Lung Cancer Incidence by Smoking Status in Korean Men: 16-Years of Observations in the Seoul Male Cancer Cohort Study

The relative risk (RR) of smoking and mortality of lung cancer in British doctors was previously reported to have increased throughout a 40-yr period. Here, we evaluated this RR based on the incidence of lung cancer in Korean men using a longer follow-up period. We compared our data to the RR reported in a study using a 10-yr follow-up period; the subjects and methods were identical to those of the previous paper with the exception of the follow-up period, which ended on December 31, 2008. We found that the RR of smoking habits in patients with lung cancer did not increase, and that the data showed narrowing 95% confidence intervals over a longer observation in Korean men. Estimated lung cancers attributable to smoking were 55.6%. These results highlight the need for an intervention program to help patients quit smoking in Korea.

Perspectives of clinical epidemiology in Korea

The establishment of clinical epidemiology has meant the improvement of the quality and quantity of clinical science because clinical epidemiology has contributed to the process of decision making across the full scope of clinical practice, including diagnosis, treatment, and care, as well as prevention. Epidemiological and statistical methodologies have been used to analyze scientific evidence on clinical problems. The orientation of evidence-based medicine introduced in the mid-1990s is the application of clinical epidemiology to clinical practice for individual patients. The concept of evidence-based medical practice has triggered the expansion of the scope and range of methods of clinical epidemiology. In spite of the global situation, the formal activity in the area of clinical epidemiology in Korean Medical Academic Association is negligible, with few clinical epidemiologists involved. One of several approaches to stimulating the practice of clinical epidemiology in Korea would be to foster clinical epidemiology as a specialization of clinical preventive medicine, which is one of the sub-specialties of preventive medicine in Korea.

Pulmonary Tuberculosis and Lung Cancer Risk in Current Smokers: The Seoul Male Cancer Cohort Study

Authors evaluated pulmonary tuberculosis (PTB) history as a risk factor for lung cancer in current male smokers in a prospective, population-based cohort study. The subjects were the 7,009 males among the participants in the Seoul Male Cancer Cohort Study for whom there was full information on PTB history and smoking habits. With a 16-yr follow-up, 93 cases of lung cancer occurred over the 99,965 person-years of the study. The estimated relative risk (RR) of PTB history of current smokers in lung cancer after adjusting for three confounders - intake of coffee and tomatoes, and age at entry - was 1.85 (95% CI: 1.08-3.19). The observed joint RRs and attributable risks (ARs) across strata of three confounders were greater than the expected, indicating a positive interaction. Thus a history of PTB in current smokers may be another risk factor for lung cancer. Based on a synergic interaction, a heavy male smoker with a PTB history would be expected to belong to the group at high risk of lung cancer.

Cardiovascular Health Metrics and All-cause and Cardiovascular Disease Mortality Among Middle-aged Men in Korea: The Seoul Male Cohort Study / 예방의학회지

OBJECTIVES: This study estimated the association of cardiovascular health behaviors with the risk of all-cause and cardiovascular disease (CVD) mortality in middle-aged men in Korea. METHODS: In total, 12 538 men aged 40 to 59 years were enrolled in 1993 and followed up through 2011. Cardiovascular health metrics defined the following lifestyle behaviors proposed by the American Heart Association: smoking, physical activity, body mass index, diet habit score, total cholesterol, blood pressure, and fasting blood glucose. The cardiovascular health metrics score was calculated as a single categorical variable, by assigning 1 point to each ideal healthy behavior. A Cox proportional hazards regression model was used to estimate the hazard ratio of cardiovascular health behavior. Population attributable risks (PARs) were calculated from the significant cardiovascular health metrics. RESULTS: There were 1054 total and 171 CVD deaths over 230 690 person-years of follow-up. The prevalence of meeting all 7 cardiovascular health metrics was 0.67%. Current smoking, elevated blood pressure, and high fasting blood glucose were significantly associated with all-cause and CVD mortality. The adjusted PARs for the 3 significant metrics combined were 35.2% (95% confidence interval [CI], 21.7 to 47.4) and 52.8% (95% CI, 22.0 to 74.0) for all-cause and CVD mortality, respectively. The adjusted hazard ratios of the groups with a 6-7 vs. 0-2 cardiovascular health metrics score were 0.42 (95% CI, 0.31 to 0.59) for all-cause mortality and 0.10 (95% CI, 0.03 to 0.29) for CVD mortality. CONCLUSIONS: Among cardiovascular health behaviors, not smoking, normal blood pressure, and recommended fasting blood glucose levels were associated with reduced risks of all-cause and CVD mortality. Meeting a greater number of cardiovascular health metrics was associated with a lower risk of all-cause and CVD mortality.

Prevalence Rate and Associated Factors of Sarcopenic Obesity in Korean Elderly Population

This study was conducted to estimate the prevalence rates and to explore associated factors of sarcopenic obesity (SO) in 2,221 Koreans over 60 yr-of age from the Fourth Korea National Health and Nutrition Examination Survey (2009). Participants were assessed by dual energy X-ray absorptiometry. Appendicular skeletal muscle mass divided by body weight was used to define sarcopenia and waist circumference was used to define obesity. We estimated the prevalence rates of SO according to age-groups, sex and region. In addition, each group was compared by demographic characteristics, metabolic status, nutrition, and physical activity. The prevalence rates of SO were 6.1% (95% confidential interval [CI] = 6.1-6.2) for men and 7.3% (95% CI = 7.3-7.3) for women, respectively. SO was positively associated with no current working and the number of combined medical conditions. High serum insulin level was positively associated with SO, whereas vitamin D was negatively associated with SO in both men and women. In conclusion, the prevalence rates of SO are 6.1% in men and 7.3% in women. SO is associated with insulin resistance, inappropriate nutrition, and low physical activity.

Completeness of Cancer Case Ascertainment in Korea Radiation Effect and Epidemiology Cohort Study

The aim of this study was to evaluate whether the completeness of case ascertainment during the follow-up of a cohort differed between the exposed and the nonexposed groups in Korea Radiation Effect and Epidemiology Cohort (KREEC). The completeness was defined as the proportion of the number of detected cases to the number of estimated cases, in which the estimation was performed by capture-recapture method. Data were obtained from the cancer registries, death certificates, and medical records during years 2004-2007. Among 11,367 subjects in the exposed group and 24,809 subjects in the unexposed group, the completeness of cancer case ascertainment were 88.2% vs 87.2% in cancer registry, 38.2% vs 41.1% in death certificate and 57.9% vs 62.0% in medical records data, 96.9% vs 97.1% for all combined sources and were not statistically different between the two groups. In conclusion, the method of ascertaining the cases in the KREEC was not biased depending on the exposure status, and thus adds credibility to the outcomes of the KREEC study as well as confirming the incident cases in the two groups.

Cancer Risk in Adult Residents near Nuclear Power Plants in Korea: A Cohort Study of 1992-2010

This study evaluated cancer risk for adult residents near Nuclear Power Plants (NPPs) in Korea through a valid prospective cohort study during 1992-2010. The study cohort was composed of 11,367 adults living within a five km radius from the NPPs for the exposed and 24,809 adults for the non-exposed or reference cohort set at two different levels of proximity; 5-30 km radius and more than 30 km radius away from NPPs. In 303,542.5 person-years of follow-up, a total of 2,298 cancer cases of all sites, or 1,377 radio-inducible cancers diagnosed during 1992-2008 were ascertained. Multiple adjusted hazard ratios and 95% confidence intervals were estimated using multivariate Cox proportional hazard model. There were no epidemiological evidence for increased risk of cancer due to radiation from NPPs. Radiological study results or surveillance data of radiation doses around NPPs could be well documented for risk estimation of radio-inducible cancers, instead of epidemiological study results of the long-time required. Continuous surveillance of quantitative measures of dose levels around NPPs and radiation exposures to the residents is warranted.

Low Cholesterol is Associated with Mortality from Cardiovascular Diseases: A Dynamic Cohort Study in Korean Adults

This study was conducted to evaluate the association of single serum total cholesterol (TC) measurement with cardiovascular diseases (CVD) deaths in Korean adults. The study subjects were taken from the multi-site collaborative dynamic prospective cohort for epidemiologic investigation on cancer risk in residents nearby nuclear power plants in Korea. A total of 12,740 adults aged 40 to 69 yr who underwent a mass screening examination were followed up from 1993 to 2008. Occurring CVD deaths were confirmed by the death certificates in the National Statistical Office, Korea. Groups with the lowest group having TC = 240 mg/dL were associated with higher CVD mortality in Cox proportional hazards analysis adjusting for age, sex, smoking and drinking status, body mass index, level of blood pressure, triglyceride and high density lipoprotein cholesterol. The distribution of adjusted hazard ratios showed the U-shaped curve. Based on the results of this study, caution should be taken in prescribing statins for primary prevention among people at low cardiovascular risk in Korean adults.

Impact of Individual and Combined Health Behaviors on All Causes of Premature Mortality Among Middle Aged Men in Korea: The Seoul Male Cohort Study / 예방의학회지

OBJECTIVES: The aim of this study was to evaluate and quantify the risk of both individual and combined health behaviors on premature mortality in middle aged men in Korea. METHODS: In total, 14 533 male subjects 40 to 59 years of age were recruited. At enrollment, subjects completed a baseline questionnaire, which included information about socio-demographic factors, past medical history, and life style. During the follow-up period from 1993 to 2008, we identified 990 all-cause premature deaths using national death certificates. A Cox proportional hazard regression model was used to estimate the hazard ratio (HR) of each health risk behavior, which included smoking, drinking, physical inactivity, and lack of sleep hours. Using the Cox model, each health behavior was assigned a risk score proportional to its regression coefficient value. Health risk scores were calculated for each patient and the HR of all-cause premature mortality was calculated according to risk score. RESULTS: Current smoking and drinking, high body mass index, less sleep hours, and less education were significantly associated with all-cause premature mortality, while regular exercise was associated with a reduced risk. When combined by health risk score, there was a strong trend for increased mortality risk with increased score (p-trend < 0.01). When compared with the 1-9 score group, HRs of the 10-19 and 20-28 score groups were 2.58 (95% confidence intervals [CIs], 2.19 to 3.03) and 7.09 (95% CIs, 5.21 to 9.66), respectively. CONCLUSIONS: Modifiable risk factors, such as smoking, drinking, and regular exercise, have considerable impact on premature mortality and should be assessed in combination.

Establishment of Korean Dietary Guidelines for Cancer Prevention

BACKGROUND: As a leading cause of death in Korea, cancer is known to be related to lifestyle including diet. In 2007, the World Cancer Research Fund announced 10 evidence-based guidelines for reducing the number of cancers. The purpose of this paper was to produce guidelines specific to and relevant to the people of Korea. METHODS: Ranging over 6 categories, 15 dietary factors known to be associated with cancers were selected after reviewing the results of relevant researches including Korean subjects and evidence-based research documents regarding the relationships between cancer and diet. The levels of intake of these selected dietary factors by Koreans were compared to the established dietary guidelines and detailed practices for cancer prevention. RESULTS: The Korean dietary guidelines for cancer prevention consists of 8 detailed recommendations along with multiple specific practices based on the analyses of data and documents on weight and intake of cereals, fruits, vegetables, meat, salt, dairy products, alcohol, and nutrient supplements. CONCLUSIONS: The Korean dietary guidelines for cancer prevention were established based on valid scientific approach by analyzing the most recent available data. For some dietary factors, however, sufficient analysis for intake levels in Koreans was not possible. Therefore, fundamental data for the establishment of national strategy and for guideline amendments for preventing cancers need to be gathered through the analyses of relationships between cause and deaths due to cancer, database reinforcement, additional research including Korean subjects, and assessment of usual intake.

Concepts and necessity of preventive medical services for the 21st century

Not only disease patterns but also the contents and concepts of medical services are rapidly changing recent years. A quick look at the evolution of health care services shows that it has evolved in two major ways. First, medical interventions are gradually moving towards the prevention before diseases development. Second, the medical services have become individualized or tailored. The shift to preventive medical care is the most anticipated change in medical services in the 21st century. Theses phenomena are believed as a logical progression in the transition and evolution of medical services, and as a equivalence of the changing medical environment, such as progress in health care technology and changes in life value etc. Clinical practice based on evidence-based medicine is what distinguishes modern medicine from traditional medicine. Preventive medical services have also been established based on scientific evidence. The academic knowledge used as a basis for preventive medical services comes from the investigation of disease etiology, i.e. epidemiology. In the 21st century, the preventive medical service will be differentiated and enlarged to broad areas of medical practice and the target of the service may be focused to the a variety of complex diseases.

Reliability of Covariates in Baseline Survey of a Cohort Study: Epidemiological Investigation on Cancer Risk Among Residents Who Reside Near the Nuclear Power Plants in Korea / 예방의학회지

OBJECTIVES: We evaluated the reliability of the possible covariates of the baseline survey data collected for the Epidemiological Investigation on Cancer Risk Among Residents Who Reside Near the Nuclear Power Plants in Korea. METHODS: Follow-up surveys were conducted for 477 participants of the cohort at less than 1 year after the initial survey. The mean interval between the initial and follow-up surveys was 282.5 days. Possible covariates were identified by analyzing the correlations with the exposure variable and associations with the outcome variables for all the variables. Logistic regression analysis with stepwise selection was further conducted among the possible covariates to select variables that have covariance with other variables. We considered that these variables can be representing other variables. Seven variables for the males and 3 variables for the females, which had covariance with other possible covariates, were selected as representative variables. The Kappa index of each variable was calculated. RESULTS: For the males, the Kappa indexes were as follow; family history of cancer was 0.64, family history of liver diseases in parents and siblings was 0.56, family history of hypertension in parents and siblings was 0.51, family history of liver diseases was 0.50, family history of hypertension was 0.44, a history of chronic liver diseases was 0.53 and history of pulmonary tuberculosis was 0.36. For females, the Kappa indexes were as follow; family history of cancer was 0.58, family history of hypertension in parents and siblings was 0.56 and family history of hypertension was 0.47. CONCLUSIONS: Most of the possible covariates showed good to moderate agreement.

Power Estimation and Follow-Up Period Evaluation in Korea Radiation Effect and Epidemiology Cohort Study / 예방의학회지

OBJECTIVES: The objective of this study was to calculate sample size and power in an ongoing cohort, Korea radiation effect and epidemiology cohort (KREEC). METHOD: Sample size calculation was performed using PASS 2002 based on Cox regression and Poisson regression models. Person-year was calculated by using data from '1993-1997 Total cancer incidence by sex and age, Seoul' and Korean statistical informative service. RESULTS: With the assumption of relative risk=1.3, exposure:non-exposure=1:2 and power=0.8, sample size calculation was 405 events based on a Cox regression model. When the relative risk was assumed to be 1.5 then number of events was 170. Based on a Poisson regression model, relative risk=1.3, exposure:non-exposure=1:2 and power=0.8 rendered 385 events. Relative risk of 1.5 resulted in a total of 157 events. We calculated person-years (PY) with event numbers and cancer incidence rate in the non-exposure group. Based on a Cox regression model, with relative risk=1.3, exposure:non-exposure=1:2 and power=0.8, 136 245PY was needed to secure the power. In a Poisson regression model, with relative risk=1.3, exposure:non-exposure=1:2 and power=0.8, person-year needed was 129517PY. A total of 1939 cases were identified in KREEC until December 2007. CONCLUSIONS: A retrospective power calculation in an ongoing study might be biased by the data. Prospective power calculation should be carried out based on various assumptions prior to the study.

Nationwide Cancer Incidence in Korea, 2003-2005 / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: To estimate the current cancer burden in Korea, newly diagnosed cancer cases and cancer incidence rates were calculated for the years 2003~2005. MATERIALS AND METHODS: The cancer incidence cases and rates were calculated from the Korea National Cancer Incidence Database. Crude and age-standardized incidence rates were calculated by gender for specified cancer sites in 5-year age groups. RESULTS: From 2003 to 2005, 398,824 cases of cancer were newly diagnosed in Korea (218,856 in men and 179,968 in women). For all sites combined, the crude incidence rate (CR) was 300.0 and 248.2 for men and women and the age-standardized incidence rate (ASR) was 297.0 and 191.2 per 100,000, respectively. Among men, five leading cancers were stomach (CR 66.0, ASR 64.2), lung (CR 48.5, ASR 50.3), liver (CR 44.9, ASR 42.1), colon and rectum (CR 37.9, ASR 37.2), and prostate cancer (CR 12.7, ASR 13.8). Among women, five leading cancers were breast (CR 37.3, ASR 29.0), thyroid (CR 36.2, ASR 28.8), stomach (CR 34.1, ASR 25.4), colon and rectum (CR 28.0, ASR 21.1), and lung cancer (CR 17.9, ASR 12.8). In the 0~14-year-old group, leukemia was the most common in both sexes; in the 15~34 group, the most common cancer was stomach cancer for men and thyroid cancer for women; in the 35~64 group, stomach cancer for men and breast cancer for women; among those 65 and over, lung cancer for men and stomach cancer, for women, respectively. CONCLUSION: The cancer incidence rates have increased in recent years, and more cancers are expected to develop as Korea is quickly becoming an aged society. The cancer incidence statistics in this report can be used as an important source to effectively plan and evaluate the cancer control program in Korea.

Ten Year Trend of Cancer Incidence in Seoul, Korea: 1993-2002 / 예방의학회지

OBJECTIVES: Effective cancer prevention and control measures can only be done when dependable data on the cancer incidence is available. The Seoul Cancer Registry (SCR) was founded to provide valid, comparable and representative cancer incidence data for Koreans. We aimed to compare the cancer incidence in the first (1993-1997) and second term (1998-2002) of the SCR, and we analyzed the annual incidence trend during that 10 years. METHODS: The SCR detects potential cancer cases through the Korean Central Cancer Registry (KCCR) data, the health insurance claims, the individual hospital's discharge records and the death certificates. About 87% of the SCR data is registered through the KCCR. The rest of the data is registered by SCR registrars who visit about 70~80 mid-sized hospitals in Seoul to review and abstract the medical records of the potential cancer patients. RESULTS: The total number of new cancer cases was higher in 1998~2002 than in 1993~1997 by 20.6% for men and 18.4% for women, respectively. The age-standardized rate (ASR) of total cancer per 100,000 increased 1% (from 295.4 to 298.3) for men and 5.1% (from 181.5 to 190.7) for women, between the two periods. The commonest cancer sites during 1998-2002 for men were stomach, liver, bronchus/lung, colorectum, bladder and prostate, and the commonest cancer sites for women were breast, stomach, colorectum, cervix uteri, thyroid and bronchus/lung. Compared with the ASRs in 1993, the ASRs in 2002 increased for colorectum (58.4% for men, 27.1% for women), prostate (81.5%), breast (58.3% for women), thyroid (141% for women), and bronchus/lung (15.4% for women). The ASRs for stomach (-18.7% for men, -20.7% for women) and uterine cervix cancer (-39.7%) had decreased. CONCLUSIONS: The cancer incidence is increasing in Seoul, Korea, especially for the colorectum and prostate for men, and for the breast, colorectum, bronchus/lung and thyroid for women.

Seasonal Variation of Food Intake in Food Frequency Questionnaire among Workers in a Nuclear Power Plant / 예방의학회지

OBJECTIVES: This study was conducted to investigate the systematic error, such as seasonal change or inadequate food items, in a food frequency questionnaire administered to workers in a Nuclear Power Plant, Korea. METHODS: We performed three repeat-tests with 28 subjects on May 13, July 8 and Dec 16, 1992. Our food frequency questionnaire (FFQ) comprised 84 foods organized into 7 food-groups, and was composed of the items of usual intake frequency (8 categories) and the amount per intake (3 or 4 categories) over the previous year. We compared the means of intake frequency and the frequency of the portion-size according to each season using Repeated Measures ANOVA and Pearson's chisquare test with Fisher's exact test. RESULTS: We found the significant seasonal changes of several food items in intake frequency measurement. These items were typical seasonal foods such as mandarin orange, plum and green vegetables, while the single questions consisted of inadequate food items such as thick beef or similar soup and various kimchi products. Significant seasonal changes in portion-size were found in only two items: cooked rice-brown and fresh.frozen fishes. CONCLUSIONS: The systematic errors observed could caused loss of validity in the FFQ. Consideration should be given for seasonal variation in FFQ survey and methodological concerns are needed to improve the quality for measuring usual diet pattern.

Cigarette Smoking and Risk of Lung Cancer in Korean Men: The Seoul Male Cancer Cohort Study

Lung cancer is the leading cause of cancer deaths in Korea. The aim of this study was to estimate lung cancer risk of cigarette smoking in Korean men by a 10-yr follow-up prospective cohort study using the primary databases. The number of subjects was 14,272 men, who had full information of smoking habits among participants in the Seoul Male Cancer Cohort Study (SMCC). Total 125,053 personyears were calculated by determining the number of days from the start of followup, January 1, 1993, until the date of lung cancer diagnosis, death from another cause, or the end of follow-up, December 31, 2002, followed by converting the number of days to years. The information of outcome was obtained by the database of Korea Central Cancer Registry, Seoul Regional Cancer Registry, and Korea Statistical Office. The relative risk (RR) and its 95% confidence interval (CI) values of smoking were calculated using Cox proportional hazards regression stratified on potential confounders. During the follow-up periods, 78 cases of lung cancer occurred. The cigarette smoking is the major risk factor and increases the 4.18-fold risk of lung cancer in Korean men. In order to control lung cancer, intervention of quitting smoking is needed.

Cancer Registration in Korea: The Present and Furtherance / 예방의학회지

It was not until 1975 that cancer registration was initiated in Korea; voluntary registration of cancer patients of training hospitals throughout the country began under the auspices of the Korean Cancer Society(KCS). However, an official cancer registration, the Korea Central Cancer Registry(KCCR), began on July 1st, 1980. Forty-five training and two non-training hospitals throughout the country initiated registration of patients in whom neoplasms had been found. Data related to case information specified are to be sent to the KCCR at the National Medical Center(it moved at National Cancer Center in 2000). The initial cancer registration of KCS was merged to the KCCR in 1980. Although the KCCR covers most all the large training hospitals in Korea, it cannot provide incidence data. It is, however, the only of its kind in the world, being neither hospital nor population based. The first population based cancer registry(PBCR) was launched in a small county, Kangwha(it has around 80,000 inhabitants), by Yonsei University Medical College in 1983. All data were collected by active methods, and incidence statistics for 1986-1992 appeared in Vol VII of the CI5. Another PBCR, Seoul Cancer Registry(SCR), started in 1991. It was supported by a civilian foundation, the Korean Foundation for Cancer Research. The basic idea of case registration of SCR was the incorporation of KCCR data to PBCR, e. g. dual sources of case registration, i.e., from the KCCR and also including cases diagnosed in small hospitals and other medical facilities. Assessing completeness and validity of case registration of SCR, the program and methodology used by the SCR was later extended to other large cities and areas in Korea, and the PBCR in each area was established. Cancer incidence statistics of Seoul for 1993- 1997, Busan for 1996-1997, and Daegu for 1997-1998, as well as Kangwha for 1993-1997, appeared eventually in Vol VIII of the CI5. The Korean or 'pillar' model for a PBCR is a new one. The KCCR data file is a reliable basis, as a pillar, for a PBCR in each area. The main framework of the model for such a registry is the incorporation of a KCCR data file with data from additionally surveyed cases; the data related to cancer deaths, medical insurance claims, and visit-and abstract surveillance of non-KCCR medical facilities. Cancer registration has been adopted as a national cancer control program by Korean government in 2004 as the Anti-Cancer Act was enacted. Since then, some officers have tried to launch a nation-wide PBCR covering whole country. In the meantime, however, cancer registration was interrupted and discontinued for years due to the Privacy Protection Law, which was solved by an amendment of the Anti-Cancer Act in 2006. It would be premature to establish the nation-wide PBCR in Korea. Instead, continuous efforts to improve the completeness of registration of the KCCR, to progress existing PBCRs, and to expand PBCRs over other areas are still to be devoted. The nation-wide PBCR in Korea will be established eventually with summation of the PBCRs of the Korean model.

Nationwide Cancer Incidence in Korea, 1999~2001; First Result Using the National Cancer Incidence Database / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The first Korean national population- based cancer registry using nationwide hospital-based recording system and the regional cancer registries provided the source to obtain national cancer incidences for the period 1999~2001. MATERIALS AND METHODS: The incidence of cancer in Korea was calculated based on the Korea Central Cancer Registry database, data from additional medical record review survey, the Regional Cancer Registry databases, site-specific cancer registry databases, and cancer mortality data from the Korea National Statistical Office. Crude and age-standardized rates were calculated by sex for 18 age groups. RESULTS: The overall crude incidence rates (CR) were 247.3 and 188.3 per 100, 000 for men and women and the overall age-standardized incidence rates (ASR) were 281.2 and 160.3 per 100, 000, respectively. Among men, five leading primary cancer sites were stomach (CR 58.6, ASR 65.6), lung (CR 42.1, ASR 50.9), liver (CR 41.9, ASR 44.9), colon and rectum (CR 24.2, ASR 27.3) and bladder (CR 7.7, ASR 9.2). Among women, the most common cancers were stomach (CR 30.8, ASR 25.8), breast (CR 25.7, ASR 21.7), colon and rectum (CR 19.6, ASR 16.7), uterine cervix (CR 18.4, ASR 15.5), and lung cancer (CR 15.1, ASR 12.4). In 0~14 age group, leukemia was most common for both sexes. For men, stomach cancer was most common in 15~64 age group, but lung cancer was more frequent for over 65 age group. For women, thyroid cancer in 15~34 age group, breast cancer in 35~64 age group, and stomach cancer in over 65 age group were most common for each age group. The proportions of death certificate only were 7.5% for men and 7.4% for women. CONCLUSION: This is the first attempt to determine the national cancer incidence and this data will be useful to plan for research and national cancer control in Korea.

Molecular Epidemiology of Colon Cancer / Journal of the Korean Cancer Association, 대한암학회지

Colorectal cancer appears to have rapidly increased over the past two decades in Korea. Environmental factors, characterized by a western life style, seem to be closely related to the increased risk of colorectal cancer. Higher intakes of meat, a lower vegetable intake, a lack of physical activity, obesity, and alcohol drinking have been suggested to be risk factors for colorectal cancer in the numerous epidemiologic studies. Several specific associations have also been observed between genetic polymorphisms and colorectal cancer. Moreover, it has been postulated that environmental factors and a genetic predisposition work in concert in colorectal cancer development. A stronger association between red meat intake and colorectal cancer among those with rapid acetylators at either the NAT1 or NAT2 locus was reported, particularly for colorectal cancer associated with K-ras mutations. The protective effect of the homozygous variant TT form of the MTHFR genotype on the risk of colon cancer seems to be modified by the level of methyl diets, i.e., by folate, which has a protective effect, or conversely by alcohol. The insulin-related pathway, which possibly explains at a mechanistic level the effect of physical activity and obesity on colon cancer, appears to be a common denominator in colon cancer and in other metabolic disorders, such as diabetes mellitus and dyslipidemia. Hyperinsulinemia has been proposed as an explanation for the association between a Western lifestyle and colon cancer risk. Further studies, that incorporate both genetic and environmental factors, are needed to fully explain and identify the underlying pathway of colorectal carcinogenesis.