Breast Cancer Screening in Denmark

• DOI: 10.7326/m16-0270
• Publication Date: 2017-01-23T21:11:24Z
• Authors: Karsten Juhl Jørg...; Peter C. Gøtzsche; Mette Kalager; Per-Henrik Zahl
• Keywords: Cancer screening

Background: Effective breast cancer screening should detect early-stage and prevent advanced disease. Objective: To assess the association between size of detected tumors to estimate overdiagnosis (detection that would not become clinically relevant). Design: Cohort study. Setting: Denmark from 1980 2010. Participants: Women aged 35 84 years. Intervention: Screening programs offering biennial mammography for women 50 69 years beginning in different regions at times. Measurements: Trends incidence (>20 mm) nonadvanced (≤20 screened nonscreened were measured. Two approaches used amount overdiagnosis: comparing among nonscreening areas; 49, 69, 70 areas. Results: was associated with lower tumors. The increased versus prescreening periods (incidence rate ratio, 1.49 [95% CI, 1.43 1.54]). first estimation approach found 271 invasive 179 ductal carcinoma situ (DCIS) lesions overdiagnosed 2010 (overdiagnosis 24.4% [including DCIS] 14.7% [excluding DCIS]). second approach, which accounted regional differences younger than age, 711 180 cases DCIS 48.3% 38.6% Limitation: Regional complicate interpretation. Conclusion: Breast a reduction cancer. It is likely 1 every 3 diagnosed offered represent increase 48.3%). Primary Funding Source: None.