The Role of Radiation Therapy in Malignant Thymoma: A Surveillance, Epidemiology, and End Results Database Analysis

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.

Rethinking the effects of adjuvant beam radiation therapy on overall survival in atypical meningioma patients: age considerations

Background

This study aimed to investigate the effects of adjuvant beam radiation therapy (ABRT) on overall survival (OS) in patients with primary single intracranial atypical meningioma (AM), with a focus on age-related outcomes.

Methods

We conducted a retrospective study using data from SEER database. Our cohort consisted of patients diagnosed with a primary single intracranial AM tumor and had undergone surgery. The primary endpoint was OS. For survival analysis, univariable and multivariable Cox regression analysis were performed. A multivariable additive Cox model was used to assess the functional relationship between age and OS in patients with or without ABRT.

Results

Of the 2,759 patients included, 1,650 underwent gross total resection and 833 received ABRT. Multivariable Cox analysis indicated that ABRT did not significantly influence OS across the entire cohort. According to the multivariable generalized additive Cox model, the relative risk of all-cause mortality increased with advancing age in both ABRT-yes and ABRT-no group. ABRT-yes had a lower relative risk than ABRT-no when age ≤ 55 years old while a higher relative risk when age > 55 years old. Subsequent multivariable Cox analysis showed that ABRT was associated with a significant lower risk for all-cause mortality in patients with age ≤ 55 years old while a significant higher risk in patients with age > 55 years old.

Conclusion

Our study found that ABRT enhanced OS in younger primary single intracranial AM patients. But we also revealed a negative correlation between OS and ABRT in older patients.

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.

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.

[Mediastinal tumors : Diagnosis and treatment of the most common tumor entities]

The mediastinum is defined as the space formed ventrally by the sternum, dorsally by the spine, and laterally by the mediastinal pleura. A mediastinal mass is frequently an incidental finding. The wide spectrum of underlying diseases and the anatomic proximity to central structures makes diagnosis and treatment challenging. In many cases, the combination of anamnesis, physical examination, imaging and laboratory tests already provides valuable information about the tumor entity. In addition to diagnostic procedures for histological examination of an unclear mediastinal tumor, radical resection is very important for the prognosis of the patients, especially in the case of tumors of the thymus. Multimodal treatment of advanced tumors that involve adjacent structures is best performed in designated centers.

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.

The role of surgery in advanced thymic tumors: A retrospective cohort study

Background

There is no definitive and detailed treatment guideline for advanced thymic tumors, thus when lymph node and other organ metastasis are present, clinical guidelines recommend chemotherapy-based multidisciplinary treatment. A consensus has been reached that surgery has beneficial effects on partial patients with stage IVA whose metastatic lesions were isolated and resectable, but because of few cases of advanced thymic tumor s and the scarcity of reports, the role of surgery in stage IVB is still unknown. The current study aimed to systematically analyze the role of surgery in advanced thymic tumors based on the Surveillance, Epidemiology, and End Results (SEER) database, with a sufficient number of cases. A secondary aim was to clarify the prognostic value of surgery in advanced thymic tumors.

Method

Data derived from a total of 979 patients with advanced thymoma or advanced thymic carcinoma were collected from the SEER database. Propensity score matching was performed to eliminate confounding factors, and Cox regression analyses were conducted to assess prognoses.

Results

Patients were assigned to four groups based on pathology and whether surgery was performed; thymoma (surgery), thymoma (no surgery), thymic carcinom a (surgery), and thymic carcinoma (no surgery). Disease-specific survival differed significantly in the thymoma (surgery) and thymoma (no surgery) groups, both before and after propensity score matching (both p < 0.001). Similarly, disease-specific survival differed significantly in the thymic carcinoma (surgery) and the thymic carcinoma (no surgery) groups (p < 0.001 before and p = 0.003 after). No total resection, distant metastasis, and thymic carcinoma were all unfavorable prognostic factors.

Conclusions

In the present study surgery had positive effects on advanced thymoma and advanced thymic carcinoma patients who could undergo surgical resection, significantly improving survival times. Total resection of the primary site was the most advantageous form of surgery. The study provides a reference for the clinical treatment of advanced thymic tumors.

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.

The Prognostic Value of Postoperative Radiotherapy for Thymoma and Thymic Carcinoma: A Propensity-Matched Study Based on SEER Database

(1) Objectives: The effect of postoperative radiotherapy (PORT) for thymoma and thymic carcinoma remains controversial. This study aimed to investigate the prognostic value of PORT for thymoma and thymic carcinoma in a population-based registry. (2) Methods: This retrospective study used the Surveillance, Epidemiology, and End Results (SEER) database to identify patients diagnosed with thymoma and thymic carcinoma between 2010 and 2019. Propensity score matching was performed to adjust statistical influences between the PORT and non-PORT groups. (3) Results: A total of 2558 patients with thymoma (n = 2138) or thymic carcinoma (n = 420) were included. In the multivariate analysis, PORT was an independent prognostic factor for OS (overall survival; p < 0.001) and CSS (cancer-specific survival; p = 0.001) in thymoma and an independent prognostic factor for OS in thymic carcinoma (p = 0.018). Subgroup analyses revealed that PORT was beneficial to OS and CSS in patients with Masaoka-Koga stage IIB-IV thymoma (OS: IIB, p < 0.001; III-IV, p = 0.005; CSS: IIB, p = 0.015; III-IV, p = 0.002) and stage IIB thymic carcinoma (OS: p = 0.012; CSS: p = 0.029). (4) Conclusion: This propensity-matched analysis identified the prognostic value of PORT in thymoma and thymic carcinoma based on the SEER database. For patients with stage IIB-IV thymoma and stage IIB thymic carcinoma, PORT was associated with improved OS and CSS. A more positive attitude towards the use of PORT for nonlocalized thymoma and thymic carcinoma may be appropriate.

“Radiotherapy for Thymic Epithelial Tumors: What Is The Optimal Dose? A Systematic Review.”

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Thymic epithelial tumors(TETs) often require a multimodal approach, including RT.

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RT dose recommendations largely derive from old data, where 2D RT was widely used.

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This systematic review focused on the optimal dose for TETs with modern RT.

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5 eligible studies reporting dose response were analyzed and synthesized.

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Current guidelines remain valid, this work might be an eye-opener fostering new data.

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.

Postoperative radiotherapy for completely resected thymoma: Differing roles in masaoka stage II and stage III disease

PURPOSE

The efficacy of radiotherapy for treating thymomas is unclear. The goal of this study was to analyze overall survival (OS) and disease-free survival (DFS) among thymoma patients to determine the impact of postoperative radiotherapy (PORT) on thymoma outcomes.

METHODS

Recorded cases of thymoma at Xinqiao Hospital were retrospectively analyzed from 1991 to 2019. Data on stage II and III thymomas were extracted from medical records. This study evaluated OS and DFS and compared outcomes between surgery and surgery-plus-radiation groups. The Kaplan-Meier method and Cox regression analysis were used to compare DFS and OS for these groups.

RESULTS

Of the 205 patients included in the current study, 142 (69.3%) presented with stage II disease and 63 (30.7%) presented with stage III disease. The median follow-up was 84.3 months. PORT did not statistically significantly improve OS (P = 0.613) and DFS (P = 0.445) in stage II thymoma patients (compared with surgery alone). However, our subgroup analysis showed a statistically significant difference in DFS in patients with stage III thymoma (P = 0.044).

CONCLUSION

Although the routine use of postoperative radiotherapy in patients with thymoma does not appear warranted, patients with stage III thymoma may benefit from adjuvant radiation. These findings, if confirmed, will provide valuable information to guide medical decision-making for thymoma treatment.

Hadrontherapy for Thymic Epithelial Tumors: Implementation in Clinical Practice

Radiation therapy is part of recommendations in the adjuvant settings for advanced stage or as exclusive treatment in unresectable thymic epithelial tumors (TETs). However, first-generation techniques delivered substantial radiation doses to critical organs at risk (OARs), such as the heart or the lungs, resulting in noticeable radiation-induced toxicity. Treatment techniques have significantly evolved for TET irradiation, and modern techniques efficiently spare normal surrounding tissues without negative impact on tumor coverage and consequently local control or patient survival. Considering its dosimetric advantages, hadrontherapy (which includes proton therapy and carbon ion therapy) has proved to be worthwhile for TET irradiation in particular for challenging clinical situations such as cardiac tumoral involvement. However, clinical experience for hadrontherapy is still limited and mainly relies on small-size proton therapy studies. This critical review aims to analyze the current status of hadrontherapy for TET irradiation to implement it at a larger scale.

Estimated Risk of Radiation-Induced Cancer after Thymoma Treatments with Proton- or X-ray Beams

Simple Summary

Thymic tumors, i.e., thymomas and thymic carcinomas, are rare tumors that derive from the remnant of the thymus gland. Although surgery is the first treatment of choice, some patients will be treated with radiotherapy. For many patients the prognosis is good, hence it is important to avoid treatment related complications such as radiation-induced secondary malignancies. Radiotherapy can be delivered with different techniques and with different particles. In the present study, we compare the calculated (estimated) risks for secondary malignancies after treatment of thymic tumors with two different photon (x-ray) radiotherapy techniques or with proton beam therapy. We use a commonly used radiobiological model to calculate the risks for radiation induced secondary malignancies for each treatment modality. In conclusion, proton beam therapy was shown to provide the potential for reducing the risk of secondary malignancies, compared to photon radiotherapy, after treatment of thymic tumors.

Abstract

We compared the calculated risks of radiation-induced secondary malignant neoplasms (SMNs) for patients treated for thymic tumors with 3D-CRT, IMRT, or single-field uniform dose (SFUD) proton beam therapy (PBT) using the pencil beam scanning (PBS) technique. A cancer-induction model based on the organ equivalent dose (OED) concept was used. For twelve patients, treated with 3D-CRT for thymic tumors, alternative IMRT and SFUD plans were retrospectively prepared. The resulting DVHs for organs at risk (OARs) were extracted and used to estimate the risk of SMNs. The OED was calculated using a mechanistic model for carcinoma induction. Two limit cases were considered; the linear-exponential model, in which the repopulation/repair of the cells is neglected, and the plateau model, in which full repopulation/repair of the irradiated cells is assumed. The calculated risks for SMNs for the different radiation modalities and dose-relation models were used to calculate relative risks, which were compared pairwise. The risks for developing SMNs were reduced for all OARs, and for both dose-relation models, if SFUD was used, compared to 3D-CRT and IMRT. In conclusion, PBS shows a potential benefit to reduce the risk of SMNs compared to 3D-CRT and IMRT in the treatment of thymic tumors.

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.

Impact of prior cancer history on outcomes in thymoma: a propensity score, population-based study

Background

Prior cancer history is a common exclusion in thymoma trials. However, whether prior cancer impacts the survival of thymoma patients and the outcomes of clinical trials remains uncertain. The aim of this study is to identify the impact of prior cancer on outcomes in thymoma.

Methods

Patients with thymoma diagnosed between 1975 to 2017 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Age, histologic types, and thymoma size were stratified to analyze. Propensity score matching (PSM), Kaplan-Meier methods and Cox proportional hazard models were used to analyze the prognostic effect of prior cancer on overall survival (OS).

Results

A total of 3,827 thymoma patients were enrolled, of whom 13.22% had a prior cancer history. The Kaplan-Meier curves showed statistically significantly different survival before (P<0.001) and after PSM (P=0.0003). Subgroup analyses stratified by histologic types and thymoma size showed that thymoma patients with prior cancer had inferior survival. But thymoma patients with prior cancer displayed similar OS among patients older than 65 years (P=0.693). In multivariate analyses, patients with prior cancer displayed inferior OS [hazard ratio (HR) =1.39, 95% confidence interval (CI), 1.18 to 1.63].

Conclusions

Prior cancer conveys an inferior OS among patients with thymoma. But it does not affect the survival adversely in older patients thus broader inclusion trial criteria may be adopted in thymoma patients with a prior cancer history.

The incidence and prognosis of thymic squamous cell carcinoma: A Surveillance, Epidemiology, and End Results Program population-based study

BACKGROUND

Thymic carcinoma represents a rare type of malignant mediastinal tumor and has been the subject of controversy. Although independent prognostic factors related to thymic carcinoma have been investigated previously, few studies have focused specifically on the survival outcomes associated with thymic squamous cell carcinoma (TSCC). This study aims at presenting a survival analysis in this rare malignant disease at population level.

METHODS

We extracted the data of 216 patients with TSCC recorded from 1973 to 2015 from the Surveillance, Epidemiology, and End Results (SEER) database of the National Cancer Institute. The patients' demographic features, clinical traits, and treatment factors were analyzed in order to identify prognostic factors, which correlate overall survival using the Kaplan-Meier method as well as a multivariate Cox regression model, for TSCC.

RESULTS

The majority of patients were male, Caucasian, married, and insured. Furthermore, 58.3%, 54.6%, and 59.7% of patients TSCC underwent surgery, radiotherapy, and chemotherapy respectively. In a multivariate analysis, age of diagnosis (hazard ratio [HR]: 1.022, 95% confidence interval [CI]: 1.003-1.040, P = .020), surgical treatment (HR: 0.282, 95% CI: 0.164-0.484, P = .000), and stage (regional vs distant HR: 0.532, 95% CI: 0.324-0.872, P = .013; localized vs distant HR: 0.297, 95% CI: 0.133-0.664, P = .003) correlated with increased overall survival, whereas adjuvant therapy, including chemotherapy and radiotherapy, did not correlate with survival. Among surgically treated patients, age of diagnosis and stage were associated with better overall survival, while chemotherapy and radiotherapy did not contribute significantly to overall survival.

CONCLUSION

Surgery, age of diagnosis, and stage were associated with better overall survival among TSCC.

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.

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.

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.

Effect of Postoperative Radiotherapy in Thymoma Patients: A SEER-Based Study

INTRODUCTION

The role of postoperative radiation therapy (PORT) for thymoma is under debate, especially in patients aged ≥60 years with an advanced stage (Masaoka stages III and IV). We aimed to evaluate the efficacy of PORT for thymoma in a population-based registry.

METHODS

A retrospective analysis of the Surveillance, Epidemiology, and End Results (SEER) database was conducted to compare the outcomes of thymoma patients with or without PORT. The primary outcomes were overall survival (OS) and cancer-specific survival (CSS). Conditional inference tree analyses were performed for risk classification according to the study variables. Cox regression was performed to evaluate the prognostic effect of PORT in the specific subgroups.

RESULTS

A total of 2,236 patients were included. The conditional inference tree analysis identified that an age ≥60, a Masaoka stage ≥3, and the year of diagnosis were important factors when classifying patients into prognostic subgroups. PORT was found to be a protective predictor of OS in patients aged ≥60 years, those with a Masaoka stage III-IV, and those diagnosed after 2005. Further subgroup analyses revealed that PORT was significantly associated with a better OS (HR = 0.77) in patients aged ≥60 years, whereas it was not significantly associated with CSS.

CONCLUSIONS

An older age (≥60 years) is critical for predicting survival outcomes in thymoma patients. Moreover, patients aged ≥60 years could benefit from PORT in terms of OS.

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.

A single-center experience: management of patients with thymic epithelial tumors

Background

Thymic epithelial tumors are rare neoplasias. There are no internationally accepted standards to treat this complex oncological disease. The studies on which our knowledge is based frequently have methodological weaknesses. If the tumor is resectable, complete surgical excision is currently the first-line therapy. Thymic epithelial tumors respond to radiation. The therapeutic benefit of adjuvant radiotherapy depends on tumor stage. To validate and improve treatment, we share our current experiences with clinical management and surgical intervention.

Methods

This single-center retrospective study included 40 patients with primarily resectable thymic epithelial tumors who underwent resection with curative intent. The survival data was collected and presented according to Kaplan-Meier. Single- and multiple predictor survival analyses were carried out using the log-rank test and Cox proportional hazards model.

Results

Single-predictor survival analysis showed survival to be dependent on the Masaoka-Koga classification, WHO histological classification, resection status, surgical technique, and Clavien-Dindo grade for postoperative complications. Multiple predictor analysis confirms that the Masaoka-Koga stage (HR = 4.876, P = 0.032) and Clavien-Dindo grade (HR = 4.904, P = 0.011) are independent prognostic factors for survival.

Conclusion

In addition to the Masaoka stage, the occurrence of severe postoperative complications represents an independent prognostic factor. Given the tumor’s sensitivity to radiation, the use of neoadjuvant radiotherapy can be considered to downstage Masaoka-Koga stages III and higher, thus reducing surgical risks. Further prospective multicenter studies are urgently needed.

[Extended Resection of Locally Advanced Thymic Tumours in Stage III]

In the treatment of locally advanced thymic tumours, specific diagnostic testing is required, with a multimodal therapeutic approach consisting of surgery, radio- and/or chemotherapy. The complete resection of the tumour represents the most important prognostic factor with regard to recurrence-free and long-term survival. Local invasive growth of malignant thymic tumours into neighbouring mediastinal structures is classified as Masaoka-Koga stage III. Surgical resection can be performed primarily or after induction therapy, depending on the extent of the tumour. However, in some cases these tumours must be classified as non-resectable, so that only palliative radio-/chemotherapy remains as therapeutic option. TNM classification for malignant thymic tumours has been recently introduced. This resembles the established Masaoka-Koga classification in many aspects, but also includes some therapy-relevant changes. A differentiation is made between stages IIIA and IIIB, with the aim of assessing the resectability of advanced thymic tumours in a more differentiated manner and consequent planning of the therapy concept. Besides the thymus, thymoma, perithymic tissue, mediastinal pleura (stage I) or pericardium (stage II), all infiltrated structures should be removed "en bloc", if possible in stage III tumours. While the lung, brachiocephalic vessels or extrapericardial pulmonary vessels can still be resected and reconstructed if necessary, infiltration of the aorta or intrapericardial pulmonary vessels often limits macroscopically complete resection.

Nomogram to predict thymoma prognosis: A population-based study of 1312 cases

Background

A thymoma is a common cancer within the anterior mediastinum; however, the prognostic characteristics have not been established. The aim of this study was to identify the prognostic factors and develop a nomogram for the prognostic prediction of patients with thymoma based on data from the Surveillance, Epidemiology, and End Results (SEER) database.

Methods

Patients with thymomas diagnosed between 1983 and 2014 were selected. Overall survival (OS) was estimated using the Kaplan–Meier method with the log‐rank test. Univariate and multivariate Cox proportional hazards regression analyses were performed to identify the independent prognostic factors, from which a nomogram for thymomas was created. External validation of the nomogram was performed using data from our center.

Results

A total of 1312 patients with thymomas were enrolled. Age, tumor size, Masaoka–Koga stage, chemotherapy administered, and surgery type were independent prognostic factors for OS. A nomogram for OS was formulated based on the independent prognostic factors and validated using an internal bootstrap resampling approach, which showed that the nomogram exhibited a sufficient level of discrimination according to the C‐index in training (0.713, 95% confidence interval 0.685–0.741) and (0.746, 95% confidence interval 0.625–0.867) validation cohorts.

Conclusion

Several prognostic factors for thymomas were identified. The nomogram developed in this study accurately predicted the 5‐year and 10‐year OS rates of patients with thymomas based on individual characteristics. Risk stratification using the survival nomogram could optimize individual therapy and follow‐up.

Evaluation of the prognostic value of surgery and postoperative radiotherapy for patients with thymic neuroendocrine tumors: A propensity-matched study based on the SEER database

Background

The prognostic value of surgery and postoperative radiotherapy (PORT) for primary thymic neuroendocrine tumors (TNETs) was estimated using the SEER database.

Methods

This retrospective study used SEER data of TNET patients between 1998 and 2015. Propensity score matching (PSM) was performed according to whether surgery was performed. The prognostic effects on overall survival (OS) and cancer‐specific survival (CSS) were evaluated using multivariate Cox regression.

Results

A total of 3947 patients were included: 293 (7.4%) TNET, 2788 (70.6%) thymoma, and 866 (21.9%) thymic carcinoma. Compared to other subtypes, TNET patients were younger, included a larger proportion of men, had a well or moderately differentiated histological grade, higher disease stage at diagnosis, and were more likely to have regional lymph node metastasis. The median OS and CSS for TNET were 82.9 (95% confidence interval 74.3–91.4) and 101.9 (95% confidence interval 91.9–111.8) months, respectively, significantly shorter than for thymomas. In the matched cohort of TNET patients, multivariate analysis of OS and CSS revealed a significantly poorer prognosis in the non‐surgery group (P < 0.001). Compared to total/radical resection, TNET patients who underwent debulking resection had significantly inferior outcomes (P < 0.05). Postoperative radiotherapy favorably impacted OS and CSS in Masaoka–Koga stage III–IV TNET patients; this OS impact was also observed in stage IIB patients.

Conclusion

TNETs are extremely rare with relatively dismal outcomes. This analysis revealed the role of complete surgical resection and the favorable effect of postoperative radiotherapy in specific TNET subgroups.

Elective Nodal Irradiation as Adjuvant Radiotherapy for Advanced Thymomas and Thymic Carcinomas

INTRODUCTION

We evaluated the clinical outcome of patients with stage III to IV thymomas (Ts) or stage II to IV thymic carcinomas (TCs) treated with complete thymectomy and local radiation therapy (LRT, targeting the tumor bed and anterior mediastinal areas only) or elective nodal irradiation (ENI, targeting the entire mediastinal and supraclavicular regions).

MATERIALS AND METHODS

Data from 47 patients diagnosed with Ts or TCs and treated with surgery and adjuvant RT from May 2002 to May 2015 were analyzed. The standard RT dose was 50.4 Gy in 28 fractions; patients with a positive resection margin received a further 4 to 10 Gy. Survival outcomes determined at 5 years included local recurrence-free survival, regional recurrence-free survival, distant metastasis-free survival, and overall survival.

RESULTS

Five-year local recurrence-free survival was similar in both groups (LRT, 94.7% vs. ENI, 96.2%; P = .849). Significant differences were seen in 5-year regional recurrence-free survival (LRT, 55.1% vs. ENI, 83.7%; P = .006); however, tumor size was seen to be a significant factor (< 7 cm, 95.2% vs. ≥ 7 cm, 48.9%; P < .001), and the LRT group contained a greater proportion of patients with ≥ 7-cm tumors (70% vs. 33%). Multivariate analysis demonstrated that tumor size was the only significant prognostic factor (P < .001). No differences in 5-year overall survival were seen (LRT, 91.7% vs. ENI, 100%; P = .106).

CONCLUSION

ENI may not be indicated in all cases, as additional benefit in reducing recurrence or improving survival was not predominant. LRT seems to be a feasible option with favorable patient outcomes.

The expanding role of radiation therapy for thymic malignancies

The role of radiation therapy (RT) in thymic malignancies has long been subject to considerable controversy. The main role for RT is in the setting of adjuvant therapy after surgical tumor resection, especially in advanced or incompletely resected cases. However, recent studies with larger patient numbers and cleaner study populations than previous studies have indicated a potentially clearer than previously assumed benefit after post-operative RT (PORT) even for completely resected patients with earlier stages of thymoma. In marginally resectable patients RT may be used in combination with neoadjuvant chemotherapy to shrink tumors and thereby potentially enable resection. In unresectable patients concurrent or sequential chemotherapy and RT can be employed as the definitive nonsurgical approach. The tendency of thymic tumors to recur in the pleural space highlights the necessity for more effective approaches to identify and treat high risk patients. Experiences in other pleural malignancies may pave the way to novel treatment modalities, for example pleural IMRT. The role of these techniques in thymic malignancies has yet to be determined and is not advisable at the current time outside of a clinical study. As the disease often takes an indolent course with excellent long-term local control (LC) and survival, late toxicities related to radiation of the mediastinum and adjacent organs at risk (OARs) have to be taken into consideration and may jeopardize the benefit patients experience from RT, especially in younger patients with a long-anticipated life expectancy. Radiation techniques, such as intensity modulated RT (IMRT) and proton beam therapy (PBT), have substantially reduced the exposure of OARs to ionizing radiation which is expected to translate into reduced long-term toxicities. Hence, the risk-benefit ratio of RT in early stage thymoma patients may be shifted favorably.

The role of postoperative radiation therapy for completely resected stage III thymoma and effect of higher heart radiation dose on risk of cardiovascular disease: A retrospective cohort study

OBJECTIVES

This study aimed to assess the efficacy of radiation therapy (RT) in patients with completely resected stage III thymoma and evaluate the relationship between higher heart dose and risk of cardiovascular disease (CVD).

PATIENTS AND METHODS

A total of 130 consecutive patients with Masaoka stage III thymoma were retrospectively reviewed from January 2003 to December 2013. Of these, 99 underwent complete tumor resection [74 received postoperative radiation therapy (S + R) and 25 received surgery alone (S alone)] and 31 patients underwent RT alone (16 due to inoperable tumors and 15 due to high surgical risk or patient refusal; R alone). Three-dimensional conformal RT/intensity-modulated RT was used for patients receiving RT.

RESULTS

The median follow-up for all patients was 70 months. The 5- and 8-year overall survival (OS) rates were 95.6% and 93.9% for S + R, 84.0% and 67.2% for S alone, and 73.3% and 73.3% for R alone (excluding patients with inoperable tumors), respectively (P = 0.004). A trend of improved disease-specific survival (DSS) was also observed in the S + R group compared with the other two groups. CVD was the main nonmalignant cause of death (3/6, 50%). The median time of CVD diagnosis was 101 months after treatment. The mean heart dose was an independent risk factor for CVD.

CONCLUSIONS

Postoperative RT after complete resection improved the survival compared with surgery alone and RT alone for patients with stage III thymoma. A higher heart dose was related to increased risk of CVD in long-term survivors.

Clinical characteristics, risk factors, and outcomes after adjuvant radiotherapy for patients with thymoma in the United States: analysis of the Surveillance, Epidemiology, and End Results (SEER) Registry (1988-2013)

PURPOSE

The surgery with adjuvant radiation for the treatment of thymoma is still debated. The aim of this study was to examine the efficacy of postoperative radiotherapy (PORT) in a population-based registry of patients with thymoma.

MATERIALS AND METHODS

We conducted a retrospective analysis of the Surveillance, Epidemiology, and End Results database to compare the outcomes of patients with thymoma who received surgery with or without PORT.

RESULTS

Among the 2234 patients of this study, the surgery with PORT group had a longer mean overall survival (OS) and cancer-specific survival (CSS) than did the surgery without PORT group (OS: 172.3 vs. 155.3 months, p = .005; CSS: 247.3 vs. 241.8 months, p = .04). PORT significantly improved OS and CSS of patients with stage III/IV disease, but decreased CSS for those with stage I/IIA disease. Although the surgery with PORT group had a higher rate of secondary cancers, the between-group difference in the disease-free interval was not significant.

CONCLUSIONS

PORT provides a significant benefit for patients with thymoma, particularly those with advanced disease. However, it also increases the risk of a second malignancy. We suggest that treatment guidelines should adopt a more positive stance on the use of PORT.

Thymoma size significantly affects the survival, metastasis and effectiveness of adjuvant therapies: a population based study

Background

Thymoma, though a rare tumor disease, is the most common tumor of the anterior mediastinum. However, tumor size, as a critical factor, has been underestimated.

Results

Age, advanced tumor stage, and preoperative radiotherapy were poor prognostic factors of overall survival (OS) and disease specific survival (DSS) (P < 0.05 for all). Besides, tumor size was significantly related to survival. The larger tumor size indicated the less OS and DSS (P < 0.001 for all). Multivariate analysis revealed elder age, advanced stage, larger size were independent adverse predictors for survival (P < 0.05 for all). Logistic analysis revealed larger tumor size had greater rate of metastasis (P < 0.001). In the group with tumors smaller than 90mm, chemotherapy was a negative predictive factor of DSS (P < 0.05 for all), and it significantly decreased OS especially with tumor sizes between 50 and 90 mm (P < 0.001).

Materials and Methods

A total of 1,272 thymoma patients were enrolled from the Surveillance, Epidemiology, and End Results (SEER) database. Survival based on thymoma size and other characteristics of tumors were analyzed by univariate and multivariate analysis. Correlation between thymoma size and thymoma metastatic status was contributed by logistic regression analysis. The efficiency of adjuvant therapy was analysis by stratification analysis.

Conclusions

Thymoma size could predict postoperative survival and guide chemotherapeutic regimens of patients. Larger tumor size indicated worse survival and higher metastatic rate. If thymoma is smaller than 90mm, traditional chemotherapy should be prohibited. While chemotherapy could be performed moderately when thymoma larger than 90 mm.

The Place and the Role of Radiation Therapy in the Treatment of Thymic Carcinoma

Thymic carcinomas arise from the epithelial cells of the thymus gland and are the most common tumors of the anterior mediastinum despite their overall rarity. Because of their rarity, their treatment remains a challenging topic. Although historically they have been treated surgically, radiation therapy (RT) has an important role either as a definitive or as a postoperative treatment. In this article, we present a review of the current therapies for the thymic carcinomas and try to identify the exact place of the RT in the optimal management of these patients.

The Impact of Postoperative Radiotherapy for Thymoma and Thymic Carcinoma

INTRODUCTION

The optimal role for postoperative radiotherapy (PORT) for thymoma and thymic carcinoma remains controversial. We used the National Cancer Data Base to investigate the impact of PORT on overall survival (OS).

METHODS

Patients who underwent an operation for thymoma or thymic carcinoma were categorized into Masaoka-Koga stage groups I to IIA, IIB, III, and IV. Patients who did not undergo an operation or those who received preoperative radiation were excluded. Kaplan-Meier estimates of OS and univariate and multivariate Cox proportional hazards regression analyses were performed. Propensity score-matched analyses were performed to further control for baseline confounders.

RESULTS

From 2004 to 2012, 4056 patients were eligible for inclusion, 2001 of whom (49%) received PORT. On multivariate analysis of OS in the thymoma cohort adjusted for age, WHO histologic subtype, Masaoka-Koga stage group, surgical margins, and chemotherapy administration, PORT was associated with superior OS (hazard ratio [HR] = 0.72, p = 0.001). Propensity score-matched analyses confirmed the survival advantage associated with PORT. Subset analysis indicated longer OS in association with PORT for patients with stage IIB thymoma (HR = 0.61, p = 0.035), stage III (HR = 0.69, p = 0.020), and positive margins (HR = 0.53, p < 0.001). The impact of PORT for stage I to IIA disease did not reach significance (HR = 0.76, p = 0.156).

CONCLUSIONS

In this large database analysis of PORT for thymic tumors, PORT was associated with longer OS, with the greatest relative benefits observed for stage IIB to III disease and positive margins. In the absence of randomized studies assessing the value of PORT, these data may inform clinical practice.

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

OBJECTIVES

The aim of this study was to determine whether postoperative radiation therapy (PORT) is associated with an overall survival (OS) benefit in patients with completely resected Masaoka or Masaoka-Koga stage II and III thymoma.

METHODS

All patients with completely resected (R0) stage II or III thymoma were identified in a large database of the International Thymic Malignancy Interest Group. Clinical, pathologic, treatment, and follow-up information were extracted. OS was the primary end point. A univariate analysis using the log-rank test was performed, and a multivariate Cox model was created to identify factors associated with OS.

RESULTS

Of 1263 patients meeting the selection criteria, 870 (69%) had stage II thymoma. The WHO histologic subtype was A/AB in 360 patients (30%) and B1/B2/B3 in 827 (70%). PORT was given to 55% of patients (n = 689), 15% (n = 180) received chemotherapy, and 10% (n = 122) received both. The 5- and 10-year OS rates for patients having undergone an operation plus PORT were 95% and 86%, respectively, compared with 90% and 79% for patients receiving an operation alone (p = 0.002). This OS benefit remained significant when patients with stage II (p = 0.02) and stage III thymoma (p = 0.0005) were analyzed separately. On multivariate analysis, earlier stage, younger age, absence of paraneoplastic syndrome, and PORT were significantly associated with improved OS.

CONCLUSIONS

We observed an OS benefit with the use of PORT in completely resected stage II and III thymoma. In the absence of a randomized trial, this represents the most comprehensive analysis of individual patient data and strong evidence in favor of PORT in this patient population.

Survival Impact of Adjuvant Radiation Therapy in Masaoka Stage II to IV Thymomas: A Systematic Review and Meta-analysis

PURPOSE

To evaluate the survival impact of postoperative radiation therapy (PORT) in stage II to IV thymomas, using systematic review and meta-analysis.

METHODS AND MATERIALS

A database search was conducted with EMBASE, PubMed, Web of Science, Cochrane Library, and Ovid from inception to August 2015. Thymic carcinomas were excluded, and studies comparing overall survival (OS) with and without PORT in thymomas were included. The hazard ratios (HRs) of OS were extracted, and a random-effects model was used in the pooled analysis.

RESULTS

Seven retrospective series with a total of 1724 patients were included and analyzed. Almost all of the patients underwent macroscopically complete resection, and thymoma histology was confirmed by the World Health Organization criteria. In the overall analysis of stage II to IV thymomas, OS was not altered with the receipt of PORT (HR 0.79, 95% confidence interval [CI] 0.58-1.08). Although PORT was not associated with survival difference in Masaoka stage II disease (HR 1.45, 95% CI 0.83-2.55), improved OS was observed with the addition of PORT in the discrete pooled analysis of stage III to IV (HR 0.63, 95% CI 0.40-0.99). Significant heterogeneity and publication bias were not found in the analyses.

CONCLUSIONS

From the present meta-analysis of sole primary thymomas, we suggest the potential OS benefit of PORT in locally advanced tumors with macroscopically complete resection, but not in stage II disease. Further investigations with sufficient survival data are needed to establish detailed treatment indications.

Conditional survival of malignant thymoma using national population-based surveillance, epidemiology, and end results (SEER) registry (1973-2011)

INTRODUCTION

Thymoma is a rare and unique tumor with a long natural history that makes it difficult to study. Consequently, there is a dearth of prospective diagnostic or therapeutic clinical trials. To our knowledge, there has not been an analysis of conditional survival of thymoma in the literature. The specific aim of this study was to study the 5-year conditional survivals of a large population of thymoma patients.

METHODS

Cases of thymoma were extracted from the Surveillance, Epidemiology, and End Results registry (1973-2011) and categorized into Masaoka-Koga stage groupings. The primary outcomes compared overall survival (OS), cause specific survival (CSS), and 5-year conditional OS and CSS, by stage. OS and CSS were calculated using the Kaplan-Meier method with the log-rank test for significance using SAS v9.3. Conditional survival was the probability of surviving an additional 5 years at any point in follow-up, and used analysis of variance to test significance.

RESULTS

A total of 2182 patients met inclusion criteria and were categorized as Masaoka-Koga stage groupings of I and IIA ("localized," 24%), IIB ("regional," 16%), III and IV ("distant," 50%), and unknown (10%). Median age was 56 (18-91), and 53% were male. Earlier stages had better OS (p < 0.0001) and CSS (p < 0.0001). Twenty-year OS for local, regional, and distant stages were 42%, 30%, and 18%, respectively. Conditional survivals remained largely unchanged throughout follow-up.

CONCLUSIONS

Conditional survival provides more relevant survival estimates for patients during follow-up. Further studies should investigate the possibility that thymoma should be considered a chronic disease.

A Review of the Place and Role of Radiotherapy in Thymoma

Thymomas, tumors that arise from the epithelial cells of the thymus gland, are the most common tumors of the anterior mediastinum despite their overall rarity. They are not classified together with malignancies although it is recognized that they can be invasive and persistent even after attempted treatment. Because of their rarity, optimal treatment protocols remain a challenging topic. Although surgery is recognized as the cornerstone of management, the role and benefit of use of postoperative radiotherapy (PORT), remains questionable. Unequivocal evidence, although exclusively from retrospective studies, indicates that stage I thymoma is adequately treated with complete resection alone. As for stage II there is still a need to better determine the indications of PORT. For stage III and IV, existing data point to the fact that PORT plays a significant role in the management of thymoma. In patients for whom radiotherapy (RT) is indicated, 50 Gy appears to be adequate for microscopic disease and higher doses should be used for macroscopic tumor. With advances in RT delivery techniques, which allow for higher doses to be delivered to larger areas affected by tumor while sparing normal tissue, it is prudent to identify a place for this modality in the optimal management of thymoma patients.

[Retrospective analysis of 50 thymic epithelial tumors in Rennes university hospital]

BACKGROUND

Thymic epithelial tumors (TET), including thymomas and thymic carcinomas, are rare and characterized by very different evolutionary patterns depending on histology and invasion stage. The therapeutic management is not well defined but is a subject of increasing interest. The descriptive and analytic objectives of this retrospective monocentric study were to analyze the clinical characteristics of patients with TET, and to assess the management of these tumors in our centre.

METHODS

Adult patients with TET managed in the Rennes university hospital in the period 2000-2011 were selected via the pathology department. Their clinical and pathological features and survival were analyzed retrospectively.

RESULTS

Fifty TET were retrieved (46 thymomas and 4 thymic carcinomas). Their clinical and histological features and their invasion stages were concordant with published studies. Their diagnostic and therapeutic managements were also in accordance with current guidelines. In univariate analysis, myasthenia and surgery were associated with better survival rates.

CONCLUSION

Management of TET in Rennes university hospital is in accordance with guidelines.

Thymoma: a population-based study of the management and outcomes for the province of British Columbia

INTRODUCTION

Thymomas are rare neoplasms with variable clinical behavior. Our primary study aim was to analyze treatment practices and outcomes in a population-based cohort of thymoma patients. We hypothesized that stage I and II thymomas would have high cure rates with resection and adjuvant radiation, whereas locally advanced cases would benefit from multimodality therapy.

METHODS

All patients, diagnosed with thymoma or thymic carcinoma in British Columbia between 1994 and 2009, were identified using the British Columbia Cancer Agency Registry. Chart review was used to collect demographic and treatment data. Detailed pathology review was performed using the World Health Organization classification.

RESULTS

One hundred and seventy-one patients were identified for analysis. The 5-year overall survival was 93.3%, 88.7%, 74.6%, 43.4% for stages I, II, III, and IV, respectively. Survival varied significantly among patients with thymoma compared with thymic carcinoma. In patients with stage II disease, adjuvant radiation did not confer an overall survival or recurrence-free survival benefit. Seventy-five patients had locally advanced disease. There was practice variation in treatment of these patients. Patients with thymoma undergoing trimodality treatment had a 5-year median overall survival of 80%, whereas patients with thymic carcinoma had poor outcomes despite aggressive treatment.

CONCLUSIONS

Survival rates in this population-based series were comparable to those in previously published reports. The ideal management of thymic tumors involves a multidisciplinary approach, particularly in locally advanced disease and selection of patients for adjuvant radiation therapy.

Multidisciplinary treatment of malignant thymoma

PURPOSE OF REVIEW

Thymomas are the most common tumors of the anterior mediastinum. Although surgery remains the only curative treatment, the use of multimodality therapy for primary unresectable thymomas has led to change the clinical management of these tumors.

RECENT FINDINGS

Nowadays Masaoka stage, WHO, and radical surgical resection are considered by many authors as independent prognostic factors for long-term survival. Radiotherapy may be useful as adjuvant therapy in cases of incomplete surgical resection with microscopic or macroscopic residual disease, or for those patients with locally advanced or metastatic unresectable disease. Chemotherapy is considered a valid option in selected patients with residual disease after local treatments or as a neoadjuvant approach to improve resectability in Masaoka stages III or IV-a thymomas. Currently, no standardized regimen for chemotherapy or agreed timing exists.

SUMMARY

So far, multimodality treatment has been related to low morbidity and long survival rate, but there are still many concerns regarding a different regimen of therapy and the correct timing.

Concurrent metastatic thymic carcinoma and postirradiation sarcoma

We present a case of concurrent metastatic thymic carcinoma and postirradiation sarcoma in the same lobe of the lung in a woman who had received partial resection of thymic carcinoma with chemoradiotherapy 11 years ago. One tumor showed similar histology to the previous carcinoma. The other tumor was a pleomorphic sarcoma, suggestive of a postirradiation sarcoma. Irradiation-induced sarcomas are rare and have not been reported in patients with thymic carcinoma. This case may serve as a model in considering the possibility of postirradiation sarcoma for patients encountering recurrent masses with the history of radiotherapy for thymic carcinoma several years ago.