Breast cancer is the most common cancer in women in Sweden, 8000 women are diagnosed annually and 1400 die of the disease. Most breast cancer patients receive adjuvant therap, but many are cured by surgery and for 7-40% the therapy doesn’t work as intended. Body size, genes, and lifestyle jointly regulate hormone and growth factors and inflammation that modulate risk and prognosis. Normal genetic variants are implicated in 20% of inter-individual drug response. Lifestyle such as coffee and smoking can interact with therapies and impact response. There are multiple tumor markers that are not currently used where targeted therapies are available. We use an integrative approach that combines information from host and tumor with registry data for optimal follow-up. We aim to yield evidence-based lifestyle recommendations to be implemented in clinical practice for primary and secondary prevention, and develop predictive tests for improved risk stratification and selection of therapy.