title: Risk of breast cancer and changes in mammographic parenchymal patterns over time.
abstract: The relationship between sequential mammographic parenchymal patterns and breast cancer was estimated and the results were applied to selective screening. In a pilot screening program 4163 Finnish women aged 40-47 years at entry were invited to be screened every second year from 1982 to 1990. Mammographic parenchymal patterns (Wolfe's classification) were recorded at each screening round. The follow-up ended in 1993 and up until that time 68 new breast cancers were diagnosed. The age-adjusted relative risk of breast cancer was 2.5 (95% CI 1.5-4.0) among women with high-risk mammographic parenchymal patterns (P2,DY) at the screenings preceding cancer diagnosis compared with those with low-risk patterns (N1,P1). After further adjustment for body mass index, number of pregnancies and size of the breast, the relative risk increased to 2.8 (95% CI 1.7-4.9). The mammographic parenchymal pattern is an independent risk factor of breast cancer but not strong enough to be used as a criterion for selective screening.
authors.affiliation: Tampere School of Public Health, University of Tampere, Finland. cstisa@uta.fi
authors.forename: T M
authors.initials: TM
authors.lastname: Salminen
authors.forename: I E
authors.initials: IE
authors.lastname: Saarenmaa
authors.forename: M M
authors.initials: MM
authors.lastname: Heikkilä
authors.forename: M
authors.initials: M
authors.lastname: Hakama
mesh_terms: D000328:Adult; D000367:Age Factors; D001940:Breast / Q000033:anatomy & histology; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000473:pathology; D004848:Epithelium / Q000033:anatomy & histology; D005260:Female; D006801:Humans; D008327:Mammography; D008875:Middle Aged; D010865:Pilot Projects; D012307:Risk Factors