The Current Staging Systems of Thymoma

1. 2010 대한흉부외과학회 춘계학회 The Current Staging Systems of Thymoma 성균관대학교 흉부외과 최용수

2. Thymoma • the most common neoplasm of the anterior mediastinum • “rather enigmatic tumor” • controversy on histologic classification & staging - low incidence - wide range of histological appearance - unique biologic behavior

3. Case : M/40, symptoms of myasthenia gravis Bx. (mediastinotomy) ; Thymoma, WHO type A Mass excision : Thymoma, WHO type B3

4. Definition & terms : confusion • Thymoma • Thymic epithelial tumor • Thymic carcinoma • Malignant thymoma • Invasive thymoma • Atypical thymoma

5. Thymoma : benign or malignant ? • Thymic carcinoma : 흉선암, malignant • Thymoma : 흉선종, benign? • invasiveness of thymoma • no clear histologic distinction • Lymphoma, melanoma : malignant tumor

6. Histologicclassification of thymic epithelial neoplasm (1) • Now excluded in the new WHO classification (2004) and • placed in a separate group of malignant epithelial tumors.

7. Histologicclassification of thymic epithelial neoplasm (2) • Now excluded in the new WHO classification (2004) and • placed in a separate group of malignant epithelial tumors.

8. WHO classification & clinical staging Okumura (2001)

9. Staging of thymoma • Staging of thymoma continues to be a controversial issue.

10. Thymoma has no official staging system!

11. Staging schemes of thymoma

13. Overall survival rates of thymoma

14. Survival curve of thymoma : Korea n=108 n=195 연세대. Chest (2005) 성균관대. Br J Ca (2007)

15. Criticisms on Masaoka staging Bedini (2005), Kondo(2005) • not well suited for the staging of thymic carcinomas • not provide an appreciable prognostic separation between stages I and II • Definition of stage II is unclear. Tumors invading the mediastinal pleura are at higher risk of recurrence than the other stage II tumors. • no description of residual tumor • Stage III thymoma is highly heterogenous in terms of involved organs. • The TNM system classification of thymic epithelial tumors has not been established.

16. Modification of Masaoka staging • Koga et al. (1994) • simplified into two groups • non-invasive for stages I and II • invasive for stages III and IV

17. Modification of Masaoka staging

18. Staging (French Classification)- Groupe d'Etudes des Tumeurs Thymique, GETT 1982

19. Verley and Hollmann classification (1985)

20. Prognostic categories for thymoma proposed by Suster and Moran (2003)

22. New staging systems for testing Asamura (2004) Masaoka staging Scheme 1 Scheme 2

23. Tumor size : thymoma prognosis • Bloomberg(1995) : 11cm • Wright(2005) : 8cm • Nakagawa(2003) : 10cm

24. Results Of Surgical Treatment Of Thymomas With Special Reference To The Involved Organs Okumura (1999) Survival of patients with stage III disease

25. Stage III Thymic Epithelial Neoplasms are Not Homogeneous with Regard to Clinical, Pathological, and Prognostic Features 성균관대.J Thorac Oncol (2009)

26. LN metatasis : 2.4% hematogenous metastasis : 5.3%

27. Proposed TNM schemes for thymoma and thymic carcinoma Yamakawa, Masaoka (1991)

28. Pattern of LN metastasis Kondo (2003) Thymic carcinoma Thymoma

30. The INT (Istituto Nazionale Tumori)TNM-Based Staging System Stage grouping Classification of residual disease

31. Progression-free survival INT(Istituto Nazionale Tumori) staging Masaoka staging

32. Thymoma vs. Thymic ca. thymoma normal thymus thymic carcinoma

33. Thymic carcinomas

37. 1. stage III thymoma 2. thymic carcinoma

39. Key points of thymic tumor staging • By multivariate analysis, the most important prognostic factors in patients with thymomas are stage and completeness of resection. • All stages and all histologic subtypes of thymoma have the potential to spread to distant sites. • Frank C. Detterbeck, Alden M. Parsons • Pearson’s thoracic and esophageal surgery, 3rd Edition. • chapter 131. Thymic tumors: A review of current diagnosis, classification and treatment

40. 감사합니다.