Table 1

Design summary of the three-component evaluation of the effect of offering organized mammography screening 1986–1998 to an annual average of 80,799 female health-plan enrollees ages ≥40 years

1. Mammography diffusionHealth-plan women enrolled each year 1986–1998Mammography use (screening or diagnostic) at least once before the index year (ever)
Ages 40–49 or 50+
Residents of five counties of WAa,bReceipt of mammography within the previous 2 years
2. Rates of late-stage diseaseCommunity women in five counties of WAFive year age-adjusted late-stage (SEER regional or distant stage) breast cancer rates by age group 40–49 or 50+
Health-plan women in the five counties of WA
3. Modeled odds of late-stage diseaseHealth-plan women ages 43–79 with invasive breast cancer (SEER regional or distant stage) diagnosed 1995–1998Odds of late-stage disease as a function of:
 (a) BCSP enrollment and BCSP mammography use (0, 1+)
Health-plan women ages 43–79 with invasive breast cancer (SEER local stage) diagnosed 1995–1998 (b) Total screening mammography use (0–1, 2+)
 (c) BCSP screening mammography use (0–1, 2+)
Health-plan women ages 43–79 frequency-matched to late-stage cases on age and length of health plan enrollment
  • a Five counties in Washington State: King, Pierce, Snohomish, Thurston, and Kitsap.

  • b WA, Washington State; SEER, Surveillance Epidemiology and End Results Reporting; BCSP, (Group Health Cooperative’s) Breast Cancer Screening Program.