The Korean National Cancer Screening Program (KNCSP) addresses prevalent cancers; however, there is a lack of comprehensive understanding regarding municipal-level disparities in screening engagement and spatial patterns. This study aimed to analyze the associations between municipal health metrics and cancer screening participation rates, and to assess whether spatial clustering persisted even after adjusting for these metrics. We calculated screening rates for stomach, colorectal, liver, breast, and cervical cancers using a customized National Health Insurance Service (NHIS) KNCSP database. The final source populations included 21,879,658 individuals in 2018 and 21,477,470 individuals in 2022. We linked 10 municipal indicators from the Korean Community Health Status Indicators (K-CHSI) database to cancer screening rates for 2018 and 2022. We evaluated the unadjusted correlation between the screening rate and municipal indicators and estimated the adjusted associations using a weighted regression model. Residual Local Indicators of Spatial Association (LISA) were employed to identify clusters of municipalities with higher or lower participation and to detect emerging spots. In 2018, the screening rate was highest for breast cancer (77.6

Introduction:Gastric cancer (GC) remains a major public health concern in Asia. Risk prediction tailored to regional biological features such as Helicobacter pylori (H. pylori) status and high-risk mucosal findings such as atrophic gastritis (AG) and intestinal metaplasia (IM) may help improve the screening workflow. Methods:Using a large, real-world, nationwide screening cohort with available endoscopic AG/IM codes, we developed 2-year GC risk prediction models that integrate AG/IM with regional demographic and lifestyle factors. We compared a conventional Cox proportional hazards model (CPHM) with the following machine learning (ML) approaches: extreme gradient boosting (XGBoost), decision tree (DT), and logistic regression (LR). Discrimination and calibration were evaluated through internal and external validations. Model interpretability was assessed using Shapley Additive Explanations (SHAP). Results:The XGBoost model demonstrated the best overall performance, achieving an AUROC of 0.764 (95% CI, 0.755-0.767), a sensitivity of 0.607 (95% CI, 0.560-0.650), and a specificity of 0.746 (95% CI, 0.744-0.750) in the internal validation. In the external validation cohort, XGBoost also showed the highest discrimination with an AUROC of 0.708 (95% CI, 0.682-0.884), a sensitivity of 0.666 (95% CI, 0.470-0.830), and a specificity of 0.597 (95% CI, 0.590-0.600). SHAP analysis consistently identified Helicobacter pylori infection, age, sex, smoking, and atrophic gastritis/intestinal metaplasia (AG/IM) as the major contributors to increased predicted gastric cancer risk. Discussion:This externally validated and interpretable short-term GC risk model incorporating endoscopically ascertained AG/IM could provide a practical approach for informing risk-adapted screening workflows. The model could help identify individuals at a higher predicted risk for prospective evaluation and closer clinical review. In addition, SHAP clarifies the main contributors to each prediction by highlighting factors most strongly associated with a higher predicted risk.

Cervical cancer is a largely preventable and controllable disease. Social perceptions regarding sexual experiences and gynecological visits contribute to stigma, which serves as a major barrier to screening and human papillomavirus vaccination. This study explored how stigma is formed and reinforced within sociocultural norms and personal psychological barriers. Focus group interviews were conducted with 14 Korean women aged 20-29 years, divided into screeners and non-screener groups, on November 23, 2024. Based on the transcriptions, Thematic analysis was performed on the transcripts to organize codes into core themes,(in compliance with qualitative research reporting standards). A total of 28 codes were grouped into 10 sub-themes and classified by group. Among them, three sub-themes were common to both screeners and non-screeners, including negative perceptions of gynecological visits, stigma associated with sexually transmitted diseases, and barriers due to a lack of information. Among screeners, four sub-themes were identified: a desire for alternative notification methods for screening, psychological barriers to screening, a sense of burden from additional tests during visits, and reluctance to share screening experiences due to perceived prejudice from others. Among non-screeners, three sub-themes were identified: stigma toward patients with cervical cancer and lack of awareness of the sensitivity of cervical cancer. To promote cervical cancer preventive behaviors, stigma must be addressed as a social process rather than solely an individual issue. Practical solutions include creating a predictable screening environment (e.g., prior notification of procedures and additional tests with consent), improving patient-centered care, and enhancing notification methods. This study provides a foundation for developing stigma-related indicators and designing follow-up studies. (e.g., individual interviews/large-scale surveys).

BACKGROUND:Evidence of gastric cancer (GC) screening's impact on GC incidence remains limited. In 2002, South Korea started a nationwide GC screening program. This study uses a quasi-experimental design to evaluate the effect of the program on GC incidence in Seoul. METHODS:Using a flexible synthetic control method (SCM), we estimated the impact of GC screening on age-standardized GC incidence in Seoul. Annual age-specific GC incidence data were obtained from the Seoul Cancer Registry and Cancer Incidence in Five Continents Plus database. Post-intervention trends in GC incidence between Seoul and the synthetic control were compared to estimate average rate ratios (RRs) with 95% confidence intervals (CIs). Several sensitivity and alternative analyses were performed, including a modified age-period-cohort (APC) analysis. RESULTS:The screening program was associated with a higher GC incidence in Seoul compared to the synthetic control, with an average post-intervention RR of 1.11 (95% CI: 0.99-1.24). After 2002, the start of the screening program, there was a noticeable increase in the post-intervention differences between Seoul and the synthetic control, which peaked in 2011 (RR 1.26), and then began to fall. The results were robust across sensitivity analyses and alternative analyses. The modified APC analysis indicated that after initially expanding and then diminishing, the effect eventually reversed, resulting in a reduction in incidence. CONCLUSIONS:These findings suggest that healthcare sectors should anticipate an immediate increase in care demands following GC screening implementation. While a subsequent reduction in GC incidence is expected, the potential preventive impact remains inconclusive.

Purpose This study aimed to develop the 2025 update to the Korean colorectal cancer (CRC) screening guidelines by systematically assessing recent evidence, integrating domestic data, and addressing changes since the 2015 guideline revision, and accordingly, provide an evidence-based standard for clinicians and policymakers.Materials and Methods A multidisciplinary committee developed the guidelines using the Grading of Recommendations, Assessment, Development and Evaluation methodology. The process involved establishing three key questions focused on efficacy, accuracy, and optimal age and interval for screening. A systematic review of international guidelines and primary literature (327 studies included) was conducted. A utility-based analysis using the Markov model was also performed to determine optimal screening ages and intervals.Results The review identified high-certainty evidence for fecal immunochemical test (FIT) in reducing CRC mortality and moderatecertainty evidence for colonoscopy. Evidence for computed tomography colonography (CTC) and stool DNA testing showed very low certainty. Based on this synthesis and cost-utility analysis, the committee conditionally recommends screening for asymptomatic, average-risk adults aged 45-74 years using either colonoscopy every 10 years or FIT every 1-2 years. CTC and stool DNA testing were not recommended owing to insufficient evidence.Conclusion The 2025 Korean Guidelines for Colorectal Cancer Screening provide the latest evidence-based recommendations tailored to the domestic context. By conditionally adopting both colonoscopy and FIT for individuals aged 45-74 years, these guidelines aim to optimize public health outcomes and reduce the colorectal cancer burden in South Korea.

INTRODUCTION:Since the early 2000s, South Korea has implemented tobacco control policies; however, smoking behaviors have not been sufficiently evaluated through age-period-cohort analysis. METHODS:A hierarchical age-period-cohort model was applied to two nationwide surveys, including socioeconomic and lifestyle factors. Age was defined at participation, period as survey year, and cohort as birth year. Current smoking prevalence was analyzed among 54 917 men and 69 551 women aged 12-80 years from the Korea National Health and Nutrition Examination Survey I-VIII (1998, 2001, 2005, and 2007-2023). Cigarettes per day (CPD) were assessed among 518 786 male and 44 410 female smokers aged 19-80 from the Korea Community Health Survey 2008-2022. RESULTS:Smoking prevalence declined after the age of the early 20s and early 40s among men and women, respectively. Among men, the cohort effect on smoking prevalence stagnated starting with the 1980s birth cohort, whereas in women, a decline was observed from the 1990s birth cohort onward. Disparities in smoking widened, particularly among individuals with lower education levels or current drinkers (p for interaction <.001). CPD exhibited an inverted U-shape, peaking in the late 40s, with minimal variation (<1 CPD) among women. After the coronavirus disease-2019 pandemic, CPD increased only among women (p < .001), while cohort effects on CPD were not significant. CONCLUSIONS:The decline in smoking prevalence stagnated, with widening disparities by educational attainment, marital status, and alcohol consumption. Policies should address these disparities and include sex-specific strategies to accelerate smoking reduction. IMPLICATIONS:This study highlights the stagnation in the decline of smoking prevalence in South Korea, particularly among recent birth cohorts with lower educational attainment and current alcohol consumption. Notably, an increase in cigarette consumption following the coronavirus disease-2019 pandemic was observed only among women. These findings underscore the importance of implementing gender-responsive and equity-oriented tobacco control policies that address behavioral and socioeconomic disparities to sustain progress in smoking reduction.

Background/Objectives: Patients with hypertension or diabetes often share common risk factors for both cardiovascular diseases and cancer. Although health knowledge is associated with preventive health behaviors, the association between knowledge of stroke and myocardial infarction (MI) symptoms and cancer screening participation remains poorly understood. Methods: This cross-sectional study analyzed data from the 2023 Community Health Survey, including 45,949 adults with hypertension and 20,357 with diabetes aged ≥40 years. Multivariate logistic regression was used to examine the association between knowledge of stroke and MI symptoms and cancer screening participation. Subgroup analyses were conducted according to age and sex. Results: Among patients with hypertension, knowledge of stroke and MI symptoms was significantly associated with higher odds of undergoing cancer screening. Similar associations were observed among patients with diabetes for stroke and MI symptom knowledge. Subgroup analysis revealed that the association for stroke knowledge was significantly more pronounced among adults aged 40–59 years with hypertension, while remaining age and sex subgroup variations were exploratory. Conclusions: Knowledge of stroke and MI symptoms was associated with participation in cancer screening among adults with hypertension and diabetes. These findings suggest that knowledge of cardiovascular symptoms may reflect overall engagement in preventive health behaviors, including cancer screening.

It remains unclear whether the associations of perceived benefits, cost burden, and sociodemographic factors are consistent across Pap smear and HPV DNA testing, two complementary approaches to cervical cancer prevention. This study therefore aims to examine whether the associations of perceived benefits and cost burden differ across two screening methods (Pap smear and HPV DNA testing), and whether the associations between key factors (perceived benefits, cost burden, and socioeconomic status) and cervical cancer screening vary by regular physician status. Data were collected from the 2023 Korean National Cancer Screening Survey (N = 2716). Higher perceived benefits were significantly associated with higher odds of Pap smear uptake (aOR = 1.90, 95% CI 1.55–2.33), whereas the association with HPV DNA testing was not significant after adjusting for covariates. Cost burden was not significantly associated with either Pap smear or HPV DNA testing. Associations between perceived benefits and Pap smear use were robust across unweighted and weighted models, regardless of regular physician status. Age, marital status, and private health insurance were associated with higher odds of Pap smear uptake among women without a regular physician, whereas these associations were weaker or non-significant among those with a regular physician. The findings suggest that having a regular physician may play an important role in mitigating sociodemographic inequalities in cervical cancer screening among Korean women.

Helicobacter pylori (H. pylori) screening reduces the incidence and mortality of gastric cancer (GC). This study evaluated the cost-effectiveness of incorporating H. pylori screening into the Korean National Gastric Cancer Screening Program. A Markov model was developed to evaluate the cost-effectiveness of adding H. pylori screening to the existing national endoscopic screening program. The model simulated a virtual cohort of individuals aged ≥ 40 years and compared the current biennial endoscopy-only strategy (S1) with eight intervention strategies involving one-time or repeated H. pylori eradication at varying ages and intervals. Sensitivity analyses were performed to test the robustness of the results. All intervention strategies resulted in higher QALYs and costs than S1. H. pylori screening at age 40 (S2) was the most cost-effective (ICUR = 3,892,429 KRW/QALY). Other cost-effective strategies included H. pylori screening at ages 40 and 50 years (S5), every 6 years from ages 40 to 60 years (S9), and every 4 years during the same period (S8). Health outcome comparisons showed reductions in both cumulative cancer incidence and mortality with eradication-based strategies. Adding H. pylori screening to Korea’s national endoscopic screening program is a cost-effective strategy for the prevention of gastric cancer. These findings support the potential integration of screening into existing national screening policies, with implications for improving health outcomes and optimizing healthcare resource use.

Women with disabilities face substantial disparities in breast cancer screening, detection, and treatment, resulting in poorer outcomes. We investigated disparities in 10-year cumulative adherence to biennial breast cancer screening associated with disability status and disability characteristics, including type and severity. This retrospective cohort study used data from the Korean National Cancer Screening Program Data and Korea National Disability Registration System. The total cohort comprised 4,956,744 women who participated in screening from 2011 to 2012 and were followed for 10 years. We ascertained the presence, type, and severity of medically verified disabilities. The 15 officially defined disability types were grouped into six categories: physical, brain injury, communication, major internal organ, intellectual disability and autism, and mental disorder. The primary outcome was completion of all five recommended biennial screening cycles. Women with disabilities had lower odds of completing all five screenings compared to those without disabilities. A gradient pattern was observed by disability severity, with lower adherence among women with severe disabilities and slightly higher adherence among those with mild disabilities. Screening adherence also differed by disability type, with the lowest participation among women with intellectual disability and autism and the highest participation among those with physical disabilities. Even with reduced or eliminated financial barriers, significant disparities were found in breast cancer screening participation, especially in women with severe disabilities and intellectual disability and autism. Policy efforts, such as a disability-responsive design and routine equity monitoring should be made to decrease this disparity in organized screening programs.

Korea introduced its National Lung Cancer Screening Program (NLCSP) with low-dose computed tomography (LDCT) in 2019. However, there are few published results of lung cancer screening at national level. We investigated the performance of LDCT for lung cancer screening and suggested recommendations for improving a nationwide population-based program. This study was a nationwide, population-based cross-sectional study. We analyzed the Korean National Health Insurance Big Data Base, which included lung cancer-related screening information between 2019 and 2020, was analyzed. Performance indicators were the number of examinations, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), overexposure, and suspected lung cancer (LCA). The performance indicators were stratified according to screening year, sex, age group, and region. A total of 149,936 examinations were done in 2019–2020. Most participants were men (98.3

PURPOSE:Research on the prevalence of prostate cancer (PCa) screening and reasons for undergoing screening is limited. We aimed to identify the factors influencing PCa screening behavior and explore the underlying motivations among Korean men. MATERIALS AND METHODS:This cross-sectional study used data from the 2023 Korean National Cancer Screening Survey, which employs a nationally representative random sampling method. This study included 1,784 men aged 40-74 years. The respondents reported their experiences with PCa screening. Multivariable logistic regression analysis was conducted to identify the factors associated with participation in PCa screening. RESULTS:The lifetime PCa screening rate was 18.6%. Among screening modalities, transrectal ultrasonography was the most frequently used (31.9%), followed by prostate-specific antigen tests (25.6%) and digital rectal examinations (21.5%). The multivariable analysis identified several factors that significantly increased the likelihood of screening participation, including older age, living with a spouse, poor self-reported health, and abstinence from alcohol consumption in the previous 12 months. Men who had undergone colorectal cancer screening were more likely to participate in PCa screening (adjusted odds ratio, 4.01; 95% confidence interval, 2.03 to 7.93) than those who had not. The primary motivations for screening were recommendations from family or social networks (31.9%) and inclusion in health examination packages (24.3%), whereas healthcare provider recommendations (18%) and symptomatic concerns (5.7%) were the least influential. CONCLUSION:Our findings highlight the importance of providing evidence-based information for PCa screening recommendations and the need for improved communication and implementation of a shared decision-making approach for PCa screening in Korea.

Gastric cancer (GC) is the fourth most prevalent cancer and a leading cause of cancer-related fatalities in South Korea. Although periodic screening policies are in place, the early detection and prediction of GC remain challenging. This study evaluated the risk of GC incidence by utilizing longitudinal health check-up data from the National Health Insurance Service-Health Screening Cohort spanning from 2009 to 2019. The criteria selected for this study are general health examination candidates aged 40 or older who have been eligible for health insurance since 2009. The exclusion criteria included individuals diagnosed with cancer prior to 2009 or before their examination date, as well as those who did not complete the examination questionnaire. A time-dependent Cox proportional hazards model was employed to analyze the time from health examination to the first GC diagnosis, comparing our results with previous cohort studies that evaluated the GC risk through general check-up parameters. Significant risk factors for GC incidence in both genders were age, high levels of AST and γ-GTP, low levels of ALT and hemoglobin. Among males, dyslipidemia, smoking and physical activities were also significantly associated with GC risk. Although further evidence is needed, low hemoglobin levels emerged as a promising potential risk factor for GC, ascertainable through routine general health check-ups.

BackgroundIn Korea, the National Cancer Screening Program (NCSP) was implemented in 1999 and provides biennial endoscopy for adults aged ≥40 years. The NCSP has contributed to the early detection of gastric cancer and reduction of associated mortality in Korea. Helicobacter pylori is the main cause of gastric cancer. Screening for and eradication of H pylori reduces the incidence and mortality of gastric cancer. Previous studies have reported that screening for H pylori is a cost-saving intervention that can significantly decrease gastric cancer burden in areas with a high prevalence of H pylori infection. However, no study has examined whether incorporating H pylori screening into national endoscopic screening is cost effective. ObjectiveThis study aims to evaluate the cost-effectiveness of incorporating H pylori screening into Korea’s National Gastric Cancer Screening Program. MethodsWe have developed a Markov model to compare two strategies: (1) endoscopy screening every 2 years starting at the age of 40 years (conventional screening), and (2) H pylori screening at the age of 40 years followed by continuous endoscopy screening every 2 years. We will also conduct a comparative analysis by varying the age at which the H pylori screening is performed. The primary outcome is the incremental cost-utility ratio (ICUR), calculated by dividing the incremental cost by the incremental quality-adjusted life-years (QALYs) between the two strategies. A probabilistic sensitivity analysis will be performed to test the uncertainty of the cost-effectiveness results. A sensitivity analysis will identify the most influential variables for cost-effectiveness. ResultsThe primary outcome parameter is the cost-effectiveness of adding H pylori testing to the current NCSP, which is expressed as the ICUR. Costs and utilities are discounted at an annual rate of 4.5%. The ICUR threshold is set at KRW 50 million (US $36,719), which is the South Korean gross domestic product per capita. This research has been funded by a Patient-Centered Clinical Research Coordinating Center grant from the Ministry of Health & Welfare, Republic of Korea (grant RS-2024-00398474). This study will analyze and synthesize previously published information and is thus exempt from institutional review board approval. Data collection started in June 2024 and was completed in May 2025. Study results will be published in peer-reviewed journals and presented at national and international conferences throughout 2025. ConclusionsWe will examine whether introducing H pylori testing and eradication therapy into the NCSP is a more cost-effective strategy for reducing gastric cancer risk than conventional endoscopy-based screening. Our study also examines the optimal age for H pylori screening, as well as the optimal screening frequency. International Registered Report Identifier (IRRID)DERR1-10.2196/72228

Importance:To accelerate cervical cancer elimination, it is essential to evaluate the combined impact of ongoing screening and human papillomavirus (HPV) vaccination efforts, as the disease remains a significant global public health concern. Objective:To estimate how different cervical cancer screening strategies, along with HPV vaccination, affect the cervical cancer burden in South Korea. Design, Setting, and Participants:This decision analytical model used a deterministic age-structured dynamic model to simulate HPV transmission and cervical cancer progression, considering sexual behavior and population structure, for the Korean population from 2024 to 2100. The study was conducted from April 2023 to September 2024. Exposures:Cervical cancer screening using Papanicolaou (Pap) or HPV testing, with HPV vaccination. Main Outcomes and Measures:The cumulative number of incident cases of cervical cancer and deaths for the projected period are reported. Results:The study modeled more than 51 million Korean residents, with 25.88 million women (50.1%) and 10.05 million women aged 18 to 49 years. Among Pap test-based strategies, biennial screening for women aged 20 years and older was associated with the lowest number of cervical cancer cases (47 358) and deaths (34 242) by 2100, with as much as a 10% mortality reduction compared with other Pap test-based strategies. High-risk HPV (hrHPV) testing every 2 or 3 years was estimated to further reduce cases by as much as 27% and deaths by 13%. Depending on the screening strategy, cervical cancer elimination based on the World Health Organization definition (4 cases per 100 000 women) could occur as early as 2038 (with 2-year hrHPV testing starting at age 25 years or older) or as late as 2055 (5-year Pap testing for individuals aged 25 to 64 years). The current screening policy (Pap test every 2 years starting at age 20 years) was estimated to reach disease elimination by 2044. In an ideal scenario with 70% screening and 90% vaccination coverage from 2030, an additional 12% of cases and 7% of deaths could be prevented. Strategies using a 2-year interval for hrHPV testing could lead to the earliest cervical cancer elimination by 2034. Conclusions and Relevance:In this decision analytical model, an ideal scenario with higher cervical cancer screening and HPV vaccination rates was associated with substantially reduced cervical cancer incidence and mortality and accelerated elimination in South Korea. Notably, hrHPV testing with 2- or 3-year screening intervals was estimated to achieve elimination as early as 2034.

OBJECTIVES:Breast cancer screening rates have increased since the introduction of the National Cancer Screening Program (NCSP) in Korea. However, it remains unclear whether socioeconomic inequalities have improved, particularly according to screening type. This study investigated inequalities in organized (government-led) and opportunistic (individually initiated) screening, stratified by education and income levels. METHODS:Data were obtained from the Korean National Cancer Screening Survey, conducted annually from 2009 to 2021, involving approximately 1,700 women each year except in 2009. Trends were analyzed using joinpoint regression to calculate average annual percent changes (AAPCs). Socioeconomic inequalities were assessed using the slope index of inequality (SII) and relative index of inequality (RII). RESULTS:Organized screening rates increased from 42.0% in 2009 to 60.2% in 2021 (AAPC, 1.9; 95% confidence interval [CI], 0.7 to 3.4), whereas opportunistic screening rates declined from 13.3% to 11.2% (AAPC, -5.4; 95% CI, -8.7 to -2.3). For organized screening, individuals with lower education levels exhibited higher participation, resulting in negative inequality indices (SII, -5.37%; RII, 0.80). No significant income-based inequality was found (SII, 1.60%; RII, 1.07). However, opportunistic screening demonstrated significant inequalities by both education (SII, 5.37%; RII, 1.92) and income (SII, 5.90%; RII, 1.96), with higher participation rates among more advantaged groups. CONCLUSIONS:The NCSP has improved breast cancer screening rates and reduced income-related inequality in organized screening. However, educational and income-based inequalities persist in opportunistic screening. To reduce screening inequities, policy efforts are needed to further promote the NCSP, including improving program quality and providing financial support for follow-up examinations.

PURPOSE:Gastric cancer (GC) prediction models hold potential for enhancing early detection by enabling the identification of high-risk individuals, facilitating personalized risk-based screening, and optimizing the allocation of healthcare resources. Materials and Methods:In this study, we developed a machine learning-based GC prediction model utilizing data from the Korean National Health Insurance Service, encompassing 10,515,949 adults who had not been diagnosed with GC and underwent GC screening during 2013-2014, with a follow-up period of 5 years. The cohort was divided into training and test datasets at an 8:2 ratio, and class imbalance was mitigated through random oversampling. RESULTS:Among various models, logistic regression demonstrated the highest predictive performance, with an area under the receiver operating characteristic curve (AUC) of 0.708, which was consistent with the AUC obtained in external validation (0.669). Importantly, the outcomes were robust to missing data imputation and variable selection. The SHapley Additive exPlanations (SHAP) algorithm enhanced the explainability of the model, identifying advancing age, being male, Helicobacter pylori infection, current smoking, and a family history of GC as key predictors of elevated risk. CONCLUSION:This predictive model could significantly contribute to the early identification of individuals at elevated risk for GC, thereby enabling the implementation of targeted preventive strategies. Furthermore, the integration of noninvasive and cost-effective predictors enhances the clinical utility of the model, supporting its potential application in routine healthcare settings.

PURPOSE:This study aimed to report the overall national trends in the rates of cancer screening based on recommendations and provide insights into the changing trends of these rates across different demographics. MATERIALS AND METHODS:This study used data from the Korean National Cancer Screening Survey (KNCSS), which surveys nationwide cancer-screening rates and includes 4,500 individuals meeting the Korean National Cancer Screening Program (NCSP) protocol age criteria. Cancer-screening rates were assessed using structured questionnaires; yearly trends were analyzed for both lifetime cancer-screening rates and rates of screening based on recommendations, and subgroup analyses were performed based on age and sex. RESULTS:The rates of cancer screening based on recommendations showed significant increments: the stomach cancer-screening rate increased from 39.2% in 2004 to 77.5% in 2023 (3.50% per year), the liver cancer-screening rate increased from 20.0% to 48.8% (4.30% per year), and the colorectal cancer, increased from 19.9% to 70.7% (5.15% per year). The breast cancer-screening rate increased from 33.2% to 72.7% (2.88% per year), and the cervical cancer, increased from 58.3% to 70.2% (1.08% per year). Despite some differences, particularly in relation to sociodemographic factors, screening rates increased significantly for all cancer types. CONCLUSION:Cancer-screening rates in Korea increased consistently from 2004 to 2023, demonstrating the effectiveness of the national cancer-screening program. However, the increments in breast, cervical and lung cancer-screening rates were relatively lower, indicating the need for additional efforts and strategies.

Background: The Korean National Cancer Screening Program (NCSP) for gastric cancer requires economic evaluation due to the low sensitivity of upper gastrointestinal series (UGIs) and the associated low cancer survival rate. This study aimed to ascertain the most cost-effective strategy for the NCSP. Methods: The hypothetical target population of this study was aged 40 years or older, and no actual participants were involved. Markov simulation models were constructed for 25 strategies, combinations of 1) screening methods (UGIs or endoscopy vs. endoscopy-only), 2) screening intervals (one, two, or three-year), and 3) upper age limit of screening (69, 74, 79 years old, or "no limit"). Costs, utility, and other input parameters were extracted from various databases and previous studies. Cost-utility, sensitivity, and scenario analyses were conducted. Results: The endoscopy-only strategy with a three-year interval with an upper age limit of 69 was the most cost-effective strategy with an incremental cost-utility ratio of KRW 13,354,106 per quality-adjusted life years. According to the probabilistic sensitivity analysis, the uncertainty of the result was significantly small. Scenario analysis is showed that as the screening rate increased, the endoscopy-only strategy saved more costs compared to the current NCSP. Therefore, it is important to maintain a high screening rate when altering the NCSP strategy. Conclusion: Endoscopy-only screening was more cost-effective method than UGIs for the NCSP. Furthermore, a three-year interval with an upper-age limit of 69 years was the most cost-effective strategy. Efforts to improve cost-effective screening guidelines will support the efficient use of medical resources. Additionally, maintaining a higher screening rate may maximize the impact of the modification in strategy on cost-effectiveness.