Postoperative radiation therapy after complete resection of thymoma has little impact on survival

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.

Risk factor analysis of thymoma resection and its value in guiding clinical treatment

BACKGROUND

In this study, relationships between clinicopathologic characteristics and progression-free survival (PFS) of patients after thymomectomy were analyzed to provide valuable suggestions regarding the treatment of thymoma.

METHODS

Data from 187 thymoma patients undergoing surgery at Beijing Tongren Hospital between January 1, 2006, and December 31, 2015, were retrospectively reviewed. We explored the risk factors for PFS among sex, age, thymoma-associated MG, completeness of resection, histologic type and TNM stage, and investigated their interrelationship.

RESULTS

Among the 187 patients, 18 patients (9.63%) had tumor recurrence/metastasis, and all of whom had in situ recurrence or pleural metastasis, and most of them (10 of 18 patients) had MG symptoms that reappeared or were aggravated. Fifteen patients (8.02%) died, and myasthenic crisis was a leading cause. Based on Cox regression analysis, only age (HR = 3.16; 95% CI: 1.44-6.91; p = 0.004) and the completeness of resection (HR = 9.03; 95% CI: 2.58-31.55; p = 0.001) were independent risk factors for PFS. Furthermore, we found that the completeness of resection was related to the histologic type (p = 0.009) and TNM stage (p < 0.001) by Fisher's exact test.

CONCLUSIONS

The results of this cohort study remind us that we should pay attention to the reappearance or aggravation of MG after thymoma resection, because it is the leading cause of death and may indicate tumor progression. Furthermore, completeness of resection was related to the histologic type and TNM stage, but it was the independent risk factors of thymoma. Therefore, R0 resection is critical to the prognosis of thymoma.

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.

Clinical outcomes for patients with thymoma and thymic carcinoma after undergoing different front-line chemotherapy regimens

Background

Front‐line platinum‐base chemotherapy for advanced thymoma and thymic carcinoma (TC) improves resectability and prolongs patients' overall survival (OS). In this study, we evaluated patients' outcomes given different front‐line regimens: cisplatin, doxorubicin, and cyclophosphamide (CAP); cisplatin and etoposide (EP); or cisplatin and paclitaxel (TP).

Materials and Methods

We retrospectively evaluated the medical records of patients with advanced thymoma and TC who were treated at our medical center between 2005 and 2015. We investigated objective response rates (ORRs), progression‐free survival (PFS), and OS after undergoing different front‐line regimens.

Results

Among the 108 enrolled patients, 37 (34%) had thymoma and 71 (66%) had TC; 45 received CAP, 36 received EP, and 27 received TP regimens. The ORRs of patients receiving CAP, EP, and TP were 51%, 50%, and 41%, respectively. For patients with stage III and IVA disease, the median PFS after CAP, EP, and TP were 34.5, 26.4, and 18.0 months (p = 0.424), respectively, and the 5‐year OS rates were 84.9%, 70.6%, and 60.0% (p = 0.509). In patients with stage IVB disease, the median PFS were 9.4, 8.2, and 11.6 months after undergoing CAP, EP, and TP (p = 0.173), respectively, and the 5‐year OS rates were 41.1%, 39.1%, and 14.3% (p = 0.788). TC pathology subtype and liver metastasis were associated with poor OS. Three patients with stage IVB TC had an OS of more than 5 years.

Conclusion

Different front‐line chemotherapy regimens may provide similar long‐term PFS and OS in patients with advanced thymoma and TC. In addition to TC and liver metastasis were associated with poor OS, other potential prognostic factors are warranted for studying.

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.

Single-center evaluation of prognostic factors for thymoma treated by surgery: a retrospective study

BACKGROUND

This study aimed to retrospectively evaluate the clinical, pathological, and treatment-related factors associated with survival in patients with surgically treated thymomas.

METHODS

Sixty patients with thymomas who underwent treatment at our institution between 2004 and 2015 were included. Survival analysis was performed based on curves that were obtained using the Kaplan-Meier method. The Wilcoxon test was used for all comparisons, and p < 0.05 was considered statistically significant.

RESULTS

Forty-seven, four, three, four, and two patients presented tumor stages I, II, III, IVa, and IVb (according to the Masaoka classification), respectively, while six, 14, 11, 22, and seven patients had type A, AB, B1, B2, and B3 thymomas, respectively. Furthermore, 53 and eight patients underwent complete resection and required additional resection of adjacent organs, respectively, and no patients died from surgery-related complications. The five-year survival and recurrence-free survival (RFS) rates were 96 and 86%, respectively. The five-year survival rate for all stages was 100% except for those with stage IVb tumors (Masaoka classification); the survival rate for those patients was 0%. Separately, the five-year RFS rates for tumor stages I, II, III, IVa, and IVb were 100, 91, 91, 81, and 71%, respectively. Finally, the five-year survival rates in cases with complete and incomplete resections were 100 and 71%, respectively, indicating that the latter group had a significantly poorer prognosis (p < 0.001).

CONCLUSIONS

These findings suggest that complete resection and the Masaoka pathological stage are significant predictors of prognosis in patients with thymomas. Surgery should aim to achieve complete resection; however, advanced cases may require multimodality therapy.

Surgical treatment strategies for invasive thymoma

A thymoma is a common anterior thymus mediastinal tumor composed of atypical epithelial tumor cells, though the morbidity rate is lower as compared to other types of thoracic malignancy such as lung cancer and lung metastasis from another primary cancer. As a result, clinical data regarding thymomas have not been well discussed as compared to those of other carcinomas. Also, because of the low morbidity rate and insufficient clinical experience, oncological characteristics and clinical treatment options are poorly understood. Surgical complete resection is the most reliable option for clinical treatment of a thymoma. This tumor can easily develop adjacent to several different structures and nearby organs, such as the pericardium, lungs, and great vessels, which are easily invaded when the size is large, and a combined resection is then needed. When en bloc resection is considered to be difficult based on evaluation with preoperative modalities, induction chemotherapy followed by surgery is recommended. Moreover, when pleural dissemination is revealed during pre- or peri-operative procedures, volume reduction surgery has been reported by several groups to extend prognosis. On the other hand, in cases with a small-sized tumor, a minimally invasive surgical procedure, such as video-assisted thoracic surgery (VATS) or robotic-assisted thoracic surgery (RATS), is usually selected. Because of the wide variety of cases with thymoma, a deliberate strategy and skillful techniques are necessary for effectual surgical treatment. In this review, we discuss strategies that have been shown to be effective for treating patients with early and advanced thymoma, including those with involved adjacent organs.

Multimodality approach in treatment of thymic tumors

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

Surgical management of thymic epithelial tumors

Resection is the mainstay of treatment for thymic epithelial tumors (TETs), with complete removal of the tumor and involved organs being the ultimate aim. The choice of surgical approach plays a major role in defining treatment success, and the optimal choice of method should thus provide an adequate surgical view to achieve complete tumor resection. While median sternotomy is considered the gold standard for access to the mediastinum, several minimally invasive approaches to thymectomy have been described, including video-assisted robotic-assisted thymectomy, although the oncological outcomes of that procedure remain unclear. A multimodal approach incorporating chemotherapy or chemoradiotherapy followed by extended surgery may improve resectability and outcomes for patients with advanced TETs. Surgical debulking is also reportedly acceptable for invasive thymoma because of its potential for achieving favorable outcomes. Re-resection is an acceptable option for patients with recurrent thymoma after initial resection, and repeat resection for recurrent pleural dissemination seems effective. Here, the literature on current clinical practices in the surgical management and treatment of TETs is reviewed.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Identification of potential agents for thymoma by integrated analyses of differentially expressed tumour-associated genes and molecular docking experiments

Thymoma, derived from the epithelial cells of the thymus, is a rare malignant tumour type. Following diagnosis with thymoma, patients generally undergo surgical treatment. However, patients with advanced-stage disease are only candidates for chemotherapy and have poor survival. Therefore, it is urgently required to explore effective chemotherapeutic agents for the treatment of thymoma. In the present study, a Bioinformatics analysis was performed to identify novel drugs for thymoma. Differentially expressed genes (DEGs) in thymoma were obtained by Gene Expression Profiling Interactive Analysis. Subsequently, these genes were processed by Connectivity Map analysis to identify suitable compounds. In addition, Metascape software was used to verify drug and target binding. Molecular docking technology was used to verify drug and target binding. Finally, absorption, distribution, metabolism and excretion parameters in the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform database were used for drug screening and for evaluation of the potential clinical value. In total, 2,447 DEGs, including 2,204 upregulated and 243 downregulated genes, were identified from 118 thymoma patients and 339 normal samples. The top 10 drugs displaying the most significant negative correlations were fulvestrant, hesperetin, zidovudine, hydrocortisone, rolitetracycline, ellipticine, sirolimus, quinisocaine, oestradiol (estradiol) and harmine. The predicted targets of these drugs were then confirmed. The score for the association between estrogen receptor 1 (ESR1) and fulvestrant was 0.99. According to the molecular docking analysis, the total scores for the interaction between ESR1 were 10.26, and those for the interaction between tamoxifen and ESR1 were 6.60. The oral bioavailability (%), drug-likeness and drug half-life for hesperetin were 70.31, 0.27 and 15.78, respectively; those for oestradiol were 53.56, 0.32 and 3.50, respectively; and those for harmine were 56.80, 0.13 and 5.04, respectively. In conclusion, several potential therapeutic drugs for thymoma were identified in the present study. The results suggested that the compounds, including fulvestrant, estradiol, hesperetin and ellipticine, represent the most likely drugs for the treatment of thymoma. Future studies should focus on testing these novel compounds in vitro and in vivo.

Clinical Outcomes of Up-front Surgery Versus Surgery After Induction Chemotherapy for Thymoma and Thymic Carcinoma: A Retrospective Study

INTRODUCTION

Although induction chemotherapy improves the resectability of thymic neoplasms, it is unclear whether surgery after induction chemotherapy can improve outcomes. We compared long-term outcomes of surgery with and without induction chemotherapy in patients with thymic neoplasms.

PATIENTS AND METHODS

We retrospectively investigated the clinical information of patients with thymic neoplasms at the National Taiwan University Hospital between 2005 and 2013.

RESULTS

Of 204 patients, 119 underwent direct surgery (group 1), 45 underwent surgery after induction chemotherapy (group 2), and 40 underwent no surgery (group 3). The 5-year overall survival rates of groups 1, 2, and 3 were as follows: for 204 patients, 96.3%, 76.4%, and 35.5% (P < .001); for 119 thymoma patients, 96.6%, 88.9%, and 100.0% (P = .835); for 85 thymic carcinoma patients, 94.7%, 69.7%, and 17.7% (P < .001); for 36 American Joint Committee on Cancer (AJCC) stage III-IVA thymoma patients, 92.9%, 83.3%, and 100% (P = .833); and for 28 stage III-IVA thymic carcinoma patients, 75.0%, 76.2%, and 62.5%, (P = .160). Univariate analysis showed that for group 2 (P = .0208) and group 3 (P < .0001), thymic carcinoma pathology type (P = .0010) and stage IVB disease (P < .0001) were poor prognostic factors. Multivariate analysis found thymic carcinoma (P = .0026) and stage IVB disease (P = .0449) to be poor prognostic factors.

CONCLUSION

Up-front surgery leads to best overall survival, and induction chemotherapy followed by surgery may improve resectability and outcomes. Only thymic carcinoma and stage IVB disease were poor prognostic factors in multivariate analysis.

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.

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.

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.

Adjuvant Radiotherapy for Stages II and III Resected Thymoma: A Single-institutional Experience

INTRODUCTION

The role of adjuvant radiation for Masaoka stages II and III thymoma remains controversial. The aim of this study was to evaluate the clinical benefit of radiation therapy for resected stages II and III thymoma patients.

METHODS

We retrospectively reviewed the medical records of 175 thymoma patients treated from July 1996 to January 2013 at University of Washington Medical Center; 88 patients with adequate follow-up and who met histologic criteria were included. We evaluated progression-free survival (PFS) and overall survival (OS), and compared these outcomes in patients treated by surgery (S) alone versus surgery plus radiotherapy (S+RT). Cox regression models and log-rank tests were used to compare PFS and OS for S versus S+RT, and they were further assessed by margin-positive versus margin-negative subgroups using Kaplan-Meier curves.

RESULTS

Among the 88 thymoma patients, 22 were stage II and 18 were stage III. For all stages II and III patients, adjuvant radiation was not identified as a significant predictor for PFS (P=0.95) or OS (P=0.63). A positive surgical margin predicted for a worse OS (hazard ratio=7.1; P=0.004). Further investigation revealed for resection margin-positive patients; S+RT had higher OS than S alone (P=0.006).

CONCLUSIONS

For stages II and III thymoma, postoperative adjuvant radiation was not associated with statistically significant differences in PFS or OS in this study. Our results indicated a potential OS benefit of adjuvant RT in patients with positive resection margins, and therefore may be considered in this patient population.

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.

[Role of Postoperative Radiotherapy for Stage I/II/III Thymic Tumor - Results of the ChART Retrospective Database]

背景与目的

胸腺肿瘤术后放疗尚存在争议，此研究目的为评价术后放疗在Ⅰ期-Ⅲ期胸腺肿瘤中的作用。

方法

搜索中国胸腺瘤研究协作组（Chinese Alliance of Research for Thymomas, ChART）数据库中1994年至2012年接受手术切除未行新辅助治疗的Ⅰ期-Ⅲ期胸腺肿瘤患者的资料。对临床病理资料进行单因素、多因素分析，Cox比例风险模型用于决定死亡风险比。

结果

ChART数据库中Ⅰ期-Ⅲ期胸腺肿瘤共1, 546例。其中649例（41.98%）接受术后放疗。术后放疗与性别、组织学类型（World Health Organization, WHO）、胸腺切除程度、是否完全切除、Masaoka-Koga分期及辅助化疗相关。手术后辅助放疗患者5年、10年总生存和无瘤生存分别为90%和80%、81%和63%，而单纯手术者5年、10年总生存和无瘤生存分别为96%和95%、92%和90%，两组生存有统计学差异（P=0.001, P＜0.001）。单因素表明年龄、组织学分类（WHO）、Masaoka-Koga分期、是否完全切除和术后放疗与总生存相关。多因素分析提示组织学分类（WHO）（P=0.001）、Masaoka-Koga分期（P=0.029）和是否完全切除（P=0.003）是总生存的独立预后因素。单因素分析表明性别、重症肌无力、组织学分类、Masaoka-Koga分期、手术方式、术后放疗和是否完全切除与无瘤生存相关。多因素分析表明组织学类型（P＜0.001）、Masaoka-Koga分期（P=0.005）和是否完全切除（P=0.006）是无瘤生存的独立预后因素。亚组分析表明不完全切除患者接受术后放疗可以提高总生存和无瘤生存（P=0.010, P=0.017）。然而，完全切除者接受术后放疗则会降低总生存和无瘤生存（P＜0.001, P＜0.001）。

结论

此回顾性研究表明不完全切除Ⅰ期-Ⅲ期胸腺肿瘤患者术后放疗可以提高总生存和无瘤生存。但是，对于完全切除患者，术后放疗总体上并未显示出生存获益。

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.

Utility of Electrocardiography (ECG)-Gated Computed Tomography (CT) for Preoperative Evaluations of Thymic Epithelial Tumors

BACKGROUND

Preoperative evaluation of invasion to the adjacent organs is important for the thymic epithelial tumors on CT. The purpose of our study was to evaluate the utility of electrocardiography (ECG)-gated CT for assessing thymic epithelial tumors with regard to the motion artifacts produced and the preoperative diagnostic accuracy of the technique.

MATERIAL/METHODS

Forty thymic epithelial tumors (36 thymomas and 4 thymic carcinomas) were examined with ECG-gated contrast-enhanced CT using a dual source scanner. The scan delay after the contrast media injection was 30 s for the non-ECG-gated CT and 100 s for the ECG-gated CT. Two radiologists blindly evaluated both the non-ECG-gated and ECG-gated CT images for motion artifacts and determined whether the tumors had invaded adjacent structures (mediastinal fat, superior vena cava, brachiocephalic veins, aorta, pulmonary artery, pericardium, or lungs) on each image. Motion artifacts were evaluated using a 3-grade scale. Surgical and pathological findings were used as a reference standard for tumor invasion.

RESULTS

Motion artifacts were significantly reduced for all structures by ECG gating (p=0.0089 for the lungs and p<0.0001 for the other structures). Non-ECG-gated CT and ECG-gated CT demonstrated 79% and 95% accuracy, respectively, during assessments of pericardial invasion (p=0.03).

CONCLUSIONS

ECG-gated CT reduced the severity of motion artifacts and might be useful for preoperative assessment whether thymic epithelial tumors have invaded adjacent structures.

Postoperative Radiotherapy in Locally Invasive Malignancies of the Thymus: Patterns of Care and Survival

INTRODUCTION

Our purpose was to determine the overall survival (OS) benefit of postoperative radiotherapy (PORT) in patients with advanced thymic malignancies and the associated predictors of PORT receipt.

METHODS

We queried the National Cancer Data Base for all stage II to III thymic malignancies. Trends in PORT use over time were analyzed using least squares linear regression. Factors predictive of PORT and OS were identified by using multivariate logistic and Cox regression analysis, respectively.

RESULTS

We identified 1156 patients between 2004 and 2012 who met the inclusion criteria. The utilization of PORT was found to increase over the study period by 41% (37% to 52% [p = 0.01]). On multivariate analysis, the factors found to be the most predictive of receipt of PORT were positive surgical margins (adjusted OR = 1.98 [p < 0.01]) and treatment at a nonacademic facility (adjusted OR = 1.44 [p = 0.01]). The 5-year OS was superior for patients receiving PORT compared with for those who did not (83% versus 79%, p = 0.03). Receipt of PORT was associated with a trend toward decreased risk for death on multivariate analysis (hazard ratio = 0.75 [p = 0.09]). In addition, a positive macroscopic margin was the most important predictor of survival (hazard ratio = 3.48 [p < 0.01]). On subgroup analysis, patients with thymic carcinoma and WHO histologic types A and AB were associated with an OS benefit with PORT, whereas types B1, B2, and B3 were not. Patients with positive margins were not associated with an OS benefit with PORT.

CONCLUSIONS

The use of PORT in patients with advanced thymic malignancies is increasing over time and is determined by both clinical and demographic factors. Receipt of PORT was associated with improved OS. The OS benefit with PORT was dependent on the WHO histologic type.

Postoperative radiotherapy and tumor recurrence after complete resection of stage II/III thymic tumor: a meta-analysis of cohort studies

BACKGROUND

Whether postoperative radiotherapy (PORT) is effective for reducing the recurrence risk in patients who received complete resection of the stage II or III thymic tumors has not been determined. A meta-analysis was performed by combining the results of all available controlled trials.

METHODS

PubMed, Cochrane's Library, and the Embase databases were searched for studies which compared the recurrence data for patients with complete resection of the stage II or III thymic tumors assigned to an observing group, or a PORT group. A random effect model was applied to combine the results.

RESULTS

Nineteen studies, all designed as retrospective cohort studies were included. These studies included 663 patients of PORT group and 617 patients of observing group. The recurrence rate for the patients in PORT group and observing group were 12.4% and 11.5%, respectively. Results of our study indicated that PORT has no significant influence on recurrent risk in patients with stage II or III thymic tumor after complete resection (odds ratio 1.02, 95% confidence interval 0.55-1.90, P=0.96). When stratified by stages, our meta-analyses did not indicate any significant effects of PORT on recurrent outcomes in either the stage II or the stage III patients. Moreover, subsequent analysis limited to studies only including patients with thymoma or thymic carcinoma also did not support the benefits of PORT on recurrent outcomes.

CONCLUSION

Although derived from retrospective cohort studies, current evidence did not support any benefit of PORT on recurrent risk in patients with complete resection of the stage II or III thymic tumors.

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.

The role of postoperative radiotherapy for stage I/II/III thymic tumor-results of the ChART retrospective database

BACKGROUND

Postoperative radiotherapy (PORT) for thymic tumor is still controversial. The object of the study is to evaluate the role of PORT for stage I to III thymic tumors.

METHODS

The Chinese Alliance for Research in Thymomas (ChART) was searched for patients with stage I to III thymic tumors who underwent surgical resection without neoajuvant therapy between 1994 and 2012. Univariate and multivariate survival analyses were performed. Cox proportional hazard model was used to determine the hazard ratio for death.

RESULT

From the ChART database, 1,546 stage I to III patients were identified. Among these patients, 649 (41.98%) received PORT. PORT was associated with gender, histological type (World Health Organization, WHO), thymectomy extent, resection status, Masaoka-Koga stage and adjuvant chemotherapy. The 5-year and 10-year overall survival (OS) rates and disease-free survival (DFS) rates for patients underwent surgery followed by PORT were 90% and 80%, 81% and 63%, comparing with 96% and 95%, 92% and 90% for patients underwent surgery alone (P=0.001, P<0.001) respectively. In univariate analysis, age, histological type (WHO), Masaoka-Koga stage, completeness of resection, and PORT were associated with OS. Multivariable analysis showed that histological type (WHO) (P=0.001), Masaoka-Koga stage (P=0.029) and completeness of resection (P=0.003) were independently prognostic factors of OS. In univariate analysis, gender, myasthenia gravis, histological subtype, Masaoka-Koga stage, surgical approach, PORT and completeness of resection were associated with DFS. Multivariate analysis showed that histological subtype (P<0.001), Masaoka-Koga stage (P=0.005) and completeness of resection (P=0.006) were independent prognostic factors for DFS. Subgroup analysis showed that patients with incomplete resection underwent PORT achieved better OS and DFS (P=0.010, 0.017, respectively). However, patients with complete resection underwent PORT had the worse OS and DFS (P<0.001, P<0.001, respectively).

CONCLUSIONS

The current retrospective study indicates that PORT after incomplete resection could improve OS and DFS for patients with stage I to III thymic tumors. However for those after complete resection, PORT does not seem to have any survival benefit on the whole.

Thymoma and thymic carcinomas

Thymomas (Ts) and thymic carcinomas (TCs) are rare tumours of the mediastinum with an incidence rate of 1.7/million per year in Europe. Histological classification is based on rate of non-malignant-appearing thymic epithelial cells and proportions of lymphocytes (A, AB, B1, B2, B3, and C), while staging system concerns localisation of the involved areas. Surgery is the mainstay of treatment with a 10-year survival of 80%, 78%, 75%, and 42% for stages I, II, III and IV, respectively, with an R0 resection. Radiotherapy has a role in selected cases (stage III patients or R1-2 residual) and platinum-based chemotherapy remains the standard of care for patients with advanced disease. A multimodality approach would be advisable when surgery is not recommended. Since molecular aberrations are poorly understood and few responses are reported, targeted therapies are yet being studied. In this review, we describe key aspects of clinical management for Ts and TCs.

State of the art: diagnostic tools and innovative therapies for treatment of advanced thymoma and thymic carcinoma

In this review article, state-of-the-art diagnostic tools and innovative treatments of thymoma and thymic carcinoma (TC) are described with special respect to advanced tumour stages. Complete surgical resection (R0) remains the standard therapeutic approach for almost all a priori resectable mediastinal tumours as defined by preoperative standard computed tomography (CT). If lymphoma or germ-cell tumours are differential diagnostic considerations, biopsy may be indicated. Resection status is the most important prognostic factor in thymoma and TC, followed by tumour stage. Advanced (Masaoka-Koga stage III and IVa) tumours require interdisciplinary therapy decisions based on distinctive findings of preoperative CT scan and ancillary investigations [magnetic resonance imaging (MRI)] to select cases for primary surgery or neoadjuvant strategies with optional secondary resection. In neoadjuvant settings, octreotide scans and histological evaluation of pretherapeutic needle biopsies may help to choose between somatostatin agonist/prednisolone regimens and neoadjuvant chemotherapy as first-line treatment. Finally, a multimodality treatment regime is recommended for advanced and unresectable thymic tumours. In conclusion, advanced stage thymoma and TC should preferably be treated in experienced centres in order to provide all modern diagnostic tools (imaging, histology) and innovative therapy techniques. Systemic and local (hyperthermic intrathoracic chemotherapy) medical treatments together with extended surgical resections have increased the therapeutic options in patients with advanced or recurrent thymoma and TC.

Adjuvant treatment in patients at high risk of recurrence of thymoma: efficacy and safety of a three-dimensional conformal radiation therapy regimen

Background

The clinical benefits of postoperative radiation therapy (PORT) for patients with thymoma are still controversial. In the absence of defined guidelines, prognostic factors such as stage, status of surgical margins, and histology are often considered to guide the choice of adjuvant treatment (radiotherapy and/or chemotherapy). In this study, we describe our single-institution experience of three-dimensional conformal PORT administered as adjuvant treatment to patients with thymoma.

Methods

Twenty-two consecutive thymoma patients (eleven male and eleven female) with a median age of 52 years and treated at our institution by PORT were analyzed. The patients were considered at high risk of recurrence, having at least one of the following features: stage IIB or III, involved resection margins, or thymic carcinoma histology. Three-dimensional conformal PORT with a median total dose on clinical target volume of 50 (range 44–60) Gy was delivered to the tumor bed by 6–20 MV X-ray of the linear accelerator. Follow-up after radiotherapy was done by computed tomography scan every 6 months for 2 years and yearly thereafter.

Results

Two of the 22 patients developed local recurrence and four developed distant metastases. Median overall survival was 100 months, and the 3-year and 5-year survival rates were 83% and 74%, respectively. Median disease-free survival was 90 months, and the 5-year recurrence rate was 32%. On univariate analysis, pathologic stage III and presence of positive surgical margins had a significant impact on patient prognosis. Radiation toxicity was mild in most patients and no severe toxicity was registered.

Conclusion

Adjuvant radiotherapy achieved good local control and showed an acceptable toxicity profile in patients with high-risk thymoma.

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.

Radiotherapy for thymic carcinoma: adjuvant, inductive, and definitive

Although historically thymoma and thymic carcinoma have been treated surgically, radiation therapy also has an important role, either as postoperative therapy to reduce the risk of mediastinal recurrence or as part of definitive treatment for patients who cannot undergo surgery. Induction chemotherapy and molecular targeted agents may also be appropriate for thymic carcinoma, the behavior of which resembles non-small-cell lung carcinoma more than that of thymoma or invasive thymoma and is increasingly being treated like lung cancer. We present here a review of current therapies for thymic malignancies and briefly discuss the potential benefits from novel technologies for such treatment.

Thymic neoplasm: a rare disease with a complex clinical presentation

Thymic neoplasms constitute a broad category of rare lesions with a wide spectrum of pathologic characteristics and clinical presentations which therefore require a high index of suspicion to diagnose. The natural history of the disease is seldom predictable, anywhere from an indolent to an aggressively malignant course. Although the classification and staging of these lesions are complex and controversial, complete radical surgical resection remains the gold standard of therapy. Radiation and chemotherapy are important elements of the multimodality approach to treating these patients and it is important for thoracic surgeons to work closely with their colleagues in other disciplines in the management of and future research endeavors in thymic neoplasm. In this review, we discuss the evaluation of the patient with an anterior mediastinal mass, the classification and staging of thymic neoplasms, the role of surgery, radiation and chemotherapy in treating this disease, as well as future directions in research for novel targeted therapies.

Is There a Role of Postoperative Radiation Therapy in Completely Resected Stage I/II Thymic Epithelial Tumor?

PURPOSE

Retrospective analyses of patients with stage I-II thymic epithelial tumors (TET) who were treated with either surgery alone (S) or surgery plus postoperative radiation therapy (SRT) were conducted to evaluate the role of adjuvant radiation therapy (RT).

MATERIALS AND METHODS

A total of 110 stage I-II TET patients following complete resection were included in this study. Postoperative radiation therapy was recommended for those with aggressive histologic type and/or invasive features according to the surgeons' judgment during the operation. A median dose of 54.0 Gy (range, 44 to 60 Gy) focused on the primary tumor bed was administered to 57 patients (51.8%).

RESULTS

In all patients, the rates of overall survival, disease-specific survival, and disease-free survival at 10 years were 91.7%, 97.1%, and 95.8%, respectively. No significant differences in disease-specific survival (100% in the S group and 93.5% in the SRT group at 10 years, p=0.12) and disease-free survival (98.1% in the S group and 94.5% in the SRT group at 10 years, p=0.41) were observed between the treatment groups, although a significantly larger number of World Health Organization (WHO)-type B2-C (p<0.001) and Masaoka stage II (p=0.03) tumors were observed in the SRT group than in the S group. No local recurrence was observed in the SRT group. No grade 2 or greater RT-related toxicities were observed in the SRT group.

CONCLUSION

Excellent outcomes were achieved in patients with stage I-II TET who underwent complete resection. Considering excellent local control and low morbidity, adjuvant RT may be considered in high risk patients with WHO-type B2-C histology and Masaoka stage II.

Long-term survival in thymic epithelial tumors: a single-center experience from China

BACKGROUND

To evaluate long-term survival in thymic epithelial tumors (TETs), we present our experiences at a single institution in China.

METHODS

We performed a retrospective analysis including 115 patients with TETs from 2001 to 2006. Histological diagnosis was completed based on the new WHO classification system. A univariate and multivariate survival analysis was performed, which included myasthenia gravis (MG), WHO histological type, Masaoka stage, completeness of resection, and adjuvant radiotherapy (RT).

RESULTS

WHO histological subtype was closely correlated with that of Masaoka stage. The overall median survival time was 84.4 months and the 7-year survival rate was 78%. In the univariate analysis, three prognostic factors, including WHO histology type, Masaoka stage and complete resection, were statistically significant. In the analysis of the cases with complete resection, adjuvant RT did not show obvious survival benefit. In the multivariate analysis, Masaoka stage was the only independent factor that predicted long-time survival.

CONCLUSIONS

Thymic carcinoma should be regarded as a different category of the disease due to its aggressive and poorer prognosis. Complete resection of the tumor and Masaoka stage I and II were found to contribute to a better survival. Adjuvant RT is not recommended for patients with complete resection in thymomas.

Entire hemithorax irradiation for Masaoka stage IVa thymomas

Thymomas are rare neoplasms that have an indolent growth with a preferentially intra-thoracic dissemination pattern. Surgery is currently the standard treatment of thymomas; however radiotherapy is often used in an adjuvant setting due to a high sensitivity of these tumors to such treatment. Postoperative entire hemithoracic irradiation has been used in selected Masaoka stage IVa cases after complete surgical excision of metastatic lesions. In the present article, the authors report three cases of Masaoka stage IVa thymoma that underwent entire hemithorax irradiation after surgical excision of metastatic lesions. The first two patients presented as stage IVa thymomas. The third case consisted of a pleural recurrence of a thymoma. Hemithoracic irradiation with low doses has been used by different authors; the available data shows that it is a well-tolerated treatment that could potentially lead to better loco-regional control and increased overall survival.