BACKGROUND AND AIMS

To measure the impact of socio-economic environment on the incidence of hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA).

METHOD

The study used data from the French Network of Cancer Registries (FRANCIM) between 2006 and 2016. Classification of patients into HCC and iCCA was performed according to the topographical and morphological codes of the 3rd edition of the International Classification of Diseases for Oncology. Patient addresses were geolocalized and assigned to an IRIS, the smallest French geographic unit. Socio-economic environment was assessed by the European Deprivation Index (EDI). Sex- and age-standardized incidence rates with 95% confidence intervals (CI) were estimated per 100 000 inhabitants, by national quintiles, for each IRIS, sex and age group. Quintile 1 (Q1) characterized the most affluent areas. A Poisson regression was performed to model the impact of deprivation.

RESULTS

We included 22 249 cases (79.64% HCC, 16.97% iCCA). Incidence rates were 11.46 and 2.39 per 100 000 person-years for HCC and iCCA, respectively. There was an over-incidence of HCC in quintiles 2, 3, 4 and 5 compared to quintile 1: Q1 10.28 [9.9-10.66] per 100 000 person-years, Q2 11.43 [10.48-12.47] (p < .0001), Q3 11.81 [10.82-12.89] (p < .0001), Q4 12.26 [11.25-13.37] (p < .001) and Q5 11.53 [10.57-12.57] (p < .0001). By contrast, there was no difference for iCCa. Deprivation was significantly associated with HCC in men (p = .0018) and women (p = .0009), but not with iCCA (p = .7407).

CONCLUSION

The incidence of HCC is related to socio-economic environment, unlike iCCA. HCC and iCCA should be studied separately in epidemiological studies.