本研究旨在调查韩国结直肠癌 (CRC) 筛查中基于社会经济地位 (SES) 的不平等。我们评估了机会性和有组织的 CRC 筛查率是否因收入和教育水平而异。我们分析了 2009 年至 2021 年韩国国家癌症筛查调查 (KNCSS) 中 27,654 名年龄 50-74 岁的无癌症个体的数据。使用连接点回归根据平均年百分比变化估计加权癌症筛查率和趋势。基于泊松回归模型，从相对和绝对方面计算不平等。有组织的筛查率从2009年的22.1%显着增加到2020年的53.1%和2021年的50.6%，年均变化为8.6%（95%）置信区间 [CI]，4.9%-12.5%）。相比之下，机会性筛查没有观察到显着趋势。机会性筛查吸收中的 SES 不平等表现为不平等斜率指数 (SII) 为 9.74%（95% CI，6.36%-13.12%），相对不平等指数 (RII) 为 2.18（95% CI，1.75%-） 2.70%）在教育水平方面；就测量收入而言，SII 为 7.03%（95% CI，4.09%-9.98%），RII 为 1.81（95% CI，1.41%-2.31%）。尽管收入不平等有增加的趋势，但在有组织筛查的总体估计中没有观察到显着的社会经济地位不平等。无论社会经济地位如何，有组织的结直肠癌筛查都可以有效提高参与率。然而，机会性筛查中发现了显着的不平等，这表明结直肠癌筛查的整体公平性还有改进的空间。

This study aimed to investigate socioeconomic status (SES)-based inequality in colorectal cancer (CRC) screening in Korea. We assessed whether the rates of opportunistic and organized CRC screening differed according to income and education levels.We analyzed data from the Korean National Cancer Screening Survey (KNCSS) of 27,654 cancer-free individuals, aged 50-74 years, from 2009 to 2021. The weighted cancer screening rates with trends were estimated with the average annual percentage change using joinpoint regression. Inequality was calculated in both relative and absolute terms, based on a Poisson regression model.The organized screening rate increased significantly from 22.1% in 2009 to 53.1% in 2020 and 50.6% in 2021, with an average annual change of 8.6% (95% confidence interval [CI], 4.9%-12.5%). In contrast, no significant trend was observed for opportunistic screening. The SES inequality in opportunistic screening uptake was indicated by a slope index of inequality (SII) of 9.74% (95% CI, 6.36%-13.12%), relative index of inequality (RII) of 2.18 (95% CI, 1.75%-2.70%) in terms of education level; and an SII of 7.03% (95% CI, 4.09%-9.98%), RII of 1.81 (95% CI, 1.41%-2.31%) in terms of measured income. Although there was an increasing trend in income inequality, no significant SES inequalities were observed in the overall estimates for organized screening.Organized CRC screening is effective in improving the participation rate, regardless of SES. However, significant inequalities were found in opportunistic screening, suggesting room for improvement in the overall equity of CRC screening.