Disparities in cancer stage at diagnosis, treatment, and mortality across socioeconomic groups in Finland

Background: Socioeconomic inequalities exist in each cancer-related aspect globally, but the evidences were relatively fragmented and unsystematic, even within high-income countries with more in-depth data. We aim to assess disparities in cancer stage at diagnosis, treatment, and mortality by socioeconomic status (SES) in Finland to assess inequalities in the whole cancer journey. Methods: All Finnish residents aged 30 years or older and newly diagnosed with cancer between 2000 and 2020 were included in this study, and information including date of diagnosis, cancer type, stage, and treatments, was extracted from the Finnish Cancer Registry. Mortality, SES (education and income) and other demographic characteristics was extracted from the Population Register. Odds ratios (OR) of diagnosed with early stage or later stage, and receiving specific treatment or not across SES groups were estimated using adjusted logistic regression models. The differences of mortality in low and high SES groups were shown in hazard ratios (HR) estimated using adjusted Cox models. Finding: Totally 377,986 Finnish residents were newly diagnosed with cancer (191,341 men and 186,645 women) between 2000 and 2020. Systematic disparities were observed in stage at diagnosis, treatment and mortality in overall cancers and subtypes of cancers, such as prostate, breast, melanoma, and uterine cancer. Patients with high education had 10–16% higher probabilities of being diagnosed with early-stage cancer than people with low education for overall cancer types in both men (OR=1.14, 95% CI=1.11–1.16) and women (OR=1.11, 95% CI=1.10–1.13). Patients with high education had 12–18% higher probabilities to receive surgery (men: OR=1.18, 95% CI=1.15–1.20; women: OR=1.18, 95% CI=1.15–1.21) comparing with patients with low education. Patients with high education had consistently around 20% lower mortality comparing to patients with low education for overall cancers (men: HR=0.79, 95% CI=0.77–0.81; women: HR=0.80, 95% CI=0.78–0.82). Similar patterns were observed across groups with different levels of income. Conclusions: Systematic disparities throughout the cancer journey exist across SES groups in Finland, with low SES people often disadvantaged in cancer stage at diagnosis, treatment, and mortality.