Behandling af primær cancer mammae: Konsekvenser af mammografiscreening i Københavns Kommune

In order to analyse changes in the pattern of primary treatment of breast cancer after introduction of mammography screening in the Copenhagen municipal area every second year, retrospective analyses of data from the Danish Breast Cancer Cooperative Group were performed. Newly diagnosed patients with breast cancer of the age of 50-69 years from the Copenhagen municipal area (1040 patients) were compared to a similar group of patients from the rest of Denmark (7353 patients). Parameters such as tumour size, lymphnode status, grade of anaplasia, frequency of breast preserving surgery and adjuvant treatment were analysed. Introduction of mammography screening resulted in almost a doubling of newly diagnosed patients with invasive breast cancer during the prevalence phase, and a significant increase in the number of patients with tumour size ≤l cm without metastases to the axillary nodes. The frequency of breast preserving surgery increased from 5 to 45% in the municipality of Copenhagen compared to 6 to 19% in the rest of the country. Ratio between low-risk versus high-risk patients increased from 1.0 before screening to 2.7 in the following prevalence phase and 2.5 in the first year of the subsequent incidence phase, while the ratio in the rest of Denmark was the same throughout the whole study period. It can be concluded that the introduction of mammography screening resulted in significant changes in the treatment pattern of patients with primary breast cancer.