title: Risk of breast cancer after false-positive results in mammographic screening.
abstract: Women with false-positive results are commonly referred back to routine screening. Questions remain regarding their long-term outcome of breast cancer. We assessed the risk of screen-detected breast cancer in women with false-positive results. We conducted a joint analysis using individual level data from the population-based screening programs in Copenhagen and Funen in Denmark, Norway, and Spain. Overall, 150,383 screened women from Denmark (1991-2008), 612,138 from Norway (1996-2010), and 1,172,572 from Spain (1990-2006) were included. Poisson regression was used to estimate the relative risk (RR) of screen-detected cancer for women with false-positive versus negative results. We analyzed information from 1,935,093 women 50-69 years who underwent 6,094,515 screening exams. During an average 5.8 years of follow-up, 230,609 (11.9%) women received a false-positive result and 27,849 (1.4%) were diagnosed with screen-detected cancer. The adjusted RR of screen-detected cancer after a false-positive result was 2.01 (95% CI: 1.93-2.09). Women who tested false-positive at first screen had a RR of 1.86 (95% CI: 1.77-1.96), whereas those who tested false-positive at third screening had a RR of 2.42 (95% CI: 2.21-2.64). The RR of breast cancer at the screening test after the false-positive result was 3.95 (95% CI: 3.71-4.21), whereas it decreased to 1.25 (95% CI: 1.17-1.34) three or more screens after the false-positive result. Women with false-positive results had a twofold risk of screen-detected breast cancer compared to women with negative tests. The risk remained significantly higher three or more screens after the false-positive result. The increased risk should be considered when discussing stratified screening strategies.
authors.affiliation: Department of screening, Cancer Registry of Norway, Oslo, Norway.|National Advisory Unit for Women's Health, Oslo University Hospital, Oslo, Norway.
authors.forename: Marta
authors.initials: M
authors.lastname: Román
authors.affiliation: Department of Epidemiology and Evaluation, IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain.|Network on Health Services in Chronic Diseases (REDISSEC), Barcelona, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Castells
authors.affiliation: Department of screening, Cancer Registry of Norway, Oslo, Norway.|Oslo and Akershus University College of Applied Sciences, Faculty of Health Science, Oslo, Norway.
authors.forename: Solveig
authors.initials: S
authors.lastname: Hofvind
authors.affiliation: Department of Public Health, University of Copenhagen, Copenhagen, Denmark.
authors.forename: My
authors.initials: M
authors.lastname: von Euler-Chelpin
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000453:epidemiology*; D003718:Denmark; D055088:Early Detection of Cancer; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008327:Mammography; D008403:Mass Screening; D008875:Middle Aged; D009664:Norway; D011159:Population Surveillance; D012306:Risk; D013030:Spain
keywords: Breast neoplasms; false-positive reactions; mammography; mass screening; risk factors