Conditional Relative Survival of Exocrine Pancreatic Cancer: A Population-Based Study.

BACKGROUND: Adjusted prognostic information is important for treatment decisions, especially in elderly patients or survivors of exocrine pancreatic cancer (EPC). This study aims to investigate conditional relative survival (CS) rates and conditional probabilities of death in patients with EPC. METHODS: Data of 77,975 individuals diagnosed with EPC between 1999 and 2019 were obtained from the Korea Central Cancer Registry. CS was analyzed across strata including histology groups (ductal adenocarcinoma excluding cystic or mucinous [group I, PDAC] and ductal adenocarcinoma specified as mucinous or cystic adenocarcinoma [group II]), and age. RESULTS: For PDAC, the overall 5-year relative survival (RS) rate at diagnosis, 3-year CS of 2-year survivors, and 5-year CS of 5-year survivors were 8.5%, 50.1%, and 77.6%, respectively. Overall conditional probabilities of death were 85.2% (≥ 80 years), 73.5% (70-79 years), and 62.0% (60-69 years) in year 1 after diagnosis. Among patients with localized or regional stage who underwent surgery, conditional probabilities of death of ≥ 80, 70-79, and 60-69 years were 37.7%, 32.5%, and 22.6% in the first year, and 26.6%, 27.2%, and 26.0% in year 2 after diagnosis. CONCLUSIONS: Half of patients with EPC who survived for 2 years survived for an additional 3 years. However, 5-year PDAC survivors require follow-up as more than 20% do not survive for a further 5 years. Elderly patients should not be excluded from active treatment for localized or regional-stage PDAC, as the CS of elderly patients who are fit enough to undergo surgery is not inferior to that of younger patients.

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

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

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

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

Effect of smoking reduction, cessation, and resumption on cancer risk: A nationwide cohort study.

BACKGROUND: The objective of this study was to investigate the effects of reduction, cessation, and resumption of smoking on cancer development. METHODS: The authors identified 893,582 participants who currently smoked, had undergone a health screening in 2009, and had a follow-up screening in 2011. Among them, 682,996 participated in a third screening in 2013. Participants were categorized as quitters, reducers I (≥50% reduction), reducers II (<50% reduction), sustainers (referent), or increasers (≥20% increase). Outcome data were obtained through December 31, 2018. RESULTS: Reducers I exhibited a decreased risk of all cancers (adjusted hazard ratio [aHR], 0.96; 95% confidence interval [CI], 0.93-0.99), smoking-related cancers (aHR, 0.95; 95% CI, 0.92-0.99), and lung cancer (aHR, 0.83; 95% CI, 0.77-0.88). Quitters had the lowest risk of all cancers (aHR, 0.94; 95% CI, 0.92-0.96), smoking-related cancers (aHR, 0.91; 95% CI, 0.89-0.93), and lung cancer (aHR, 0.79; 95% CI, 0.76-0.83). In further analysis with 3 consecutive screenings, additional smoking reduction (from reducers II to reducers I) lowered the risk of lung cancer (aHR, 0.74; 95% CI, 0.58-0.94) in comparison with sustainers. Quitting among reducers I further decreased the risk of all cancers (aHR, 0.90; 95% CI, 0.80-1.00), smoking-related cancers (aHR, 0.81; 95% CI, 0.81-0.92), and lung cancer (aHR, 0.66; 95% CI, 0.52-0.84) in comparison with sustainers. Smoking resumption after quitting, even at a lower level, increased the risk of smoking-related cancers (aHR, 1.19; 95% CI, 1.06-1.33) and lung cancer (aHR, 1.48; 95% CI, 1.21-1.80) in comparison with sustained quitting. CONCLUSIONS: Smoking cessation and, to a lesser extent, smoking reduction decreased the risks of cancer. Smoking resumption increased cancer risks in comparison with sustained quitting. LAY SUMMARY: Worldwide, tobacco use is the single leading preventable risk factor for cancer and cancer death. This study examined the effects of reduction, cessation, and resumption of smoking on cancer development by measuring smoking behavior repetitively. Although smoking reduction has a substantial cancer prevention benefit for those who cannot quit, cessation should be encouraged whenever possible. Quitters should be monitored to ensure that they do not resume smoking.

Trends in incidence and survival of patients with vulvar cancer in an Asian country: Analysis of the Korean Central Cancer Registry 1999-2018.

OBJECTIVE: To report 20-year trends in incidence and survival of vulvar cancer in Korea. METHODS: Using data from the Korean Central Cancer Registry, age-standardized incidence rates (ASRs) and annual percentage changes (APCs) were calculated. Net survival (NS) was estimated by the Pohar-Perme method, and conditional net survival (CNS) was calculated. RESULTS: A total of 2221 patients was diagnosed with vulvar cancer during the 1999-2018 period, with an ASR of 0.32 per 100,000 person-years. Among the cases, 51.4% were squamous cell carcinoma (SqCC), 21.3% were Paget disease, and 8.6% were basal cell carcinoma (BCC). There was an increase in incidence for all vulvar cancer (APC 2.4%, 95% CI 1.8-3.0). However, although BCC (APC 7.0%, 95% CI 3.3-10.8) and Paget disease (APC 5.9%, 95% CI 4.2-7.6) increased, SqCC did not (APC 0.2%, 95% CI -0.8-1.2). There was an increase in incidence in all age groups. The 5Y NS was 74.0% overall, and it did not improve significantly during the study period. The 5Y CNS of vulvar cancer increased continuously with time survived: from 74.0% (71.4-76.4) at baseline to 98.1% (95% CI, 85.4-99.8) at 5 years after diagnosis. CONCLUSIONS: The incidence of vulvar cancer in Korea showed a different pattern from those in the US and Europe: SqCC incidence was relatively low and remained stable, but the incidence of BCC and Paget's disease increased. Survival did not improve in the past two decades. Patients can be considered cured after surviving for 5 years.

Trend Analysis and Prediction of Hepatobiliary Pancreatic Cancer Incidence and Mortality in Korea.

BACKGROUND: This study aimed to analyze the current trends and predict the epidemiologic features of hepatobiliary and pancreatic (HBP) cancers according to the Korea Central Cancer Registry to provide insights into health policy. METHODS: Incidence data from 1999 to 2017 and mortality data from 2002 to 2018 were obtained from the Korea National Cancer Incidence Database and Statistics Korea, respectively. The future incidence rate from 2018 to 2040 and mortality rate from 2019 to 2040 of each HBP cancer were predicted using an age-period-cohort model. All analyses, including incidence and mortality, were stratified by sex. RESULTS: From 1999 to 2017, the age-standardized incidence rate (ASIR) of HBP cancers per 100,000 population had changed (liver, 25.8 to 13.5; gallbladder [GB], 2.9 to 2.6; bile ducts, 5.1 to 5.9; ampulla of Vater [AoV], 0.9 to 0.9; and pancreatic, 5.6 to 7.3). The age-standardized mortality rate (ASMR) per 100,000 population from 2002 to 2018 of each cancer had declined, excluding pancreatic cancer (5.5 to 5.6). The predicted ASIR of pancreatic cancer per 100,000 population from 2018 to 2040 increased (7.5 to 8.2), but that of other cancers decreased. Furthermore, the predicted ASMR per 100,000 population from 2019 to 2040 decreased in all types of cancers: liver (6.5 to 3.2), GB (1.4 to 0.9), bile ducts (4.3 to 2.9), AoV (0.3 to 0.2), and pancreas (5.4 to 4.7). However, in terms of sex, the predicted ASMR of pancreatic cancer per 100,000 population in females increased (3.8 to 4.9). CONCLUSION: The annual incidence and mortality cases of HBP cancers are generally predicted to increase. Especially, pancreatic cancer has an increasing incidence and will be the leading cause of cancer-related death among HBP cancers.

Conditional relative survival and competing mortality in patients who underwent surgery for lung cancer: A nationwide cohort study.

We aimed to investigate the conditional relative survival (CRS) and competing mortality in patients who underwent surgery for newly diagnosed lung cancer. Using a nationwide population-based database, we calculated 5-year CRS on 1 to 5 years survival after surgery. These rates were reported according to age, sex, socioeconomic status, comorbidities and treatment received. We also estimated cause-specific mortality with the consideration of competing risk. We identified 34 349 patients newly diagnosed with primary lung cancer from 2007 to 2013. The 5-year CRS after surgery was 71.7% at baseline improving steadily to 85.4% by 5 years, suggesting evidence of persistent excess mortality risk. Throughout the period, lung cancer was the most common cause of death, contributing to 83.6% mortality 1 year after surgery and 66.3% 5 years after surgery. Other causes of death included cardiovascular disease and respiratory disease, which increased continuously with time after surgery. CRS rates for patients with lung cancer improved over time but did not reach the level of the general population even 5 years after surgery. Although the main cause of death continues to be lung cancer, death from noncancer causes increased with time after surgery. Evidence-based decisions could be made on the dynamic risk profiles of the patients.

The emergence of oral cavity cancer and the stabilization of oropharyngeal cancer: Recent contrasting epidemics in the South Korean population.

BACKGROUND: By analyzing the recent epidemiologic trajectory of head and neck squamous cell carcinoma (HNSCC) in South Korea, we tracked 2 findings that have been reported recently in other countries: the stabilization of human papillomavirus (HPV)-related HNSCC incidence and the acceleration of oral cavity cancer incidence. METHODS: We analyzed data from the comprehensive population-based Korean Central Cancer Registry for the period 1999 to 2017. The age-standardized incidence rate (ASR), annual percent change (APC), and relative survival were calculated. RESULTS: The ASR of total HNSCC decreased from 1999 to 2017 (APC, -0.2 [95% CI, -0.3 to -0.0]), as did the ASR of HPV-unrelated HNSCC (APC, -0.6 [95% CI, -0.8 to -0.5]); however, the ASR of HPV-related HNSCC increased (APC, 2.9 [95% CI, 2.5 to 3.2]). The rapidly increasing incidence of tonsil squamous cell carcinoma, which was the main subsite of HPV-related HNSCC, stabilized after 2011 (APC pre-2011, 6.8 [95% CI, 5.0 to 8.3]; APC post-2011, 1.6 [95% CI, -2.1 to 5.5]), and the difference was significant (P = .017). In contrast, oral cavity cancer incidence demonstrated the only increase among HPV-unrelated subsites, with the increase occurring after 2006 (APC pre-2006, 1.6 [95% CI, 0.3 to 2.8]; APC post-2006, 2.8 [95% CI, 2.2 to 3.5]); the main cause of this change was an increase in the ASR of tongue cancer. CONCLUSION: This study demonstrates the recent stabilization of tonsil cancer incidence and the contrasting increase in oral cavity cancer incidence, unlike other HPV-unrelated cancers. These trends require further surveillance and understanding in terms of tumor biology and prevention.

Mobile Phone Use and Time Trend of Brain Cancer Incidence Rate in Korea.

This study evaluated the time trends in mobile phone subscriber number by mobile network generation (G) and brain cancer incidence by type in Korea. We obtained data from the Information Technology Statistics of Korea (1984-2017) and Korea Central Cancer Registry (1999-2017). The average annual percent change was estimated using Joinpoint regression analysis. We evaluated 29,721 brain cancer cases with an age-standardized incidence rate (ASR) of 2.89/100,000 persons. The glioma and glioblastoma annual ASR significantly increased in 2.6% and 3.9% of males and 3.0% and 3.8% of females, respectively. The ASR for frontal lobe involvement was the highest. The ASR of gliomas of unspecified grade annually increased by 7.8%; those for unspecified topology and histology decreased. The incidence of glioma, glioblastoma, frontal, temporal, and high-grade glioma increased among those aged ≥60 years. No association was observed between the mobile phone subscriber number and brain cancer incidence in Korea. Furthermore, long-term research is warranted because of the latency period of brain cancer. © 2021 Bioelectromagnetics Society.

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.

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.

Changes in ovarian cancer survival during the 20 years before the era of targeted therapy.

BACKGROUND: The survival of patients with ovarian cancer has improved because of surgery and chemotherapy. This study aimed to estimate the changes in survival rates among Korean women with ovarian cancer prior to the introduction of targeted therapy for ovarian cancer. METHODS: Data were obtained from the Korea Central Cancer Registry regarding patients who were diagnosed with epithelial ovarian cancer between 1995 and 2014. The relative survival rates were calculated for 5-year periods using the Ederer II method. Cox proportional hazard models were created to assess the associations of demographic and clinicopathological factors with ovarian cancer survival. RESULTS: During the study period, 22,880 women were diagnosed with epithelial ovarian cancer. The 5-year relative survival rate improved from 57.2% during 1995-1999 to 63.8% during 2010-2014 (P < 0.001). Survival outcomes improved between 1995 and 1999 and 2010-2014 for the serous and endometrioid carcinoma subtypes (P < 0.001). However, no improvements were observed for the mucinous and clear cell carcinoma subtypes (P = 0.189 and P = 0.293, respectively). Multivariate analysis revealed that younger age, early stage, recent diagnosis, primary surgical treatment, and non-serous histological subtype were favorable prognostic factors. CONCLUSION: Survival outcomes have improved for serous and endometrioid epithelial ovarian cancer in the last 20 years. However, no improvement was observed for patients with mucinous and clear cell carcinoma subtypes.

Risk of second primary Cancer among bladder Cancer patients: a population-based cohort study in Korea.

BACKGROUND: For the expanding population of bladder cancer survivors in Korea, the development of subsequent cancers is a significant concern. Here, we provide the second primary cancer incidence rates and types in Korean patients with bladder cancer. METHODS: Using population-based data from the Korea Central Cancer Registry from 1993 to 2013, we studied the standardized incidence ratios among 48,875 individuals with an initial diagnosis of bladder cancer. Standardized incidence ratios for second primary cancers were evaluated according to age at diagnosis, latency, diagnostic year, and treatment. RESULTS: Over the same period, the overall risk of a second primary cancer was reduced by 6% in patients with bladder cancer compared with the development of a new malignancy in the general population (standardized incidence ratio = 0.94; 95% CI, 0.91-0.97, p < 0.05). For specific cancers, the standardized incidence ratios for stomach, colon, liver, and non-Hodgkin lymphoma were significantly lower in patients with bladder cancer. However, the risk of prostate and kidney cancer in patients with bladder cancer were significantly increased. The risk of lung squamous cell carcinoma and lung adenocarcinoma as second primary cancers was significantly elevated in patients with bladder cancer. CONCLUSION: Korean patients with bladder cancer have a 6% lower risk of developing a second primary cancer. However, they have a higher risk of developing subsequent prostate and kidney cancers, lung squamous cell carcinoma, and lung adenocarcinoma, suggesting the need for continual intensive cancer surveillance among bladder cancer survivors.

Trends in incidence and survival of esophageal cancer in Korea: Analysis of the Korea Central Cancer Registry Database.

BACKGROUND AND AIM: The diagnostic and therapeutic modalities of esophageal cancer have recently improved in Asia, and its prognosis is expected to change. This study provides a population-based report on the epidemiology of esophageal cancer in Korea. METHODS: Cancer incidence data from 1999 to 2013 were obtained from the Korea Central Cancer Registry, covering the entire population. Age-standardized incidence rates and annual percent changes were calculated according to subsites and histological types. Five-year relative survival rates were estimated for cases diagnosed between 1993 and 2013. Relative excess rates were compared between patients diagnosed from 2009 to 2013 and 2006 to 2008. RESULTS: The age-standardized incidence rates decreased from 8.8 per 100 000 populations in 1999 to 5.9 in 2013 with an annual percent change of -2.6% in men and -2.2% in women. The most common histological type was squamous cell carcinoma, accounting for 90.2% of all esophageal cancers in 2013, followed by adenocarcinomas (3.1%), and their incidences decreased. The proportion of localized and regional cancer tended to increase compared with that of distant cancer. Five-year relative survival of squamous cell carcinoma improved from 12.1% (1993-1995) to 34.6% (2009-2013). Relative excess rate was 0.72 (95% confidence interval 0.65-0.80) in localized stage and 0.88 (95% confidence interval, 0.82-0.95) in regional stage comparing patients diagnosed from 2009 to 2013 and 2006 to 2008. CONCLUSIONS: The incidence of esophageal cancer has decreased in Korea for the past 15 years, and 5-year survival rates have improved significantly. These increases may be attributable to more effective detection of early-stage disease.

Population attributable risks of modifiable reproductive factors for breast and ovarian cancers in Korea.

BACKGROUND: Breast and ovarian cancers are predominant female cancers with increasing prevalence. The purpose of this study was to estimate the population attributable risks (PARs) of breast and ovarian cancer occurrence based on the relative risks (RRs) of modifiable reproductive factors and population-specific exposure prevalence. METHODS: The PAR was calculated by using the 1990 standardized prevalence rates, the 2010 national cancer incidence with a 20 year lag period, the meta-analyzed RRs from studies conducted in the Korean population for breast cancer, and the meta-analyzed RRs from a Korean epithelial ovarian cancer study and a prior meta-analysis, and ovarian cancer cohort results up to 2012. For oral contraceptive and hormone replacement therapy use, we did not consider lag period. RESULTS: The summary PARs for modifiable reproductive factors were 16.7% (95% CI 15.8-17.6) for breast cancer (2404 cases) and 81.9% (95% CI 55.0-100.0) for ovarian cancer (1579 cases). The modifiable reproductive factors included pregnancy/age at first birth (8.0%), total period of breastfeeding (3.1%), oral contraceptive use (5.3%), and hormone replacement therapy use (0.3%) for breast cancer and included breastfeeding experience (2.9%), pregnancy (1.2%), tubal ligation (24.5%), and oral contraceptive use (53.3%) for ovarian cancer. CONCLUSIONS: Despite inherent uncertainties in the risk factors for breast and ovarian cancers, we suggest that appropriate long-term control of modifiable reproductive factors could reduce breast and ovarian cancer incidences and their related burdens by 16.7% and 81.9%, respectively.

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.

Elevated risks of subsequent primary malignancies in patients with thyroid cancer: a nationwide, population-based study in Korea.

BACKGROUND: Thyroid cancer affects relatively young adults, and its overall survival is excellent. With long life expectancy, the development of subsequent cancers is an important concern for survivors of thyroid cancer. The objective of this study was to investigate the incidence and types of second primary malignancies in Korean patients with thyroid cancer. METHODS: The study cohort included 178,844 registrants with thyroid cancer from the Korea Central Cancer Registry (KCCR) database between 1993 and 2010. Standardized incidence ratios (SIRs) were calculated using a statistical software program (SEER*Stat 8.0.4). RESULTS: Among 178,844 patients with thyroid cancer, 2895 (1.6%) were diagnosed with subsequent second primary malignancies. The overall risks of a second primary cancer were elevated by 6% in patients who had thyroid cancer compared with the general population during the same period. The elevated risks for developing second cancers were observed in all sites except the stomach and cervix. The elevated risk of second primary cancers was observed within the first 10 years of follow-up. Leukemia and cancers of the salivary gland, kidney, prostate, lung, and breast had the most significantly elevated risks as secondary cancers and presented as early as during the first 5 years after the initial diagnosis of thyroid cancer. CONCLUSIONS: This is the largest, standardized, population-based study to date using nationwide data from the entire Korean population. The risks of several cancers were elevated significantly during follow-up, thus alerting physicians to pay special attention in their care of patients with thyroid cancer and long-term survivors.

Attributable fraction of alcohol consumption on cancer using population-based nationwide cancer incidence and mortality data in the Republic of Korea.

BACKGROUND: In the Republic of Korea, cancer is the most common cause of death, and cancer incidence and mortality rates are the highest in East Asia. As alcoholic beverages are carcinogenic to humans, we estimated the burden of cancer related to alcohol consumption in the Korean population. METHODS: The cancer sites studied were those for which there is convincing evidence of a positive association with alcohol consumption: oral cavity, pharynx, esophagus, colon, rectum, liver, larynx and female breast. Sex- and cancer-specific population attributable fractions (PAF) were calculated based on: 1) the prevalence of alcohol drinkers among adults ≥ 20 years of age in 1989; 2) the average daily alcohol consumption (g/day) among drinkers in 1998; 3) relative risk (RR) estimates for the association between alcohol consumption and site-specific cancer incidence obtained either from a large Korean cohort study or, when more than one Korean study was available for a specific cancer site, meta-analyses were performed and the resulting meta-RRs were used; 4) national cancer incidence and mortality data from 2009. RESULTS: Among men, 3% (2,866 cases) of incident cancer cases and 2.8% (1,234 deaths) of cancer deaths were attributable to alcohol consumption. Among women, 0.5% (464 cancer cases) of incident cancers and 0.1% (32 deaths) of cancer deaths were attributable to alcohol consumption. In particular, the PAF for alcohol consumption in relation to oral cavity cancer incidence among Korean men was 29.3%, and the PAFs for pharyngeal and laryngeal cancer incidence were 43.3% and 25.8%, respectively. Among Korean women, the PAF for colorectal cancer incidence was the highest (4.2%) and that for breast cancer incidence was only 0.2%. Avoiding alcohol consumption, or reducing it from the median of the highest 4th quartile of consumption (56.0 g/day for men, 28.0 g/day for women) to the median of the lowest quartile (2.80 g/day for men, 0.80 g/day for women), would reduce the burden of alcohol-related cancers in Korea. CONCLUSIONS: A reduction in alcohol consumption would decrease the cancer burden and a significant impact is anticipated specifically for the cancers oral cavity, pharynx, and larynx among men in the Republic of Korea.

Attributable fraction of tobacco smoking on cancer using population-based nationwide cancer incidence and mortality data in Korea.

BACKGROUND: Smoking is by far the most important cause of cancer that can be modified at the individual level. Cancer incidence and mortality rates in Korea are the highest among all Asian countries, and smoking prevalence in Korean men is one of the highest in developed countries. The purpose of the current study was to perform a systematic review and provide an evidence-based assessment of the burden of tobacco smoking-related cancers in the Korean population. METHODS: Sex- and cancer-specific population-attributable fractions (PAF) were estimated using the prevalence of ever-smoking and second-hand smoking in 1989 among Korean adults, respectively, and the relative risks were estimated from the meta-analysis of studies performed in the Korean population for ever-smoking and in the Asian population for passive smoking. National cancer incidence data from the Korea Central Cancer Registry and national cancer mortality data from Statistics Korea for the year 2009 were used to estimate the cancer cases and deaths attributable to tobacco smoking. RESULTS: Tobacco smoking was responsible for 20,239 (20.9%) cancer incident cases and 14,377 (32.9%) cancer deaths among adult men and 1,930 (2.1%) cancer incident cases and 1,351 (5.2%) cancer deaths among adult women in 2009 in Korea. In men, 71% of lung cancer deaths, 55%-72% of upper aerodigestive tract (oral cavity, pharynx, esophagus and larynx) cancer deaths, 23% of liver, 32% of stomach, 27% of pancreas, 7% of kidney and 45% of bladder cancer deaths were attributable to tobacco smoking. In women the proportion of ever-smoking-attributable lung cancer was 8.1%, while that attributable to second-hand smoking among non-smoking women was 20.5%. CONCLUSIONS: Approximately one in three cancer deaths would be potentially preventable through appropriate control of tobacco smoking in Korean men at the population level and individual level. For Korean women, more lung cancer cases and deaths were attributable to second-hand than ever-smoking. Effective control programs against tobacco smoking should be further developed and implemented in Korea to reduce the smoking-related cancer burden.

Red meat consumption is associated with an increased overall cancer risk: a prospective cohort study in Korea.

Cancer is a leading cause of death, and the dietary pattern in Korea is changing rapidly from a traditional Korean diet to a Westernised diet. In the present study, we investigated the effects of dietary factors on cancer risk with a prospective cohort study. Among 26,815 individuals who participated in cancer screening examinations from September 2004 to December 2008, 8024 subjects who completed a self-administered questionnaire concerning demographic and lifestyle factors, and a 3 d food record were selected. As of September 2013, 387 cancer cases were identified from the National Cancer Registry System, and the remaining individuals were included in the control group. The hazard ratio (HR) of cancer for the subjects older than or equal to 50 years of age was higher (HR 1.80, 95% CI 1.41, 2.31; P< 0.0001) than that for the other subjects. Red meat consumption, Na intake and obesity (BMI ≥ 25 kg/m²) were positively associated with overall cancer incidence in men (HR 1.41, 95% CI 1.02, 1.94; P= 0.0382), gastric cancer (HR 2.34, 95% CI 1.06, 5.19; P= 0.0365) and thyroid cancer (HR 1.56, 95% CI 1.05, 2.31; P= 0.0270), respectively. Participants who had at least three dietary risk factors among the high intakes of red meat and Na, low intakes of vegetables and fruits, and obesity suggested by the World Cancer Research Fund/American Institute for Cancer Research at baseline tended to have a higher risk of cancer than the others (HR 1.26, 95% CI 0.99, 1.60; P= 0.0653). In summary, high intakes of red meat and Na were significant risk factors of cancer among Koreans.