Role of Postoperative Radiotherapy in Nonlocalized Thymoma

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.

Re-exploration of prognosis in type B thymomas: establishment of a predictive nomogram model

OBJECTIVE

To explore the risk factors for disease progression after initial treatment of type B thymomas using a predictive nomogram model.

METHODS

A single-center retrospective study of patients with type B thymoma was performed. The Cox proportional hazard model was used for univariate and multivariate analyses. Variables with statistical and clinical significance in the multivariate Cox regression were integrated into a nomogram to establish a predictive model for disease progression.

RESULTS

A total of 353 cases with type B thymoma were retrieved between January 2012 and December 2021. The median follow-up was 58 months (range: 1-128 months). The 10-year progression-free survival (PFS) was 91.8%. The final nomogram model included R0 resection status and Masaoka stage, with a concordance index of 0.880. Non-R0 resection and advanced Masaoka stage were negative prognostic factors for disease progression (p < 0.001). No benefits of postoperative radiotherapy (PORT) were observed in patients with advanced stage and non-R0 resection (p = 0.114 and 0.284, respectively).

CONCLUSION

The best treatment strategy for type B thymoma is the detection and achievement of R0 resection as early as possible. Long-term follow-up is necessary, especially for patients with advanced Masaoka stage and who have not achieved R0 resection. No prognostic benefits were observed for PORT.

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.

Real-world study of treatment and outcome of type B2 + B3 thymoma: The neglected part of thymoma

BACKGROUND

This study aimed to examine the treatment and prognosis of patients with type B2 + B3 thymoma and compare it with those patients with type B2 and B3 thymoma.

METHODS

We conducted a retrospective analysis of the results of 39 patients with type B2 + B3 thymoma, 133 patients with type B2 thymoma, and 64 patients with type B3 thymoma. The Kaplan-Meier technique was used to generate survival curves. For multivariate analysis, the Cox proportional hazard model was applied.

RESULTS

With a median follow-up of 60 months (range: 1-128 months), the percentage of patients with tumor, node, metastasis (TNM) stage III and IV disease gradually increased from 19.5% to 25.6% to 35.9% among those with histological subtypes B2, B2 + B3, and B3, respectively, p = 0.045. Twenty-three patients experienced recurrence or metastasis. The total 10-year progression-free survival (PFS) rates were 86.0% overall (85.0% in type B2, 87.2% in type B2 + B3, and 87.5% in type B3). Age, R0 resection, and Masaoka-Koga stage were found to have a significant on PFS in all patients. There was no statistically significant difference in PFS between different histotypes of thymoma, p = 0.650. PFS was predicted by R0 resection in all histotypes and by the Masaoka-Koga stage in the type B2 subgroup.

CONCLUSION

Combining the two staging methods to guide the diagnosis and treatment of patients with B2 + B3 thymoma is recommended. R0 resection is recommended to reduce recurrence. Patients with B2 + B3 thymoma have a prognosis similar to those with a B2 thymoma or a B3 thymoma alone.

Thymoma and Thymic Carcinoma: Surgical Resection and Multidisciplinary Treatment

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

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

Background

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

Methods

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

Results

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

Conclusion

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

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.

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.

“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.

Outcomes of thymoma after multimodal therapy and determinants of survival: A 16-year experience of a tertiary cancer center

Background

In this study, we aimed to evaluate the factors that contribute to survival outcomes in patients with thymoma treated with multimodal approaches.

Methods

A total of 203 patients (105 males, 98 females; median age: 49 years; range, 17 to 77 years) with Masaoka-Koga Stage II-IV thymoma between January 2002 and December 2018 were retrospectively analyzed. Data including diagnosis of myasthenia gravis, diagnosis of diabetes mellitus, disease stage, histological type of tumor, capsule invasion and surgical margin status, lymphadenectomy, adjuvant radiotherapy or chemotherapy, time from surgery to the first day of adjuvant treatment, length of hospital stay, and overall and disease-free survival rates were recorded.

Results

Of the patients, 91 had Stage II, 67 had Stage III, and 45 had Stage IV disease. A total of 123 patients (61%) had myasthenia gravis. Seventy-six patients received adjuvant radiotherapy and 48 patients received either neoadjuvant (n=35) or adjuvant (n=25) chemotherapy. Higher disease stage, presence of R1 resection, and treatment with chemotherapy were significant factors for decreased disease-free survival time. Older age, higher disease stage, longer postoperative hospital stay, chemotherapy, and disease recurrence were effective contributors to decreased overall survival time. Adjuvant radiotherapy had a statistically significant positive effect on overall survival only in patients with completely resected Stage IV disease (five-year overall survival: 94.7% vs. 79.1%, respectively; p=0.015). In the multivariate analysis, older age (hazard ratio: 4.26), higher disease stage (hazard ratio: 2.95), and longer hospitalization time (hazard ratio: 3.81) were significant prognostic factors for overall survival. Patients with local recurrence who underwent complete resection had a survival time comparable to non-recurrent patients (p=0.753).

Conclusion

For patients with thymoma, higher disease stage, age ≥50 years, longer hospitalization, and need for chemotherapy are associated with worse survival rates. Adjuvant chemotherapy has a positive impact on Stage IV disease. Resection of recurrent lesions has a valuable impact on survival.

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.

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.

Thymic Epithelial Neoplasms: Tumor-Node-Metastasis Staging

Thymic epithelial neoplasms are a group of malignant tumors that includes thymoma, thymic carcinoma, and thymic neuroendocrine tumors. Although several staging systems have been developed over the years for use with these cancers, they have been interpreted and implemented in a nonuniform manner. Recently, the International Association for the study of Lung Cancer and the International Thymic Malignancy Interest Group developed a tumor-node-metastasis staging system that has been universally accepted and correlates with patient survival and outcomes. Although pathologic staging is determined by histologic examination of the resected tumor, imaging plays an important role in clinical staging and is important for informing therapeutic decisions.

Surgical feasibility and long-term outcome of superior vena cava replacement for advanced thymoma in patients undergoing preoperative chemotherapy or chemoradiotherapy

Background

The aim of this study was to investigate the long‐term outcome of superior vena cava (SVC) replacement after chemotherapy or chemoradiotherapy for advanced thymoma.

Methods

The medical information of patients with advanced thymoma who underwent thymoma resection and SVC replacement in Beijing Tongren Hospital from 2002 to 2017 were reviewed. We compared surgical outcomes, postoperative complications and long‐term prognosis in the chemoradiotherapy + surgery group (CRT + surgery group, 19 cases) and the surgery group (26 cases).

Results

The operation time (486.05 ± 148.01 vs. 370.77 ± 124.32 min; p = 0.007) and intraoperative blood loss (1400 ml [IQR 1125–2105 ml] vs. 855 ml [IQR 555–1682.5 ml], p = 0.036), poor wound healing (three cases [15.79%] vs. zero cases [0.0%], p = 0.036) in the CRT + surgery group were significantly higher than those of the surgery group. There was no significant difference between the CRT + surgery group and the surgery group in postoperative chest tube drainage time, hospitalization time, postoperative arrhythmia and incidence of pneumonia. Kaplan Meier analysis showed that the recurrence‐free survival (RFS) curves of the CRT + surgery group patients were better than those of the surgery group (p = 0.031). However, overall survival (OS) between the two groups was not significantly different (p = 0.069).

Conclusions

Thymoma resection and SVC replacement is feasible for patients undergoing preoperative induction chemotherapy or chemoradiotherapy for advanced thymoma. Although patients in the CRT + surgery group had a longer operation time and increased intraoperative bleeding, the RFS rate seemed to be better than that in the surgery group.

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.

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.

Does size matter? A national analysis of the utility of induction therapy for large thymomas

Background

Tumor size of 8 cm or greater is a risk factor for recurrence after thymoma resection, but the role of induction therapy for large thymomas is not well defined. This study tested the hypothesis that induction therapy for thymomas 8 cm and larger improves survival.

Methods

The use of induction therapy for patients treated with surgical resection for Masaoka stage I–III thymomas in the National Cancer Database between 2006–2013 was evaluated using logistic regression, Kaplan-Meier analysis, and Cox-proportional hazards methods.

Results

Of the 1,849 patients who met inclusion criteria, 582 (31.5%) had tumors ≥8 cm. Five-year survival was worse in patients with tumors ≥8 cm compared to smaller tumors [84.6% (95% CI: 81.2–88.1%) vs. 89.4% (95% CI: 87.2–91.7%), P=0.003]. Induction therapy was used in 166 (9.0%) patients overall and was more likely in patients with tumors ≥8 cm [adjusted odds ratio (AOR) 3.257, P<0.001]. Induction therapy was not associated with improved survival in the subset of patients with tumors ≥8 cm in either univariate [80.9% (95% CI: 72.6–90.1%) vs. 85.4% (95% CI: 81.8–89.3%), P=0.27] or multivariable analysis [hazard ratio (HR) 1.54, P=0.10]. Increasing age (HR 1.56/decade, P<0.001) and Masaoka stage III (HR 1.76, P=0.04) were associated with worse survival in patients with tumors ≥8 cm.

Conclusions

Survival after thymoma resection is worse for tumors 8 cm or larger compared to smaller tumors and is not improved by induction therapy. Size alone should not be a criterion for using induction therapy prior to thymoma resection.

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

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

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

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

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

Nomogram to predict the prognosis of parotid gland mucoepidermoid carcinoma: a population-based study of 1306 cases

Background

Mucoepidermoid carcinoma (MEC) is a common cancer in the oral salivary gland malignancy, which mainly occurs in the parotid gland. The aim of this study is to identify independent prognostic factors and establish a nomogram model for parotid gland mucoepidermoid carcinoma (P-MEC) patients using the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) database.

Method

Patients with P-MEC were selected from between 2004 and 2015. The overall survival (OS) and cancer-specific survival (CSS) rates were 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.

Results

A total of 1,306 patients with P-MEC were enrolled. Age, grade, T stage, N stage, M stage, chemotherapy, and surgery type were independent prognostic factors for OS and CSS. A nomogram for OS was formulated based on these 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 (0.877, 95% CI [0.855–0.898]).

Conclusion

Several prognostic factors for P-MEC were identified. The nomogram developed in this study accurately predicted the 5- and 10-year OS rates of American patients with P-MEC based on individual characteristics. Risk stratification using the survival nomogram can optimize individual therapies and follow-up.

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.

Patterns of Failure Following Postoperative Radiation Therapy Based on "Tumor Bed With Margin" for Stage II to IV Type C Thymic Epithelial Tumor

PURPOSE

The study purpose was to report failure patterns in Masaoka-Koga stage II to IV type C thymic epithelial tumor (TET) after postoperative radiation therapy (PORT) and to evaluate the suitability of PORT target volume confined to the "tumor bed only with margin."

METHODS AND MATERIALS

A retrospective review of 53 patients with stage II to IV type C TET was performed. The clinical outcomes, failure patterns in relation to PORT target volume, and prognostic factors were analyzed.

RESULTS

During a median follow-up period of 69 months, 14 deaths and 25 recurrences were observed. The 5-year rates of overall survival, disease-specific survival, and freedom from recurrence were 81.0%, 91.5%, and 49.7%, respectively. The failure patterns in relation to PORT target volume were in-field failure in 2 patients (3.8%), marginal in 2 (3.8%), and out of field in 23 (43.4%), respectively. The most common failure site was the pleura (12 patients), followed by the lung parenchyma (8 patients). Relapse involving the regional lymph nodes was observed in 6 patients, of whom 4 had synchronous distant failure and only 2 had isolated ipsilateral supraclavicular lymph node failure.

CONCLUSIONS

The policy of PORT target volume confined to only the tumor bed seems reasonable in treating patients with stage II to IV type C TET. The development of a more effective systemic therapy regimen is warranted.

Thymic tumors and results of radiotherapy

Aim

The aim of this study was to evaluate thymic epithelial tumors (TETs) for treatment outcomes and prognostic factors on survival.

Background

TETs are very rare neoplasms and multidisciplinary approach is recommended according to prognostic factors.

Materials and methods

Between 1995 and 2013, 31 patients were treated with median 5400 cGy (range: 1620-6596 cGy) radiotherapy (RT). Eleven patients received adjuvant or concurrent chemotherapy. There were 25 thymomas, 4 thymic carcinomas and 2 thymic neuroendocrin carcinomas. According to Masaoka, staging and WHO classification, cases were divided to good (n: 10), moderate (n: 9) and poor (n: 12) prognostic risk groups. Survival was calculated from diagnosis.

Results

In January 2016, 22 cases were alive with median 51.5 months (range: 2-170.5) follow-up. Recurrences were observed in 29% of patients in median 29.5 months (range: 6.5-105). Local control, mean overall (OS) and disease-free survival (DFS) rates were 86%, 119 and 116 months, respectively. There was a significant difference for R0 vs. R+ resection (81% vs. 43%, p = 0.06, and 69% vs. 46%, p = 0.05), Masaoka stage I-II vs. III-IV (75% vs. 52%, p = 0.001, and 75% vs. 37%, p < 0.001), and also prognostic risk groups (100% vs. 89% vs. 48%, p = 0.003, and 100% vs. 87% vs. 27%, p = 0.004) in terms of 5-year OS and DFS, respectively.

Conclusion

In our study, prognostic risk stratification was shown to be a significant predictor of survival. There is a need to investigate subgroups that may or may not benefit from adjuvant RT.

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.

Surgery for malignant lesions of the chest which extensively involved the mediastinum, lung, and heart

OBJECTIVE

Radical resection for thoracic malignancies that invade the great vessels or heart structure is an uncommon, high-risk operation. To help surgeons determine therapeutic strategy, we reviewed the patient characteristics and outcomes of combined thoracic and cardiovascular surgery for thoracic malignancies.

METHODS

Surgical resections of lung cancer, mediastinal tumor and pulmonary artery sarcoma invading great vessels or heart structures were reviewed from the literature.

RESULTS

Pneumonectomy was often performed for lung cancer invading the aorta, superior vena cava, and left atrium. Complete resection (R0), no mediastinal lymph node metastasis and without using cardiopulmonary bypass led to a good prognosis. Induction therapy was often performed for complete resection. Regarding mediastinal tumors, thymic epithelial tumors or germ cell tumors occasionally invaded the great vessels or heart structures. For these malignancies, multimodality therapy was often performed, and complete resection could be one of the prognostic factors. The resection of primary pulmonary artery sarcoma (PPAS) is also a combined thoracic and cardiovascular surgery. The primary treatment for PPAS is surgical resection; specifically, pulmonary endarterectomy and pneumonectomy, because PPAS has substantial resistance to chemotherapy or radiotherapy. The prognosis of PPAS is poor, but surgical resection has potential for long-term survival.

CONCLUSION

Although these surgeries are uncommon and invasive for the patients, selecting appropriate patients, aggressive multimodality therapy, and performing combined thoracic and cardiovascular surgery can contribute to a good outcome.

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.