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Editor,—The EUROCARE study of Gattaet al (OpenUrlPubMedWeb of Science) provides important information on survival for colorectal cancer in different parts of Europe. In particular, it relates survival to stage, a feature which was absent from earlier studies.1-3 The study also looks at procedures used in determining stage which may be important factors in accurate staging—for example, higher numbers of lymph nodes sampled will be more likely to detect lymph node metastases and consequent upstaging of tumours.4
However, the usefulness of this study is reduced by inaccuracies in the descriptions of staging and choice of staging system. The authors have chosen to use Dukes' staging system which has been in use for at least 50 years and has been well characterised by many studies with long term follow up.5-9 Unfortunately, they have given incorrect labels to some of the stages in this system. In tables 2 and 3, Dukes' stages A and B are described as being “confined to the bowel wall” which is incorrect. Dukes' stage A is invasion into, but not through, the bowel wall whereas Dukes' stage B is invasion through the bowel wall but without lymph node metastases.7 Dukes' stages A and B combined could have been correctly labelled as no lymph node metastases. In the methods section …