Type B thymoma: Is prognosis predicted only by World Health Organization classification?

• Published in: The Journal of thoracic and cardiovascular surgery Vol. 139; no. 6; pp. 1431 - 1435.e1
• Main Authors: Kim, Hong Kwan, MD, Choi, Yong Soo, MD, Kim, Jhingook, MD, PhD, Shim, Young Mog, MD, PhD, Han, Joungho, MD, PhD, Kim, Kwhanmien, MD, PhD
• Format: Journal Article
• Language: English
• Published: New York, NY Mosby, Inc 01.06.2010; Elsevier
• Subjects: Adult; Aged; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Cardiology. Vascular system; Cardiothoracic Surgery; Female; Humans; Male; Medical sciences; Middle Aged; Neoplasm Recurrence, Local - epidemiology; Pneumology; Prognosis; Retrospective Studies; Survival Rate; Thymoma - classification; Thymoma - mortality; Thymoma - surgery; Thymus Neoplasms - classification; Thymus Neoplasms - mortality; Thymus Neoplasms - surgery; Tumors of the respiratory system and mediastinum; World Health Organization; Young Adult; World; DFS; 13; World Health Organization; disease-free survival; OS; overall survival; WHO; Prognosis; Thymoma; Mediastinum disease; Malignant tumor; Thymus pathology; Type; Public health organization; Classification; Anesthesia; Thymic epithelial tumor; Benign neoplasm; Circulatory system; Cardiology; Predictive factor; Cancer
• ISSN: 0022-5223; 1097-685X
• DOI: 10.1016/j.jtcvs.2009.10.024

Objective The prognostic relevance of subtypes within type B thymomas is controversial. The objective of this study was to evaluate the utility of World Health Organization (WHO) classification in patients with type B thymoma. Methods This was a retrospective review of 100 patients who underwent thymectomy for WHO type B thymoma. Recurrence patterns and survival were compared among subtypes. Results There were 22 type B1 tumors, 43 type B2 tumors, and 35 type B3 tumors. Incomplete resection occurred in 5 patients with type B1 thymoma, 8 with type B2 thymoma, and 8 with type B3 thymoma ( P  = .87). Of the 79 patients with complete resection, tumor recurrence occurred in 1 (5.9%) patient with type B1 thymoma, 2 (5.7%) with type B2 thymoma, and 2 (7.4%) with type B3 thymoma, and all of these patients had Masaoka stage III disease. Disease-free survival at 5 years was 93%, 85%, and 82% in type B1, B2, and B3, respectively (B1 vs B2; P = .79; B2 vs B3; P = 0.6). Disease-free survival at 5 years was 94%, 100%, 61%, and 50% in Masaoka stages I, II, III, and IV, respectively (I vs II; P = .26; II vs III; P = .028; III vs IV; P = .002). Conclusions Tumor recurrence was significantly associated with advanced Masaoka stage regardless of the WHO subtype of type B thymomas. Given the heterogeneity of WHO type B thymomas, Masaoka stage should always be considered when predicting prognosis and planning adjuvant treatment for patients with type B thymomas.