Objectives: To compare the prognostic value of the sixth and seventh editions of the TNM classification, and of additional prognostic factors, in colorectal cancer.
Background: The seventh TNM edition was released in 2009 with the aim of providing a more precise prediction of prognosis.
Methods: Clinical and histopathological data of 2229 patients with colorectal cancer who underwent tumor resection between 1990 and 2006 were analyzed and compared by using the sixth and seventh editions of the TNM classification and a statistically calculated model of prognostic factors.
Results: With the sixth edition, 5-year survival was 96% for stage I, 90% for IIA, 86% for IIB, 90% for IIIA, 72% for IIIB, 48% for IIIC, and 13% for IV. With the seventh edition, 5-year survival was 96% for stage I, 90% for IIA, 84% for IIB, 87% for IIC, 89% for IIIA, 72% for IIIB, 36% for IIIC, 15% for IVA, and 10% for IVB. The stage shifted for only 155 (7%) patients: from IIB to IIC (2%), from IIIB to IIIC (1%), and from IIIC to IIIA/B (4%). The performance of the seventh edition [concordance index (c-index) 0.83; 95% confidence interval (CI), 0.82–0.85] revealed no relevant improvement compared with the sixth edition (c-index 0.83; 95% CI, 0.82–0.84), or compared to a model based on independent prognostic factors (c-index 0.84; 95% CI, 0.83–0.86).
Conclusions: The seventh TNM edition did not provide greater accuracy in predicting colorectal cancer patients' prognosis but resulted in a more complex classification for daily clinical use.
In 2009, the seventh edition of the TNM classification system was introduced. Although complexity and number of subgroups increased, no improvement was detected in the prognostic value compared to the sixth edition and in comparison to a proposed prognostic model based on clinical and histopathological parameters.
*Department of Surgery,
†Institute of Statistics and Epidemiology, Klinikum rechts der Isar,
§Institute of Pathology, Technische Universität München, Munich, Germany;
‡Department of Surgery, Kantonsspital Liestal, Liestal, Switzerland; and Technische Universität München, Munich, Germany.
Reprints: Helmut Friess, MD, Chirurgische Klinik und Poliklinik, Klinikum rechts der Isar der Technischen Universität München, Ismaninger Street 22, 81675 Munich, Germany. Email: Friess@chir.med.tu-muenchen.de.
U Nitsche and M Maak contributed equally to this work.
Disclosure: This study received no financial support.