Ageing and Out-of-Region Cancer Care in South Korea: Determinants and Age-Group Treatment Effects

Background

As South Korea enters a super-aged society, understanding how ageing affects out-of-region cancer care is essential. We examined factors associated with out-of-region care after cancer diagnosis and estimated the effect of age group.

Methods

We used the Cancer Public Library Database linking National Health Insurance Service claims with the national cancer registry. Out-of-region care was defined as inpatient or outpatient cancer claims within 1 year after incidence, where the patient’s residence area differed from the treating institution’s area. Logistic regression identified associated factors, and doubly robust estimation estimated average treatment effects by age group.

Results

Out-of-region care decreased with age. Logistic regression showed lower odds in older age groups, while female sex, advanced stage, and pancreas, liver, gallbladder, lung, prostate, and kidney cancer were associated with higher odds than thyroid cancer. Regional disparities were marked outside Seoul, whereas lower income, disability, and larger household size were associated with lower odds. Doubly robust estimation showed a clear age gradient. Non-elderly patients had a higher probability of out-of-region care than elderly patients across most cancer sites, with large effects for pancreas, gallbladder, lung, liver, and brain/CNS cancer. Within the elderly population, utilization was highest in the young-old and lowest in the oldest-old. The average treatment effect was 0.068 for young-old vs old-old, 0.124 for young-old vs oldest-old, and 0.064 for old-old vs oldest-old.

Conclusions

Ageing was associated with lower out-of-region cancer care, with heterogeneity by cancer site and residence. Policies should strengthen regional cancer care capacity and age-responsive care pathways.

Key messages

• Out-of-region cancer care in South Korea declines with age, with the lowest use among the oldest-old and substantial variation by cancer site.

• Regional cancer policy should strengthen local care capacity and age-responsive pathways to reduce access gaps in a super-aged society.