Prognosis of thymic epithelial tumors according to the new World Health Organization histologic classification.

Research paper by Moo Suk MS Park, Kyung Young KY Chung, Kil Dong KD Kim, Woo Ick WI Yang, Jae Ho JH Chung, Young Sam YS Kim, Joon J Chang, Joo Hang JH Kim, Sung Kyu SK Kim, Se Kyu SK Kim

Indexed on: 01 Sep '04Published on: 01 Sep '04Published in: The Annals of Thoracic Surgery


The aim of this study was to document the prognosis of thymic epithelial tumors (TETs) according to new the World Health Organization (WHO) classification.We retrospectively reviewed 150 patients with TETs that were confirmed pathologically during 11 years (from 1992 to 2002) in Severance Hospital, Seoul, Korea.TETs were classified as type A, AB, B1, B2, B3, or C, tumors and these represented 7 (4.7%), 26 (17.3%), 13 (8.7%), 45 (30.0%), 26 (17.3%), and 33 (22.0%) cases, and the 5-year survival rates were 100%, 93%, 89%, 82%, 71%, and 23%, respectively. Their Masaoka stages were I, II, III, IVa, and IVb, with 53 (35.3%), 39 (26.0%), 20 (13.3%), 22 (14.7%), and 16 (10.7%) cases. Tumor invasiveness, recurrence, completeness of resection, and tumor-related death were more frequent in types AB, B2, B3, and C than in types A and B1. Multivariate analysis showed that Masaoka stage (p < 0.001) and the WHO classification (p = 0.019) were significant independent prognostic factors.The WHO classification is associated with tumor invasiveness, recurrence, completeness of resection, and tumor-related death, and has good correlation with Masaoka stage. The WHO histologic subtypes are an independently significant prognostic factor with respect to survival in our multivariate analysis. Types AB, B2, B3, and C showed invasive behaviors and R1 or R2 resections were frequently performed. Postoperative adjuvant radiotherapy was effective, but long-term follow-up is recommended because of decreased survival after 5 years following operation. The WHO classification may be helpful in clinical practice for the assessment and treatment of TET patients.