Anne Lu1, Meinoshin Okumura2
1Mediastinum Editorial Office, AME Publishing Company; 2National Hospital Organization Osaka Toneyama Medical Center, Osaka, Japan
Editor's Note: Tumors of the thymus gland are a group of rare diseases, on which both patients and doctors lack of knowledge and information. International Thymic Malignancy Interest Group (ITMIG) has launched the initiative: May – Thymic Malignancy Awareness Month. ITMIG aims to increase the knowledge of these rare neoplasms among patients and their families, as well as among doctors of various specialties with a series of events including the interviews with mediastinal disease experts released on the journal Mediastinum. Prof. Meinoshin Okumura, as a prominent expert in the field of thymic diseases, was invited for the interview.
Mediastinum: Would you please briefly introduce the evolution of surgical management of thymic malignancy?
Prof. Okumura: The first surgical operation for mediastinal lesion was resection of a tuberculosis-related lesion by Milton in 1897 as far as I know. The first thymectomy for myasthenia gravis was done through cervical approach by Sauerbruch in 1911. Blalock resected thymoma through sternotomy in 1936. The symptom of myasthenia gravis was improved, and the relation between thymoma and myasthenia gravis was suggested. Keynes performed simultaneous resection of the thymus and the thyroid gland for a patient with myasthenia gravis and hyperthyroidism. After these accomplishments, surgery for mediastinal tumors became widely accepted.
In Japan, the first thymectomy for myasthenia gravis was done by Tashiro in 1939, and the first removal of mediastinal tumor was done by Tsuda for resection of dermoid cyst in 1948.
Mediastinum: Would you please clarify in which situation experts of multidisciplinary team are needed to select appropriate treatment strategies for patients?
Prof. Okumura: Multidisciplinary treatment should be considered when complete resection of the primary tumor seems difficult or when metastasis to the pleura is suspected. Chemotherapy alone is chosen as the preoperative induction therapy for thymoma, but concurrent chemoradiotherapy is more commonly administered for thymic carcinoma.
Multidisciplinary treatment is also performed when surgical resection was incomplete. In most cases, radiotherapy is performed.
Mediastinum: What are the most widely used staging systems for thymic tumors?
Prof. Okumura: The most commonly used staging system has been Masaoka’s clinico-pathological staging system. Although UICC approved the TNM-based staging system proposed by IASLC in 2016, most clinicians are not familiar with this novel staging system, and TNM classification is not commonly adopted yet.
Mediastinum: What are the key advances and challenges in developing a comprehensive and consistent staging system for thymic tumors?
Prof. Okumura: Global database is essential for developing the staging system. In 2010’s, ITMIG proposed establishing the global database and the academic societies in each continent and region agreed to it. Finally, clinical data of nearly 10000 cases were collected, and IASLC analyzed. International collaboration of academic societies is the key of staging project.
Mediastinum: Is there any significant or innovative research on thymic tumors that impresses you most in recent years? And what kinds of research are most needed to further the understanding of thymic tumors in your opinion?
Prof. Okumura: Japanese group reported effectiveness of lenvatinib for thymic carcinoma, and its indication to unresectable thymic carcinoma was approved by the social health insurance system in Japan. Because lenvatinib is a multi-kinase inhibitor, thymic carcinoma might have addiction to oncogene. I hope that a kinase responsible for growth of thymic carcinoma will be determined, and more effective drug will be developed in the future.
Mediastinum: Would you please introduce the most significant achievements of Japanese Association for Research of the Thymus (JART) in recent years? What are its future goals?
Prof. Okumura: Retrospective database of nearly 3000 thymic epithelial tumor cases was established in 2013, and this JART database contributed to establishing TNM-based staging system of UICC version 8. In addition, 12 scientific manuscripts were published by analysis of JART database.
JART database was updated last year, and another result will be obtained in the near future.
Mediastinum: Would you have any suggestions or expectation for ITMIG to promote global efforts and cooperation in the filed of thymic malignancies research.
Prof. Okumura: I suggest more studies in thymoma-associated autoimmune diseases. Especially, outcome of the patients with Good’s syndrome is quite poor, and we need to know the characteristics of this disease in more details and sharing the information in ITMIG would lead to standard treatment strategy.
Figure 1.Prof./ Dr. Meinoshin Okumura
Dr. Meinoshin Okumura (Figure 1), MD, PhD received his medical degree from Osaka University School of Medicine after which he completed his resident at Department of Surgery, Osaka University Hospital. He was a Research Fellow at the Department of Surgery, Osaka University Hospital from 1990-1992. Dr. Okumura was a Post-Doctoral Fellow at Howard Hughes Medical Institute, and Department of Pathology, Washington University, St. Louis, MO, USA from 1993-1996. From 1996-2002, Dr. Okumura is an Assistant Professor at the Department of Surgery, Osaka University Hospital and then he was appointed as the Chief Surgeon at Department of Surgery, National Kinki Chuo Hospital from 2002-2004. And the he was promoted to Associate Professor at Department of Surgery, Osaka University Hospital in 2004. And since 2007, he was the Professor at Department of General Thoracic Surgery, Osaka University, Graduate School of Medicine, Osaka University Hospital. He has moved to Toneyama National Hospital, Osaka Japan and has been the president and the hospital director since 2018.
Dr. Okumura has joined the board of surgery in Japan and the board of general thoracic surgery in Japan. He has also taken an active part in academic activities. He was the President of Japanese Association for Chest Surgery (JACS) from 2013 to 2017. He is the President of Japanese Association for Research on the Thymus (JART), as well as the member of European Society of Thoracic Surgeons (ESTS), European Association of Cardiothoracic Surgery (EACTS) and International Thymic Malignancy Interest Group (ITMIG). He has been an International councillor of ESTS from 2019.
Dr. Okumura specializes in surgery for lung cancer, thymic tumors, myasthenia gravis, and lung transplantation. He also focuses on basic research for oncology, immunology, and regenerative medicine.
Provenance and Peer Review: This article was commissioned by the editorial office, Mediastinum for the series “Meet the Professor”. The article did not undergo external peer review.
Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form. The series “Meet the Professor” was commissioned by the editorial office without any funding or sponsorship. AL reports that she is a full employee of AME Publishing Company. MO declares no conflicts of interest.
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