Personalized cancer care, for breast cancer patients in particular, is one of the priority programs of the University Medical Centre Utrecht (UMCU). Researchers of the Cancer Epidemiology group of the Julius Centre for Health Sciences and Primary Care, a division of the UMCU, play a key role in this programme and in the UMCU Cancer Centre. The research focus of this group of twenty researchers is on the prevention, early detection and diagnosis of breast cancer. Researchers of this group have been involved in the set-up and evaluation of one of the first breast cancer screening programs in the Netherlands (1975) and within this framework there is a consolidated research line on breast density for over 10 years now. The Cancer Epidemiology group is closely collaborating with the Radiology Department of the UMCU. Together they coordinate the DENSE (Dense tissue and Early breast Neoplasm ScrEening) trial, a large multicentre randomized controlled trial (>30,000 women) investigating the additional value of MRI for women with extremely dense breasts in in the population based breast cancer screening program in the Netherlands.