The superiority of the seventh edition of the TNM classification depends on the overall survival of the patient cohort

Comparative analysis of the sixth and seventh TNM editions in patients with gastric cancer from Japan and the United Kingdom

Authors

  • Tsutomu Hayashi MD,

    1. Department of Gastrointestinal Surgery, Kanagawa Cancer Center, Yokohama, Japan
    Search for more papers by this author
    • The first 2 authors contributed equally to this article.

  • Takaki Yoshikawa MD, PhD,

    Corresponding author
    1. Department of Gastrointestinal Surgery, Kanagawa Cancer Center, Yokohama, Japan
    • Department of Gastrointestinal Surgery, Kanagawa Cancer Center, 1-1-2 Nakao, Asahi-Ku, Yokohama, Japan
    Search for more papers by this author
    • The first 2 authors contributed equally to this article.

    • Fax: (011) 81-45-361-4692

  • Kiran Bonam MBBS,

    1. Section of Pathology and Tumour Biology, Leeds Institute of Molecular Medicine, St. James's University Hospital, Leeds, United Kingdom
    Search for more papers by this author
  • Henry M. Sue-Ling MD,

    1. Department of Oesophagogastric Surgery, St. James's Institute of Oncology, Leeds Teaching Hospitals National Health Service Trust, Leeds, United Kingdom
    Search for more papers by this author
  • Masataka Taguri PhD,

    1. Department of Biostatistics and Epidemiology, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
    Search for more papers by this author
  • Satoshi Morita PhD,

    1. Department of Biostatistics and Epidemiology, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
    Search for more papers by this author
  • Akira Tsuburaya MD,

    1. Department of Gastrointestinal Surgery, Kanagawa Cancer Center, Yokohama, Japan
    Search for more papers by this author
  • Jeremy D. Hayden MD,

    1. Department of Oesophagogastric Surgery, St. James's Institute of Oncology, Leeds Teaching Hospitals National Health Service Trust, Leeds, United Kingdom
    Search for more papers by this author
  • Heike I. Grabsch MD, PhD

    Corresponding author
    1. Section of Pathology and Tumour Biology, Leeds Institute of Molecular Medicine, St. James's University Hospital, Leeds, United Kingdom
    • Section of Pathology and Tumour Biology, Leeds Institute of Molecular Medicine, University of Leeds, Wellcome Trust Brenner Building, St. James's University Hospital, Beckett Street, Leeds LS9 7TF, UK
    Search for more papers by this author
    • Fax: (011) 44-113-343-8431


Abstract

BACKGROUND:

The objective of this study was to investigate whether the seventh edition of the American Joint Committee on Cancer/International Union Against Cancer TNM classification (TNM7) had superior discriminatory ability over the sixth edition of the TNM classification (TNM6) in patients with gastric cancer regardless of their country of origin.

METHODS:

In total, 538 patients from the Kanagawa Cancer Center Hospital (Yokohama, Japan) (KCCH) and 519 patients from the Leeds Teaching Hospitals National Health Service Trust (Leeds, United Kingdom) (LTHT) who underwent surgery for gastric cancer were selected. Overall survival was used for statistical analysis. Hazard ratios (HRs) were estimated with disease stage as a continuous variable to evaluate the discriminatory ability of the TNM stage groups. The estimates of log HRs (logHRs) for the TNM6 and the TNM7 stage groups were compared.

RESULTS:

In the KCCH cohort, 82 patients (15%) were upstaged, and 26 patients (5%) were downstaged between TNM6 and TNM7 compared with 253 patients (49%) and 53 patients (10%), respectively, in the LTHT cohort. The logHRs for a 1-stage increase within TNM6 and TNM7 were 1.06 and 1.16, respectively, in the KCCH cohort and 0.57 and 0.79, respectively, in the LTHT cohort. The differences in logHRs between TNM6 and TNM7 were significant in each cohort (KCCH: logHR, 0.11; P = .024; LTHT: logHR, 0.21; P = .0002) and between the 2 cohorts.

CONCLUSIONS:

TNM7 had superior discriminatory ability compared with TNM6 in both cohorts. The improved ability to discriminate patients with different survival probability when using TNM7 was greater in the LTHT cohort. The current findings indicated that the discriminatory ability of the TNM stage groups may depend on the baseline survival characteristics of the patient cohort. Cancer 2013. © 2013 American Cancer Society.

Ancillary