Purpose: To evaluate the utility of the proposals of the International Association for the Study of Lung Cancer (IASLC) in the forthcoming 7th edition of lung cancer staging system to classify patients submitted to radical surgical resection of non-small cell lung cancer and to compare their value in predicting long-term prognosis with the existing 6th edition of the American Joint Committee on Cancer (AJCC)/Union Internationale Contre le Cancer (UICC) TNM classification.
Methods: Nine hundred twenty-one patients received an anatomic resection and hilar-mediastinal dissection for primary non-small cell lung cancer during the period 1990 to 2005. Histopathologic staging following the actual AJCC/UICC TNM classification were as follows: 207 T1, 562 T2, 148 T3, and 4 T4; 570 N0, 149 N1, 198 N2, and 4 N3; 163 stage IA, 346 IB, 23 IIA, 157 IIB, 224 IIIA, and 8 IIIB. Stages reclassified using the proposals of IASLC for the new staging system were as follows: 101 T1a, 106 T1b, 400 T2a, 103 T2b, 210 T3, and 1 T4; 163 stage IA, 262 IB, 157 IIA, 106 IIB, 230 IIIA, and 4 IIIB.
Results: Follow-up was obtained for 836 patients. Mean follow-up was 46.5 +/- 48.9 months. N-status (unchanged between the 2 classifications) was confirmed to be a significant prognostic factor. Significant differences in 10-year disease-related survival were demonstrated between stages IIB and IIIA only (35% vs 14%) of the AJCC/UICC TNM classification and between stages IB and IIA (60% vs 46%) and stages IIB and IIIA (39% vs 15%) of the IASLC proposals for a new classification.
Discussion: The proposals of IASLC in the forthcoming 7th edition of the lung cancer staging system are demonstrated to be better able to separate prognostically distinct groups of patients operated for non-small cell lung cancer than the accepted existing 6th AJCC/UICC TNM classification.