Cancer incidence in first-generation migrants and host populations in seven European registries, including Ukrainian-born migrants in Poland: a population-based study

Background: Where people are born shapes their cancer risk, yet European cancer surveillance rarely records migration background. We estimated cancer incidence in first-generation migrants and assessed whether birth-country incidence stratifies their cancer risk. Methods: We harmonised data from six population-based cancer registries in Belgium, the Netherlands, Spain (Murcia, Tarragona), Italy (Turin), and Switzerland (Ticino) for 2003 to 2017, examining breast, colorectal, cervical, stomach, liver, and lung cancer in first-generation migrants and host populations. Countries of birth were grouped into quartiles of GLOBOCAN age-standardised incidence by cancer site and sex (birth-country incidence categories). We estimated cumulative risks (CR) and migrant-to-host cumulative risk ratios (CRR). Ukrainian-born migrants in Poland were analysed separately for 2022 and 2023. Findings: The cancer risk among individuals with a migration background increased with birth-country incidence for cervical, stomach, and liver cancer. For cervical cancer, CRR rose from close to 1 in migrants from low-incidence countries to 4,9 (95% CI 3,5-6,9) in those from high-incidence countries in Turin. Breast and colorectal cancer diagnosis risk was lower than in host populations in every category. Across the six cancers combined, migrants had lower risk in 9 of 11 registry and sex strata, as lower breast, colorectal, and lung cancer risk outweighed higher cervical, stomach, and liver cancer risk. Ukrainian-born migrants in Poland (n=4450) had higher CR at most anatomical sites than the host population. Interpretation: The cancer risk among individuals with a migration background relative to host populations depends on country of birth and cancer site. Birth-country incidence is a useful way of grouping migrants by risk. National averages can mask residual risk in subgroups, e.g. migrants born in high-incidence countries had up to five times the cervical cancer risk of host populations with rates near or below the WHO elimination threshold. Routine recording of country of birth can support risk-tailored prevention and cancer service planning for displaced populations.