Comparison of 6th, 7th, and 8th editions of the TNM staging in non-small cell lung cancer patients: Validation of the 8th edition of TNM staging.

BACKGROUND

In this study, we aimed to evaluate the effects of the transition from the 6 edition of the Tumor, Node, Metastasis (TNM) staging system to the 7 edition, and from the 7 edition to the 8 edition by comparing the stage migrations. We also aimed to externally validate the 8 edition of the TNM staging system.

METHODS

Between September 2005 and June 2015, a total of 1,077 patients (986 males, 91 females; mean age: 59.6±8.3 years; range, 35 to 84 years) with non-small cell lung cancer who underwent lung resection were retrospectively analyzed. We re-staged patients according to 6, 7, and 8 TNM staging and compared the stage migrations of cases among the three staging systems.

RESULTS

Stage migration in the transition to the 7 edition of the TNM staging system was observed in 368 (34.1%) patients whereas it was observed in 541 (50.2%) patients in the transition to the 8 edition (p<0.001). The rate of upstaging in transition to the 7 edition staging system was 50.2% (n=185), whereas it was 98.1% (n=531) for the transition to the 8 edition (p<0.001). The survival rates of Stages 1B, 2B and 3A increased with transition to the 7 edition and the survival rates of Stages 1B, 2A, 2B, 3A, and 3B increased with the transition to the 8 edition. The best stratification in the survival curves in the 6th edition was between 1B-1A and 3B-3A. In the 7 edition, it occurred between 1B-1A, 3A-2B and 3B-3A and, in the 8 edition, between 1B-1A and 3B-3A.

CONCLUSION

Stratification according to the 7 edition showed better prognostic validity compared to the 6 edition; and that of the 8 edition was better compared to the 7 edition.