Risk of upper gastrointestinal cancer and death in persons with negative screening results: results from the National Cancer Screening Program in South Korea.

BACKGROUND: The Korea National Cancer Screening Program (KNCSP) offers upper endoscopy or upper gastrointestinal series (UGIS) biannually for people aged ≥ 40 years. This study aimed to assess the effect of negative screening results on the incidence of and mortality from upper gastrointestinal (GI) cancer. METHODS: A population-based retrospective cohort of 15,850,288 men and women was constructed using data from 3 national databases. The participants were followed until the end of 2017 for data on cancer incidence and in 2019 for data on the vital status. Cox proportional hazard model with time-varying exposure was used to assess the association. RESULTS: By the end of the follow-up period, 230,783 upper GI cancer cases and 99,348 upper GI cancer deaths were recorded. Negative gastric cancer screening was significantly associated with a lower risk of upper GI cancer in both UGIS (adjusted hazard ratio [aHR] = 0.81, 95% CI = 0.80-0.82) and upper endoscopy (aHR = 0.67, 95% CI = 0.67-0.68) groups. The HRs for upper GI mortality were 0.55 (95% CI = 0.54-0.56) and 0.21 (95% CI = 0.21-0.22) for the UGIS and upper endoscopy groups, respectively. The most significant reductions in the risk of upper GI cancer (UGIS: aHR = 0.76, 95% CI = 0.74-0.77; upper endoscopy: aHR = 0.60, 95% CI = 0.59-0.61) and death (UGIS: aHR = 0.54, 95% CI = 0.52-0.55; upper endoscopy: aHR = 0.19, 95% CI = 0.19-0.20) were observed among individual aged 60-69 years. CONCLUSION: Negative screening cases, especially in upper endoscopy of the KNCSP, were associated with an overall reduction in the risk of and mortality from upper GI cancer.

Effect of colorectal cancer screening on long-term survival of colorectal cancer patients: Results of the Korea National Cancer Screening Program.

The Korea National Cancer Screening Program (KNCSP) provides fecal immunochemical test-based colorectal cancer (CRC) screening for people aged ≥50 years. Our study aimed to investigate the long-term survival effects of CRC screening based on screening history and interval time since screening. The study cohort was obtained by linking three national databases, namely the Korea Central Cancer Registry, KNCSP database and Death Certificate. We included 32 509 CRC patients diagnosed in 2008 to 2009, who underwent CRC screening via the KNCSP between 2004 and 2009. The patients were followed-up until 2019, and their survival was assessed according to their CRC screening history. Cox proportional hazards regression was used to compare time to deaths among CRC patients according to CRC screening history, after adjusting for covariates. Of the 32 509 patients, 20 022 (61.5%) patients were alive by the end of 2019. Long-term survival was significantly higher among screened patients (68.2%) than nonscreened (57.2%) individuals. Compared to never-screened patients, the hazard ratio (HR) for CRC-specific death in screened patients was 0.77 (95% CI%, 0.73-0.80). Lowest HR was observed in screened, localized CRC patients (HR, 0.48; 95% CI, 0.42-0.56); HR for CRC-specific death was the lowest in patients screened within 12 months of diagnosis (HR, 0.70; 95% CI, 0.66-0.74), following which, the HRs increased with increasing time interval. CRC screening was positively associated with favorable prognosis in CRC patients aged 50 to 79 years. The effects on long-term survival according to interval time was the best among individuals screened within 1 year before diagnosis.

Socioeconomic inequality in organized and opportunistic screening for gastric cancer: results from the Korean National Cancer Screening Survey 2009-2022.

Objectives: This study aimed to evaluate the socioeconomic inequality in gastric cancer (GC) screening in Korea. Socioeconomic inequality was assessed using both organized and opportunistic screening according to income and educational level. Methods: GC screening data were obtained from the 2009-2022 Korean National Cancer Screening Survey. The final analysis included 47,163 cancer-free men and women. The weighted cancer screening rate was estimated using joinpoint regression. The inequality indices were measured in terms of both the absolute slope index of inequality (SII) and the relative index of inequality (RII) using the Poisson regression model. Results: The organized screening rate for GC increased from 38.2% in 2009 to 70.8% in 2022, whereas the opportunistic screening rate decreased from 18.8 to 4.5%. Regarding educational inequality, a negative SII value was observed [-3.5, 95% confidence interval (CI), -7.63-0.83%] in organized screening, while a positive SII (9.30%; 95% CI, 6.69-11.91%) and RII (1.98%; 95% CI, 1.59-2.46) were observed in opportunistic screening. Furthermore, income inequality was not found in organized GC screening; however, overall SII and RII for opportunistic screening were 7.72% (95% CI, 5.39-10.5) and 1.61 (95% CI, 1.42-1.81), respectively. Conclusion: Organized screening rates have grown gradually over time and account for the majority of GC screenings in South Korea. While no socioeconomic inequalities were found in organized screening, significant socioeconomic inequalities were found in opportunistic screening.

Socioeconomic inequality in organized and opportunistic screening for colorectal cancer: results from the Korean National Cancer Screening Survey, 2009-2021.

OBJECTIVES: 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. METHODS: We analyzed data from the Korean National Cancer Screening Survey 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. RESULTS: 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 to 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 to 13.12), relative index of inequality (RII) of 2.18 (95% CI, 1.75 to 2.70) in terms of education level; and an SII of 7.03% (95% CI, 4.09 to 9.98), RII of 1.81 (95% CI, 1.41 to 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. CONCLUSIONS: 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.

Effect of gastric cancer screening on long-term survival of gastric cancer patients: results of Korean national cancer screening program.

BACKGROUND: Gastric cancer (GC) is the most common cancer type in Korea. Korean National Cancer Screening Program (KNCSP) offer either upper gastrointestinal series (UGIS) or upper endoscopy biennially for adults aged ≥ 40. This study aimed to investigate the effect of cancer screening program on the long-term survival among GC patients. METHODS: A nationwide population-based cohort was constructed based on three national databases. Overall, 46,701 GC patients diagnosed in 2008 and 2009 were included in our final analysis, and they were followed-up until the end of 2019. Survival curves were estimated using the Kaplan-Meier analysis with the log-rank test. Cox proportional-hazards regression analysis was used to report the hazard ratios (HRs) with 95% confidence intervals. RESULTS: A total of 18,614/46,701 (39.9%) patients died during the median follow-up time of 10.5 years. The survival rate was higher among screened patients (65.8%) than never-screened patients (49.1%). Screened patients had 53% (HR, 0.47; 95% CI 0.45-0.48) lower risk of death from GC. The HRs of GC-specific mortality was lower in upper endoscopy group (HR = 0.36; 95% CI = 0.34-0.37) compared with UGIS (HR = 0.69; 95% CI = 0.67-0.73). Screened patients within 2 years prior to cancer diagnosis had a 35% reduction in risk of GC death. The figure decline to approximately 19% among patients with interval time since last screening of > 3 years. CONCLUSIONS: Our findings emphasized the positive effects of GC screening on long-term GC patient survival. Also, patients screened by upper endoscopy or within 2 years before diagnosis had the best survival outcomes.

Effect of mammography screening on the long-term survival of breast cancer patients: results from the National Cancer Screening Program in Korea.

OBJECTIVES: This study investigated the effect of mammography screening on the long-term survival of breast cancer (BC) patients aged 40 years or older according to their screening history and duration since screening. METHODS: The study cohort was organized from 3 nationwide databases of the Korean National Cancer Screening Program, the Korean Central Cancer Registry, and death certificates. We included 24,387 women diagnosed with invasive BC or ductal carcinoma in situ in 2008 and 2009 and followed up until December 31, 2019. Cox proportional-hazards regression was used to investigate the effect of BC screening on the risk of death. RESULTS: Overall, 20,916 of 24,387 patients (85.8%) were alive at the end of the follow-up period (median: 10.5 years). The long-term survival rate was significantly lower in the never-screened group (80.3%) than in the screened group (88.9%) (p<0.001). A 35% reduction in the risk of BC death (hazard ratio [HR], 0.65; 95% confidence interval [CI], 0.60 to 0.70) from screening was observed. A subgroup analysis according to the cancer stage showed 62%, 36%, and 24% lower risks of BC death for the localized stage, regional stage, and distant stage, respectively. Women aged 40-49 years received the least benefit from BC screening (HR, 0.71; 95% CI, 0.62 to 0.81). CONCLUSIONS: Mammography screening was effective in reducing the risk of BC-specific death in Asian women across all cancer stages. However, this effect was relatively small among women in their 40s, suggesting that more detailed and specialized screening strategies are needed for that age group.

Effect of Pap smears on the long-term survival of cervical cancer patients: a nationwide population-based cohort study in Korea.

OBJECTIVES: This study aimed to investigate the effect of cervical cancer screening by Papanicolaou (Pap) smears on the long-term survival of cervical cancer patients. METHODS: We constructed a retrospective cohort of 14,903 women diagnosed with invasive cancer or carcinoma in situ in 2008 and 2009 and followed up until December 31, 2019, by using individual-level data from 3 national databases of the Korean National Cancer Screening Program, the Korean Central Cancer Registry, and death certificates. Cox proportional-hazards regression was used to investigate the effect of cervical cancer screening on mortality. RESULTS: In total, 12,987 out of 14,867 patients (87.4%) were alive at the end of the follow-up period (median: 10.5 years). Screened patients had a 38% lower risk of cervical cancer death than never-screened patients (hazard ratio [HR], 0.62; 95% confidence interval [CI], 0.54 to 0.70). Screening was associated with 59% and 35% lower risks of death, respectively, in screened patients with localized and regional stages. Furthermore, lower HRs among women who received screening were observed in all age groups, especially women aged 50-59 years (HR, 0.54; 95% CI, 0.42 to 0.69). The lowest HR for cervical cancer death was reported among patients screened within the past 2 years (HR, 0.54; 95% CI, 0.47 to 0.63), and the HRs increased with increasing time intervals. CONCLUSIONS: Pap smear screening significantly reduced the risk of cervical cancer-specific death in Korean women across all cancer stages.

The classification capability of the Asia Pacific Colorectal Screening score in Korea: an analysis of the Cancer Screenee Cohort.

OBJECTIVES: This study aimed to validate a simple risk assessment tool for estimating the advanced colorectal neoplasia (ACN) risk at colonoscopy screenings and potential factors relevant for implementing this tool in the Korean population. METHODS: Our study analyzed data from the Cancer Screenee Cohort Study conducted by the National Cancer Center in Korea. The risk level was assessed using the Asia Pacific Colorectal Screening (APCS) score developed by the Asia-Pacific Working Group on Colorectal Cancer. Logistic regression models were used to examine the associations between colorectal-related outcomes and the risk level by APCS score. The discriminatory performance of the APCS score for various colorectal-related outcomes was assessed using C-statistics. RESULTS: In 12,520 individuals, 317 ACN cases and 4,528 adenoma cases were found. The APCS tool successfully classified the study population into different risk groups, and significant differences in the ACN rate and other outcomes were observed. The APCS score demonstrated acceptable discrimination capability with area under the curve values ranging from 0.62 to 0.65 for various outcomes. The results of the multivariate logistic regression model revealed that the high-risk group had a 3.1-fold higher risk of ACN (95% confidence interval, 2.08 to 4.67) than the average-risk group. Body mass index (BMI) was identified as a significant predictor of ACN in both multivariate and subgroup analyses. CONCLUSIONS: Our study highlighted significant differences in colorectal-related screening outcomes by colorectal risk level measured using the APCS score, and BMI could be used to improve the discriminatory capability of the APCS score.

Acceptance on colorectal cancer screening upper age limit in South Korea.

BACKGROUND: The Korea National Cancer Screening Program currently provides screening for colorectal cancer (CRC) for adults older than 50 years with no upper age limit. In general, people are likely to only pay attention to the benefits of cancer screening and to neglect its risks. Most consider the benefits of cancer screening as being far greater than the risks and are unaware that any potential benefits and harms can vary with age. AIM: To report acceptance of an upper age limit for CRC screening and factors associated therewith among cancer-free individuals in Korea. METHODS: The present study analyzed data from the Korea National Cancer Screening Survey 2017, a nationally representative random sample of 4500 Korean individuals targeted for screening for the five most common types of cancer. A total of 1922 participants were included in the final analysis. The baseline characteristics of the study population are presented as unweighted numbers and weighted proportions. Both univariate and multivariate logistic regression models were developed to examine factors related with acceptance of an upper age limit for CRC screening; subgroup analysis was also applied. RESULTS: About 80% (1554/1922) of the respondents agreed that CRC screening should not be offered for individuals older than 80 years. Specifically, those who had never been screened for CRC had the highest acceptance rate (91%). Overall, screening history for CRC [screened by both fecal occult blood test and colonoscopy, adjusted odds ratio (aOR) = 0.33, 95%CI: 0.22-0.50] and other cancers (aOR = 0.55, 95%CI: 0.34-0.87), as well as a family history of cancer (aOR = 0.66, 95%CI: 0.50-0.87), were negatively associated with acceptance of an upper age limit for CRC screening. In contrast, metropolitan residents (aOR = 1.86, 95%CI: 1.29-2.68) and people who exercised regularly (aOR = 1.42, 95%CI: 1.07-1.89) were more likely to accept an upper age limit. After subgrouping, we found gender, marital status, and lifetime smoking history among never-screened individuals and residential region, family history of cancer, and physical activity among never-screened individuals to be associated with acceptance of an upper age limit. CONCLUSION: This study describes acceptance of an upper age limit for CRC screening and factors associated with it, and provides perspectives that should be considered, in addition to scientific evidence, when developing population-based cancer screening policies and programs.