Socioeconomic disparities in treatment and survival of oesophageal and gastric cancer in the Netherlands: a nationwide population-based study.

Background: In the Netherlands, all inhabitants are required to have health insurance that covers standard medical care. While this regulated system aims to ensure equal access, recent evidence suggests that socioeconomic status (SES) disparities still exist. This study investigates SES-related differences in treatment and survival among patients with gastric or oesophageal cancer. Methods: This nationwide population-based study included gastroesophageal cancer patients diagnosed in 2015-2022. Patients were stratified into three SES-groups using median disposable household income per postal code area, an additional stratification was performed by histological subtype. Multivariable logistic regression was used to assess the likelihood of receiving specific treatments for different tumour types. Age-standardized relative survival was calculated as the ratio of observed survival to expected survival based on age, sex, calendar year, and median household income group in the general population. Findings: In total, 30,184 gastroesophageal cancer patients were categorized. In curable gastric cancer, patients with middle income had a significantly higher likelihood of receiving surgery compared to low income (OR 1.48 (95% CI 1.21-1.80), p < 0.001). For oesophageal cancer, both middle- (OR 1.17 (95% CI 1.05-1.30), p < 0.001) and high-income patients (OR 1.27 (95% CI 1.13-1.43), p < 0.001) were more likely to undergo surgery than those with low income. In palliative settings, middle- and high-income patients were also more likely to receive systemic therapy, in oesophageal cancer (OR 1.38 (95% CI 1.21-1.57), p < 0.001; OR 1.53 (95% CI 1.34-1.74), p < 0.001) and in gastric for high income (OR 1.27 (95% CI 1.05-1.55), p = 0.014). Relative survival analyses further demonstrated that middle- and high-income groups consistently had higher median, and 5-year survival compared to the low-income group. Interpretation: Despite universal health insurance, socioeconomic disparities in treatment and survival of gastroesophageal cancer patients persist in the Netherlands, reflecting not inequitable access but broader life-course health disparities that influence treatment fitness and outcomes. These findings highlight the need to address broader social and systemic determinants to improve equity in cancer care, in the Netherlands and globally. Funding: This study received no funding.