Clinicopathological analysis of thymic malignancies with a consistent retrospective database in a single institution: from Tokyo Metropolitan Cancer Center

Abstract

BackgroundThymic epithelial tumors (TETs), which comprise thymoma and thymic carcinoma, are rare cancers with specific morphological and clinical features. Their clinical characteristics and outcomes have gradually been clarified by assessing large-scale, retrospective data obtained with international cooperation.MethodsThe study is a retrospective review of 187 Japanese patients with TETs who attended our institution from 1976 to 2012. Relevant clinical features of patients with TETs and their tumors, including histology, staging, treatment strategies, and overall survival, were investigated. Differences in survival were assessed by the Kaplan–Meier method and uni- and multi-variate Cox proportional hazards regression analyses.ResultsThe 187 patients included 52 patients with stage I, 37 with stage II, 22 with stage III, and 76 with stage IVa/IVb tumors according to the Masaoka–Koga Staging System. As to histological type, five patients had type A, 33 type AB, 19 type B1, 39 type B2, and 15 type B3 thymomas, whereas 68 patients had thymic carcinoma, including 11 with neuroendocrine carcinomas according to the 2004 WHO classification. Either insufficient data were available to classify the tumors of the remaining eight patients or they had rare types. Immunological abnormalities were present in 26 patients, most of whom had thymomas (21.8% of the thymoma group). Most of the patients who presented with symptoms had myasthenia gravis or extensive thymic carcinoma. Secondary cancers were present in 25 patients (13.3%). The overall 5- and 10-year survival rates for thymoma were 85.4 and 71.5%, respectively, and those for thymic carcinoma were 33.8 and 2.3%, respectively. OS differed significantly between stage IVa thymomas and thymic carcinomas. The stage and whether the tumors were thymomas or thymic carcinomas were significant determinants of survival according to multivariate analysis.ConclusionThe efficacy of treatments for thymoma and thymic carcinoma should be investigated separately because these tumors differ in their clinical features and prognosis.

Usefulness of Diffusion-weighted MR Imaging in Predicting Masaoka-Koga Clinical Staging of Thymic Epithelial Tumors by Using the Apparent Diffusion Coefficient

“…In our study (1), 32% of thymomas (eight of 25 patients) were classified as stage I and 24% (six of 25 patients) were classified as stage II. In the study by Okuma et al (2), 43.7% of thymomas were stage I and 26.1% were stage II. The difference in the percentage of high-risk disease in the early disease group in our study compared to that in the study by Okuma et al (2) may be due to the large number of patients (n = 187) in their study compared to our pilot study.…”

“…Having an effective imaging biomarker that is able to help differentiate early from advanced stage disease before surgery would be beneficial for determining the treatment strategy because the latter requires neoadjuvant chemotherapy (2,3). Unfortunately, in the present study, this finding is influenced by the low percentage of high-risk thymomas in the early stage disease group (two of nine patients, 22%), which reflects, for this cohort, a strong correlation between Masaoka-Koga staging and the Jeong simplification of the World Health Organization (WHO) classification.…”

“…Typical RPF imaging features have been described (2,3). However, the images may also show some variations, such as an atypical position, atypical shape (malignant RPFs are mostly lobulated marginally), and different enhancement patterns (related to different pathophysiologic stages of RPF) (2).…”

First-Line Treatment with Carboplatin plus nab-Paclitaxel and Maintenance Monotherapy with nab-Paclitaxel for a Thymic Carcinoma: A Case Report

“…It is uncertain whether carboplatin plus nab -paclitaxel therapy is effective for all histopathological subtypes of thymic carcinomas. These histopathological subtypes are as follows: squamous cell carcinomas; neuroendocrine carcinomas, including small-cell and large-cell neuroendocrine carcinomas, and carcinoid tumors; mucoepidermoid carcinomas; and others [ 1 ]. The histopathological subtypes of the 3 cases previously reported were as follows: squamous cell carcinoma [ 7 ], large-cell neuroendocrine carcinoma [ 8 ], and lymphoepithelioma-like carcinoma [ 9 ]; all of them were reported to be effectively treated with carboplatin plus nab -paclitaxel.…”

“…Thymic carcinomas are rare malignant tumors located in the anterior mediastinum. These tumors arise from the thymic epithelium and have been reported to account for 12−36% of all thymic epithelial tumors [ 1 , 2 , 3 ]. Complete surgical resection is the preferred method of treatment for thymic carcinomas with no distant metastases.…”