Population-based mammography screening in clinical practice. Results from the prevalence round in Uppsala county.

The results from the prevalence round of a population-based mammography screening program in Uppsala county are presented. We invited 48,517 women aged 40 to 74 years to mammography screening. The age subgroup 40 to 54 years was examined with two-view mammograms, while women in age group 55 to 74 years were offered one-view screening. The number of attending women was 41,761 (86% of those invited), of whom 2,002 (4.8%) were recalled for further examination, and 423 (1.0%) were referred for surgical biopsy. A total of 241 (0.58%) women were diagnosed to have breast cancer. About 1/3 of the cancers were stage 2 or more advanced, but only 20% of the invasive cancers had lymph node metastasis. The median size of an invasive cancer was 16 mm. After age-adjusting the cancer rate, the results indicate that the Swedish two-county study can be duplicated in clinical practice.