No abstract

Objective To investigate whether screening for thyroid cancer led to the current “epidemic” in South Korea.Design Review of the medical records of nationally representative samples of patients with a diagnosis of thyroid cancer in 1999, 2005, and 2008.Setting Sample cases were randomly selected from South Korea’s nationwide cancer registry, using a systematic sampling method after stratification by region.Participants 5796 patients with thyroid cancer were included (891 in 1999, 2355 in 2005, and 2550 in 2008).Main outcome measures The primary outcome was age standardised incidence of thyroid cancer and the changes in incidence between 1999 and 2008 according to the methods used to detect tumours (screen detection versus clinical detection versus unspecified).Results Between 1999 and 2008, the incidence of thyroid cancer increased 6.4-fold (95% confidence interval 4.9-fold to 8.4-fold), from 6.4 (95% confidence interval 6.2 to 6.6) per 100 000 population to 40.7 (40.2 to 41.2) per 100 000 population. Of the increase, 94.4% (34.4 per 100 000 population) were for tumours less than 20 mm, which were detected mainly by screening. 97.1% of the total increase was localised and regional tumours according to the Surveillance, Epidemiology, and End Results (SEER) summary stage. Where cases were clinically detected, 99.9% of the increased incidences (6.4 per 100 000 population) over the same period were tumours less than 20 mm.Conclusion The current “epidemic” of thyroid cancer in South Korea is due to an increase in the detection of small tumours, most likely as a result of overdetection. Concerted efforts are needed at a national level to reduce unnecessary thyroid ultrasound examinations in the asymptomatic general population.

PurposeThe National Cancer Screening Program (NCSP) in Korea supports cancer screening for stomach, liver, colorectal, breast, and cervical cancer. This study was conducted to assess trends in participation rates among Korean men and women invited to undergo screening via the NCSP as part of an effort to guide future implementation of the program in Korea.Materials and MethodsData from the NCSP for 2002 to 2012 were used to calculate annual participation rates with 95% confidence intervals (CI) by sex, insurance status, and age group for stomach, liver, colorectal, breast, and cervical cancer screening.ResultsIn 2012, participation rates for stomach, liver, colorectal, breast, and cervical cancer screening were 47.3%, 25.0%, 39.5%, 51.9%, and 40.9%, respectively. The participation rates increased annually by 4.3% (95% CI, 4.0 to 4.6) for stomach cancer, 3.3% (95% CI, 2.5 to 4.1) for liver cancer, 4.1% (95% CI, 3.2 to 5.0) for colorectal cancer, 4.6% (95% CI, 4.1 to 5.0) for breast cancer, and 0.9% (95% CI, –0.7 to 2.5) for cervical cancer from 2002 to 2012.ConclusionParticipant rates for the NCSP for the five above-mentioned cancers increased annually from 2002 to 2012.

BackgroundThere is a lack of agreement on which gastric cancer screening method is the most effective in the general population. The present study compared the relative performance of upper-gastrointestinal series (UGIS) and endoscopy screening for gastric cancer.MethodsA population-based study was conducted using the National Cancer Screening Program (NCSP) database. We analyzed data on 2,690,731 men and women in Korea who underwent either UGIS or endoscopy screening for gastric cancer between January 1, 2002 and December 31, 2005. Final gastric cancer diagnosis was ascertained through linkage with the Korean Central Cancer Registry. We calculated positivity rate, gastric cancer detection rate, interval cancer rate, sensitivity, specificity, and positive predictive value of UGIS and endoscopy screening.ResultsThe positivity rates for UGIS and endoscopy screening were 39.7 and 42.1 per 1,000 screenings, respectively. Gastric cancer detection rates were 0.68 and 2.61 per 1,000 screenings, respectively. In total, 2,067 interval cancers occurred within 1 year of a negative UGIS screening result (rate, 1.17/1,000) and 1,083 after a negative endoscopy screening result (rate, 1.17/1,000). The sensitivity of UGIS and endoscopy screening to detect gastric cancer was 36.7 and 69.0%, respectively, and specificity was 96.1 and 96.0%. The sensitivity of endoscopy screening to detect localized gastric cancer was 65.7%, which was statistically significantly higher than that of UGIS screening.ConclusionOverall, endoscopy performed better than UGIS in the NCSP for gastric cancer. Further evaluation of the impact of these screening methods should take into account the corresponding costs and reduction in mortality.

PurposeThe Korean National Cancer Screening Survey (KNCSS), a nationwide cross-sectional survey, has been conducted annually since 2004. The current study was conducted to report on the trends in screening rates among Korean men and women, and to evaluate policies regarding cancer screening programs implemented to reduce the burden of cancer.Materials and MethodsThe current study used KNCSS data. The eligible study population included men aged 40-74 years and women aged 30-74 years with no cancer history. The lifetime screening rate, screening rate with recommendation, and changes in annual rates were calculated for five major cancers (i.e., stomach, liver, colorectal, breast, and cervix uteri).ResultsThe screening rates with recommendation increased by 4.2% (95% confidence interval [CI], 3.7% to 4.8%) annually for stomach cancer, 1.2% (95% CI, 0.1% to 2.4%) for liver cancer, 3.0% (95% CI, 1.8% to 4.1%) for colorectal cancer, 3.7% (95% CI, 2.7% to 4.8%) for breast cancer, and 1.3% (95% CI, 0.8% to 1.8%) for cervical cancer. In 2013, the screening rates with recommendation for stomach, liver, colorectal, breast, and cervical cancers were 73.6%, 33.6%, 55.6%, 59.7%, and 67.0%, respectively.ConclusionBoth the lifetime screening rates and screening rates with recommendation for the five above-mentioned cancers increased annually from 2004 to 2013.

BackgroundCancer screening rates in Korea for five cancer types have increased steadily since 2002. With regard to the life-time cancer screening rates in 2009 according to cancer sites, the second highest was breast cancer (78.1%) and the third highest was cervical cancer (76.1%). Despite overall increases in the screening rate, disparities in breast and cervical cancer screening, based on sociodemographic characteristics, still exist.MethodsData from 4,139 women aged 40 to74 years from the 2005 to 2009 Korea National Cancer Screening Survey were used to analyze the relationship between sociodemographic characteristics and receiving mammograms and Pap smears. The main outcome measures were ever having had a mammogram and ever having had a Pap smear. Using these items of information, we classified women into those who had had both types of screening, only one screening type, and neither screening type. We used logistic regression to investigate relationships between screening history and sociodemographic characteristics of the women.ResultsBeing married, having a higher education, a rural residence, and private health insurance were significantly associated with higher rates of breast and cervical cancer screening after adjusting for age and sociodemographic factors. Household income was not significantly associated with mammograms or Pap smears after adjusting for age and sociodemographic factors.ConclusionsDisparities in breast and cervical cancer screening associated with low sociodemographic status persist in Korea.

OBJECTIVESAssessing 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.METHODSThe 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.RESULTSThe 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.CONCLUSIONSThe 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.

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.