Appropriate cytotoxic drug usages in solid tumors: conformity to official labelling and level of scientific evidence

Abstract

The definition of appropriate use of drugs is questioned in oncology. Daily therapeutic practices were compared to official labelling and to published scientific data in this retrospective study. It was carried out in two respective specialised centers, from January to September 2004. All chemotherapies administered for adult solid tumours and including one of the eleven studied drugs were evaluated. The analysis of use was performed by drug : conformity to the validated labelling and level of scientific evidence (at the period study). The study included 1,561 drug uses in 1,211 patients. The overall rate of conformity to official labelling was 81.7 % (67.1 % of strict conformity). In 73.8 % of cases, the indications were supported by at least one randomized phase III trial. The results appeared to be significantly different in rare tumours. The potential economic stake of the "contrat de bon usage" was estimated as less than 5 % in our study. This analysis showed an appropriate and controlled use of onerous drugs in solid tumours. The official labelling of drugs are unable to answer to all clinical situations. The definition of a sufficient level of evidence is mandatory for the use of scientific data in clinical practice. This process has to be adapted for rare tumours.