Application of the revised lung cancer staging system (IASLC Staging Project) to a cancer center population

Objective: The International Association for the Study of Lung Cancer (IASLC) proposed a revision to the Union Internationale Contre le Cancer (UICC-6) staging system for non-small cell lung cancer. The goal of our study was to compare these systems in patients undergoing surgery for non-small cell lung cancer to determine whether one system is superior in staging operable disease. Methods: Pathologic stages in 1154 patients undergoing complete resection over a 9-year period were analyzed. Patients were assigned a stage based on both IASLC and UICC-6 systems. We tested for statistically meaningful differences between the two staging systems using the Wilcoxon signed rank test and the permutation test. Results: The IASLC system is more effective than the UICC-6 system at ordering and differentiating patients (P=.009). Application of the IASLC system resulted in 202 (17.5%) patients being reassigned to a different stage (P=.012), with the most common shifts occurring from IB to IIA and IIIB to IIIA. The 5-year and median survivals of the IASLC IIIA patients including those shifted from the UICC-6 IIIB were 37% and 35 months, respectively. Reclassifying UICC-6 IIIB to IASLC IIIA did not reduce survival for the newly characterized IIIA cohort. Conclusion: Our data confirm that the proposed IASLC staging system is more effective at differentiating stage than the UICC-6 system. Reclassifying patients from UICC-6 IIIB to IASLC IIIA will shift some patients from a stage previously considered unresectable to a stage frequently offered surgical resection. Further study and validation of the IASLC system are warranted.