Cancer risk among individuals of migrant origin in Belgium during the 2000s - Evidence of migration as a 'cancer risk transition'?

Recent research has shown a generally lower cancer risk and mortality among migrants from less-industrialised country origin. However, while rates are usually lower for 'lifestyle-related' cancers (e.g. breast, prostate, lung, colorectal), they are typically elevated for 'infection-related' ones such as liver and stomach cancer. Although these observations appear in line with the theory of 'migration as a rapid epidemiological transition', changes in cancer risk after migration have yet to be investigated, effectively testing if migration also entails a 'rapid cancer risk transition'. This study therefore examines cancer risk among migrants in Belgium, focusing on colorectal cancer as a typically lifestyle-related cancer on the one hand, and infection-related cancers on the other hand. We subdivide migrant groups of more and less industrialised country origin according to duration of stay, and calculate absolute and relative incidence rates between 2004 and 2013. Our findings corroborate the transition assumptions for men from Turkey and Morocco, but cannot support them for women. Italian male immigrants have an in-between position: their colorectal cancer risk does not differ from that of Belgian men, but infection-related and non-cardia stomach cancer risks are higher and remain so with longer duration of stay. The fact that rates for migrants from the Netherlands and France generally do not differ from those of Belgians further strengthens support for a cancer transition among male migrants. Further examinations should focus on changes in health-related behaviour that can explain persistently low colorectal cancer risks among Turkish and Moroccan migrants and can inform preventive strategies for other population subgroups. Knowledge about the higher non-cardia stomach cancer risk among Turkish, Moroccan, and Italian men can support early detection strategies by primary care providers when patients present with gastric symptoms, especially because this cancer tends to have unfavourable prognosis.