The IASLC/ITMIG Thymic Malignancies Staging Project: Development of a Stage Classification for Thymic Malignancies

Postoperative radiotherapy is effective for thymic carcinoma but not for thymoma in stage II and III thymic epithelial tumors: the Japanese Association for Research on the Thymus Database Study

BACKGROUND

The efficacy of postoperative radiotherapy (PORT) for thymic epithelial tumors is still controversial. Using the Japanese Association for Research on the Thymus (JART) database, this study was aimed at clarifying the efficacy of PORT for Masaoka stage II and III thymic carcinoma and thymoma.

METHODS

The JART database registered the records of 2835 patients collected from 32 Japanese institutions from 1991 to 2010. Thymic carcinoma and thymoma at stage II or III were extracted. The efficacy of PORT with respect to relapse-free survival (RFS) and overall survival (OS) was evaluated with the Kaplan-Meier method and Cox regression analysis.

RESULTS

There were 1265 patients in all: 155 thymic carcinoma cases (12.3%) and 1110 thymoma cases (87.7%). Eight hundred ninety-five (70.8%) were at stage II, and 370 (29.2%) were at stage III. Four hundred three cases (31.9%) underwent PORT. PORT for stage II and III thymic carcinoma was associated with increasing RFS (hazard ratio, 0.48; 95% confidence interval, 0.30-0.78; P = .003) but was not associated with OS (hazard ratio, 0.94; 95% confidence interval, 0.51-1.75; P = .536). PORT for stage II and III thymoma was not associated with RFS or OS (P = .350). A subgroup analysis of stage III thymoma showed no factor associated with the efficacy of PORT.

CONCLUSIONS

In this study, PORT did not increase RFS or OS for stage II or III thymoma but increased RFS for stage II and III thymic carcinoma.

Thymic carcinoma outcomes and prognosis: results of an international analysis

OBJECTIVES

The objectives of this collaborative study were to characterize patients with thymic carcinoma, their treatment patterns, and association with overall survival (OS) and recurrence-free survival (RFS).

METHODS

Clinical, pathologic, treatment, and follow-up information were analyzed. OS and RFS were the primary outcome measures.

RESULTS

In 1042 cases of thymic carcinoma, 42 (5%) patients had pathologic Masaoka stage I, 138 (17%) had stage II, 370 (45%) had stage III, and 274 (33%) had stage IV disease. Overall, 166 patients (22%) underwent induction chemotherapy and 48 (6%) had preoperative radiation therapy. An R0 resection was performed in 447 cases (61%), R1 in 102 cases (14%), and R2 in 184 cases (25%). Squamous cell carcinoma was the predominant histologic subtype (n = 560; 79%). Adjuvant chemotherapy was administered to 237 (31%) patients, and 449 (60%) received adjuvant radiation therapy. The median OS was 6.6 years (95% confidence interval [CI], 5.8-8.3) and the cumulative incidence of recurrence at 5 years was 35% (95% CI, 30%-40%). In univariate analysis, early Masaoka stage, R0 resection, chemotherapy, and radiation therapy were associated with OS. Early Masaoka stage and R0 resection were also associated with RFS. On multivariable analysis, R0 resection and radiation therapy were associated with prolonged OS. Radiation therapy and male gender were associated with prolonged RFS.

CONCLUSIONS

R0 resection and radiation therapy are associated with improved OS, whereas radiation therapy and male gender are associated with longer RFS.

Outcome of primary neuroendocrine tumors of the thymus: a joint analysis of the International Thymic Malignancy Interest Group and the European Society of Thoracic Surgeons databases

OBJECTIVE

Primary neuroendocrine tumors of the thymus (TNET) are exceedingly rare. We studied a large series of TNET identified through the International Thymic Malignancy Interest Group and the European Society of Thoracic Surgeons databases.

METHODS

This was a retrospective multicenter study of patients undergoing operation for TNET between 1984 and 2012. Outcome measures were: overall survival (OS) and cumulative incidence of recurrences (CIR). OS was analyzed using the Kaplan-Meier method and CIR was analyzed using competing risk analysis. Associations with clinical and prognostic factors for OS and CIR were evaluated using the log rank test and Gray test.

RESULTS

Two hundred five patients with TNET were treated: 25 patients received induction therapy (19 chemotherapy [CT] and 6 radiotherapy [RT]). Data about resection status were available in 47% of cases: complete resection was performed in 52 patients (54%). Masaoka-Koga stages I, II, III, and IV were observed in 12, 33, 56, and 47 patients, respectively. Atypical carcinoid was the commonest histologic subtype (71 cases; 40%). One hundred one patients with TNET received adjuvant treatment; 52 patients died and 36 experienced a recurrence. The median OS was 7.5 years; 5-year OS was 68%, and 5-year CIR was 39%. OS was significantly influenced by Masaoka-Koga stage (P = .02) and completeness of resection (P = .03). CIR significantly increased in high Masaoka-Koga stages (P = .04). Histologic subtype was not associated with either OS or CIR.

CONCLUSIONS

Our results confirm the high biologic aggressiveness of these rare neoplasms; pathologic stage and completeness of resection were demonstrated to be strong prognostic factors, whereas histology did not influence patients outcome.

What is the role of lymph nodal metastases and lymphadenectomy in the surgical treatment and prognosis of thymic carcinomas and carcinoids?

A best evidence topic in thoracic surgery was written according to a structured protocol. We looked at the clinical relevance of lymph node involvement and nodal (N) stage, in thymomas, thymic carcinomas and carcinoids. The possible role of lymphadenectomy in addition to thymectomy was also evaluated. A total of 605 papers were found, of which nine represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers were tabulated. In the Yamakawa-Masaoka classification, based on 226 patients, lymph nodes were classified as anterior mediastinal (N1), defined as nodes surrounding the thymus gland; intrathoracic (N2), all nodes within the thorax excluding N1; and extrathoracic nodes (N3). Kondo validated the Yamakawa-Masaoka classification in a multicentric cohort of 1320 patients. Thymomas presented nodal involvement in 1.8% of cases, carcinomas in 27% of cases, and carcinoids in 28% of cases. The role of nodal status in defining the stage was even more emphasized in the staging system developed by Tsuchiya for thymic carcinomas. In the Istituto Nazionale Tumori classification, thymomas with N1 or N2 were considered as locally advanced disease with a 95-month disease-free survival rate for locally advanced disease of 46.9 vs 98.6% for locally restricted disease (absence of nodal involvement). Weissferdt and Moran, on a series of 65 thymic carcinomas, underlined the clinical relevance of nodal involvement. Positive lymph nodes were associated with significantly worse survival (P = 0.01070). Okuma, in a series of 68 advanced stage thymic carcinomas, showed that curative-intent surgical treatment was related to prolonged survival (P = 0.03). In particular, IVb tumours due to node-only involvement had better survival when radical resection was achieved when compared with IVb due to distant metastases (P = 0.03). Sung et al. showed the importance of harvesting 10 or more lymph nodes and dissecting intrathoracic lymph nodes to ensure a more complete stadiation of thymic carcinomas. The results underline the clinical relevance and prognostic value of nodal involvement in thymic carcinomas and carcinoids. In these cases, lymphadenectomy is desirable to allow the real definition of N status.

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.

Diagnostic features and subtyping of thymoma lymph node metastases

Aim. The purpose of the present study was to characterize the morphological features of thymoma metastases in lymph nodes and to evaluate the possibility of their subtyping according to the 2004 WHO classification of thymus tumors. Materials and Methods. We reviewed 210 thymoma cases in our series of thymic epithelial tumors (TET), including their recurrences and lymphogenous metastases. Three cases of lymph node metastases, one case occurring synchronously with the primary tumor and one synchronously with the first relapse (both in intrathoracic location) and one case of metastasis observed in a laterocervical lymph node subsequently to two thymoma relapses were found. Results. The metastatic nodes were variably but extensively involved in all cases. The histological features were similar in both primary tumors and metastases. Thymoma metastases were subtyped according to the WHO classification as B3 (one case) and B2 (two cases), and distinctive features in comparison to metastatic epithelial neoplasias from other sites were observed. Conclusion. Thymoma lymph node metastases, although rare, can be subtyped according to the WHO classification on the basis of their morphological and immunohistochemical features. Clinically, the presence of nodal metastases may herald subsequent relapses and further metastases even in extrathoracic sites.

European perspectives in thoracic surgery

Europe, the old Continent, has been the cradle of thoracic surgery from the beginning of the last century. The structure and the activities of the European Society of Thoracic Surgeons (ESTS) activities are directed to enlighten the path, provide the tools and set the standards for a quality inspired practice in thoracic surgery.

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.

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.