Regional disparities in lung cancer surgery and survival in South Korea: a nationwide population-based retrospective cohort study using linked cancer registry and national health insurance data.

Abstract

Background: Lung cancer incidence is rising in South Korea, where cancer care is increasingly concentrated in capital-region hospitals. Whether this centralization improves surgical outcomes for patients residing outside the capital region-or mainly imposes travel and access burdens without a universal survival benefit-remains unresolved. We examined regional patterns of surgical hospital utilization and stage-specific survival among non-capital residents undergoing lung cancer surgery.

Methods: In this nationwide population-based retrospective cohort study, we linked the Korea Central Cancer Registry and the Korean National Health Insurance Service databases to identify adults newly diagnosed with lung cancer (2012-2019). Among 52,521 patients who underwent lung cancer surgery, 27,482 resided in non-capital regions, of whom 13,893 (50.6%) underwent index surgery at capital-region hospitals and 13,589 (49.4%) at non-capital hospitals. Multivariable logistic regression (2017-2019) identified factors associated with capital-region surgery, and Cox proportional hazards models estimated adjusted hazard ratios (aHRs) for 1-, 3-, and 5-year all-cause mortality by stage, hospital type, and histology. Follow-up extended from diagnosis to death or December 31, 2022.

Results: Among non-capital residents, surgery at capital-region hospitals was more frequent among women, younger patients, higher-income groups, and those with fewer comorbidities. The likelihood of capital-region surgery increased with income [highest vs. lowest quintile, adjusted odds ratio (aOR) 4.357; 95% confidence interval (CI), 3.560-5.333] and was higher among urban residents (aOR 2.124; 95% CI, 1.948-2.316) and medical insurance holders versus Medical Aid recipients (aOR 3.064; 95% CI, 2.522-3.772). Survival did not differ by hospital region for localized-stage disease, whereas non-capital hospitals showed higher mortality for regional (3-year aHR 1.219; 95% CI, 1.076-1.382; 5-year aHR 1.188; 95% CI, 1.067-1.322) and distant stages (5-year aHR 1.239; 95% CI, 1.011-1.519).

Conclusions: The survival advantage of capital-region hospitals was not universal but confined to advanced-stage disease, likely reflecting unequal access to systemic therapy, clinical trials, and multidisciplinary care rather than differences in surgical quality. Early-stage lung cancer can be safely managed in regional hospitals with adequate surgical capacity. A stage-specific delivery strategy-strengthening regional early-stage surgery while improving non-capital access to advanced treatment-is needed to ensure equitable cancer care nationwide.