The first international congress uniting European and American oncologists and scientists to discuss cancer screening, diagnosis and follow-up in mentally deficient subjects took place in Montpellier from 5 to 7 February 2014. This congress was the initiative of the Oncodéfi Association in partnership with the Cancéropôle Grand Sud-Ouest (South-West Major Cancer Cluster).

Professor Marie-Odile Réthoré, at the Jérôme-Lejeune Institute, emphasised the fact the "screening is often a laborious process for people who are mentally deficient". The question of early screening for mentally deficient subjects is crucial because their life expectancy can increase. According to Joanne Wilkinson (Boston University): "the mortality rate is twice as high in this population. Some of these deaths are linked to late diagnosis".