Income inequalities, tumor stage at diagnosis, and treatment in patients with non-small cell lung cancer: A population-based study in the Netherlands

This study investigated the association between income, tumor stage, and treatment in non-small cell lung cancer (NSCLC) patients, stratified by Eastern Cooperative Oncology Group performance status (ECOG-PS). Patients diagnosed with NSCLC between 2017 and 2022 were selected from the Netherlands Cancer Registry (N = 71,025). Median household income at postal code level served as a proxy for income. Logistic regression was used to investigate the association between income, tumor stage at diagnoses and treatment. All analyses were stratified by ECOG-PS (PS0-1 vs. PS2+). Patients with an intermediate or higher income were more likely to be diagnosed with a stage IV tumor compared with those with a lower income. This was seen in patients with PS0-1 (odds ratio [OR]_{intermediate_vs_lower}: 1.13 [95% confidence interval [95% CI]: 1.08–1.18], OR_{higher_vs_lower}: 1.23 [1.18–1.29]) and PS2+ (OR_{intermediate_vs_lower}: 1.19 [1.11–1.27], OR_{higher_vs_lower}: 1.30 [1.19–1.41]). In patients with PS0-1 and a stage II or III tumor, those with an intermediate or higher income more often received a cancer treatment (stage II OR_{intermediate_vs_lower}: 1.47 [1.09–1.99], OR_{higher_vs_lower}: 1.54 [1.13–2.11], stage III OR_{intermediate_vs_lower}: 1.20 [1.03–1.40], OR_{higher_vs_lower}: 1.30 [1.09–1.55]). In patients with PS0-1 and a stage IV tumor, those with an intermediate or higher income more often received immunotherapy (OR_{intermediate_vs_lower}: 1.10 [1.02–1.19], OR_{intermediate_vs_lower}: 1.30 [1.20–1.41]) and systemic treatment (OR_{intermediate_vs_lower}: 1.29 [1.20–1.39], OR_{higher_vs_lower}: 1.50 [1.37–1.63]). The latter was also found in patients with PS2+ (OR_{intermediate_vs_lower}: 1.22 [1.08–1.38], OR_{higher_vs_lower}: 1.42 [1.23–1.64]). We thereby showed that even in a country with a universal healthcare system, large differences can be seen in the treatments of NSCLC patients according to income.