MA10.02 Clinical Staging in the 8th Edition TNM for Lung Cancer is Inaccurate

MA10.02 Clinical Staging in the 8th Edition TNM for Lung Cancer is Inaccurate

S398 study is to validate the prognostic performance of this new staging system, focusing on the upgraded “T” and “M” parameters, in North American l...

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S398

study is to validate the prognostic performance of this new staging system, focusing on the upgraded “T” and “M” parameters, in North American lung cancer patients. Methods: We analyzed 1,163,465 non-small cell lung cancer (NSCLC) cases collected from 2004 to 2013 in the United States in the National Cancer Database (NCDB). After excluding patients with more than one malignant primary tumor or tumor size larger than 10 cm, 545,776 NSCLC patients were included in the final data analysis. We defined 8th T and M parameters according to the primary coding guidelines of the Collaborative Staging Manual and Coding Instructions for the new 8th AJCC/UICC lung cancer staging system. Kaplan-Meier survival curves and log-rank tests were used to compare survival difference among different stage groups, and Cox regression models were used for multivariate analysis adjusting for potential confounders. Results: We validated that the new staging system can provide better survival prognosis for NSCLC patients in the NCDB cohort than the existing 7th staging system. The median survival time for T1a is 58 months (N¼15,860), for T1b is 47 months (N¼78,379), and for T1c is 25 months (N¼79,828) (p<2e-16). The median survival time for T2a is 19 months (N¼111,925), for T2b is 12 months (N¼54,601), for T3 is 10 months (N¼105,234), and for T4 is 7 months (N¼99,949) (p<2e-16). And the median survival time for M0 is 25 months (N¼411,048), for M1a is 8 months (N¼49,352), for M1b is 5months (N¼42,224), and for M1c is 3 months (N¼15,926 cases) (p<2e-16). Multivariate analysis showed that these staging parameters are significantly associated with survival when adjusting other factors. Conclusion: Both upgraded “T” and “M” parameters of the 8th AJCC/UICC lung cancer staging systems are significantly associated with NSCLC patient survival outcomes using data from the NCDB, indicating a good validation performance in patients from North America. Keywords: AJCC/UICC cancer stage, non-small cell lung cancer, national cancer database, survival analysis

Journal of Thoracic Oncology

Vol. 12 No. 1S

Background: The new classification for lung cancer refines the T-descriptor criteria into more categories. We examined whether this affects the accuracy of clinical staging, and how this affects the final stage of patients. Methods: 71 patients underwent resection for primary lung cancer from January 2014 to December 2014. Tcomponent was measured based on the maximum tumor size on CT, PET-CT and histology report. The possible effect on staging based on T-component was compared between both TNMs. Results: PET-CT more accurately estimates the pathological size of the tumor (mean difference from histology: CT 3mm (range -1.6 to 2.6cm) and PET-CT 1.3mm (-2 to 2.5cm). Discordance between radiological and pathological T-stage was higher with the 8th edition (7th edition concordance CT 42(59%) and PET-CT 31(43%), 8th edition CT 31(44%) and PET-CT 29(41%) (CT p¼0.01; PET-CT p¼0.7)). The final stage groupings was also more discrepant in the 8th edition. Concordance was for CT 7th Edition 37(54%) vs 8th Edition 21(31%) (p<0.001), and for PET-CT 34(48%) vs 19(28%) (p<0.001). The discrepancy in stage grouping is contributed significantly by T-stage discordance. In the 30 patients who were not upstaged pathologically by pleural invasion or nodal staging, there is a over 50% increase in inaccuracy of clinical staging in the 8th edition. The CT concordance was 7th edition 24(80%), 8th edition 13(43%) (p<0.001); and for PET-CT 23(77%) vs 10(33%) (p<0.001). Conclusion: We showed that the 8th edition TNM lung cancer staging system was associated with a significant increase in discordance between clinical and pathological staging due to differences in measurement of tumor size and consequently T-stage groupings by different modalities. This has implications for prognostication and clinical trial interpretation especially in patients who do not undergo surgery for pathological stage confirmation.

MA10.02 Clinical Staging in the 8th Edition TNM for Lung Cancer is Inaccurate Aleksander Mani,1 Ashok Kar,1 Mariano Dimartino,2 Josephine Mayer,3 Kelvin Lau1 1Thoracic Surgery, St Bartholomew’S Hospital, London/United Kingdom, 2St. Bartholomew’S Hospital, London/United Kingdom, 3 Queen’s Hospital, London/United Kingdom

Keywords: Staging, 7th Edition, lung cancer, 8th Edition