Application of the Revised Lung Cancer Staging System (IASLC Staging Project) to a Cancer Center Population
Edmund S. Kassis1, Ara A. Vaporciyan1, Stephen G. Swisher1, Arlene M. Correa1, Neby Bekele2, Jeremy J. Erasmus3, Wayne L. Hofstetter1, Ritsuko Komaki4, Reza J. Mehran1, Cesar A. Moran5, Katherine M. Pisters6, David C. Rice1, Garrett L. Walsh1, Jack A. Roth1; 1The University of Texas MD Anderson Cancer Center, Department of Thoracic and Cardiovascular Surgery, Houston, TX; 2The University of Texas MD Anderson Cancer Center, Department of Bioinformatics & Computational Biology, Houston, TX; 3The University of Texas MD Anderson Cancer Center, Department of Radiology, Houston, TX; 4The University of Texas MD Anderson Cancer Center, Department of Radiation Oncology, Houston, TX; 5The University of Texas MD Anderson Cancer Center, Department of Pathology, Houston, TX; 6The University of Texas MD Anderson Cancer Center, Department of Thoracic/Head and Neck Medical Oncology, Houston, TX
Comment on this Abstract
Objective: The International Association for the Study of Lung Cancer (IASLC) recently proposed a revision to the current UICC-6 staging system for non-small cell lung cancer (NSCLC). The T descriptors and stage groupings have been redefined while the nodal descriptors remain unchanged. The goal of this study was to apply the proposed changes to a cancer center population undergoing surgery for NSCLC and directly compare the proposed IASLC and UICC-6 staging systems to determine if one system is superior in its ability to classify operable patients based on stage.
Methods: Pathologic stages in 1,154 patients undergoing R0 surgical resection from a prospectively collected database over a 9-year period were analyzed. Each patient was assigned a stage based on both IASLC and UICC-6 staging systems. The effectiveness of each staging system was evaluated statistically using a log-rank trend test. Statistically meaningful differences between the two staging systems were evaluated with a computationally intensive log-rank test.
Results: Ordering and separation of stages in our patient population is visually comparable to the IASLC test and validation sets. The IASLC staging system is significantly more effective in differentiating between low, mid, and high stage patients compared to the UICC-6 system (p=0.006). Reassigning patients to the IASLC system resulted in 202 (17.5%) patients being reassigned to a different stage (p=0.012), with the most common shifts occurring from IB to IIA and IIIB to IIIA (Table 1). Three patients were downstaged from stage IV to IIIA (n=2) and IIIB (n=1). The five-year and median survivals of the IIIA patients in the IASLC system including those shifted from the UICC-6 IIIB was 37% and 35 months, respectively. Reclassifying UICC-6 IIIB to IASLC IIIA did not reduce survival for operable patients.
Conclusion: Our data confirms that the proposed IASLC staging system is more effective at differentiating prognostic stage groupings than the UICC-6 system. Use of this system will help to identify those patients at higher risk for recurrence and will facilitate adjuvant treatment decisions and research. 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.
Table 1
| UICC-6, N(%) | IASLC, N (%) |
| IA | 358 (31) | 358 (31) |
| IB | 305 (26.4) | 242 (21.1) |
| IIA | 74(6.4) | 185 (16) |
| IIB | 160 (13.9) | 110 (9.5) |
| IIIA | 153 (13.3) | 216 (18.7) |
| IIIB | 66 (5.7) | 8 (0.69) |
| IV | 38 (3.3) | 35 (3) |
Patients were assigned a pathologic stage based on the UICC-6 and IASLC staging systems. Re-classification of patients between systems resulted in a statistically significant shift of patients between stage groupings (p=0.012).
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