Cost-Utility Analysis for Colorectal Cancer Screening According to the Initiating Age of National Cancer Screening Program in Korea.

BACKGROUND: This study aimed to identify the most cost-effective strategy for colorectal cancer screening using the fecal immunochemical test (FIT), focusing on screening initiation age in Korea. METHODS: We designed Markov simulation models targeting individuals aged 40 years or older. Twelve strategies combining screening initiation ages (40, 45, or 50 years old), termination ages (80 or no limit), and intervals (1 or 2 years) were modeled, and the most cost-effective strategy was selected. The robustness of the results was confirmed using one-way and probabilistic sensitivity analyses. Furthermore, the cost-effectiveness of the qualitative and quantitative FIT methods was verified using scenario analysis. RESULTS: The 2-year interval strategy with a screening age range of 45-80 years was the most cost-effective (incremental cost-utility ratio = KRW 7,281,646/quality adjusted life years). The most sensitive variables in the results were transition rate from advanced adenoma to local cancer and discount rate. The uncertainty in the model was substantially low. Moreover, strategies starting at the age of 40 years were also cost-effective but considered suboptimal. The scenario analysis showed that there was no significant difference in cost-effectiveness between strategies with various relative screening ratio of quantitative and qualitative method. CONCLUSION: The screening method for advancing the initiation age, as presented in the 2015 revised national screening recommendations, was superior regarding cost-effectiveness. This study provides a new paradigm for the development of a national cancer screening system in Korea, which can be utilized as a scientific basis for economic evaluations.

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.

Role of breast cancer screening in the overdiagnosis of thyroid cancer: results from a cross-sectional nationwide survey.

BACKGROUND: South Korea has the highest incidence of thyroid cancer worldwide, raising questions regarding the possibility of overdiagnosis. Examining the factors affecting thyroid cancer screening is crucial in elucidating the reasons for this unusually high incidence of thyroid cancer. Therefore, in the present study, we investigated the association between breast cancer screening and thyroid cancer screening to determine the potential role of breast cancer screening in the overdiagnosis of thyroid cancer in South Korea. METHODS: We analyzed the data of women aged > 30 years who were enrolled in the 2014 Korean National Cancer Screening Survey. Self-reported breast cancer screening behavior was categorized as follows: no screening, mammography only, ultrasonography only, and both ultrasonography and mammography. Thyroid cancer screening behavior was categorized as follows: those who had or had not undergone ultrasonography screening. Logistic regression analysis was used to examine the associations between breast and thyroid cancer screening behaviors. RESULTS: Of the 2270 participants, a total of 569 (25.1%) were screened for thyroid cancer. Those who underwent only mammography, only ultrasonography, or both mammography and ultrasonography were more likely to be screened for thyroid cancer than those who did not undergo breast cancer screening (odds ratio [OR]: 1.47, 95% confidence interval [CI] 1.06-2.04; OR 2.71, 95% CI 1.83-4.02; OR 2.75, 95% CI 1.99-3.80, respectively). CONCLUSIONS: Our findings indicate that thyroid cancer screening in Korea is likely to be performed on an opportunistic basis. Therefore, a nationwide public health and medical initiative is needed to curb the unnecessary use of thyroid screening in the asymptomatic general population.

Increased Screening Rates for Thyroid Cancer Among Residents Living Near Nuclear Power Plants.

Frequent screening for thyroid cancer has been suggested as a probable explanation for the observed high risk of thyroid cancer in nuclear power plant (NPP) areas. We aimed to compare thyroid cancer screening rates of residents living near NPPs to those of the general population. This study utilized data from two national survey-based studies in 2016 and in 2014, respectively, for residents (n = 1,200) living in administrative districts within 5 km of NPP sites as the interest group, and the general population (n = 228,712) including distant-living residents (n = 19,100) in administrative districts within 30 km of NPP sites as reference groups. We observed an increase in screening rates in residents near NPPs, which may lead to a higher possibility of thyroid cancer detection. Therefore, further epidemiological studies investigating radiation-induced thyroid cancer risk among residents near NPPs should be carefully designed and interpreted considering possible detection bias.

A Web-Based Decision Aid for Informed Prostate Cancer Screening: Development and Pilot Evaluation.

BACKGROUND: Prostate-specific antigen-based routine screening is not recommended for the general population due to conflicting results with mortality reduction. We aimed to develop a web-based decision aid (DA) for informed decision making for prostate cancer screening. METHODS: Using the International Patient Decision Aid Standards (IPDAS) development process model, we developed our DA based on patient and clinician interviews and multidisciplinary expert discussions. The prototype consisted of predicting individual prostate cancer risk and informed decision-making, including knowledge, risk and benefit, cost, personal value, and decision making. We conducted a pilot study on 101 healthy men, evaluating the effectiveness of DA by measuring knowledge, attitude, and intention to screen before and after using the DA, as well as decisional conflict and usefulness after using the DA. RESULTS: Of the 101 participants (median age 60 [50-69] years), 84% had not undergone screening for prostate cancer in the past two years. After using the DA, knowledge on prostate cancer screening increased (mean score [of 10] before versus after: 6.85 ± 1.03 versus 7.57 ± 1.25; P < 0.001), and intention to not screen increased from 27.7% to 51.5% (P < 0.001), but attitude toward screening did not change (P = 0.564). After use of the DA, 79 participants reported no decisional conflict, and the usefulness score was high (mean score [of 100] 77.35 ± 7.69), with 85% of participants reporting that the DA helped with decision making. CONCLUSION: Our web-based DA yielded increased knowledge, decreased screening intention, and high perceived usefulness. These findings indicate potential clinical relevance, especially among younger individuals.

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.

Korean colonoscopy screening pilot study (K-cospi) for screening colorectal cancer: study protocol for the multicenter, community-based clinical trial.

BACKGROUND: The Korean National Cancer Screening Program has been providing annual fecal immunochemical test for colorectal cancer (CRC) to adults aged 50 years and older since 2004. The Korean Colonoscopy Screening Pilot Study was developed to evaluate the effectiveness of colonoscopy screening for CRC incidence and mortality, screening-related complications, and acceptability of colonoscopy as a primary modality for the national CRC screening program. METHODS: This study and its protocols have been approved by the Korean Public Institutional Review Board and the National Cancer Center Institutional Review Board. We obtain written informed consent from all participants. The target population is males and females aged 50-74 years living within the pilot sites. A total of 26,640 participants will be recruited for colonoscopy screening. Subjects who have been diagnosed with CRC, who are currently undergoing treatment for CRC, or who have undergone colonoscopy screening within the past 5 years are not allowed to participate. All participants need to complete baseline questionnaires. This pilot study is currently conducted by 104 endoscopists from 57 national cancer screening institutions (42 primary, 10 secondary, and 5 tertiary institutions) located in Goyang-si, Gimpo-si, and Paju-si. The number of endoscopists, medical institutions, and districts participating in the pilot study will be expanded, if necessary. Participating endoscopists at each medical institution perform colonoscopy and report the colonoscopy results to a centralized electronic case report system. We conduct a telephone survey after 7 days and 4 weeks post-colonoscopy to assess for procedure-related complications and satisfaction of the participants. In case of abnormal findings from colonoscopy screening, we track the results from follow-up diagnostic tests. Data from this pilot study will be linked to the diagnostic workup results, the Korean Cancer Registry, and death certificate data for analysis of the performance, long-term effects, and cost-effectiveness of colonoscopy. DISCUSSION: The results will provide critical information to determine whether the introduction of colonoscopy as the primary modality of the Korean National Cancer Screening Program would be acceptable and feasible. Trial registration Korean Clinical Research Information Service registry, KCT0004142. Registered on 15 July 2019, http://cris.nih.go.kr/cris/en/search/search_result_st01.jsp?seq=16227.

Effect of Digital Mammography for Breast Cancer Screening: A Comparative Study of More than 8 Million Korean Women.

Background Full-field digital mammography (FFDM) has been accepted as a superior modality for breast cancer screening compared with conventional screen-film mammography (SFM), especially in women younger than 50 years or with dense breasts. Purpose To evaluate the accuracy of FFDM for breast cancer screening. Materials and Methods Data from January 1, 2011 to December 31, 2013 in the database from a nationwide breast cancer screening program linked with the national cancer registry were retrospectively analyzed. The study included Korean women aged 40-79 years who had undergone screening mammography with SFM, computed radiography (CR), or FFDM. The sensitivity, specificity, positive predictive value (PPV), and absolute and relative differences among these modalities were calculated, followed by pairwise comparison tests with multiple testing corrections. The areas under the receiver operating characteristic curve (AUCs) were also estimated and compared by using the DeLong method with Bonferroni correction. Results Among the 8 482 803 women included (mean age, 55 years ± 10), 34.4% (2 920 279 of 8 482 803), 51.7% (4 385 807 of 8 482 803), and 13.9% (1 176 717 of 8 482 803) underwent SFM, CR, and FFDM, respectively. The sensitivity and PPV were higher for FFDM than for SFM (adjusted odds ratio, 1.77 [95% confidence interval {CI}: 1.62, 1.95] for sensitivity and 1.36 [95% CI: 1.29, 1.43] for PPV) and CR (adjusted odds ratio, 1.70 [95% CI: 1.56, 1.85] for sensitivity and 1.26 [95% CI: 1.20, 1.32] for PPV), whereas specificity was lower with FFDM. The overall AUC for FFDM was 0.80 (95% CI: 0.80, 0.81), which was higher than that for SFM (0.75 [95% CI: 0.75, 0.76]) and CR (0.76 [95% CI: 0.75, 0.76]). P < .05 was found for differences in sensitivity, PPV, and AUC among modalities overall and in most of the subgroups of age, breast density, and screening round. Conclusion Full-field digital mammography allows better discrimination or prediction of breast cancer in the general female population than screen-film mammography or computed radiography, regardless of age, breast density, or screening round. © RSNA, 2019 Online supplemental material is available for this article.

Increasing Trend in Young-Onset Colorectal Cancer in Asia: More Cancers in Men and More Rectal Cancers.

BACKGROUND: The incidence of young-onset colorectal cancer (CRC) is reported to be increasing in the Western world. There are no population-based studies assessing the trend across Asia. METHODS: We performed a multinational cohort study involving four Asian countries/regions, namely Taiwan, Korea, Japan, and Hong Kong. The magnitude and direction of trend in the incidence of young-onset CRC (age < 50) were quantified using Joinpoint Regression Program to estimate average annual percentage change (AAPC). RESULTS: In Taiwan (1995-2014), incidence of young-onset CRC significantly increased in both men (colon cancer: 4.9-9.7 per 100,000; rectal cancer: 4.0-8.3 per 100,000) and women (colon cancer: 5.1-9.7 per 100,000; rectal cancer: 3.8-6.4 per 100,000). In Korea (1999-2014), incidence of young-onset CRC significantly increased in both men (colon cancer: 5.0-10.4 per 100,000; rectal cancer: 4.9-14.0 per 100,000) and women (colon cancer: 4.1-9.6 per 100,000; rectal cancer: 4.1-9.1 per 100,000). The most pronounced change was observed with male rectal cancer, increasing by 3.9% per year in Taiwan (AAPC + 3.9, 95% confidence interval + 3.3 to +4.5, P < 0.05) and 6.0% per year in Korea (AAPC +6.0, 95% confidence interval + 4.5 to +7.6, P < 0.05). Only a significant increase in rectal cancer was noted in Japan (male rectal cancer: 7.2-10.1 per 100,000, female rectal cancer 4.7-6.7 per 100,000) and Hong Kong (male rectal cancer: 4.4-7.0 per 100,000). CONCLUSIONS: Increasing trend in young-onset CRC is not limited to the Western world. This finding may have implications on screening program for CRC in these countries/regions.

Employment conditions and use of gastric cancer screening services in Korea: a nationwide survey.

BACKGROUND: Although it is well known that employment conditions exert considerable effects on health and health equity, the association between employment conditions and the use of preventative health services has rarely been studied. We explored whether inequities in the use of preventative services were associated with employment conditions. We used gastric cancer screening as a surrogate for the use of preventative health services. METHODS: The study population was derived from the Korea National Health and Nutrition Survey IV (2007-2009), which included data on 5626 individuals over 40 years of age. Employment conditions were grouped by employment status, work hours, employment contract term, and salary source. Participants who had undergone gastroscopy or an upper gastrointestinal series within the past 2 years were considered to have used cancer screening services according to the National Cancer Screening Program guidelines. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multiple logistic regression analysis. As the survey procedure incorporated sample weights, we adjusted our calculations to consider the complex sample design. RESULTS: Self-employed workers were less likely to participate in regular cancer screening than were wage workers (OR = 0.79, 95% CI = 0.68-0.92), and part-time workers were less likely to participate than were full-time workers (OR = 0.81, 95% CI = 0.67-0.99). Among wage workers, temporary workers and daily workers exhibited lower participation rates than did regular workers (OR = 0.81, 95% CI = 0.63-1.05 and OR = 0.58, 95% CI = 0.44-0.76, respectively). Dispatched workers also exhibited lower participation rates (OR = 0.45, 95% CI = 0.25-0.80). CONCLUSIONS: We found obvious inequities in the use of preventative health services associated with various employment conditions. Self-employed, irregular, and dispatched workers were significantly less likely to participate in cancer screening than were other workers. Political efforts should be made to reduce employment insecurity and to improve participation in preventative screening services by vulnerable employees so as to resolve the evident health inequities.

Effectiveness of the Korean National Cancer Screening Program in Reducing Gastric Cancer Mortality.

BACKGROUND & AIMS: It is not clear whether screening for gastric cancer by upper endoscopy or upper gastrointestinal (UGI) series examinations (looking at the upper and middle sections of the gastrointestinal tract by imaging techniques) reduces mortality. Nevertheless, the Korean National Cancer Screening Program for gastric cancer was launched in 1999 to screen individuals 40 years and older for gastric cancer using these techniques. We evaluated the effectiveness of these techniques in gastric cancer detection and compared their effects on mortality in the Korean population. METHODS: We performed a nested case-control study using data from the Korean National Cancer Screening Program for gastric cancer since 2002. A total of 16,584,283 Korean men and women, aged 40 years and older, comprised the cancer-free cohort. Case subjects (n = 54,418) were defined as individuals newly diagnosed with gastric cancer from January 2004 through December 2009 and who died before December 2012. Cases were matched with controls (subjects who were alive on the date of death of the corresponding case subject, n = 217,672) for year of entry into the study cohort, age, sex, and socioeconomic status. Odds ratios (ORs) and 95% confidence intervals (CIs) were obtained via conditional logistic regression analysis. RESULTS: Compared with subjects who had never been screened, the overall OR for dying from gastric cancer among ever-screened subjects was 0.79 (95% CI, 0.77-0.81). According to screening modality, the ORs of death from gastric cancer were 0.53 (95% CI, 0.51-0.56) for upper endoscopy and 0.98 (95% CI, 0.95-1.01) for UGI series. As the number of endoscopic screening tests performed per subject increased, the ORs of death from gastric cancer decreased: 0.60 (95% CI, 0.57-0.63), 0.32 (95% CI, 0.28-0.37), and 0.19 (95% CI, 0.14-0.26) for once, twice, and 3 or more times, respectively. CONCLUSIONS: Within the Korean National Cancer Screening Program, patients who received an upper endoscopy were less likely to die from gastric cancer; no associations were found for UGI series.

Risk of Interval Cancer in Fecal Immunochemical Test Screening Significantly Higher During the Summer Months: Results from the National Cancer Screening Program in Korea.

OBJECTIVES: This study aimed to evaluate the impact of seasonal variations in climate on the performance of the fecal immunochemical test (FIT) in screening for colorectal cancer in the National Cancer Screening Program in Korea. METHODS: Data were extracted from the National Cancer Screening Program databases for participants who underwent FIT between 2009 and 2010. We compared positivity rates, cancer detection rates, interval cancer rates, positive predictive value, sensitivity, and specificity for FIT during the spring, summer, fall, and winter seasons in Korea. RESULTS: In total, 4,788,104 FIT results were analyzed. FIT positivity rate was lowest during the summer months. In the summer, the positive predictive value of FIT was about 1.1 times (adjusted odds ratio (aOR) 1.08, 95% confidence interval (CI) 1.00-1.16) higher in the overall FIT group and about 1.3 times (aOR 1.29, 95% CI 1.10-1.50) higher in the quantitative FIT group, compared to those in the other seasons. Cancer detection rates, however, were similar regardless of season. Interval cancer risk was significantly higher in the summer for both the overall FIT group (aOR 1.16, 95% CI 1.07-1.27) and the quantitative FIT group (aOR 1.31, 95% CI 1.12-1.52). In addition, interval cancers in the rectum and distal colon were more frequently detected in the summer and autumn than in the winter. CONCLUSIONS: The positivity rate of FIT was lower in the summer, and the performance of the FIT screening program was influenced by seasonal variations in Korea. These results suggest that more efforts to reduce interval cancer during the summer are needed in population-based screening programs using FIT, particularly in countries with high ambient temperatures.

Comparison of cervical cancer screening among women with and without hysterectomies: a nationwide population-based study in Korea.

BACKGROUND: Cervical cancer screening is not recommended for women who underwent hysterectomy with no history of cervical intraepithelial neoplasia (CIN) of grade 2 or higher. We aimed to determine the cervical cancer screening rate in Korean women who underwent hysterectomies and compare it to that in women with intact uteri. METHODS: We used data from the 2014-2016 Korean National Cancer Screening Survey; 6807 women aged 30-74 years were included in the study. Participants were asked about their experiences with cervical cancer screening, hysterectomy status, and other variables associated with cancer screening. RESULTS: The screening rates among women who have undergone a hysterectomy vs. those who have not during the past 2 years were 61.8% (95% confidence interval [CI], 58.8-64.9) and 64.7% (95% CI, 64.1-65.3), respectively. Among younger women (30-44 years) and women with a family history of cancer, those with hysterectomies showed a higher cervical cancer screening rate than those without (77.8% vs. 57.1% and 75.0% vs. 67.1%, respectively). CONCLUSIONS: Despite available evidence and clinical recommendations, a considerable number of Korean women who no longer have a cervix continue to undergo unnecessary cervical cancer screening. It is necessary to identify the exact underlying causes for this phenomenon, and systematic efforts are required to prevent unnecessary screening for women who have undergone a hysterectomy.

Higher satisfaction with an alternative collection device for stool sampling in colorectal cancer screening with fecal immunochemical test: a cross-sectional study.

BACKGROUND: Identifying preferences for stool collection devices may help increase uptake rates for colorectal cancer screening via fecal immunochemical test (FIT). This study surveyed satisfaction with different devices utilized to collect stool samples for FIT: a conventional container and a sampling bottle (Eiken OC-Sensor). METHODS: This cross-sectional study was conducted at the National Cancer Center, Korea. Participants aged 50-74 years who used either a conventional container or a sampling bottle to collect a stool sample for FIT were asked to complete a questionnaire designed to survey their satisfaction with the stool collection process and their intentions to undergo FIT in subsequent screening rounds. In total, 1657 participants (1224 conventional container, 433 sampling bottle) were included for analysis. RESULTS: Satisfaction with the sampling bottle was higher than that with the conventional container (79.9% vs.73.0%, p = 0.005, respectively; aOR = 1.52, 95% CI: 1.16-2.00). Participants satisfied with the sampling bottle were more likely to be female, be of younger age (50-64 years old), have higher household income, and have prior experience with FIT. Intentions to undergo subsequent screening were stronger among those given the sampling bottle than those given the conventional container (aOR = 1.78, 95% CI: 1.28-2 .48). CONCLUSIONS: Satisfaction with the stool collection process was higher with the sampling bottle. However, additional studies are needed to validate whether the increased satisfaction and stronger intentions to undergo subsequent screening with the sampling bottle could actually lead to increased uptake in subsequent rounds, along with analysis of the device's cost effectiveness.

Health Effects from Occupational Radiation Exposure among Fluoroscopy-Guided Interventional Medical Workers: A Systematic Review.

A systematic review was conducted to provide an overview of the health effects of occupational radiation exposure from interventional fluoroscopy procedures on medical radiation workers. Among the 34 studies that met the inclusion criteria, most studies were cross-sectional (76%) and published after 2011 (65%) in a handful of countries. Although diverse outcomes were reported, most studies focused on cataracts. Radiation health effects were rarely assessed by risk per unit dose. Interventional radiation medical workers represent a small subset of the population studied worldwide. Further epidemiologic studies should be conducted to evaluate health outcomes among interventional radiation medical workers.

Perceptions of colorectal cancer screening and recommendation behaviors among physicians in Korea.

BACKGROUND: Physician recommendations for colorectal cancer (CRC) screening have consistently been shown to be a strong predictor of screening. The aim of this study was to investigate perceptions of CRC screening modalities and recommendation behaviors among physicians in Korea. METHODS: A cross-sectional, nationally representative survey conducted between November 2013 and February 2014. In total, 379 physicians (241 primary care physicians and 138 physicians affiliated with the Korean Association for the Study of Intestinal Diseases responded to this survey (overall response rate of 31.4%). RESULTS: About 29% of all respondents "always" recommended and about 67% "sometimes" recommended CRC screening. Colonoscopy was perceived as an effective primary screening tool for CRC, and 80% of the physicians recommended colonoscopy for CRC screening. Only 7% recommended FOBT. In multivariate analysis, recommending FOBT was associated with stronger belief in the screening efficacy of FOBT (aOR 3.70, 95% CI 2.09, 6.57), weaker belief in the screening efficacy of colonoscopy (aOR 0.29, 95% CI 0.12, 0.69), and negative decisional balance for colonoscopy screening (aOR 0.82, 95% CI 0.71, 0.95). CONCLUSIONS: Although FOBT is provided free-of-charge through a nationwide CRC screening program, colonoscopy was more commonly recommended and preferred by physicians.

Alanine aminotransferase and gamma-glutamyl transferase have different dose-response relationships with risk of mortality by age.

BACKGROUND & AIMS: It remains unclear whether the respective dose-response relationships between serum alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT) levels and risk of mortality are consistent by age. METHODS: We used sampled cohort data from the National Health Insurance Corporation to conduct a retrospective cohort study. A total of 313 252 participants who received medical health check-ups from 2002 to 2008 were assessed for risk of death according to serum ALT and GGT levels over an average of 6 years. The hazard ratios (HRs) for mortality were analysed with Cox proportional hazard model. RESULTS: The crude mortality rate increased linearly with increasing serum ALT and GGT levels in adults aged <60 years. However, the all-cause mortality rate showed a J-shaped relationship with increasing serum ALT levels whereas all-cause mortality rate showed a linear relationship with increasing serum GGT levels in adults aged ≥60 years. The HR of death showed U-shaped relationships with increasing serum ALT levels in adults aged ≥60 years. On the contrary, the HR of death from any cause had a linear association with increasing serum GGT levels among all age groups. CONCLUSIONS: In this study, U-shaped relationship patterns were demonstrated between serum ALT levels and risk for all-cause mortality in adults aged ≥60 years while serum GGT levels showed a linear relationship with risk for all-cause death. Very low levels of serum ALT in elderly patients suggest that they are at high risk of mortality.

A qualitative study of women's views on overdiagnosis and screening for thyroid cancer in Korea.

BACKGROUND: The incidence of thyroid cancer in Korea has increased by about 25 % every year for the past 10 years. This increase is largely due to a rising incidence in papillary thyroid cancer, which is associated with an overdiagnosis of small tumors that may never become clinically significant. This study was conducted to explore Korean women's understanding of overdiagnosis and to investigate changes in screening intention in response to overdiagnosis information. METHODS: Focus group interviews were conducted among women of ages 30-69 years, who are commonly targeted in Korea for cancer screening. Women were divided into four groups according to thyroid cancer screening history and history of thyroid disease. Of 51 women who were contacted, 29 (57 %) participated in the interviews. RESULTS: Prior awareness of thyroid cancer overdiagnosis was minimal. When informed about the risks of overdiagnosis, the participants were often surprised. Overcoming initial malcontent, many women remained skeptic about overdiagnosis and trusted in the advice of their physicians. Meanwhile, some of the study participants found explanations of overdiagnosis difficult to understand. Further, hearing about the risks of overdiagnosis had limited impact on the participants' attitudes and intentions to undergo thyroid cancer screening, as many women expressed willingness to undergoing continued screening in the future. CONCLUSION: A large majority of Korean women eligible for and had undergone thyroid cancer screening were unaware of the potential for overdiagnosis. Nevertheless, overdiagnosis information generally had little impact on their beliefs about thyroid cancer screening and their intentions to undergo future screening. Further research is needed to determine whether these findings could be generalized to the wider Korean population.

The radiologic technologists' health study in South Korea: study design and baseline results.

PURPOSE: To describe the study design, methods, and baseline results of a prospective cohort of radiologic technologists which we have initiated in South Korea. METHODS: The cohort participants were enrolled through a self-administered questionnaire survey administered from April 2012 to May 2013. Survey data were linked with radiation dosimetry, a cancer registry, and health insurance data by personal identification numbers. A nationwide representative survey was also conducted using a stratified random sampling design with face-to-face interviews. RESULTS: A total of 12,387 radiologic technologists were enrolled, which accounted for approximately 63% of all diagnostic radiologic technologists working in South Korea. For nationwide survey, 585 workers were interviewed using the detailed questionnaire, and buccal cells were also collected by scraping the inside of the cheek. The majority of study subjects were under 50-year-old and male workers. The average annual effective dose of radiation declined both men (from 2.75 to 1.43 mSv) and women (from 1.34 to 0.95 mSv) over the period of 1996-2011. A total of 99 cancers (66 cancers in men and 33 in women) were reported from 1992 to 2010. The standardized incidence ratio of all cancer combined was significantly lower in men (SIR = 0.75, 95% CI 0.58-0.96) than general population, but the ratios for thyroid cancer were significantly higher than expected among both men and women. CONCLUSIONS: This cohort provides comprehensive information on work activities and health status of diagnostic radiologic technologists. In addition, the nationwide representative sample provides unique opportunities compared with previous radiologic technologist studies.

Different socioeconomic inequalities exist in terms of the prevention, diagnosis and control of diabetes.

OBJECTIVE: To evaluate socioeconomic disadvantage in prevalence, awareness and control of diabetes in universal coverage healthcare system. METHODS: Data from the fifth KNHNES (2010-12) were analyzed. The sample included 10,208 individuals with diabetes aged ≥30 years. Diabetes was defined by (i) a self-reported previous diagnosis of diabetes made by a physician, (ii) the current use of oral hypoglycaemic agents and/or insulin or (iii) fasting plasma glucose ≥126 mg/dl. Subjects who were first diagnosed by the survey were classified as 'undiagnosed'. Inadequate control was defined as HbA1c ≥6.5%. RESULTS: It was estimated that 26.4% of subjects with diabetes were not aware of their condition and 73.1% of cases of diabetes were not adequately controlled. Inequalities in socioeconomic status were related to the diabetes prevalence in both men and women. Educational level was not predictive of diagnosis or control in men or women, whereas lower household income level was associated with diagnosis in men only. CONCLUSIONS: This widespread lack of awareness and inadequate control underscore the need for intensive efforts in these domains. Monitoring is expected to highlight the gaps in the preventive and care services offered to the most vulnerable individuals and it may induce governments and practitioners to address these issues.