Background: Organised mammography screening can reduce mortality from breast cancer. A pilot project for organised mammography screening was started in four Norwegian counties in 1995/1996. This paper evaluates the results from the first screening round with focus on early indicators predicting future mortality reduction.
Materials and methods: All women aged 50-69 were offered two-view mammography biennially. The screening examinations were performed in dedicated screening units, and the mammograms were read at breast diagnostic centres located in university hospitals. All test results and information about diagnostic procedures and treatment were reported to The Cancer Registry of Norway and registered in a central screening database. This database was essential in order to monitor and evaluate the pilot project.
Results: 79.5% of the invited women accepted and about 127,000 women were examined. The detection rate was 6.7 cancers per 1,000 women screened. 53.1% of the invasive tumours were less than 15 mm; about one fifth of the patients had axillary lymph node metastasis.
Interpretation: The obtained results met the predefined aims. Thus a future mortality reduction of at least 30% is expected. The parliamentary decision on expanding the pilot project to a nationwide programme seems well founded.