System for thymic disease research and clinical practice in Japan.

Japanese Association for Research of the Thymus (JART) established by emeritus professor Akira Masaoka is a cross-sectional association of physicians and researchers and have worked in clinical and basic research on thymic neoplasms and thymus-related diseases in collaboration with The Japanese Surgical Society (JSS), Japanese Association for Chest Surgery (JACS), Japanese Association for Thoracic Surgery (JATS), Japan Lung Cancer Society (JLCS), Japanese Respiratory Society (JRS) and Japanese Association for Respiratory Endoscopy (JARE). JART has performed several clinical trials, and the most important establishment of JART in recent days is the project of the nation-wide retrospective database of thymic epithelial tumors, which contributed to UICC TNM staging. Currently, JART is building the prospective database in collaboration with the Japanese Joint Committee for Lung Cancer Registry (JJCLCR). 2021 Mediastinum. All rights reserved.

Several academic associations in Japan have been working together to research thymic diseases and apply those results to clinical practice, with the relationships of these associations and their functions shown in .

Figure 1

Associations related to thymic disease research and clinical practice in Japan.

The Japanese Surgical Society (JSS) is the largest association in the field of surgery in Japan and covers all fields, including gastrointestinal, liver, cardiac, general thoracic, breast, endocrine organ surgery, and pediatric surgery, as well as traumatology, with 39,742 members in 2019. General thoracic surgery accounts for 8% of the JSS, while they also belong to both the Japanese Association for Chest Surgery (JACS) and Japanese Association for Thoracic Surgery (JATS), with the latter group covering all fields of thoracic surgery (cardiovascular, esophageal, lung, mediastinal). Thus, active surgeons treating thymic diseases are members of JSS, JACS, and JATS concurrently.

The Japan Lung Cancer Society (JLCS) was formed for physicians in all fields who treat lung cancer and thoracic malignancies. Also, the Japanese Association for Research of the Thymus (JART) is a cross-sectional association of physicians and researchers in the fields of thoracic surgery, medical oncology, neurology, radiology, pathology, and basic immunology, with 550 members in 2018. Most general thoracic surgeons and medical oncologists involved in treating lung cancer cases are also members of the Japanese Respiratory Society (JRS) and Japanese Association for Respiratory Endoscopy (JARE).

JACS, JATS, JLCS, JRS, JARE, JART, and the Japan Asbestos Mesothelioma Interest Group (JAMIG) jointly operate the Japanese Joint Committee for Lung Cancer Registry (JJCLCR), which has constructed and maintains a nationwide database of lung cancer, thymic epithelial tumor, and malignant mesothelioma cases. The Japan Clinical Oncology Group (JCOG), which is independent of these academic associations, is supported by the Japanese government and conducts clinical trials, with JCOG 9605 and JCOG 9606 reported by Kunitoh et al. (1,2).

Based on the advocacy of Prof. Akira Masaoka at Nagoya City University, JART was founded in 1982. Annual meetings are conducted, with the 39th meeting hosted by Prof. Atsushi Watanabe in Sapporo, Hokkaido, in 2019, during which 60 abstracts were presented. The “General Rules for Study of Mediastinal Tumors” was edited by the former president of JART, Professor Emeritus Yoshitaka Fujii at Nagoya City University, in 2009 ().

Figure 2

Cover of “General Rules for Study of Mediastinal Tumors”.

JART has initiated three clinical trials. JART01, a prospective study of carboplatin + paclitaxel as chemotherapy for thymoma, was unfortunately discontinued because of the appearance of fatal myocarditis as a severe side effect (3). JART02 was conducted as a surgical trial to compare a partial with a subtotal thymectomy (4), while JART03, performed in collaboration with Lung Oncology Group in Kyushu (LOGIC), was a prospective study of cisplatin + TS1 + RT as chemoradiotherapy for locally advanced thymic carcinoma (5).

Another important achievement by JART was development of a nationwide retrospective database of 2,793 thymic epithelial tumor cases surgically treated in Japan between 1991 and 2010. Thirty-two experienced institutes participated in the project. Findings of recurrence-free survival after a macroscopically complete resection according to pathological type are shown in . Ten research papers that used this database have been published in English language journals (6-15). The JART retrospective database also contributed to establishing UICC TNM staging in collaboration with ITMIG and IASLC (16). Presently, JART and JJCLCR are concurrently building a prospective database of thymic epithelial tumor cases.

Figure 3

Results acquired from JART retrospective database regarding recurrence-free survival after a macroscopically complete resection according to pathological type. JART, Japanese Association for Research of the Thymus.

JART has played an important role for communication with global societies. Further collaborations among Japanese societies and international associations are expected, and will contribute to advancement in research of thymic diseases.