Validation of the Eighth Edition TNM Lung Cancer Staging System.

ABSTRACT

INTRODUCTION: We performed a validation study at our institution, the International Union Against Cancer (Union for International Cancer Control latest version of TNM Classification of Malignant Tumors Eighth Edition). METHODS: Data were collected from the Queensland Oncology Online registry of NSCLC or SCLC cases between 2000 and 2015 and validated against the Queensland Integrated Lung Cancer Outcomes Project registry using case identification number, first name, last name, and date of birth. Where data were available, cases were classified according to the Union for International Cancer Control TNM seventh edition stage groupings and then compared with the eighth edition groupings. Kaplan-Meier curves were plotted, and the log-rank test of survival differences was performed with SPSS version 25 (IBM Corp, Armonk, NY). RESULTS: Of the 3636 cases, 3352 and 1031 had complete clinical and pathologic staging, respectively. Median survival time was found to reduce with increasing clinical stage seventh edition (IA 88, IB 44, IIA 31, IIB 18, IIIA 15, IIIB 8, and IV 5 mo) versus eighth edition TNM stage (IA1 not reached, IA2 88, IA3 53, IB 56, IIA 36, IIB 22, IIIA 14, IIIB 9, IIIC 8, IVA 6, and IVB 3 mo). A similar overall pattern was reflected in the pathologic stage seventh edition (IA 124, IB 110, IIA 48, IIB 42, IIIA 26, IIIB 31, and IV 27 mo) versus eighth edition (IA1 not reached, IA2 122, IA3 125, IB 144, IIA 98, IIB 57, IIIA 31, IIIB 24, and IVA 7 mo). The log-rank test for survival curves was significant at p < 0.001. CONCLUSIONS: Our external validation study confirms the prognostic accuracy of the eighth edition TNM lung cancer classification. Our analyses also indicated that IIIB, IIIC, and IVA stage groups had similar survival outcomes and suggest further research for refinement.