This fourth national monitoring report for Swiss Cancer Screening shows the results of organised mammogra-phy screening in Switzerland for the years 2010-2015, subdivided into two triennial periods, 2010-2012 and 2013-2015, respectively.
The number of regional programmes increased from 7 in 2010 to 10 in 2015, currently covering the geograph-ical area of 12 cantons. In 2015, 56.5 percent of the 50-69 years old women in Switzerland lived in an area covered by a breast cancer screening programme, nearly a doubling of coverage since 2010.
The results in this monitoring report are based on available data from 7 programmes (VD, VS, GE, FR, BEJUNE, SG-GR, TG) in the period 2010-2012 and from 8 programmes (with BE) in the period 2013-2015. The coverage by invitation rate increased from 91% in 2010-2012 to 98% in 2013-2015. Almost 290,000 from the 680,000 eligible women in 2013-2015 attended for screening, resulting in a participation rate of 42.5%. The participa-tion decreased by more than 4% compared to 2010-2012, mainly due to the low participation in the large new programme of Canton of Bern. Similar decreases between the two triennial periods were found in the first round participation (32.9% vs. 38.3%) and in the reattendance of the women who participated in the previous round (81.7% vs. 85.6%). Without Bern, the overall participation rate was stable around 47% and the first round participation around 38-39%. Participation rates are likely slightly underestimated, as some participa-tion records could not be extracted from the new information system MC-SIS.
Prevalent screening in 2013-2015 led to a recall rate (73.0 per 1000 women screened) slightly higher than recommended by the European Guidelines but substantially lower than in 2010-2012 (86.9 per 1000). The main consequence of the reduced recall rate is a substantially lower false-positive rate (67 vs. 80 per 1000). There is a concomitant but less pronounced decrease in breast cancer detection (6.1 vs. 6.9 per 1000) given the slightly increased positive predictive value of the screening examination (8.4% vs. 8.0%). Although the classi-fications of tumour characteristics are partly incomplete, most tumour distribution proportions are in accord-ance with the European Guidelines.