Background: The overall survival rates among cancer patients have been improving. However, the increase in survival is not uniform across socioeconomic status. Thus, we investigated income disparities in the 5-year survival rate (5YSR) in cancer patients and the temporal trends. Methods: This study used a national cancer cohort from 2002 to 2018 that was established by linking the Korea Central Cancer Registry and the National Health Insurance Service (NHIS) claim database to calculate the cancer survival rate by income level in the Republic of Korea. Survival data were available from 2002 onward, and the analysis was based on the actuarial method. We compared the survival of the earliest available 5-year period of 2002–2006 and the latest available 5-year period of 2014–2018, observing until 31 December 2021. Income level was classified into six categories: Medical Aid beneficiaries and five NHIS subtypes according to insurance premium. The slope index of inequality (SII) and relative index of inequality were used to measure absolute and relative differences in 5YSR by income, respectively. Results: The 5YSR between the 2002–2006 and 2014–2018 periods for all cancers improved. A significant improvement in 5-year survival rates (5YSR) over the study period was observed in lung, liver, and stomach cancer. The SII of survival rates for lung (17.5, 95% confidence interval (CI) 7.0–28.1), liver (15.1, 95% CI 10.9–19.2), stomach (13.9, 95% CI 3.2–24.7), colorectal (11.4, 95% CI 0.9–22.0), and prostate (10.7, 95% CI 2.5–18.8) cancer was significantly higher, implying higher survival rates as income levels increased. The SII for lung, liver, and stomach cancer increased, while that of thyroid, breast, cervical, prostate, and colorectal cancer decreased over the study period. Conclusions: Although substantial improvement in the 5YSR was observed across cancer types and income levels from 2002 to 2018, this increase was not uniformly distributed across income levels. Our study revealed persistent income disparities in the survival of cancer patients, particularly for lung and liver cancer.
背景：癌症患者的总体生存率持续改善，但生存率的提升在不同社会经济地位人群中并不均衡。本研究旨在探讨癌症患者五年生存率（5YSR）的收入差异及其时间变化趋势。方法：本研究通过整合韩国中央癌症登记库与国民健康保险公团（NHIS）理赔数据库，构建了2002年至2018年的全国性癌症队列，用于计算韩国不同收入水平人群的癌症生存率。生存数据自2002年起可获取，分析基于精算方法。我们比较了最早可得的2002-2006年与最近可得的2014-2018年两个五年区间的生存情况，随访截止至2021年12月31日。收入水平分为六类：医疗救助受益者及根据保险费划分的五类NHIS参保类型。采用不平等斜率指数（SII）和相对不平等指数分别衡量不同收入群体间5YSR的绝对差异与相对差异。结果：所有癌症的5YSR在2002-2006年与2014-2018年期间均有所提升。肺癌、肝癌和胃癌的五年生存率在研究期间呈现显著改善。肺癌（17.5，95%置信区间[CI] 7.0-28.1）、肝癌（15.1，95% CI 10.9-19.2）、胃癌（13.9，95% CI 3.2-24.7）、结直肠癌（11.4，95% CI 0.9-22.0）和前列腺癌（10.7，95% CI 2.5-18.8）的SII显著较高，表明生存率随收入水平上升而提高。在研究期间，肺癌、肝癌和胃癌的SII呈上升趋势，而甲状腺癌、乳腺癌、宫颈癌、前列腺癌和结直肠癌的SII则有所下降。结论：尽管2002年至2018年间各类癌症及不同收入水平人群的5YSR均显著改善，但这种增长在不同收入水平间分布不均。本研究揭示了癌症患者生存率持续存在的收入差异，尤其在肺癌和肝癌患者中更为明显。
Disparities in Overall Survival Rates for Cancers across Income Levels in the Republic of Korea
肿瘤(癌症)患者之家