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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.

OBJECTIVES We aimed to identify and compare the characteristics and factors associated with parental intention to vaccinate daughters under 12 years old against human papillomavirus (HPV), examining data from 2016 and 2020. METHODS Data were obtained from the Korean National Cancer Screening Survey conducted in 2016 and 2020. The present study included 3,510 parents with daughters under 12 years old. Changes in parental intention-to-vaccinate rates were calculated. To identify factors associated with parental intention to vaccinate their daughters, the chi-square test and logistic regression analysis were used. RESULTS The percentage of respondents intending to vaccinate their daughters increased from 33.4% in 2016 to 58.9% in 2020, constituting a 25.5 percentage point (%p) increase. Since 2016, the proportion of men expressing positive intention towards HPV vaccination increased by 31.5%p, while that of women demonstrated a 20.9%p increase. Logistic regression analysis indicated that parents with a strong intention to vaccinate their daughters tended to be younger, more educated, and aware of the free vaccination program available, as well as to have a history of HPV vaccination and to have undergone cervical cancer screening within 2 years, compared to those who did not intend to vaccinate. Being a mother with a history of HPV vaccination was the strongest predictor of positive intention to vaccinate a daughter. CONCLUSIONS The intention among parents to vaccinate daughters remains relatively low, although it is rising. To increase the HPV vaccination rate, strong recommendations and education should be provided to parents and the younger generation.

OBJECTIVES Since 2002, the Korean government has provided breast cancer screening as part of the National Cancer Screening Program. This study reported trends in the screening rate among Korean women from 2005 to 2020, including organized and opportunistic screening for breast cancer. METHODS Data from the Korean National Cancer Screening Survey, an annual cross-sectional nationwide survey, were collected using a structured questionnaire between 2005 and 2020. The study population included 23,702 women aged 40-74 years with no history of cancer. We estimated the screening rate based on the current recommendation of biennial mammographic screening for breast cancer. In addition, a joinpoint trend analysis was performed for breast cancer screening rates among various subgroups. RESULTS In 2020, the breast cancer screening rate was 63.5%, reflecting an annual increase of 7.72% (95% confidence interval 5.53 to 9.95) between 2005 and 2012, followed by non-significant trends thereafter. In particular, a significant decrease in the breast cancer screening rate was observed in the subgroups aged 50-59 years old, with 12-15 years of education, and living in rural areas. CONCLUSIONS Although there has been substantial improvement in breast cancer screening rates in Korean women, the trend has flattened in recent years. Therefore, continual efforts are required to identify subgroups with unmet needs and solve barriers to the uptake of breast cancer screening.

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

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.

OBJECTIVES The coronavirus disease 2019 (COVID-19) pandemic has negatively affected every aspect of medical care. However, information regarding the impact of the pandemic on cancer screening is lacking. This study aimed to explore cancer screening changes by geographic region before and during the pandemic in Korea. METHODS Korean National Cancer Screening Survey data for 2019 and 2020 were used. Changes in the screening rate before and during the COVID-19 pandemic were calculated by subtracting the rate in 2020 from the rate in 2019. Multivariate logistic regression analyses examined the differences in screening rates at the national and 16 provincial levels before and after the COVID-19 outbreak. RESULTS The 1-year screening rates for the four types of cancer decreased during the pandemic (stomach cancer: -5.1, colorectal cancer: -3.8, breast cancer: -2.5, cervical cancer: -1.5%p). In metropolitan areas, the odds of undergoing screening tests during the pandemic were significantly lower than before the pandemic for stomach (adjusted odds ratio [aOR], 0.66; 95% confidence interval [CI], 0.56 to 0.76), colorectal (aOR, 0.63; 95% CI, 0.50 to 0.79), and breast cancers (aOR, 0.75; 95% CI, 0.60 to 0.94). Furthermore, the likelihood of undergoing stomach cancer screening during the pandemic was significantly lower than before the pandemic in non-metropolitan urban areas (aOR, 0.81; 95% CI, 0.70 to 0.94), while it was higher in rural areas (aOR, 1.54; 95% CI, 1.10 to 2.16). CONCLUSIONS Since the COVID-19 pandemic, the cancer screening rate has decreased significantly, especially in large cities. Public health efforts are required to improve cancer screening rates.

OBJECTIVES Through a survey on perception of lung cancer screening and accompanying medical radiation exposure in Korea, the present study was to investigate its current situations and evaluate various perception of physicians regarding it in order to propose measures for improvements. METHODS Medical specialists in national cancer screening institutions selected through stratified random sampling were subjected to face-to-face interview using a structured questionnaire. We investigated physicians’ perception on effectiveness of lung cancer screening depending on screening modality, selection criteria for subjects of screening, types of equipment used to screen, and perception for seriousness of adverse effects following the test. In addition, odds ratios to underestimate risk of radiation exposure from screening were calculated through logistic regression analysis. RESULTS Each response that chest X-ray is effective for lung cancer screening and that smoking history is not considered prior to screening recommendation accounted for more than 60% of respondents, suggesting the chance of unnecessary screening tests. Regarding adverse effects of lung cancer screening, about 85% of respondents replied that false positive, radiation exposure, and overdiagnosis could be ignored. About 70% of respondents underestimated radiation dose from lung cancer screening, and a low proportion of physicians informed patients of radiation exposure risk. CONCLUSIONS It was found that most physicians underestimated harms of lung cancer screening including radiation exposure and were lack of awareness regarding lung cancer screening. It should be noted that physicians need to have proper perceptions about screening recommendation and accompanying possible harms, for successful implementation of the screening program.

OBJECTIVES To investigate the screening rates for gastric, breast, and cervical cancer in people with diabetes compared with people without diabetes. METHODS Data from the Korea National Health and Nutrition Examination Survey (2007-2009) were used. Cancer-free men who were 40 years old and over and cancer-free women who were 30 years old and over were included. The lifetime screening rate and regular screening rate were compared in people with and without diabetes. RESULTS Fewer people with diabetes than people without diabetes had ever received cancer screening (53.5 vs. 59.5%, p

OBJECTIVES Assessing long-term success and efficiency is an essential part of evaluating cancer control programs. The mortality-to-incidence ratio (MIR) can serve as an insightful indicator of cancer management outcomes for individual nations. By calculating MIRs for the top five cancers in Organization for Economic Cooperation and Development (OECD) countries, the current study attempted to characterize the outcomes of national cancer management policies according to the health system ranking of each country. METHODS The MIRs for the five most burdensome cancers globally (lung, colorectal, prostate, stomach, and breast) were calculated for all 34 OECD countries using 2012 GLOBOCAN incidence and mortality statistics. Health system rankings reported by the World Health Organization in 2000 were updated with relevant information when possible. A linear regression model was created, using MIRs as the dependent variable and health system rankings as the independent variable. RESULTS The linear relationships between MIRs and health system rankings for the five cancers were significant, with coefficients of determination ranging from 49 to 75% when outliers were excluded. A clear outlier, Korea reported lower-than-predicted MIRs for stomach and colorectal cancer, reflecting its strong national cancer control policies, especially cancer screening. CONCLUSIONS The MIR was found to be a practical measure for evaluating the long-term success of cancer surveillance and the efficacy of cancer control programs, especially cancer screening. Extending the use of MIRs to evaluate other cancers may also prove useful.