Disparities in initiating standard first-line cancer treatment and survival for patients with an immigrant background: a Danish register-based cohort study

BACKGROUND AND PURPOSE: Individuals with an immigrant background may face barriers to healthcare. However, evidence on differences in cancer treatment and survival between patients with an immigrant background and patients of Danish origin is limited. PATIENTS AND METHODS: We included patients aged ≥50 years diagnosed with a first primary colon, lung, prostate, or kidney cancer between 2011 and 2022 from national clinical cancer databases. First-line treatment initiation (30/90 days) and survival (1/5 years) were assessed using risk ratios (RRs) comparing patients with an immigrant background to those of Danish origin. Immigrant backgrounds were categorized according to their origin in (1) other Western countries, (2) Central and Eastern Europe, and (3) the Middle East, North Africa, and Central Asia. RESULTS: Overall, there were no systematic differences in the initiation of first-line treatment or survival between patients with an immigrant background and patients of Danish origin. Exceptions included lower probability of initiating treatment (30-day RR: 0.76 [95% confidence interval (CI): 0.62; 0.93] and 90-day RR: 0.92 [95% CI: 0.87; 0.98]) and 1-year risk of death (RR: 0.85 [95% CI: 0.77; 0.93]) among lung cancer patients from Central and Eastern Europe, lower 30-day treatment initiation among patients from the Middle East, North Africa, and Central Asia (RR: 0.80 [95% CI: 0.64; 1.00]), and higher 5-year risk of death among prostate cancer patients from other Western countries (RR: 1.16 [95% CI: 1.01; 1.34]). INTERPRETATION: Overall, patients with an immigrant background had similar initiation of first-line cancer treatment and survival to those of Danish origin, with some statistically significant differences but no consistent pattern across cancer types or regions of origin.