Medicine Quality of breast cancer screening not equally good in all cantons

The quality of breast cancer screening programs in Switzerland varies from canton to canton. Nevertheless, according to a study published on Tuesday, the results are in line with the European standard.

14 cantons invite all women between the ages of 50 and 69 (50 to 74 in 9 cantons) to a mammography screening every two years. Screening can also take place outside of a public health program, through so-called opportunistic screening, which is the only option in the twelve cantons without a public program.

The results of these programs have been regularly monitored since 2010 to ensure quality. The study published on Tuesday by the University Center for General Medicine and Public Health (Unisanté) in Lausanne was conducted on behalf of the Swiss Cancer Screening Association.

The study is based on three million anonymized data sets of screening tests carried out in ten programmes in 14 cantons (VD, VS, GE, FR, BE-JU-NE, TG, SG-GR, BE-SO, BS, TI).

The report focused mainly on women aged 50 to 69. In addition, the period between 2019 and 2021 was compared with previous periods for this 6th monitoring, as Unisanté stated in a press release on Tuesday.

Differences in quality

Among other things, the analysis revealed persistent differences in the quality of screening between the programs. The risk of a woman receiving a false positive result during her first screening can triple (from 6 to 17.4 per 1000 women screened), depending on the canton in which she has her mammogram.

In the screenings that followed every two years, the interpretations of the images became more homogeneous and stable overall. The comparison with the previous X-ray examination facilitated the diagnosis. According to the study, the reasons for the observed differences between the various programs are not clear.

Good effectiveness

On average, cancer was detected in seven out of 1000 women who participated in screening for the first time. According to Unisanté, the benefits of early detection are generally greater if a woman regularly participates in screening. Another encouraging result is that more than 70 percent of breast cancers are detected at an early stage.

Breast cancer is the most common cancer in women. In Switzerland, around 6500 women are affected every year. 80 percent of them are aged 50 or older at the time of diagnosis.