A study to see how genes affect response to the hormone therapy letrozole in women with advanced breast cancer

This study was looking at blood and tissue samples and linking them to side effects and treatment outcome in women taking the hormone therapy letrozole (Femara) for advanced breast cancer.

People respond to medication in different ways. For example, the same cancer treatment may cause side effects in one person, such as sickness, but not in another. Or someone having a particular drug may have a better outcome than someone else taking the same drug for the same type of cancer. We know from research that the inherited instructions in our cells (our genes) affect how we respond to treatment.

Researchers had already developed tests to help doctors tell in advance how people will respond to cancer treatment. In this study, researchers wanted to test how useful these methods were in predicting side effects and treatment outcome in different people. They studied blood and tissue samples of women taking the hormone therapy letrozole for advanced breast cancer. They also found out more about the side effects and treatment results they had. The main aims of this study were to

• Identify genes which may help predict which treatment works best for different people, and who will get side effects

• Find out the costs involved in introducing tests to predict treatment outcome in different people