized according to Masaoka-Koga stage groups from the National Cancer Database. Patients were grouped by treatment status (surgery only or surgery followed by adjuvant therapy). Kaplan-Meier estimates of overall survival and univariate and multivariate Cox proportional hazards regression analyses were performed.

RESULTS

From 2004 to 2013, 632 surgical patients with stage IIB and III thymic carcinoma were selected for analysis. In stage IIB patients, the adjuvant therapy group had improved survival compared with the surgery only group (P = .01), although no survival difference was observed in patients who had R0 resection between the 2 groups (P = .59). In multivariate analysis, age (P < .001) and grade III and IV (P = .02) negatively impacted survival; the adjuvant therapy improved survival (P < .02). For stage III cancer, the adjuvant therapy group had improved survival compared with the OS group regardless of margin status. In multivariate analysis, tumor size exceeding 70 mm (P = .02) and positive margin (P < .01) negatively affected survival; adjuvant therapy improved survival (P < .01).

CONCLUSIONS

Adjuvant therapy showed no benefit in patients with stage IIB cancer who had R0 resection. Use of adjuvant therapy should be strongly considered for stage IIB cancer patients with positive margins and all stage III thymic cancer patients.

A Recurrence Predictive Model for Thymic Tumors and Its Implication for Postoperative Management: a Chinese Alliance for Research in Thymomas Database Study

OBJECTIVE

Our aim was to investigate appropriate postoperative management based on the risk of disease recurrence in thymic epithelial tumors after complete resection.

METHODS

The Chinese Alliance for Research in Thymomas retrospective database was reviewed. Patients having stage I to IIIa tumors without pretreatment and with complete resection were included. Clinicopathologic variables with statistical significance in the multivariate Cox regression were incorporated into a nomogram for building a recurrence predictive model.

RESULTS

A total of 907 cases, including 802 thymomas, 88 thymic carcinomas, and 17 neuroendocrine tumors, were retrieved between 1994 and 2012. With a median follow-up of 52 months, the 10-year overall survival rate was 89.5%. Distant and/or locoregional recurrences were noted in 53 patients (5.8%). The nomogram model revealed histologic type and T stage as independent predictive factors for recurrence, with a bootstrap-corrected C-index of 0.86. On the basis of this model, patients with T1 thymomas or T2 or T3 type A, AB, or B1 thymomas had a significantly lower incidence of recurrence (low-risk group) than those with T2 or T3 type B2 or B3 thymomas and all thymic carcinomas and neuroendocrine tumors (high-risk group) (2.7% versus 20.1% [p < 0.001]). In the high-risk group, more than half of the recurrences (55.2% [16 of 29]) were seen within the first 3 postoperative years, whereas all recurrences but one were recorded within 6 years after surgery. Recurrence occurred quite evenly over 10 postoperative years in the low-risk group.

CONCLUSIONS

A 6-year active surveillance should be considered in high-risk patients regardless of adjuvant therapy. For low-risk patients, annual follow-up may be sufficient. Studies examining postoperative adjuvant therapies would be plausible in high-risk patients.

The role of salvage radiotherapy in recurrent thymoma

Purpose

To explore the role of salvage radiotherapy (RT) for recurrent thymoma as an alternative to surgery.

Materials and Methods

Between 2007 and 2015, 47 patients who received salvage RT for recurrent thymoma at Yonsei Cancer Center were included in this study. Recurrent sites included initial tumor bed (n = 4), pleura (n = 19), lung parenchyma (n = 10), distant (n = 9), and multiple regions (n = 5). Three-dimensional conformal and intensity-modulated RT were used in 29 and 18 patients, respectively. Median prescribed dose to gross tumor was 52 Gy (range, 30 to 70 Gy), with equivalent doses in 2-Gy fractions (EQD₂). We investigated overall survival (OS), progression-free survival (PFS), and patterns of failure. Local failure after salvage RT was defined as recurrence at the target volume receiving >50% of the prescription dose.

Results

Median follow-up time was 83 months (range, 8 to 299 months). Five-year OS and PFS were 70% and 22%, respectively. The overall response rate was 97.9%; complete response, 34%; partial response, 44.7%; and stable disease, 19.1%. In multivariate analysis, histologic type and salvage RT dose (≥52 Gy, EQD₂) were significantly associated with OS. The high dose group (≥52 Gy, EQD₂) had significantly better outcomes than the low dose group (5-year OS: 80% vs. 59%, p = 0.046; 5-year PFS: 30% vs. 14%, p=0.002). Treatment failure occurred in 34 patients; out-of-field failure was dominant (intra-thoracic recurrence 35.3%; extrathoracic recurrence 11.8%), while local failure rate was 5.8%.

Conclusion

Salvage RT for recurrent thymoma using high doses and advanced precision techniques produced favorable outcomes, providing evidence that recurrent thymoma is radiosensitive.

Optimal management of thymic malignancies: current perspectives

Thymic epithelial tumors (TETs) belong to orphan oncology. The incidence of TETs is about 1.3–3.2 cases per million worldwide. Following pathology, evolution and prognosis are variable. The World Health Organization classification distinguishes thymomas and thymic carcinomas. TETs are composed of thymic epithelial tumoral cells and normal lymphocytes. The mean age at diagnosis is 50–60 years-old. There are no identified risk factors. TETs are frequently associated with paraneoplastic syndromes as myasthenia gravis. The complete R₀ surgical resection is the most significant prognosis factor on survival. In 2010, the French National Institute of Cancer labeled the RYTHMIC network as a specific tumor board including thoracic surgeons, oncologist, and radiation therapist to define standard of care for the management of TETs. The aim of the review was to update knowledge to optimize the standard of care.

Proton therapy for thymic malignancies: multi-institutional patterns-of-care and early clinical outcomes from the proton collaborative group and the university of Florida prospective registries

Objective: Thymic malignancies (TM) are rare tumors with long-term survivorship, causing concerns for radiotherapy-related late side effects. Proton therapy (PT) reduces the radiation dose to organs at risk, potentially decreasing long-term toxicities while preserving disease control. We report patterns-of-care and early clinical outcomes after PT for thymoma and thymic carcinoma. Methods: Between January 2008 and March 2017, 30 patients with TMs enrolled on one of two IRB-approved prospective protocols and received postoperative or definitive PT. Clinical outcomes, pathology, treatment dose, toxicities, and follow-up information were analyzed. Results: Twenty-two thymoma patients with a median age of 52.1 years (range, 23-72) received a median RT dose of 54 Gy (RBE) (range, 45-70) either postoperatively (91%) or definitively (9%); 23% received adjuvant chemotherapy. Among eight thymic carcinoma patients, the median age was 65.5 years (range, 38-88) and median RT dose was 60 Gy (RBE) (range, 42-70) delivered postoperatively (75%) or definitively (25%); 50% received chemotherapy. Median follow-up for all patients was 13 months (range, 2-59 months). Five patients relapsed, one locally (3%). Three patients died of disease progression, including two thymomas and one thymic carcinoma patient; a fourth died of intercurrent disease. One patient with thymic carcinoma and 1 with thymoma are alive with disease. No patients treated with PT for their initial disease (de novo) experienced grade ≥3 toxicities. The most common grade 2 toxicities were dermatitis (37%), cough (13%), and esophagitis (10%). Conclusion: Adjuvant and definitive PT are being used in the treatment of TMs. Early results of the largest such cohort reported to date demonstrates an acceptable rate of recurrence with a favorable toxicity profile. Longer follow-up and a larger patient cohort are needed to confirm these findings.

Favourable health-related quality of life reported in survivors of thymic malignancies

OBJECTIVES

The management of patients with locally advanced thymic malignancies remains controversial. Differing combinations of surgical resection, chemotherapy and radiation are used in the management of initial and relapsed disease. Treatment-related toxicities and quality of life could inform therapeutic options. This study describes health utility scores (HUS) in survivors with locally advanced thymic malignancies and investigates the impact of multimodality regimens on HUS.

METHODS

In a cross-sectional study (2014-2017), patients with Masaoka Stage II-IVa thymic malignancies completed various self-reported questionnaires, including EuroQol-5-Dimensions with visual analogue scale (VAS), Eastern Cooperative Oncology Group (ECOG) and Edmonton Symptom Assessment Scale tools. Trimodality versus uni- or bimodality regimens and aggressive versus non-aggressive management of recurrent disease were compared using regression analyses.

RESULTS

Of the 72 patients, 43 (60%) were male with a median age of 58 years, 65 (90%) had thymoma while 7 (10%) had thymic carcinomas; and median time since diagnosis was 50.5 months (range: 3-266). Median HUS and VAS did not differ between groups (trimodality n = 24 vs uni- or bimodality n = 48: HUS = 0.77 vs 0.80, P = 0.29; VAS = 80 vs 75, P = 0.79, respectively). The distributions of patient-reported ECOG were also similar (P = 0.86). Edmonton Symptom Assessment Scale scores for every assessed symptom were similar for different modalities of therapy. Median scores on these tools were also similar regardless of recurrence status or management of relapsed disease (aggressive versus non-aggressive).

CONCLUSION

Survivors with Stage II-IVa thymic malignancies report favourable HUS, VAS and self-reported ECOG with minimal symptom burden. These outcomes may be independent of number and type of initial treatment modalities or management of recurrence.