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Cancer drugs: often insufficiently evaluated

Evaluation of a drug’s effectiveness must be based on rigorous and reliable data relating to clinical outcome that are tangible for patients. In the field of oncology, there is much room for improvement.

The quality of clinical trials carried out in the field of oncology is often inadequate. Only 7% of marketing authorisations for cancer drugs are based on trials whose main aim is to evaluate the length of the patient’s survival period, which is, in many cases, the benefit patients are hoping for.

In practice, all too often the criteria for measuring effectiveness are heterogeneous and there is no correlation between a favourable evaluation based on these criteria and a prolongation of the patients’ life or an improvement in the overall length of survival.

Paradoxical results have even been observed, where there is improved survival with no aggravation of the cancer but a shorter overall survival period.

Furthermore, in trials on cancer drugs the study of adverse effects is also frequently imprecise. Many trials are never published in detail and numerous severe adverse effects are omitted in publications.

In short, improvements need to be made in order to take better account of patients’ real interests in the evaluation of cancer drugs.

©Prescrire September 2009

Source: "Effets des anticancéreux sur la durée de survie : souvent mal évalués" Rev Prescrire 2009; 29 (305): 218-221.
"Effects of cancer drugs on survival: often poorly evaluated" Prescrire Int 2009; 18 (102): 180-183.

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