The data of the literature demonstrate the poor global results of surgical treatment of the principal gastrointestinal cancers: oesophagus, stomach, bile ducts, liver, exocrine pancreas, colon and rectum. Surgery which was thought to be curative all too frequently proves to be simply a palliative procedure. The risk of failure is so high that a strategy should now be systematically adopted, combining surgery, radiotherapy, chemotherapy and symptomatic treatments. The rigor of this multidisciplinary approach is based on comparative studies confirming the prospective series and measuring the quality and duration of survival. Some protocols provide considerable improvement, for example preoperative radiotherapy of cancers of the rectum, or propose an interesting alternative such as the combination of radiotherapy and chemotherapy in cancer of the oesophagus. The participation of surgeons in multicentre prospective studies should validate and improve current oncological practice while also evaluating the contribution of a new method such as laparoscopic surgery. This commitment includes a definition of therapeutic objectives, definition of the reference treatment, selection of the criteria of the quality of the procedures involved in this treatment and objective assessment of the results.