If we assume that screening reduces breast cancer mortality by 15% and that overdiagnosis and overtreatment is at 30%, it means that for every 2000 women invited for screening throughout 10 years, one will avoid dying of breast cancer and 10 healthy women, who would not have been diagnosed if there had not been screening, will be treated unnecessarily. Furthermore, more than 200 women will experience important psychological distress including anxiety and uncertainty for years because of false positive findings. To help ensure that the women are fully informed before they decide whether or not to attend screening, we have written an evidence-based leaflet for lay people that is available in several languages on www.cochrane.dk. Because of substantial advances in treatment and greater breast cancer awareness since the trials were carried out, it is likely that the absolute effect of screening today is smaller than in the trials. Recent observational studies show more overdiagnosis than in the trials and very little or no reduction in the incidence of advanced cancers with screening.
Surgical biopsy of non-palpable mammary lesions. Technique and results.
In a randomized controlled trial with mammographic screening for early detection of breast cancer, 314 non-palpable breast lesions were examined by open biopsy between 1978 and 1983. These biopsies were performed after the lesions had been indicated by the hooked wire technique. In 185 cases the findings turned out to be benign while 129 proved to be malignant. Satisfactory initial biopsies were achieved in 95% of the cases. A model for the management of mammary lesions found in such a screening programme is described and some difficulties are discussed.