Income-based disparities in the risk of distant-stage cervical cancer and 5-year mortality after the introduction of a National Cancer Screening Program in Korea

OBJECTIVES This study assessed the socioeconomic gradient in the risk of distant-stage cervical cancer (CC) at presentation and 5-year mortality for new CC patients after the introduction of a national Cancer Screening Program (NCSP) in Korea. METHODS All new CC cases from 2007 to 2017 were retrieved from the Korea Central Cancer Registry database linked with the National Health Information Database of the National Health Insurance Service. The age-standardized cumulative incidence of CC, adjusted odds ratios (ORs) of distant metastasis at presentation, and adjusted all-cause mortality hazard ratios (HRs) within 5 years post-diagnosis were assessed according to the income gradient. RESULTS The 11-year age-standardized cumulative incidence of CC ranged from 48.9 to 381.5 per 100,000 women, with the richest quintile having the highest incidence. Of 31,391 new cases, 8.6% had distant metastasis on presentation, which was most frequent among Medical Aid beneficiaries (9.9%). Distant-stage CC was more likely when the income level was lower (OR, 1.46; 95% confidence interval [CI]), 1.28 to 1.67 for the lowest compared to the richest) and among Medical Aid beneficiaries (OR, 1.50; 95% CI, 1.24 to 1.82). The 5-year mortality was greater in the lower-income quintiles and Medical Aid beneficiaries than in the richest quintile. CONCLUSIONS The incidence of CC was higher in the richest quintile than in the lower income quintiles, while the risk of distant-stage CC and mortality was higher for women in lower income quintiles in the context of the NCSP. A more focused approach is needed to further alleviate disparities in the timely diagnosis and treatment of CC