BACKGROUND: We designed and assessed a new TNM staging system (herein called the INT [Istituto Nazionale Tumori] system) for thymic @entity5 in order to overcome the perceived drawbacks of Masaoka's system, which represents the current standard. METHODS: In all, 123 cases were evaluated. The histologic types according to the World Health Organization (WHO) classification were as follows: subtype A: 5 cases; AB: 40; B1: 16; B2: 29; B3: 16; and C: 17 cases. There were 45 Masaoka's stage I, 33 stage II, 26 stage III, and 19 stage IV cases. A total of 11 INT definitions were grouped into three stages: locally restricted disease (75 cases), which included Masaoka's stage I and selected stage II cases (no @entity3 ); locally advanced disease (37 cases), which included Masaoka's stage III cases plus those staged II owing to @entity3 and those staged IV owing to intrathoracic nodal or limited @entity14361 ; and @entity262 (11 cases), which included the remaining Masaoka's stage IV cases. RESULTS: Completeness of resection, WHO types, and both staging systems were significant prognostic factors (p < 0.0001) on univariate analysis. The 95-month progression-free survival rates according to Masaoka's system were stage I: 100%; II: 93.6%; III: 46.3%; and IV: 23.2%. The INT system corresponding figures were as follows: locally restricted disease: 98.6%; locally advanced disease: 46.9%; and @entity262 : 11.7%. The INT system was the prognostic factor with the greatest impact (p = 0.0218) on multivariate analysis (Masaoka's system: p = 0.2012; completeness of resection: p = 0.6855; histology: p = 0.9386). CONCLUSIONS: The INT system allows finer disease descriptions than Masaoka's system, resulting in a stage grouping with higher prognostic distinctiveness.

Proposal of a novel system for the staging of thymic XXXX .

@entity5 :: ('MESH:D009369', 'Disease') :: ['epithelial tumors'] @entity262 :: ('MESH:D034721', 'Disease') :: ['systemic disease'] @entity14361 :: ('MESH:C566895', 'Disease') :: ['pleuropericardial involvement'] @entity3 :: ('MESH:D009362', 'Disease') :: ['pleural invasion']
@entity5 :: (MESH:D009369,Disease) :: ['epithelial tumors']
