Comparison of Neoadjuvant Chemotherapy Followed by Surgery to Upfront Surgery for Thymic Malignancy

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

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

Prognosis of Concurrent Versus Sequential Chemo-Radiotherapy Induction Followed by Surgical Resection in Patients with Advanced Thymic Epithelial Tumors: A Retrospective Study

BACKGROUND

This study aimed to evaluate the prognosis of concurrent chemo-radiotherapy (CCRT) versus sequential chemo-radiotherapy (SCRT) induction followed by surgical resection in patients with advanced thymic epithelial tumors (TETs).

METHODS

This retrospective study included patients with advanced TETs who underwent CCRT or SCRT induction followed by surgical resection at the Second General Hospital of Guangdong Province between January 2008 and December 2019. The primary outcomes were induction response rate and surgical complete resection rate. The secondary outcomes were surgery combined resection, post-induction T staging, postoperative TNM staging, postoperative pathological tumor regression grade, progression-free survival (PFS) and overall survival (OS), and adverse events (AEs).

RESULTS

A total of 31 patients were included, 15 of whom received CCRT and the other 16 SCRT. The induction response rates were 80.0 and 62.5%, respectively, the post-induction step-down rates were 46.7 and 31.3%, respectively, and the post-induction R0 resection rates were 80.0 and 68.8%, respectively, without significant differences between CCRT and SCRT groups (all P > 0.05). The 5-year OS rate was 64.2 and 51.6%, respectively, and PFS was 42.3 and 21.4%, respectively, without significant differences between CCRT and SCRT groups (both P > 0.05). AEs in the hematologic system were significantly higher with CCRT compared with SCRT (P = 0.009).

CONCLUSIONS

Patients with advanced TETs might have a good prognosis with both CCRT and SCRT induction therapy, while SCRT induction may result in a lower probability of AEs in the hematologic system.

Unradical Surgery for Locally-Advanced Thymoma: Is it time to evolve Perspectives?

OBJECTIVES

Nearly-one-third of thymomas are locally-advanced at diagnosis. The traditional dogma that surgery is justified in case a complete resection can be achieved has remained unmovable until today. This study aimed to investigate feasibility and oncologic efficacy of incomplete resection for locally-advanced thymomas in a contest of multimodality therapy.

MATERIALS AND METHODS

A retrospective analysis was conducted using data of prospectively maintained thymomas database in a single high-volume centre. Data on 285 consecutive patients undergoing surgery for stage III and IVa thymomas between 1995 and 2019 were reviewed. Patients who underwent incomplete resection with curative-intent (removal of at least 90% of tumour burden) were included. Long-term outcomes and predictors of cancer-specific survival (CSS) and progression-free survival (PFS) were analyzed. Secondary endpoint was to assess adjuvant therapy efficacy.

RESULTS

The study included 79 patients, 60 with microscopic residual tumour (76%, R1) and 19 with macroscopic residual disease (24%, R2). Masaoka-Koga stage was: III in 41 patients (52%) and IVa in 38 (48%). Histology was B2-thymomas (n = 31, 39.2%) followed by B3 (n = 27, 34.2%). Five- and 10-years CSS was 88% and 80%. Seventy patients (90%) underwent adjuvant treatment; they showed CSS comparable to radical resected patients (5-years: 89.1% vs 98.9%, respectively; 10-years: 81.8% vs 92.7%, respectively, p = 0.43). The site of residual disease, Masaoka-Koga stage and WHO histology did not affect prognosis. Stepwise multivariable analysis confirmed adjuvant therapy as a favourable CSS prognostic factor (HR, 0.51; 95% CI, 0.33-0.79, p = 0.003). Stratifying by subgroups, R2-patients who received postoperative chemo(radio)therapy (pCRT) showed a significantly better prognosis than R2-patients treated by consolidation radiotherapy alone (10-years CSS: 60%, p < 0.001).

CONCLUSION

In locally-advanced thymomas, whenever a radical surgery cannot be achieved, incomplete resection has proved to be effective in a contest of multimodality strategy, independently of WHO histology, Masaoka-Koga stage and site of residual disease.

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.

Outcomes of Extended Resection for Locally Advanced Thymic Malignancies

BACKGROUND

Thymic malignancies are rare tumors about which data are limited. Our objective here was to evaluate the outcomes and risk factors for complications and death in patients who underwent extended surgery to remove thymic malignancies.

METHODS

We retrospectively included patients who underwent extended resection of locally advanced, nonmetastatic thymic malignancies at our institution. Patients were deemed eligible for resection by a multidisciplinary team. During surgery, priority was given to achieving complete resection rather than to sparing organs.

RESULTS

The 108 patients had a mean age of 53 ± 15 years (range, 9-83); among them, 91 had thymoma, 12 thymic carcinoma, and 5 neuroendocrine tumor. The Masaoka stage was III or higher in 86 patients; examination of operative specimens resulted in downstaging of 22 patients. Tumor-free resection margins were achieved in 98 patients. Overall 5- and 10-year survival rates were 80% and 68%, respectively. Myasthenia gravis, present in 36 patients, was the only independent significant risk factor for major postoperative complications. Age older than 70 years, thymic carcinoma or neuroendocrine tumor, pT3 or pT4 stage, and R1 or R2 resection margins independently predicted death. The number of resected structures was not associated with survival. Thymic carcinoma or neuroendocrine tumor was independently associated with shorter disease-free survival.

CONCLUSION

In an expert center, extended resection targeting complete resection rather than organ preservation provided good outcomes in patients with locally advanced thymic malignancies. The risk/benefit ratio of surgery should be assessed with special care in patients who are elderly or have myasthenia gravis.

Presurgical radiation and chemotherapy in preparation for thoracic tumor resection

PURPOSE OF REVIEW

This article aims at describing the role of neoadjuvant chemotherapy, radiation therapy as well the novel immunotherapy and targeted therapy in thoracic oncology with focus on anesthetic considerations of such treatments for the surgical patient.

RECENT FINDINGS

In recent years, immune check point inhibitors have changed the landscape of thoracic oncology treatment. In this review, we summarize the key studies that have been fundamental in this change.

SUMMARY

Rather than a comprehensive review, the purpose of this work is to provide the reader with an overview of the most common neoadjuvant regimens used in current practice, with the corresponding most prevalent adverse effects as it pertains for patients with esophageal and lung cancer, malignant pleural mesothelioma and mediastinal tumors. Considerations relevant to the anesthesiologist, including specific toxicities related to each treatment type, and the impact of each treatment type on perioperative outcomes and complications will be discussed.

Outcomes of extended surgical resections for locally advanced thymic malignancies: a narrative review

BACKGROUND AND OBJECTIVE

Thymic malignancies represent the most common anterior mediastinal neoplasms, as well as rare and challenging tumors. Surgery is the cornerstone in the treatment of thymic malignancies, although a multidisciplinary approach is mandatory, for both, locally advanced or metastatic disease. In our narrative review, we explored the recent literature to investigate clinical and radiological assessment, multimodality approach and outcomes of locally advanced thymic tumors. More than one-third of patients affected by an anterior mediastinal mass are asymptomatic at diagnosis. In case of locally advanced thymoma, symptoms are related to compression or invasion of adjacent structures, such as the superior vena cava (SVC), innominate veins and pericardium. Paraneoplastic syndromes, such as myasthenia gravis (MG), are related to release of antibodies, hormones and cytokines.

METHODS

Diagnostic methods must be chosen accurately to avoid unnecessary surgical resections, to define the best strategy of care, and to plan the surgical strategy. Therefore, each case must be evaluated in a multidisciplinary context, where surgery plays an essential role.

KEY CONTENT AND FINDINGS

In this narrative review, we describe indications and surgical techniques for the treatment of locally advanced thymoma; focusing on oncological outcomes after different approaches.

CONCLUSIONS

In conclusion, aggressive surgery is always indicated, when possible, and when a complete resection can be planned, yet, the multidisciplinary approach is mandatory, in case of both locally or metastatic advanced disease.

CT Radiomic Features for Predicting Resectability and TNM Staging in Thymic Epithelial Tumors

BACKGROUND

To explore the performance of a computed tomography based radiomics model in the preoperative prediction of resectability status and TNM staging in thymic epithelial tumors.

METHODS

We reviewed the last preoperative computed tomography scan of patients with thymic epithelial tumors prior to resection and pathology evaluation at our institution between February 2008 and June 2019. A total of 101 quantitative features were extracted and a radiomics model was trained using elastic net penalized logistic regressions for each aim. In the set-aside testing sets, discriminating performance of each model was assessed with area under receiver operating characteristic curve.

RESULTS

Our final population consisted of 243 patients with: 153 (87%) thymomas, 23 (9%) thymic carcinomas, and 9 (4%) thymic carcinoids. Incomplete resections (R1 or R2) occurred in 38 (16%) patients, and 67 (28%) patients had more advanced stage tumors (stage III or IV). In the set-aside testing sets, the radiomics model achieved good performance in preoperatively predicting incomplete resections (area under receiver operating characteristic curve: 0.80) and advanced stage tumors (area under receiver operating characteristic curve: 0.70).

CONCLUSIONS

Our computed tomography radiomics model achieved good performance to predict resectability status and staging in thymic epithelial tumors, suggesting a potential value for the evaluation of radiomic features in the preoperative prediction of surgical outcomes in thymic malignancies.

Establishment of multi-center database on thymic epithelial tumors (TETs) and current situation in Korea

The Korean Association for Research on the Thymus (KART) was established in January 2014 with the following members: Asan Medical Center, Samsung Seoul hospital, Seoul national university hospital and Severance hospital, known to be the top four hospitals with the most amount of surgical cases on thymic epithelial tumor (TET). The aim of KART is to establish a multi-center TET database and present the clinical features and treatment outcomes in Korea. The KART database which was based on the International Thymic Malignancy Interest Group (ITMIG) database system included 1,462 cases of retrospectively collected thymoma and thymic carcinoma from Jan 2000 to Dec 2013. Masaoka-Koga stage I consisted of 34%, stage IIA 22% and stage IIB 17%. The overall 5- and 10-year survival rates were 90% and 76% respectively. As the Masaoka-Koga stage progressed, the survival rates decreased. Through the collaboration of ITIMG, 1,327 cases from KART were registered in the database of Cancer Research And Biostatistics (CRAB) in 2019. The Korean Association for Thoracic Surgical Oncology (KATSO) is the only organization in which all thoracic surgeons in South Korea are registered. Because KART was established with the purpose of collecting data on a national scale, KART is in collaboration to produce a nationwide database system with KATSO. The new database system is planning to collaborate with the ITMIG CRAB database and will adopt a TNM staging system developed in parallel to the Masaoka-Koga system. Data is planned on being collected retrospectively and prospectively and KART data will be the foundation of the retrospective data. Once the KATSO database is fully established, the national data of TET will be used to establish a guideline and standard of the treatment for TET in South Korea and KATSO will collaborate with ITMIG.

Induction Therapy Followed by Surgery for Unresectable Thymic Epithelial Tumours

BACKGROUND AND OBJECTIVES

The treatment of unresectable thymic epithelial tumours (TETs) remains controversial. Here, we present the efficacy and safety of induction therapy followed by surgery for unresectable TET.

METHODS

Eighty-one patients with unresectable TETs treated with induction therapy followed by surgery were selected from a retrospective review of consecutive TETs from January 2005 to January 2021. Clinicopathological data were analyzed to assess tumour responses, resectability, adverse events, progression-free survival (PFS) and overall survival (OS).

RESULTS

Induction therapy produced a major tumour response rate of 69.1%, a tumour response grade (TRG) 1-3 rate of 84.0% and an R0 resection rate of 74.1%. The most common toxic effects were all-grade neutropenia (35.8%) and anaemia (34.6%). The 10-year OS and PFS rates were 45.7% and 35.2%. Multivariate analysis showed that ypTNM stage, ypMasaoka stage, complete resection, and TRG were significant independent prognostic factors. Exploratory research revealed that different induction modalities and downstaging of T, N, M, TNM, or Masaoka classifications did not significantly alter the pooled hazard ratio for survival.

CONCLUSIONS

Induction therapy followed by surgery is well tolerated in patients with unresectable TETs, with encouraging R0 resection rates. Multimodality management provides good control of tumors for unresectable TET patients.

Induction Strategy for Locally Advanced Thymoma

Surgery remains cornerstone for the management of thymoma. Complete surgical resection (R0), is recognized as the constant and significant factor for prognosis. However, in locally advanced (Masaoka-Koga stages III-IVa) thymomas, achieving R0 resection remains challenging due to local-regional invasion of the disease. Induction treatment, with the aim of reducing bulky tumor mass, offers new strategy to facilitate totally surgical resection. Herein, we reviewed recent progress and provided a comprehensive overview of induction strategy in locally advance thymoma.

Superior Vena Cava Reconstruction in Masaoka Stage III and IVa Thymic Epithelial Tumors

BACKGROUND

We present here a case series of patients who underwent resection for Masaoka Stage III and IVa Thymic Epithelial Tumors (TETs) with invasion into the superior vena cava.

METHODS

29 patients with Stage III and IVa TETs were treated surgically in three institutions. Operative resections involved replacing the superior vena cava from one of the innominate veins (n=18) or via reconstruction by truncal replacement (n=2) or patchplasty (n=9).

RESULTS

Fifteen patients underwent neoadjuvant treatment. Thirty and 90-day mortality rate were 3.4% and 10.3%, respectively. For Stage III patients, the median overall survival and DFS were 39 and 30 months, respectively. The median overall survival and DFS in patients with Masaoka Stage IVa disease were 67 and 21 months, respectively. Undergoing only preoperative chemotherapy (p=0.007) or receiving no chemotherapy (p=0.009) had a disease-free survival that was significantly higher than receiving both pre- and postoperative chemotherapy.

CONCLUSIONS

SVC resection and reconstruction in Masoaka Stage III and IVa TETs can be performed with acceptable morbidity and mortality. Stage IVa patients with SVC involvement can be treated with similar results as Stage III patients with multimodality treatment.

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.

Thymic Epithelial Neoplasms: Radiologic-Pathologic Correlation

Thymic epithelial neoplasms, as classified by the World Health Organization, include thymoma, thymic carcinoma, and thymic carcinoid. They are a rare group of tumors and are often diagnosed incidentally in the work-up of parathymic syndrome, such as myasthenia gravis, or when mass effect or local invasion causes other symptoms. In each of these scenarios, understanding the radiologic-pathologic relationship of these tumors allows clinical imagers to contribute meaningfully to management decisions and overall patient care. Integrating important imaging features, such as local invasion, and pathologic features, such as necrosis and immunohistochemistry, ensures a meaningful contribution by clinical imagers to the care team.

Thymic Neuroendocrine Tumors and Thymic Carcinoma: Demographics, Treatment, and Survival

OBJECTIVE

Although rare, thymic neuroendocrine tumors (TNET) and thymic carcinoma (TC) are the most common thymic nonthymomatous malignancies; their survival outcomes have not been thoroughly compared. We analyzed the clinical, treatment, and survival characteristics of TNET and TC.

METHODS

We retrospectively identified patients with a histologic diagnosis of TNET or TC in the National Cancer Database (2004 to 2015). Exclusion criteria were age <18 years and unstaged tumors. Descriptive statistics, survival analysis, and multivariable Cox regression analyses were used in elucidating associations.

RESULTS

One thousand four hundred eighty-nine patients were included (TNET: 19.8%). Patients with TNET were significantly younger (57 vs 62.5 years), more likely to be male (70.5% vs 60.0%), and have localized tumors (45.4% vs 32.3%). Patients with TC more frequently underwent chemotherapy (56.1% vs 34.9%), radiation (56.9% vs 39.3%), and trimodality therapy (21.3% vs 11.5%), while resection rates were similar (55.3% vs 58.3%). The 5-year survival was 62% for TNET and 52% for TC, but comparable following multivariable adjustment. Age, stage, and Charlson-Deyo score were negative predictors of survival, while surgery and trimodality therapy were positive predictors. On subanalysis, adjuvant radiation therapy (ART) improved the survival of margin-positive tumors and was an independent predictor of survival for both tumor types (hazard ratio = 0.5).

CONCLUSIONS

Our analysis of the largest series of TNET and TC showed a survival rate surpassing 50% at 5 years. These outcomes seem to be influenced by surgical resection and ART. Standardized staging and surgical protocols including lymph node sampling are still warranted to better elucidate the treatment algorithm of these tumors.

Thymic Malignancy-Updates in Staging and Management

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