Multidisciplinary Treatment for Advanced Invasive Thymoma with Cisplatin, Doxorubicin, and Methylprednisolone

Screening of optimal candidates for postoperative radiotherapy among patients with resectable thymic tumors: a multicenter retrospective study

OBJECTIVE

The role of postoperative radiotherapy (PORT) in resectable thymic epithelial tumors remains debatable. This study aimed to identify patient populations in whom PORT would be beneficial and analyzed the prognostic factors that influence survival in patients with resectable thymic tumors.

METHODS

A retrospective analysis was conducted on 497 patients with resectable thymic epithelial tumors, including cases treated at our facility (January 2014 to December 2018) and cases from the SEER database (January 2014 to December 2015). Patients' data analyzed included age, gender, Masaoka-Koga stage, postoperative pathological type, and adjuvant therapy. Survival analysis was performed using the Kaplan-Meier method, while prognostic factors were evaluated using the Cox proportional hazards model.

RESULTS

No significant difference in survival outcomes was observed between patients with Masaoka-Koga stage I/IIA thymic tumors who underwent surgery alone compared with those who had surgery with adjuvant radiotherapy. However, patients with stage IIB and III/IVA tumors had significant survival benefits from PORT. In indolent histological subtypes (types A, AB, and B1), PORT did not provide a significant survival advantage compared to surgery alone. Conversely, patients with aggressive subtypes (types B2 and B3) and thymic carcinoma (type C) experienced improved long-term survival with PORT. Additionally, male patients, along with those with tumors ≥ 55 mm, age < 58 years, and incomplete resection, also benefited from PORT. Univariate and multivariate Cox regression analyses revealed several prognostic factors that affect survival, including age, gender, Masaoka-Koga stage, histological type, tumor size, PORT, postoperative chemotherapy, and recurrence. Independent prognostic factors identified were sex, Masaoka-Koga stage, histological grading, PORT, and postoperative chemotherapy.

CONCLUSIONS

PORT provides significant survival benefits in patients with Masaoka-Koga stage IIB and III/IVA thymic tumors, aggressive histological subtypes, and thymic carcinoma.

Successful treatment of type B2 thymoma with steroid and radiotherapy

An 86-year-old woman with leg edema and dyspnea on exertion was admitted to our hospital. Chest computed tomography (CT) revealed a mass in the anterior mediastinum with pericardial invasion. Histological examination with endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) led to the diagnosis of Masaoka stage IVa type B2 thymoma. For palliation, radiotherapy (32 Gy/16 fractions) and prednisolone (30 mg/day) were administered and tapered. After treatment, both the pericardial effusion and tumour size decreased. Combination therapy with steroids and radiotherapy may be effective for treating thymomas.

Multidisciplinary treatment of giant thymoma, paving the way to complete surgical resection: a case report

BACKGROUND

A multidisciplinary treatment approach is recommended for patients with extensive, advanced, or recurrent thymomas. However, detailed treatment strategies, such as chemotherapy regimens and optimal surgical procedures, are still under debate.

CASE PRESENTATION

We report a case of gigantic locally advanced thymoma. A 70-year-old male was referred to our hospital following the detection of abnormal chest shadows. Chest X-ray and computed tomography (CT) scans revealed a 21-cm mass in the anterior mediastinum, encircling the pulmonary hilum and extending into the left thoracic cavity. PET/CT showed increased 18F-fluorodeoxyglucose uptake at the tumor site. Based on a trans-percutaneous CT-guided needle biopsy, the tumor was diagnosed as a Type B2 thymoma at the clinical IIIA stage. The patient underwent four cycles of preoperative induction chemotherapy, including cisplatin, doxorubicin, and methylprednisolone (CAMP), resulting in a partial response; the tumor shrank to 12 cm and FDG uptake decreased. Considering the patient's age and comorbidities, we performed total thymectomy, along with partial resections of the parietal, mediastinal and visceral pleura, pericardium, and left upper lobectomy. This approach achieved complete histological resection, mitigating the risk of recurrence. Pathological analysis confirmed a thymoma, ypT3 (lung) N0M0 stage IIIA, with no malignancy in the pericardial or pleural effusions. No recurrence was detected 9 months post-surgery.

CONCLUSIONS

We report a case of giant thymoma successfully treated with multidisciplinary strategy. Surgical treatment alone may not have achieved complete resection, but after inducing significant tumor shrinkage with preoperative CAMP therapy, we were able to achieve complete resection. This treatment strategy may be effective in large thymoma cases.

Therapeutic options in thymomas and thymic carcinomas

INTRODUCTION

Radical surgery is the best therapeutic option for thymic malignancies. However, patients with advanced or recurrent thymic malignancies often require chemotherapy or radiotherapy. Since thymic malignancies are rare cancers, the efficacy and safety of treatments have been verified based on small Phase 2 trials or retrospective studies.

AREA COVERED

We comprehensively reviewed the treatment strategies for thymic malignancies, including surgery, radiotherapy, and pharmacotherapy, including cytotoxic chemotherapy, molecular-targeted therapy, and immunotherapy. Additionally, we reviewed specific situations, such as pleural dissemination, central nervous system metastasis, and paraneoplastic syndrome.

EXPERT OPINION

Cytotoxic chemotherapy remains the standard option in pharmacotherapy. However, multikinase inhibitors, such as sunitinib and lenvatinib, and immune checkpoint inhibitors including pembrolizumab have been developed to treat thymic carcinomas. Now, a Phase 2 study is evaluating whether lenvatinib plus pembrolizumab benefits patients with type B3 thymoma or thymic carcinoma. Phosphatidylinositol 3-kinase/AKT/ mammalian target of rapamycin inhibitors may contribute to disease control and octreotide scan is only applicable to somatostatin analogues. Although the genomic characteristics of thymic malignancies have been analyzed, few actionable mutations have been detected in general. The development of a treatment strategy using combination pharmacotherapy is anticipated.

The Never-Ending History of Octreotide in Thymic Tumors: A Vintage or A Contemporary Drug?

Simple Summary

Thymic epithelial tumors are rare tumors frequently associated with paraneoplastic syndromes, the most common being myasthenia gravis and pure red cell aplasia. While patients with limited-stage cancer can often undergo resolutive surgery, advanced surgically unresectable and metastatic tumors can be refractory to first-line platinum-based treatment and represent a medical challenge. Somatostatin receptor expression was documented in thymic tumors both in vivo and in vitro and represents the rationale for therapeutic use. Despite single-case reports and three single-arm phase II studies, as well as the inclusion of somatostatin analogs in National Comprehensive Cancer Network guidelines, the role of these drugs in thymic epithelial tumors is still rather undefined.

Abstract

Thymic epithelial tumors are rare tumors usually presenting as a mass located in the anterior mediastinum and/or with symptoms deriving from associated paraneoplastic syndromes. Unresectable platinum-refractory tumors are often treated with alternative regimens, including chemotherapeutic agents as well as chemo-free regimens. The most popular unconventional therapy is represented by the somatostatin analog octreotide, which can be used alone or with prednisone. The in vivo expression of somatostatin receptors documented by imaging with indium-labeled octreotide or gallium-68 Dotapeptides, the successful use of octreotide and prednisone in a chemo-refractory patient, and, thereafter, the experiences from a case series have enforced the idea that this treatment merits consideration—as proved by its inclusion in the National Comprehensive Cancer Network guidelines. In the present review, we analyze the preclinical basis for the therapeutic use of somatostatin and prednisone in refractory thymic tumors and discuss the available studies looking at future perspectives.

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.

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.

Role of modern neoadjuvant chemoradiotherapy in locally advanced thymic epithelial neoplasms

PURPOSE

To improve resectability in patients with stage III-IVA thymic epithelial neoplasms, neoadjuvant chemotherapy and radiotherapy are considered. This retrospective study aimed to investigate the efficacy and safety of neoadjuvant therapies using modern techniques in thymic epithelial neoplasms.

METHODS

We included 32 patients with Masaoka stage III-IV disease treated at our institution from January 2010 to December 2017. Data regarding clinicopathologic characteristics, treatment protocols, toxicities, and survival were collected. Response was evaluated according to the Response Evaluation Criteria in Solid Tumours 1.1. Survival was assessed using the Kaplan-Meier method. Adverse events were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0.

RESULTS

Neoadjuvant radiotherapy alone, chemotherapy alone, sequence chemoradiotherapy, and concurrent chemoradiotherapy were administered to 10 (31.3%), 9 (28.1%), 3 (9.4%), and 10 (31.3%) patients, respectively. Twenty-nine patients (90.6%) underwent R0 resection. The median follow-up time was 38.0 months (3.3-109.5 months). After neoadjuvant therapy, 18 patients (56.3%) achieved partial response and 14 (43.8%) had stable disease. Pathologic complete response was achieved in 6 patients (18.8%), all of whom had thymic carcinoma. The 5-year overall and progression-free survival rates were 90.9% and 67.5%, respectively. For patients with thymic carcinoma, the 5-year overall and progression-free survival rates were 80.0% and 66.2%, respectively. Grade 3 toxicities were observed in only 1 patient (leukopenia).

CONCLUSIONS

For patients with primary unresectable thymic neoplasms, neoadjuvant chemoradiotherapy is an efficient and safe choice, with favorable response and survival and moderate toxicities. Patients with thymic carcinoma might benefit more from neoadjuvant therapies.

Octreotide in the treatment of malignant thymoma - Case report

Thymomas are the most common mediastinal tumors. Systemic therapy for patients with unresectable or recurrent thymomas is a challenging field in the current oncology research. There is some evidence that somatostatin analogs combined with corticosteroids may have a role in the treatment of advanced malignant thymoma; however, the role of these agents have not been fully evaluated.

Case report

A 39-year-old man with metastatic thymoma was administered long-acting depot injection form of octreotide. Octreotide scan before the treatment initiation revealed low uptake. CT control after three months of the treatment revealed marked regression of pleural metastases, while the primary tumor mass remained stable. The treatment response was lasting for 9 months.

Conclusion

We describe an interesting case of marked clinical and radiological response of advanced malignant thymoma to the treatment with octreotide in a heavily pre-treated patient, even though octreotide scan revealed low uptake.

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.

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.

Evaluating the effectiveness of chemotherapy for thymic epithelial tumors using the CD-DST method

BACKGROUND

Thymic epithelial tumors (TET) are frequently eligible for curative-intent surgical resection. For locally advanced TETs, chemotherapy has been used to both reduce the tumor burden and achieve prolonged disease control. However, effective therapy for this disease largely remains to be determined. Here, we report the chemosensitivity of 100 patients with TETs determined by the collagen gel droplet embedded culture-drug sensitivity test (CD-DST).

METHODS

A total of 100 patients with TETs underwent surgical resection. The efficacy of antitumor agents on TET cells was tested by CD-DST.

RESULTS

Thymic epithelial tumors were pathologically confirmed after surgery: two cases were type A thymoma, 17 were type AB, 12 were type B1, 44 were type B2, 12 were type B3, and there were 13 cases with thymic carcinoma. A total of 36% patients with TETs were sensitive to different types of chemotherapeutic agents. There was no significant differences in age, histological type, clinical staging, or association with autoimmune diseases between sensitive and nonsensitive cases. Type B1 and B2 thymoma were relatively more sensitive to chemotherapeutic agents (6/12 and 18/44, respectively), while sensitivity of type B3 cases to chemotherapeutic agents was much lower (only 2/12). Cases with type A thymoma were not sensitive to any antitumor drugs. Among 11 chemotherapeutic agents tested in our study, the sensitivity of TETs to EPI was the highest (16%). No patients with thymoma were sensitive to Alimta (Pemetrexed).

CONCLUSIONS

Our work illuminates the effectiveness of chemotherapy for TETs and provides important clues for choosing antitumor drugs with relatively high drug sensitivity to TETs in advance.

Multimodality therapy for thymoma patients with pleural dissemination

BACKGROUND

Although multidisciplinary treatment is recommended for patients with advanced stage and recurrent thymoma, a detailed treatment strategy remains controversial. We have performed a multimodality therapy of induction chemotherapy (CAMP therapy: cisplatin, doxorubicin, and methylprednisolone) combined with surgery for those patients. We now conducted a retrospective study for investigating the results of this multimodality therapy for thymoma patients with pleural dissemination.

PATIENTS AND METHODS

Between 2003 and 2017, 201 patients underwent surgical resection for thymomas. Twenty-six of them received induction CAMP therapy followed by surgery, and 19 of them with pleural dissemination were enrolled in this study. Those cohort were divided into 2 groups by employing surgical procedures: extrapleural pneumonectomy (EPP) group (n = 10) and resection of plural dissemination (RPD) group (n = 9).

RESULTS

The median age of all patients was 49 years. Based on the WHO classification, the histological diagnoses of those thymomas were as follows: Type B1 (n = 1), Type B2 (n = 13), and Type B3 (n = 5). Seven patients were complicated with myasthenia gravis (MG). Clinical stage of the 13 primary cases based on the Masaoka classification were stage IV, and the remaining six cases had recurrent pleural dissemination after surgery. Partial response in induction CAMP therapy was obtained in 78.9% (n = 15) of the patients. Adverse events (Grade 4) occurred in 2 patients (10.5%). Postoperative complications (Grade 4) were observed in 2 patients (10.5%). In all of the enrolled patients, the five-year overall survival rate (5Y-OS) and 5-year progression-free survival rate (5Y-PFS) were 76.7% and 55.1%, respectively. In the EPP group, 5Y-OS and 5Y-PFS were 83.3% and 83.3%, respectively, and in the RPD group, 70.0% and 29.6%, respectively.

CONCLUSIONS

Multidisciplinary treatment using induction CAMP therapy and surgical resection for thymoma patients with pleural dissemination was effective and feasible. Because of the low recurrent rate of disease, young patients with good cardiopulmonary function and well-controlled MG might be good candidates for EPP.

Induction Therapy for Thymoma

Thymomas are uncommon tumors that can present as locally advanced tumors in approximately 30% of the patients. Stage and complete resection are the strongest prognostic factors. For locally advanced tumors, induction treatment may improve the ability to achieve a complete resection. Combination treatment with cisplatin, doxorubicin, and cyclophosphamide is the most commonly used induction regimen. Similar rates of resectability are noted with the use of induction chemotherapy and chemoradiation therapy; however, more tumor necrosis is noted with the addition of radiation.

Mutation analysis of the EGFR gene and its downstream signaling pathway in thymic carcinoma patients from a Chinese Han population

INTRODUCTION

For thymic carcinoma (TC), which is a rare epithelial neoplasm of the thymus gland, median survival with current treatments is only 2 years.

OBJECTIVES

Mutations in the epidermal growth factor receptor (EGFR) gene or its downstream effectors may cause constitutive activation that leads to cell proliferation and metastases. Thus, molecular profiling is essential for selecting TC patients who may respond to anti-EGFR therapies.

METHODS

Genomic DNA was extracted from 61 histological samples of TCs. Real-time polymerase chain reaction (PCR) and direct sequencing were used to assess the mutations in the EGFR downstream pathway.

RESULTS

Gene mutations were identified in seven patients (11.5%). In particular, the identified mutations included four mutations in the KRAS gene, one mutation in the BRAF gene, one mutation in the PIK3CA gene, and only one mutation in the EGFR gene itself. Gene mutations in the EGFR downstream pathway were associated with shorter survival time and were observed to be an independent prognostic factor for TC patients.

CONCLUSION

Mutations in the EGFR downstream pathway are not rare in TCs. These data offer interesting possibilities for the future management of TCs, particularly in the era of new targeted therapies.

Efficacy and safety of the combination of paclitaxel and platinum in advanced thymic carcinoma

This study aimed to assess the efficacy and safety of a combination of paclitaxel and cisplatin/carboplatin for the treatment of advanced thymic carcinoma. Thirty‐seven patients (23 men and 14 women, median age 47 years, performance status score ≤2) with pathologically or cytologically diagnosed advanced thymic carcinoma were recruited. Patients received 175 mg/m² paclitaxel on day 1 and 75 mg/m² cisplatin or 300 mg/m² carboplatin on day 2 of a 21 day cycle for at least two cycles to evaluate efficacy and adverse events. No complete response (CR) was observed; 11 patients had a partial response (PR), 16 patients had no change (NC), and 10 had progressive disease, resulting in an overall response rate of 29.7%, a stable rate of 43.2%, and a disease control rate (CR + PR + NC) of 72.9%. Grade I/II and III/IV neutropenia were observed in 21 (56.7%) and 13 (35.1%) patients, respectively. Four (10.8%) patients developed grade I/II thrombocytopenia. Grade I/II and III/IV nausea and vomiting were observed in 19 (51.2%) and five (13.5%) patients, respectively. Grade I/II liver dysfunction was observed in seven (18.9%) patients. Two patients with grade III liver dysfunction recovered after hepatoprotective treatment. The combination of paclitaxel and platinum was effective and well tolerated in patients with advanced thymic carcinoma.

Outcomes of Thymoma Treated with Multimodality Approach: A Tertiary Cancer Center Experience of 71 Patients

Aims

To explore the demographics and clinical outcome of patients with thymoma treated with a multimodality approach at our institute.

Methods

A total of 71 patients with thymoma (Masaoka stage II-IV and WHO subtype AB-B3) treated from 1999-2013 were included in this retrospective analysis. Age, stage, WHO subtypes, details of surgery, radiotherapy, and chemotherapy were noted. Progression-free survival (PFS) was estimated using Kaplan-Meier method and SPSS (version 21.0) was used for statistical analysis.

Results

Male:female ratio was 56:15 with median age at presentation of 41 years. Stage-wise distribution was 6:46:19 for stage II, stage III, and stage IV, respectively. A total of 31 patients (44%) had associated myasthenia gravis and 3 had pure red cell aplasia. A total of 57 patients (80%) underwent radical thymectomy and all of these patients received adjuvant radiotherapy. A total of 15 patients and 7 patients received adjuvant chemotherapy and neoadjuvant chemotherapy, respectively. At median follow-up of 19.3 months (range 7.9-72.3 months), 2-year and 3-year PFS rate for the entire cohort was 78.3% and 57.1%, respectively. On univariate analysis, surgery (hazard ratio [HR] 3.881; 95% confidence interval [CI] 1.784-19.220; p = 0.006) and stage (HR 5.457; 95% CI 1.567-18.996; p = 0.0001) were significant prognostic factors and association with myasthenia gravis (HR 0.404; 95% CI 0.151-1.078; p = 0.078) trended towards better PFS. Stage retained its prognostic significance (HR 5.501; 95% CI 2.076-14.573; p = 0.0006) on multivariate analysis.

Conclusions

Multimodality management of locally advanced thymoma yields decent survival outcomes. Masaoka stage is an independent prognostic factor for survival and radical surgery should be contemplated in all cases of locoregionally limited thymoma.

Available evidence and new biological perspectives on medical treatment of advanced thymic epithelial tumors

Thymic epithelial tumors (TETs) are rare primary mediastinal tumors arising from thymic epithelium. Their rarity and complexity hinder investigations of their causes and therapy development. Here, we summarize the existing knowledge regarding medical treatment of these tumors, and thoroughly review the known genetic aberrations associated with TETs and the present status of potential biological treatments. Epidermal growth factor receptor (EGFR), stem-cell factor receptor, insulin-like growth factor-1 receptor (IGF1R), and vascular endothelial growth factors (VEGF-A, VEGF-B, and VEGF-2) are overexpressed in TETs. EGFR overexpression in TETs is associated with higher stage, and IGF1R overexpression has poor prognostic value. Data indicate that anti-IGF1R monoclonal antibodies, and inhibitors of angiogenesis, somatostatin receptors, histone deacetylase, mammalian target of rapamycin, and cyclin-dependent kinases may be active against TETs. Continued investigations in this field could lead to advancement of targeted and biological therapies for TETs.

Management of metastatic malignant thymoma with advanced radiation and chemotherapy techniques: report of a rare case

Malignant thymomas are rare epithelial neoplasms of the anterior superior mediastinum that are typically invasive in nature and have a higher risk of relapse that may ultimately lead to death. Here we report a case of an advanced malignant thymoma that was successfully treated with neoadjuvant chemotherapy followed by surgical resection and subsequently with advanced and novel radiation therapy techniques. A 65-year-old male was diagnosed with a stage IV malignant thymoma with multiple metastatic lesions involving the left peripheral lung and pericardium. Initial neoadjuvant chemotherapy with a cisplatin-based regimen resulted in a partial response allowing the inoperable tumor to become operable. Following surgical resection of the residual disease, the tumor recurred within a year. The patient then underwent a course of targeted three-dimensional intensity modulated radiation therapy (IMRT) and image-guided radiation therapy (IGRT). Five years after radiation therapy, the localized soft tissue thickening at the left upper lung anterior pleural space had resolved. Seven years after radiation therapy the tumor mass had completely resolved. No recurrences were seen and the patient is well even 8 years after IMRT/IGRT with a favorable outcome. Chemotherapy with targeted three-dimensional IMRT/IGRT should be considered the primary modality for the management of advanced malignant thymoma patients.

The correlation of morphological features of chest computed tomographic scans with clinical characteristics of thymoma

OBJECTIVES

Chest computed tomography (CT) scanning has been widely utilized in thymoma identification and staging as well as in follow-up monitoring for recurrence. However, the relationship between some CT imaging features and pathological types, clinical stage, completeness of resection, or prognosis in thymoma has not been well explored.

METHODS

We retrospectively reviewed preoperative CT imaging for 238 thymoma patients, who had undergone thymectomy from October 2007 to December 2011. All CT parameters were assessed in each case based on clinical and pathological data. Survival analysis was performed by using the Kaplan-Meier and log-rank tests.

RESULTS

Tumour contours (P = 0.008), homogeneity (P = 0.009), degree of enhancement (P = 0.013), fat plane obliteration with adjacent structures (P < 0.001), the presence of mediastinal lymphadenopathy (P = 0.010), irregular infiltration into the lung (P = 0.012) and tumour shape (P = 0.007) were associated with the World Health Organization (WHO) histological classification. Lobulated or irregular tumour contours (P < 0.001), presence of calcifications (P = 0.002), infiltration of surrounding fat (P < 0.001), irregular infiltration into the lung (P < 0.001), irregular infiltration into vascular (P < 0.001), more abutment of vessels (P < 0.001) and pulmonary changes adjacent to the tumour (P < 0.001) were associated with the more advanced Masaoka-Koga clinical stage. Tumour contours (P < 0.001), infiltration of surrounding fat (P = 0.008), irregular infiltration into the lung (P < 0.001) and degree of abutment of vessel circumference (P = 0.001) were associated with completeness of resection. With multivariate analysis, no CT image features could reliably predict on the overall or disease-free survival rate.

CONCLUSIONS

CT imaging does have some features, which are significantly correlated with the WHO classification, the Masaoka-Koga clinical staging and the completeness of resection, although it has no definite role to evaluate preoperatively the survival rate of thymoma patients.

A phase I/II trial of belinostat in combination with cisplatin, doxorubicin, and cyclophosphamide in thymic epithelial tumors: a clinical and translational study

PURPOSE

This phase I/II study sought to determine the safety and maximum tolerated dose (MTD) of a novel schedule of belinostat, a histone deacetylase inhibitor (HDAC) administered before and in combination with cisplatin (P), doxorubicin (A), and cyclophosphamide (C) in thymic epithelial tumors (TET). Antitumor activity, pharmacokinetics, and biomarkers of response were also assessed.

EXPERIMENTAL DESIGN

Patients with advanced, unresectable TET received increasing doses of belinostat as a continuous intravenous infusion over 48 hours with chemotherapy in 3-week cycles. In phase II, belinostat at the MTD was used.

RESULTS

Twenty-six patients were enrolled (thymoma, 12; thymic carcinoma, 14). Dose-limiting toxicities at 2,000 mg/m(2) belinostat were grade 3 nausea and diarrhea and grade 4 neutropenia and thrombocytopenia, respectively, in two patients. Twenty-four patients were treated at the MTD of 1,000 mg/m(2) with chemotherapy (P, 50 mg/m(2) on day 2; A, 25 mg/m(2) on days 2 and 3; C, 500 mg/m(2) on day 3). Objective response rates in thymoma and thymic carcinoma were 64% (95% confidence interval, 30.8%-89.1%) and 21% (4.7%-50.8%), respectively. Modulation of pharmacodynamic markers of HDAC inhibition and declines in regulatory T cell (Treg) and exhausted CD8(+) T-cell populations were observed. Decline in Tregs was associated with response (P = 0.0041) and progression-free survival (P = 0.021). Declines in TIM3(+) CD8(+) T cells were larger in responders than nonresponders (P = 0.049).

CONCLUSION

This study identified the MTD of belinostat in combination with PAC and indicates that the combination is active and feasible in TETs. Immunomodulatory effects on Tregs and TIM3(+) CD8(+) T cells warrant further study.

Diagnostic Utility of PET CT in Thymic Tumours with Emphasis on 68Ga-DOTATATE PET CT in Thymic Neuroendocrine Tumour - Experience at a Tertiary Level Hospital in India

INTRODUCTION

18 Fluorine-fluoro-2-deoxyglucose positron emis-sion tomography/computed tomography (18F- FDG-PET/CT) is of importance in assessing high-risk thymoma and thymic carcinomas. Detection of advanced thymoma versus thymic carcinoma by routine cross sectional anatomical imaging such as computed tomography (CT), magnetic resonance imaging (MRI) often poses a diagnostic dilemma. In this case series we observed the utility of FDG uptake to predict advanced thymoma and distinguish thymoma from thymic cancer.

MATERIALS AND METHODS

We reviewed 18F- FDG-PET/CT scans of 12 patients (8 males, 4 females); age 24-60yrs with thymic epithelial malignancy from January 2011 to May 2013. FDG activity in lesions was quantified using maximum standardised uptake value (SUVmax) and correlated with Masaoka staging and WHO classification. All patients fasted 4 hr prior to 18F-FDG PET/CT. Images from vertex to mid-thigh were acquired 60min post injection of 3.7 -4.7 MBq/kg (Mega Becquerel)/kilogram of18F-FDG and SUV max of each tumour was measured. One patient underwent DOTATATE scan, received 138MBq of 68Gallium (68Ga)-DOTATATE injection IV and imaging was done after 60 min.

RESULTS

Higher FDG uptake of SUVmax 7.35 was seen in type B3 thymoma. FDG uptake was higher in thymic carcinoma (20.45 in primary and 17.46 in the node) or neuroendocrine differentiation (NED) than in patients with thymomas (ranged 7.35 - 3.02). No significant association was observed between higher focal FDG uptake and advanced-stage disease in thymoma. In NED 68Ga - DOTATATE imaging identified more lesions than in FDG.

CONCLUSION

PET CT is a valuable diagnostic tool in evaluation of thymic tumours, to assess in initial workup, for treatment response and for prognostication. 68Ga-DOTATATE PET/CT is beneficial in assessing neuroendocrine thymic tumours. Focal FDG uptake cannot predict advanced thymoma but is helpful in distinguishing thymoma from thymic carcinoma, or the more aggressive thymoma B3.

Key components of chemotherapy for thymic malignancies: a systematic review and pooled analysis for anthracycline-, carboplatin- or cisplatin-based chemotherapy

Purpose

Thymic malignancies, comprising thymoma and thymic carcinoma, are rare. Consequently, optimal chemotherapy for advanced thymic malignancies remains controversial. Platinum-based chemotherapy is currently the consensus treatment based on the results of single-arm phase II trials and retrospective investigations. However, comparison of cisplatin-based and carboplatin-based chemotherapy has yet to be undertaken; the effectiveness of the addition of anthracycline also remains uncertain.

Methods

In the present study, clinical trials and retrospective data regarding platinum-based chemotherapy were analyzed. The endpoint was the response rate to each chemotherapy. For advanced thymoma, we compared platinum with anthracycline-based chemotherapy and platinum with non-anthracycline-based chemotherapy. For advanced thymic carcinoma, anthracycline-based versus non-anthracycline-based chemotherapy and carboplatin-based versus cisplatin-based chemotherapy were compared. This analysis included a retrospective study of response of advanced thymic carcinoma to irinotecan and cisplatin in our institution.

Results

The response rate for the 314 patients from 15 studies with advanced thymoma, including both prospective and retrospective data, was 69.4 % [95 % confidence interval (CI) 63.1–75.0 %] for platinum with anthracycline-based chemotherapy and 37.8 % (95 % CI 28.1–48.6 %; p < 0.0001) for platinum with non-anthracycline-based chemotherapy. The response rates after anthracycline-based and non-anthracycline-based chemotherapy for advanced thymic carcinoma were similar (41.8 vs. 40.9 %; p < 0.91), whereas the response rates after cisplatin-based and carboplatin-based chemotherapy for advanced thymic carcinoma differed significantly (53.6 vs. 32.8 %; p = 0.0029) in 206 patients from 10 studies.

Conclusions

Platinum with anthracycline-based chemotherapy is an optimal combination for advanced thymoma. For advanced thymic carcinoma, cisplatin-based chemotherapy may be superior to carboplatin-based chemotherapy.

ASXL1 and DNMT3A mutation in a cytogenetically normal B3 thymoma

The molecular drivers of thymoma are poorly understood. Outside of the identification of rarely occurring epidermal growth factor receptor and v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog mutations via candidate gene sequencing, mutations in common cancer genes have yet to be observed. Only a single thymoma genome sequence has been previously reported, with no mutations in known cancer genes identified. Thus, we attempted to identify somatic driver mutations in a cytogenetically normal thymoma. A stage IVB type B3 thymoma from a 47-year-old male of Asian descent with no history of myasthenia gravis or other autoimmune condition was genomically evaluated. Exome sequencing and low-pass whole-genome sequencing was performed to identify somatic point mutations, copy number changes and structural variants. Mutations in known tumor suppressors DNMT3A (p.G728D) and ASXL1 (p.E657fs), consistent with mutations of known consequence in acute myeloid leukemia, were identified. Contrary to a previous report, this finding suggests the genetic etiology of thymomas may not be fundamentally distinct from other tumor types. Rather, these findings suggest that further sequencing of cytogenetically normal thymoma samples should reveal the specific molecular drivers of thymoma.

Therapy for thymic epithelial tumors

Thymoma is the most common tumor of the anterior mediastinum. This tumor is associated with unique paraneoplastic syndromes. The rarity of this tumor has somewhat obscured the optimal treatment for this disease. The World Health Organization classification system, which published in 1999, appears to be an advance in our understanding of thymoma. The Masaoka classification is now the most widely accepted and is an excellent predictor of the prognosis of thymoma. Now the International Thymic Malignancy Interest Group is currently engaged in the development of a validated formal TNM classification system for thymic malignancies. The optimal treatment of thymoma is performed according to its clinical stage. Surgery remains the mainstay of treatment for thymic epithelial tumors. Minimally invasive surgery including thoracoscopic surgery and robotic surgery for stage I and II thymomas is increasing now. The value of postoperative radiotherapy in completely resected stage II or III tumors is questionable. As thymomas have a moderate response rate to chemotherapy or radiotherapy, multimodality therapy involving surgery, chemotherapy and radiotherapy appears to increase the rate of complete resection and survival in the advanced (stage III and IV) thymomas.

Thymic neoplasms: an update on the use of chemotherapy and new targeted therapies. A literature review

Thymic malignancies represent a wide range of clinical, histological and molecular entities, with probably considerable heterogeneity even among tumors of the same histotype. Systemic chemotherapy with cisplatin-based regimens continues to represent the standard of care in metastatic or inoperable refractory/recurrent diseases and ADOC regimen (including cisplatin, doxorubicin, vincristine and cyclophosphamide) demonstrated the longer overall response rate and median survival in the first line setting, although no randomized trial is available; and there is still a lack of standard treatment after first-line failure. To date research efforts are focused on translational studies on molecular pathways involved in thymic tumors carcinogenesis, aimed to better understand and predict the efficacy of chemotherapy and targeted therapy. Recent molecular characterization includes identification of a number of oncogenes, tumor suppressor genes, chromosomal aberrations, angiogenic factors, and tumor invasion factors involved in cellular survival and proliferation and in tumor growth. The use of biologic drugs is currently not recommended in a routine practice because there are limited data on their therapeutic role in thymic epitelial tumors. Because of the lack of data from adequate-sized, prospective trials are required for validation and the enrolment of patients with advanced disease into available clinical trials has to be encouraged.

Pediatric thymomas: report of two cases and comprehensive review of the literature

PURPOSE

Thymomas are rare pediatric malignancies with indolent behavior. There are fewer than 50 reported cases and no comprehensive review. We sought to evaluate our recent experience with pediatric thymomas, and comprehensively review the extant literature.

METHODS

A systematic search of the PubMed database was performed using keywords: "thymoma", "pediatric", "juvenile", "childhood", and "child". Additional studies were identified by a manual search of the reference list.

RESULTS

We report two patients with thymomas. We identified 22 case reports or series that described 48 patients; 62 % were male, 15 % presented with myasthenia gravis. Fifty percent were Masaoka Stage I, 15 % were Stage II, 13 % were Stage III, and 23 % were Stage IV. Four patients with early stage (I or II) disease were treated with adjuvant therapies in addition to surgical excision, while five patients with late stage (III or IV) disease treated with surgical excision alone. Of studies reporting at least 2-year follow-up, survival was 71 %.

CONCLUSION

Pediatric thymomas are rare tumors with a slight male predominance. Wide variations were observed in the treatment of thymomas across all stages. Our review indicates a need for large database and multi-institutional studies to clearly elucidate clinical course, prognostic factors and outcome.

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.

Systemic treatment of advanced thymic malignancies

The rarity of thymic malignancies prevents us from performing large randomized clinical trials. As a result, systemic treatment decisions are often guided by a small amount of prospective trial data, retrospective series, and individual case reports. In recent years, we have begun to unravel the molecular biology of thymic tumors. It is becoming more apparent as a result of gene expression profiling and genomic clustering studies that the subclassifications of type A, AB, B1, B2, B3, and thymic carcinoma have different molecular features that may be clinically relevant. Genomic profiling distinguishes type B3 thymoma and thymic carcinoma as distinct entities from type A and type B2 thymoma. Furthermore, type B2 thymomas can be separated from other subgroups in that it has a more distinct lymphocytic component than the other groups where epithelial cells predominate. Next generation RNA sequencing has recently identified a large microRNA cluster on chromosome 19q13.42 in types A and AB thymomas, which is absent in type B thymomas and thymic carcinomas. This cluster has been shown to result in activation of the phosphoinositide 3-kinase (PI3K)/AKT pathway, which suggests a possible role for PI3K inhibitors in these subtypes. The presence of KIT mutations in thymic carcinomas is also well described. Herein we discuss the chemotherapeutic and targeted treatment options for advanced thymic malignancies and highlight important advances in our understanding of the molecular biology of these rare tumors.

Chemotherapy for thymic carcinoma and advanced thymoma in adults

BACKGROUND

Thymic carcinoma or advanced thymoma is a rare cancer of the thymus gland that tends to be aggressive and infiltrate neighbouring organs, making total resection very difficult. Induction or adjuvant chemotherapy, or both, are often used in a multimodality approach to treat people affected by this condition, but the effectiveness of chemotherapy for thymic carcinoma or advanced thymoma remains uncertain.

OBJECTIVES

To assess the role of chemotherapy in adults with thymic carcinoma or advanced thymoma.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2012, Issue 7), MEDLINE (accessed via Ovid from 1966 to July 2012), EMBASE (accessed via Ovid, from 1980 to July 2012), Latin American and Caribbean Literature on Health Sciences (LILACS), the Chinese Biological Medicine Database (CBM, 1978 to July 2012), China National Knowledge Infrastructure (CNKI, 1980 to July 2012) and the Chinese scientific periodical database VIP Information (VIP, 1989 to July 2012). There was no language restriction in searching for studies.

SELECTION CRITERIA

We planned to include randomised controlled trials (RCTs) of  trials using chemotherapy (either single-agent or combination chemotherapy plus surgery, radiotherapy or not) for thymic carcinoma and/or advanced thymoma. We planned to include all adults (aged 18 years and over) diagnosed with thymic carcinoma and/or with Masaoka stage III or IV thymic tumours. The intended primary outcomes were overall survival (OS) and progression-free survival (PFS).

DATA COLLECTION AND ANALYSIS

Two review authors independently evaluated the search results according to the inclusion and exclusion criteria. There were no studies identified for inclusion and therefore no data extraction was completed.

MAIN RESULTS

No RCTs were eligible for inclusion in this review. We report details of excluded prospective studies in an additional table and try to provide some useful evidence regarding current practice.

AUTHORS' CONCLUSIONS

There were no RCTs eligible for inclusion in this review. In current practice the most common regimen for adult patients with thymic carcinoma or advanced thymoma is cisplatin-based chemotherapy. Considering the condition is rare, it is suggested that an international group is set up to organise and evaluate prospective collection of data from cohorts of patients to inform current clinical practice.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Results of surgical resection for patients with thymoma according to World Health Organization histology and Masaoka staging

OBJECTIVES

Thymomas are relatively rare tumors. In this study, we investigated the clinical features of patients who underwent surgical resection for thymoma.

PATIENTS AND METHODS

This study clinicopathologically evaluated 54 consecutive patients who underwent a surgical resection of thymoma in our department between 1994 and 2006.

RESULTS

A complete resection was performed in 52 patients, while two patients underwent an incomplete resection due to pleural dissemination. Combined resection with adjacent organs was performed for the lung (n=6), pericardium (n=5), and large vessels (brachiocephalic vein in three, superior vena cava in two). The concomitant autoimmune diseases were observed in 20 patients (37%), and they included myasthenia gravis in 17 patients, macroglobulinemia in one, pemphigus vulgaris in one, and stiff person syndrome in one patient. The histologic types of the World Health Organization classification diagnosed as type A in four patients, type AB in 14, type B1 in eight, type B2 in 15, and type B3 in 11. There were 27, 17, eight, and two patients with Masaoka stages I, II, III, and IV, respectively. Four patients died, and the causes of death included recurrence of thymoma in two, gastric carcinoma in one, and respiratory failure due to myasthenia gravis in one patient. The overall survival rate at 10 years was 94.6% in patients with stages I and II disease and 77.1% in patients with stages III and IV disease.

CONCLUSIONS

Long-term survival can be expected not only for patients at early stages, as well as for patients with stages III and IV disease if surgical resection is completed macroscopically.

Thymoma: from chemotherapy to targeted therapy

Thymic malignancies are rare epithelial tumors that may be aggressive and difficult to treat. Thymomas are frequently eligible for upfront surgical resection. However, nearly 30% of patients present with locally advanced tumor at time of diagnosis, and chemotherapy is then used to reduce the tumor burden-possibly allowing subsequent surgery and/or radiotherapy. Metastatic and recurrent thymic malignancies may be similarly treated with chemotherapy. More recently, the molecular characterization of thymoma led to the identification of potentially druggable targets, laying the foundation to implement personalized medicine for patients.

Thymic malignancies: from clinical management to targeted therapies

PURPOSE

A key challenge in the treatment of thymoma and thymic carcinoma (TC) is in improving our understanding of the molecular biology of these relatively rare tumors. In recent years, significant efforts have been made to dissect the molecular pathways involved in their carcinogenesis. Here we discuss the results of large-scale genomic analyses conducted to date and review the most active chemotherapies and targeted treatments.

METHODS

We reviewed the literature for chemotherapeutic trials in the last 20 years and trials involving targeted therapies between 1999 and 2010. The search was supplemented by a review of abstracts presented at the annual meetings of the American Society of Clinical Oncology (from 1999 to 2010), at the first International Conference on Thymic Malignancies in 2009, and at a follow-up meeting of the newly formed International Thymic Malignancies Interest Group in 2010.

RESULTS

Surgery remains the treatment of choice for operable tumors, whereas chemotherapy is standard in locally advanced and metastatic disease. Thus far, targeted therapies have been developed empirically. Histone deacetylase inhibitors have shown some activity in thymoma whereas sunitinib may be active in TC. There are no data to support the use of HER2- or EGFR-targeted therapies in thymic malignancies.

CONCLUSION

Drug development for the treatment of thymic malignancies is difficult because of the rarity of these tumors. Ethnic differences are becoming apparent, with aggressive subtypes being observed in Asians and African Americans. Incremental improvements in our understanding of tumor biology suggest that molecular profiling-directed therapies may be the preferred route of investigation in the future.