An example of a pragmatic trial in the treatment of basocellular carcinoma of the skin.

A clinical trial is generally defined by a comparison of two or more treatments. This definition encloses two radically different viewpoints: problems of knowledge (explanatory approach) and problems of decision (pragmatic approach). The pragmatic approach is still not used very often; we describe a clinical trial using this approach in order to discuss its advantages and drawbacks; the trial compares radiotherapy and surgery in basal cell carcinoma of the skin. These two techniques are likely to give similar carcinological results, so that the therapeutic decision will have to take into account other criteria such as the aesthetic factor, the fonction and the cost not only in terms of money but also in terms of the psychological burden of the treatment, as side effects, etc. The choice of the weights to be attributed to these various criteria raises a problem, especially since the results of the trial may be different when varying the weights. This prompts a discussion of the possibility of extrapolating the therapeutic choice after the trial.