National breast screening programs for women of average risk are offered in nearly all European countries adhering to standards laid out in the European Guidelines for Quality Assurance in Breast Cancer Screening and Diagnosis. These include 2D mammography as the primary screening modality, double reading, centrally collected and evaluated data, technical quality control, and performance targets. Variations do exist on the ages and risk factors of women invited to participate in routine screening, screening intervals, coverage and supplemental screening modalities utilized.
Opportunistic mammography exists in some countries either as the sole screening system or in addition to the national breast screening program. In opportunistic screening, women are advised by their physician or they decide on their own to have a screening mammogram, and programmatic results are not officially monitored. Screening intervals vary depending on many factors (socioeconomic, breast awareness status etc.). Part of the cost is out of pocket payment or reimbursed by private insurance.