Intensity Modulated Radiation Therapy Plus Etoposide/Cisplatin for Patients With Limited Advanced Unresectable Thymic Epithelial Tumors: A Prospective Phase 2 Study

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.

Hypofractionated Radiotherapy as a Standalone Treatment Modality for Locally Advanced Type B2 Thymoma in an Octogenarian Patient: 45 Gy in 15 Fractions

Thymic epithelial tumors (TETs), particularly type B2 thymomas, are rare neoplasms primarily found in the anterior mediastinum. The current therapeutic approach includes surgery, chemotherapy, and radiotherapy, but there is limited research on radiotherapy as a standalone treatment. This case report aims to elucidate the clinical outcomes of hypofractionated radiotherapy as a standalone treatment for locally advanced type B2 thymoma, offering insights into its potential efficacy and role in clinical practice.

American Radium Society Appropriate Use Criteria for Radiation Therapy in the Multidisciplinary Management of Thymic Carcinoma

Importance

Thymic carcinoma is rare, and its oncologic management is controversial due to a paucity of prospective data. For this reason, multidisciplinary consensus guidelines are crucial to guide oncologic management.

Objective

To develop expert multidisciplinary consensus guidelines on the management of common presentations of thymic carcinoma.

Evidence Review

Case variants spanning the spectrum of stage I to IV thymic carcinoma were developed by the 15-member multidisciplinary American Radium Society (ARS) Thoracic Appropriate Use Criteria (AUC) expert panel to address management controversies. A comprehensive review of the English-language medical literature from 1980 to 2021 was performed to inform consensus guidelines. Variants and procedures were evaluated by the panel using modified Delphi methodology. Agreement/consensus was defined as less than or equal to 3 rating points from median. Consensus recommendations were then approved by the ARS Executive Committee and subject to public comment per established ARS procedures.

Findings

The ARS Thoracic AUC panel identified 89 relevant references and obtained consensus for all procedures evaluated for thymic carcinoma. Minimally invasive thymectomy was rated as usually inappropriate (regardless of stage) due to the infiltrative nature of thymic carcinomas. There was consensus that conventionally fractionated radiation (1.8-2 Gy daily) to a dose of 45 to 60 Gy adjuvantly and 60 to 66 Gy in the definitive setting is appropriate and that elective nodal irradiation is inappropriate. For radiation technique, the panel recommended use of intensity-modulated radiation therapy or proton therapy (rather than 3-dimensional conformal radiotherapy) to reduce radiation exposure to the heart and lungs.

Conclusions and Relevance

The ARS Thoracic AUC panel has developed multidisciplinary consensus guidelines for various presentations of thymic carcinoma, perhaps the most well referenced on the topic.

Chinese expert consensus on the diagnosis and treatment of thymic epithelial tumors

Thymic epithelial tumors (TETs) are a relatively rare type of thoracic tumor, accounting for less than 1% of all tumors. The incidence of TETs is about 3.93/10000 in China, slightly higher than that of European and American countries. For resectable TETs, complete surgical resection is recommended. Radiotherapy or chemotherapy may be used as postoperative adjuvant treatment. Treatment for advanced, unresectable TETs consist mainly of radiotherapy and chemotherapy, but there is a lack of standard first- and second-line treatment regimens. Recently, targeted therapies and immune checkpoint inhibitors have shown promising outcomes in TETs. Based on the currently available clinical evidences and the opinions of the national experts, the Thymic Oncology Group of Yangtze River Delta Lung Cancer Cooperation Group (East China LUng caNcer Group, ECLUNG; Youth Committee) established this Chinese expert consensus on the clinical diagnosis and treatment of TETs, covering the epidemiology, diagnosis, treatment, prognosis and follow-up of TETs.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Chemoradiotherapy for untreated Masaoka-Koga stage IVB thymic carcinoma: a single-center retrospective study

BACKGROUND

Thymic carcinoma (TC) is a rare type of a malignant tumor. The optimal treatment for Masaoka-Koga stage IVB TC patients is controversial due to the rarity of the disease. Chemotherapy is still the preferred option, but the outcomes are unsatisfactory. Whether radiotherapy combined with chemotherapy could improve prognosis remains unclear.

METHODS

Untreated stage IVB TC patients who have received first-line chemotherapy were included in the present study. The patients who have undergone surgery were excluded. The primary outcomes were objective response rate (ORR) and progression-free survival (PFS).

RESULTS

Sixty-seven patients were included in the study. A total of 31 patients received chemoradiotherapy (ChemoRT cohort), and the remaining 36 patients only received chemotherapy (Chemo cohort). The median follow-up period was 40.3 months. The ORR for the ChemoRT and Chemo cohorts was 61.3 and 27.8%, respectively (P = 0.006). Furthermore, PFS (P = 0.003) and OS (P = 0.046) were significantly superior in the ChemoRT cohort. Radiotherapy maintained a significant favorable effect on PFS in multivariate analysis (P = 0.014), but the effect on OS was insignificant (P = 0.249). There was no advantage in PFS (P = 0.302) in the ChemoRT cohort in patients who received < 4 cycles of chemotherapy. In contrast, radiotherapy significantly improved PFS (P = 0.005) in patients who received ≥ 4 cycles of chemotherapy.

CONCLUSIONS

Chemoradiotherapy used as the first-line treatment improved ORR and PFS in Masaoka-Koga stage IVB TC patients. Patients receiving more cycles of chemotherapy may have a better chance to benefit from chemoradiotherapy.

An Updated Review on Radiation Treatment Management in Thymus Cancers

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

Hypofractionated Radiation Therapy Combined With Weekly Chemotherapy in Patients With Unresectable or Recurrent Thymic Epithelial Tumor: A Prospective, Single-Arm Phase 2 Study (GASTO-1042)

PURPOSE

This prospective phase 2 study aimed to evaluate the efficacy and safety of hypofractionated radiation therapy (HRT) combined with concurrent weekly chemotherapy in patients with unresectable or recurrent thymic epithelial tumors (TETs).

METHODS AND MATERIALS

Patients with unresectable or recurrent intrathoracic TETs that could be encompassed within the radiation fields were enrolled. HRT using intensity modulated radiation therapy (IMRT) technique was administered with 3 different levels of radiation doses (51 Gy/17 fractions (fx), 48 Gy/12 fx, and 45 Gy/9 fx; biologically effective dose of 66.3-67.5Gy), combined with weekly docetaxel (25 mg/m²) and nedaplatin (25 mg/m²). Weekly thymosin α1 (1.6 mg) was administered from the start to 2 months after radiation therapy. The objective response rate (ORR), progression-free survival (PFS), overall survival (OS), health-related quality of life (QOL), and toxicity were recorded.

RESULTS

Fifty eligible patients enrolled from August 1, 2018, to July 1, 2020, were analyzed. Most patients (82.0%) had stage IVB tumors. Patients had IMRT-HRT (36-51 Gy in 9-17 fx, median biologically effective dose of 67.2 Gy) and concurrent weekly docetaxel/nedaplatin (2-4 cycles). During a median follow-up of 25.0 months (14.0-40.0), the ORR was 83.7%, the 2-year PFS was 59.1%, and the 2-year OS was 90.0%. There was 1 (2.0%) in-field recurrence while 19 (38.0%) patients developed out-of-field recurrence. Grade 3 pneumonitis was observed in 1 patient (2.0%). The ORR, 2-year PFS, 2-year OS, and toxicity were similar among 3 dose levels. Fourteen (28.0%) patients had 2 to 4 courses of radiation therapy because of recurrent diseases. Only 1 suffered from grade 1 pulmonary fibrosis during follow-up. Most patients (88%) maintained a stable QOL within 1 year after radiation therapy.

CONCLUSIONS

IMRT-HRT and concurrent weekly docetaxel/nedaplatin was effective and well tolerated in unresectable or recurrent TETs. Considering the common out-of-field recurrence, this combined regimen could be an option for repeated radiation therapy. Thymosin α1 might help lower the incidence of pneumonitis and maintain the QOL.

“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.

[Mediastinal Tumors]

If mediastinal tumours cause symptoms these are related to their anatomical localization or a paraneoplastic syndrome. The differential diagnosis is based on the clinical situation with finding the lesion, and, furthermore, taking into account the age and sex of the patient, and the mediastinal compartment where the lesion is located. Cross-sectional radiographic diagnostic is essential for defining the therapeutic strategy. The anterior mediastinum is dominated by thymic tumours, mediastinal lymphomas, germ cell tumours and ectopic mediastinal poiters. The middle mediastinal compartment is the most frequent place of mediastinal cystic tumours, whereas the posterior mediastinum is the domain of neurogenic tumours. For selected cases a tissue biopsy is required. Surgery is the mainstay for most mediastinal tumours. Median sternotomy is the most frequent conventional surgical technique while minimally invasive surgery with thoracoscopic and above all robot assisted operation techniques are increasingly frequent. Combined chemotherapy and modern radiotherapy are essential components of the comprehensive treatment for mediastinal tumours.

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.

Importance of resection for locoregional disease control in Masaoka stage IVA thymic neoplasms

BACKGROUND AND OBJECTIVES

It is unclear if a specific strategy for simultaneous treatment of primary thymic neoplasms and pleural metastases confers benefit for Masaoka stage IVA disease. We reviewed our experience with thymic neoplasms with concurrent pleural metastases to identify factors influencing outcomes.

METHODS

Records of patients who presented with stage IVA thymic neoplasms from 2000 to 2018 were assessed. Multivariate Cox proportional hazards analyses were completed to determine predictors of progression-free and overall survival.

RESULTS

Forty-eight patients were identified, including 34 (71%) who underwent surgery. Median overall and progression-free survival were 123 and 21 months, respectively. The extent of resection varied, and was most commonly thymectomy plus partial pleurectomy (22, 65%). Median progression-free survival for patients who underwent surgical resection versus those who had not was 24 versus 12 months (P = .018). Following surgical resection, mediastinal recurrence was uncommon (2, 6%, vs 7, 50% nonoperatively). Five-year survival rates in these groups were suggestive of possible benefit to surgery (87% vs 68%).

CONCLUSIONS

Thymic neoplasms with pleural dissemination represents a treatment challenge. As part of a multidisciplinary approach, surgery appears to be associated with more favorable long-term results, although selection bias may account for some of the survival differences observed.