Improving breast cancer screening through geomedicine

The red dots show where women who have not had a mammogram live. © EPFL-LASIG

The red dots show where women who have not had a mammogram live. © EPFL-LASIG

A joint study carried out by Geneva University Hospitals (HUG) and EPFL has shown that breast cancer early-detection efforts are not reaching entire neighborhoods in Geneva. The emerging field of geomedicine played a key role in this research.

In Switzerland, breast cancer currently afflicts some 90,000 women and causes 1,400 deaths every year. The best way to protect against this disease is through early detection, but not all women undergo the same level of screening – and it turns out that the neighborhood in which they live has something to do with it.

That's the finding of a recent study by Geneva University Hospitals (HUG) and EPFL that looked at 5,002 women between the ages of 50 and 74 living in Geneva. The researchers, applying spatial analysis to public health data, created a map that shows the relationship between geography and participation in Geneva Canton’s early-detection program. The data used to generate the map – including where the women live, their income and their level of education – were collected by the HUG’s Bus Santé (health bus).

The study found that 12% of the women surveyed have never had a mammogram, and that most of these women live in the same neighborhoods. The map therefore shows that early-detection efforts do not reach some parts of the city – and probably haven’t for a number of years.

Better prevention

The aim of the study is to help breast cancer prevention groups better target their campaigns. It is based on a research collaboration between Idris Guessous, primary care director at HUG, and Stéphane Joost, a research and teaching associate at EPFL’s Laboratory of Geographic Information Systems (LASIG). Guessous and Joost also co-wrote the article that has just appeared in Cancer Medicine.

The Geneva neighborhoods where women are least likely to be screened for breast cancer are Rive Droite, the city center, Meyrin, Onex and Jonction. The researchers attribute this to socioeconomic factors, as these neighborhoods are less well-off than the city’s Rive Gauche and their residents are not as well educated. The study also shows that women who live in the same neighborhood tend to influence each other’s behavior. The researchers discovered that residents’ distance from a mammogram center was not a factor in mammography adherence.

Previous research

Guessous and Joost have also set up the GIRAPH (Geographic Information Research and Analysis in Population Health) Lab. Scientists at this lab collate environmental, spatial and health data in an effort to learn more about the causes and mechanisms underlying diseases, particularly in urban areas. The same geomedicine-based approach was used in two other recent studies in Switzerland: a joint study on the spatial dependence of body weight in Lausanne, published in 2016 in the British Medical Journal Open, and a study on the quality of sleep among Lausanne residents, appearing in June 2018 in the International Journal of Hygiene and Environmental Health.