Thymic tumors are relatively rare, and fall under the rubric of an orphan disease. This makes it difficult to have solid foundation of evidence on which to base treatment recommendations. More importantly, it severely limits the ability to develop an evidence base on multiple levels: it is difficult to develop the ideas for prospective studies, even more difficult to find funding for them, and a challenge to accrue adequate numbers of patients. In fact, examination of SEER database results spanning several decades reveals that no significant progress has been achieved.1
The treatment of thymic malignancies has been largely empiric. A review of published studies from 1989 through 2009 found that only 5% involved cohorts of greater than 100 patients, and even fewer were prospective. Development of treatment guidelines, therefore, is difficult, and relies on expert opinion. The first formal treatment guidelines for thymic malignancies were assembled by the Japanese Association for Research in Thymoma (JART) in 2009, and these are currently undergoing revision. The NCCN, a longstanding leader in the development and dissemination of clinical guidelines, also proposed guidelines for thymic malignancies in 2009,2 which are updated annually, with the current version appearing elsewhere in this issue (to view the most recent version of these guidelines, visit NCCN.org). However, these proposed management strategies remain primarily empirically based, and underscore the need for an organized effort to provide a scientific basis for clinical care.
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Ettinger DS, Riely GJ, Akerley W. NCCN Clinical Practice Guidelines in Oncology: Thymomas and Thymic Carcinomas. Version 2, 2013. Available at: NCCN.org. Accessed April 1, 2013.
Kondo K, Monden Y. Thymoma and myasthenia gravis: a clinical study of 1,089 patients from Japan. Ann Thorac Surg 2005;79:219–224.
Ruffini E, Van Raemdonck D, Detterbeck F. Management of thymic tumors: a survey of current practice among members of the European Society of Thoracic Surgeons. J Thorac Oncol 2011;6:614–623.
Ruffini E, Detterbeck C, Van Raemdonck D. Tumors of the thymus: report of the European Society of Thoracic Surgeons (ESTS) database project on 2151 patients. Lancet Oncol, in press.
Detterbeck F, Moran C, Huang J. Which way is up? Policies and procedures for surgeons and pathologicsts regarding resection specimens of thymic malignancy. J Thorac Oncol 2011;6:S1730–1738.
Detterbeck F, Nicholson A, Kondo K. The Masaoka-Koga stage classification for thymic malignancies: clarification and definition of terms. J Thorac Oncol 2011;6:S1710–1716.
Gomez D, Komaki R, Yu J. Radiation therapy definitions and reporting guidelines for thymic malignancies. J Thorac Oncol 2011;6:S1743–1748.
Marchevsky A, Marx A, Strobel P. Policies and reporting guidelines for small biopsy specimens of mediastinal masses. J Thorac Oncol 2011;6:S1724–1729.
Marom E, Rosado-de-Christenson M, Bruzzi J. Standard report terms for chest computed tomography reports of anterior mediastinal masses suspicious for thymoma. J Thorac Oncol 2011;6:S1717–1723.
Toker A, Sonett J, Zielinski M. Standard Terms, definitions, and policies for minimally invasive resection of thymoma. J Thorac Oncol 2011;6:S1739–1742.
Detterbeck C, Huang J. Definitions, policies and procedures for assessing clinical outcomes for thymic malignancies: overview. J Thorac Oncol 2011;6:S1689–1690.
Verghese E, den Bakker M, Campbell A. Interobserver variation in the classification of thymic tumours—a multicentre study using the WHO classification system. Histopathology 2008;53:218–223.