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A woman with newly diagnosed breast cancer is deciding on a course of therapy, guided by her physician. Evidence on the average prognosis 1 and effectiveness of therapeutic interventions is available from studies of large groups of patients with breast cancer in observational studies and randomised trials. But the patient and doctor are faced with making a decision in an individual case, where the prognosis and response to treatment may deviate from average. One way to select the optimal treatment is to consider a test that predicts treatment effect, such as the human epidermal growth factor receptor 2 (HER-2) status. 2 The use of HER-2 status in breast cancer management is an example of the translation of results from prognosis research toward improved patient outcomes. The prognosis of breast cancer patients is highly variable, 1 HER-2 was discovered as a prognostic factor, 3 which provided a specific target for an intervention (trastuzumab), which was then evaluated in trials which recruited women with HER-2 positive cancers (see fig 1 ). After the success of these trials in improving clinical outcome, trastuzumab is now given to the subgroup (stratum) of women who are HER-2 positive, but not to those testing negative; 4 this type of approach has been termed stratified medicine.
Fig 1 Example of stratified medicines research, with translation from discovery of human epidermal growth factor receptor 2 (HER-2) status as a prognostic factor for metastatic breast cancer 5 to development of trastuzumab treatment and use in clinical practice. Path element adapted from chart 7.1 in the Cooksey report (2006) (made available for use through the Open Government License)
The aims of this fourth paper in our PROGRESS series ( www.progress-partnership.org ) are to describe the rationale for stratified medicine, and to explain why prognosis research is pivotal for this purpose; from identifying priority areas for stratification, to discovering candidate factors that may predict treatment response, through to trials and health technology assessment that examine the impact of stratified medicine approaches in healthcare. We identify current challenges and deficiencies in such research and make recommendations for improvement with examples across a variety of disease areas.
What is stratified medicine?
Stratified medicine refers to the targetting of treatments (including pharmacological and non-pharmacological interventions) according to the biological...