Socioeconomic disparities in incidence, treatment, and survival of intrahepatic cholangiocarcinoma: insights from a nationwide cohort study in Sweden

Abstract

Background: The incidence of intrahepatic cholangiocarcinoma (iCCA) is rising globally, yet the role of socioeconomic status (SES) in shaping disease burden and care within universal healthcare systems remains poorly understood. This study assessed SES-related disparities in the incidence, treatment, and survival of iCCA in Sweden.

Methods: National registry data were used to identify all adult cases of iCCA diagnosed from 2011 to 2021 (n = 1827). Data from the Swedish quality register for liver cancer were cross-linked with socioeconomic and healthcare registers. Household income- categorised as low (lowest national quartile), medium, or high (highest quartile)-was used as the SES indicator. Incidence rates (IRs), treatment patterns, and survival were analysed across income strata.

Findings: The age-standardized IR increased from 1.35 in 2011 to 1.94 per 100,000 person-years in 2021, with the steepest rise observed among men and individuals with low income. Compared to those with high-income, individuals with low income had higher IR ratios of all-stage (1.32, 95% confidence interval [CI]: 1.15-1.52) and late-stage iCCA (1.46, 95% CI: 1.17-1.81). Preventable liver diseases were more prevalent in the low-income patients, while primary sclerosing cholangitis and inflammatory bowel disease were more common among high-income patients. Low income was associated with lower odds of receiving systemic therapy (adjusted odds ratio 0.54, 95% CI: 0.38-0.77) and higher mortality risk among those treated (adjusted hazard ratio 1.34, 95% CI: 1.09-1.65).

Interpretation: Despite universal healthcare access, substantial socioeconomic disparities persist in the incidence, treatment, and outcomes of iCCA in Sweden.

Funding: The Swedish Cancer Society and The Royal Swedish Academy of Sciences.

Keywords: Inequalities; Intrahepatic cholangiocarcinoma; Socioeconomic status; Survival.

Fig. 1

Age-standardised incidence rates (ASIRs) of intrahepatic cholangiocarcinoma (iCCA) in Sweden between 2011 and 2021. Panel (a) presents ASIRs of all-stage, early-stage and intermediate- or late-stage iCCA across the study period, while panels (b) and (c) present ASIRs for men and women, respectively. Panels (d–f) present ASIRs for individuals with high, medium, and low household income, respectively. Restricted cubic splines were used to fit lines representing changes in the all-stage and stage-specific ASIRs of iCCA during the study period for each individual panel (a–f).

Fig. 2

Age-specific incidence rates (IRs) of intrahepatic cholangiocarcinoma (iCCA) in Sweden between 2011 and 2021. Panel (a) presents IRs of all-stage, early-stage and intermediate- or late-stage iCCA across the study period, while panels (b) and (c) present IRs for men and women, respectively. Panels (d–f) present IRs for individuals with high, medium, and low household income, respectively.

Fig. 3

Associations of the individual level variables sex, country of birth, and household income with incidence rates of all-stage (panel a), early-stage (panel b) and intermediate- or late-stage (panel c) of intrahepatic cholangiocarcinoma (iCCA) among adults (18 years and older) in Sweden between 2011 and 2021. The fully adjusted models included adjustments for age and calendar year, as well as for all included independent variables.

Fig. 4

Results from multivariable Cox regression models showing adjusted hazard ratios for overall mortality in patients with intrahepatic cholangiocarcinoma in Sweden from 2011 to 2021. All models were adjusted for age at diagnosis. Panel (a) presents results for patients treated with surgery, while panels (b), (c), and (d) present results from patients treated with systemic therapy, other palliative treatments, and best supportive care, respectively.