A cluster randomized controlled trial was performed in Bogotá, Colombia between 2007-2008 to evaluate the effects of an opportunistic (hospital-based) screening program (intervention) vs. usual care (control) in which 26 clinics were randomized to an intervention (N=13) or control arm (N=13). At intervention clinics general practitioners were instructed to perform clinical breast examination (CBE) on all women aged 50-69 years attending clinics for non-breast health related issues, and to refer them for mammographic screening. Physicians from control clinics were not specifically instructed to perform breast-screening or refer women for mammography, but could do so if they thought it appropriate ('usual care'). Women were followed for 2 years post-randomization.
Female Aged 50-69 Resident in Bogotá, Colombia or surrounding cities; Had not had a mammogram in the previous two years; No history of breast cancer Attending health-centers for reasons unrelated to breast health
