Grant: Operating Grant - Secondary Analysis of Databases

Anti-estrogen therapy (AET) reduces the risk of recurrence and death from breast cancer by up to 30%. To maximize AET benefits, patients must take pills daily for five years. However, many women do not take AET as recommended. Women >=65 years are particularly at risk of not finishing AET therapy. Since close to 40% of new breast cancers are diagnosed in this age group, we need to better understand the challenges in taking AET in older women with breast cancer. Our goal is to describe patterns of adherence to AET in Quebec women with breast cancer >=65 years, and to identify what characteristics predict whether these women take AET as recommended. We will use databases managed by the provincial health insurance agency, which include information on the patient, the doctor, and all medical services received. Since all Quebecers >=65 years participate in the public drug insurance plan, these databases also document all medications dispensed in community pharmacies. As such, we have a unique opportunity to measure adherence to AET in the entire population of breast cancer survivors, and to examine what characteristics predict whether a woman will take AET as prescribed. Characteristics we will examine are: patient age, education, income, health conditions and hospitalizations, treating physician experience with breast cancer, type of surgery, chemotherapy and radiation therapy received, and the number and types of other drugs the patients receive while taking AET. By identifying characteristics that make a woman less likely to take AET as recommended, the information gained from this study will help physicians target counseling and resources to patients who need it most. These results, along with health information technology, will also be used to develop a system to notify physicians immediately when problems in AET adherence occur. This will allow clinicians to direct rapid action in helping patients improve adherence, maximizing breast cancer survival rates.