[Difficulties encountered in the evaluation of prognostic criteria of breast cancer: apropos of the experience of the René Huguenin center].

The use of prognostic factors to help select breast cancer patients for adjuvant therapy is of considerable concern to the oncology community. This need for selection of prognostically less favorable cases is stimulating investigators to identify new and more powerful prognostic factors. Unfortunately however, this identification process is becoming more confusing because of a lack of guidelines for investigators to use to study new factors and for reviewers and readers to use to evaluate papers on this topic. In this paper, we will describe across our experience the main problems encountered in the study of biological prognostic studies. Considering evaluation criteria to be developed in the future, it appears that only multicentric and multidisciplinary structures are able to define decisional trees based on technically and clinically validated parameters in particular patients subgroups. Such a structure exists at the european level ("Receptor Study Group" of the EORTC) and a similar structure has now been created in France to answer these questions.