title: Early- and late-onset breast cancer types among women in the United States and Japan.
abstract: BACKGROUND
  Although differences in breast cancer incidence among Occidental and Asian populations are often attributed to variations in environmental exposures and/or lifestyle, fewer studies have systematically examined the effect of age-related variations.
  
  
  METHODS
  To further explore age-related geographic breast cancer variations, we compared age-specific incidence patterns among cases of female invasive breast cancer from the Surveillance, Epidemiology, and End Results (SEER) program and the Osaka Cancer Registry (1978-1997).
  
  
  RESULTS
  In SEER, there were 236,130 Whites, 21,137 Blacks, and 3,304 Japanese-Americans in Hawaii with invasive breast cancer. In Osaka, there were 25,350 cases. Incidence rates per 100,000 woman-years ranged from 87.6 among Whites to 21.8 in Osaka. Age-specific incidence rates increased rapidly until age 50 years for all race/ethnicity groups, and then continued to increase more slowly for Whites, Blacks, and Japanese-Americans in Hawaii but plateaud for Osaka. Age-specific incidence rates in SEER reflected bimodal (early-onset and late-onset) breast cancer populations, whereas Osaka had only an early-onset age distribution. These age-specific differences in incidence among SEER and Osaka persisted after adjustment for calendar-period and birth-cohort effects using age-period-cohort models.
  
  
  CONCLUSIONS
  Results confirm striking age-specific differences among Occidental and native Japanese breast cancer populations, probably due to complex age-related biological and/or environmental variations among Occidental and Asian breast cancer populations.
authors.affiliation: Biostatistics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, 6120 Executive Boulevard, Room 8105, Rockville, MD 20852-7244, USA. matsunora@mail.nih.gov
authors.forename: Rayna K
authors.initials: RK
authors.lastname: Matsuno
authors.forename: William F
authors.initials: WF
authors.lastname: Anderson
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Hideaki
authors.initials: H
authors.lastname: Tsukuma
authors.forename: Ruth M
authors.initials: RM
authors.lastname: Pfeiffer
authors.forename: Ken
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Susan S
authors.initials: SS
authors.lastname: Devesa
authors.forename: Paul H
authors.initials: PH
authors.lastname: Levine
mesh_terms: D000328:Adult; D017677:Age Distribution; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D001213:Asian; D001943:Breast Neoplasms / Q000453:epidemiology / Q000208:ethnology* / Q000209:etiology; D018270:Carcinoma, Ductal, Breast / Q000453:epidemiology / Q000208:ethnology / Q000209:etiology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005006:Ethnicity; D005260:Female; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008875:Middle Aged; D018299:Neoplasms, Ductal, Lobular, and Medullary / Q000453:epidemiology / Q000208:ethnology / Q000209:etiology; D011159:Population Surveillance; D012307:Risk Factors; D018426:SEER Program; D015996:Survival Rate; D014481:United States / Q000453:epidemiology