Background: In non-small-cell lung cancer (NSCLC), the evaluation of anatomic tumor extension [tumor, node, metastasis (TNM) stage] is indispensable for the exchange of scientific information or determining prognosis.
Objective: To quantify changes in TNM stages (numerical migration) and survival (prognostic migration) resulting from the application of classificatory certainty criteria to patients with NSCLC who had undergone surgical treatment.
Methods: The study population included 1,844 patients registered by the Bronchogenic Carcinoma Cooperative Group of the Spanish Society of Pneumology and Thoracic Surgery (GCCB-S). For every patient, two evaluations were made of each component of the TNM classification: an initial classification, defined by a local representative, and a confirmed classification resulting from the application of stricter classificatory criteria by the GCCB-S Central Review Board.
Results: The results revealed scant numerical migration in the cT category (11.5% of the study population) and a general tendency toward a downstaging. In contrast, the initial cN1 category experienced a complete numerical migration and the initial cN2 category a very large numerical migration (from 200 to 22 cases). In the small group of patients for whom there was a classificatory change in cT (n = 212), the migration for the cT2 category was accompanied by a less favorable prognosis (p = 0.039, log-rank test). However, the migration of this small subset of patients did not affect the general prognosis of the study population for cT2. In cN2, the 3-year survival rate migrated from 0.42 to 0.29.
Conclusions: Numerical migration resulting from the application of stricter classificatory criteria was relevant, but had little, although unfavorable, global prognostic impact.
Copyright 2002 S. Karger AG, Basel