Distal Colon Cancer Research Articles

Increased risk of colorectal cancer in type 2 diabetes is independent of diet quality.

BackgroundPoor diet increases the risk of both colorectal cancer and type 2 diabetes. We investigated the role of diet in the association between diabetes and colorectal cancer.MethodsWe analyzed data from 484,020 individuals, aged 50–71 years who participated in the prospective National Institutes of Health-AARP Diet and Health Study and were cancer free at baseline (1995–1996). History of diabetes was self-reported. Diet quality was measured with the Healthy Eating Index-2005 (HEI-2005), using a self-administered food-frequency questionnaire. Cox regression models were constructed to estimate the hazard ratios (HR) and 95% confidence intervals (CI) of first primary incident colorectal cancer, overall and by anatomical location.ResultsDuring an average follow-up of 9.2 years, we identified 7,598 new cases of colorectal cancer. After controlling for non-dietary confounders, diabetes was associated with increased risk of colorectal cancer (HR 1.27, 95% CI: 1.18, 1.36). Further adjustment for diet quality did not attenuate this association. Diabetes was associated with a HR of 1.23 (95% CI: 1.07, 1.40) in individuals with good diet (quartile 4 of HEI-2005) and 1.58 (95% CI: 1.34, 1.86) in those with poor diet (quartile 1 of HEI-2005), compared to those with no diabetes and good diet. Moreover, diabetes was associated with a stronger risk of proximal than distal colon cancer (HR: 1.33 vs. HR: 1.20), while poor diet was associated with a weaker risk of proximal colon cancer (HR: 1.18 vs. HR: 1.46).ConclusionDiabetes and poor diet, independently and additively are associated with the increased risk of colorectal cancer.

Colon and Rectal Cancer Survival by Tumor Location and Microsatellite Instability

Cancers in the proximal colon, distal colon, and rectum are frequently studied together; however, there are biological differences in cancers across these sites, particularly in the prevalence of microsatellite instability. We assessed the differences in survival by colon or rectal cancer site, considering the contribution of microsatellite instability to such differences. This is a population-based prospective cohort study for cancer survival. This study was conducted within the Colon Cancer Family Registry, an international consortium. Participants were identified from population-based cancer registries in the United States, Canada, and Australia. Information on tumor site, microsatellite instability, and survival after diagnosis was available for 3284 men and women diagnosed with incident invasive colon or rectal cancer between 1997 and 2002, with ages at diagnosis ranging from 18 to 74. Cox regression was used to calculate hazard ratios for the association between all-cause mortality and tumor location, overall and by microsatellite instability status. Distal colon (HR, 0.59; 95% CI, 0.49-0.71) and rectal cancers (HR, 0.68; 95% CI, 0.57-0.81) were associated with lower mortality than proximal colon cancer overall. Compared specifically with patients with proximal colon cancer exhibiting no/low microsatellite instability, patients with distal colon and rectal cancers experienced lower mortality, regardless of microsatellite instability status; patients with proximal colon cancer exhibiting high microsatellite instability had the lowest mortality. Study limitations include the absence of stage at diagnosis and cause-of-death information for all but a subset of study participants. Some patient groups defined jointly by tumor site and microsatellite instability status are subject to small numbers. Proximal colon cancer survival differs from survival for distal colon and rectal cancer in a manner apparently dependent on microsatellite instability status. These findings support the premise that proximal colon, distal colon, and rectal cancers are clinicopathologically distinct.

Abstract 165: Predicting risk of colorectal cancer depending on tumor pathology features for first-degree relatives of persons with colorectal cancer.

Abstract Background: We hypothesised that colorectal cancer (CRC) risk for relatives of persons diagnosed with CRC could be predicted by tumor molecular pathology features. Methods: We studied a cohort of 5200 first-degree relatives (2550 women) of 792 probands with an incident invasive CRC who were recruited to the Australasian Colorectal Cancer Family Registry via population cancer registries. We excluded 32 families that were known to be Lynch syndrome. For the probands, a standardised tumor morphology review had been conducted; BRAF V600E mutation testing had been performed; and the DNA mismatch repair (MMR) status was determined by microsatellite instability and/or immunohistochemistry for MMR proteins. We calculated standardized incidence ratios (SIR) by comparing the number of CRCs observed in relatives with the number expected based on Australian incidence rates specific for age and sex. We also compared CRC risks for relatives of probands depending on the presence or absence of specific tumor pathology features. Results: We observed 191 CRCs in relatives at mean age at diagnosis of 62.7 (SD 14.3) years and SIR was 2.14 (95% confidence interval, CI 1.85-2.48). Compared with the general population, an increased risk of CRC was observed for relatives of probands with MMR-proficient CRC (SIR 1.98, 95% CI 1.71-2.32), MMR-deficient CRC (SIR 3.60, 95% CI 2.20-6.23), rectal cancer (SIR 1.71, 95% CI 1.36-2.18), distal colon cancer (SIR 2.12, 95% CI 1.63-2.82) and proximal colon cancer (SIR 2.90, 95%CI 2.27-3.75). An increased risk of CRC was observed for relatives of probands with proximal colon cancer compared with rectal cancer (hazard ratio, HR 1.70, 95% CI 1.21-2.39, p=0.002) and for relatives of probands with MMR-deficient CRC compared with MMR-proficient CRC (HR 1.84, 95% CI 1.09-3.12, p=0.02). There was no evidence of increased risk of CRC for relatives of probands with other pathology features of CRC (tumor grade, margin, peritumoral lymphocytes, tumor infiltrating lymphocytes, Crohn-like reactions, venous invasion, BRAF mutation and contiguous adenoma) compared with those without these features. Conclusions: First-degree relatives of persons with MMR-deficient CRC (not caused by Lynch syndrome) have a higher risk of CRC compared with first-degree relatives of persons with MMR-proficient CRC. Citation Format: Aung K. Win, Daniel D. Buchanan, Christophe Rosty, Graham G. Giles, John L. Hopper, Mark A. Jenkins. Predicting risk of colorectal cancer depending on tumor pathology features for first-degree relatives of persons with colorectal cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 165. doi:10.1158/1538-7445.AM2013-165

Abstract 4813: The increased risk of colon cancer due to cigarette smoking may be greater in women than men.

Abstract Background: The International Agency for Research on Cancer (IARC) has recently established cigarette smoking as a risk factor for colon cancer. Norway has one of the highest incidence rates of colon cancer in the world especially among women. We examined the association between different measures of smoking exposure and colon cancer by gender in a large Norwegian cohort. Methods: We followed 602,242 participants aged 19-67 years at enrollment who completed a questionnaire in 1972-2003, by linkage to national registries through December 2007. We used Cox proportional hazard regression models to estimate hazard ratios (HR) and 95% confidence intervals (CIs) adjusting for age, body mass index, physical activity and education. Results: During a mean follow-up time of 14 years, 2,152 men and 1,846 women developed colon cancer. Women ever smokers had a 19% increased risk (HR=1.19, 95% CI=1.09-1.32) and men ever smokers had an 8% increased risk (HR=1.08, 95% CI=0.97-1.19) compared with never smokers. The association was more consistent for proximal than distal colon cancer among women ever smokers. The dose-response association between latency, number of years smoked, number of cigarettes per/day, number of pack-years and colon cancer risk among women was stronger than in men. Test for heterogeneity of the smoking effect between men and women was significant among ever smokers only for proximal colon cancer (Wald p=0.02). Conclusions: The results provide further evidence that smoking plays a role in the etiology of colon cancer. Female smokers may be more susceptible to proximal colon cancer than male smokers. Citation Format: Ranjan Parajuli, Eivind Bjerkaas, Aage Tverdal, Randi Selmer, Loic Le Marchand, Elisabete Weiderpass, Inger Torhild Gram. The increased risk of colon cancer due to cigarette smoking may be greater in women than men. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4813. doi:10.1158/1538-7445.AM2013-4813

Novel DNA Variants and Mutation Frequencies of hMLH1 and hMSH2 Genes in Colorectal Cancer in the Northeast China Population

Research on hMLH1 and hMSH2 mutations tend to focus on Lynch syndrome (LS) and LS-like colorectal cancer (CRC). No studies to date have assessed the role of hMLH1 and hMSH2 genes in mass sporadic CRC (without preselection by MSI or early age of onset). We aimed to identify novel hMLH1 and hMSH2 DNA variants, to determine the mutation frequencies and sites in both sporadic and LS CRC and their relationships with clinicopathological characteristics of CRC in Northeast of China. 452 sporadic and 21 LS CRC patients were screened for germline and somatic mutations in hMLH1 and hMSH2 genes with PCR–SSCP sequencing. We identified 11 hMLH1 and seven hMSH2 DNA variants in our study cohort. Six of them were novel: four in hMLH1 gene (IVS8-16 A>T, c.644 GAT>GTT, c.1529 CAG>CGG and c.1831 ATT>TTT) and two in hMSH2 gene (−39 C>T, insertion AACAACA at c.1127 and deletion AAG at c.1129). In sporadic CRC, germline and somatic mutation frequencies of hMLH1/hMSH2 gene were 15.59% and 17.54%, respectively (p = 0.52). Germline mutations present in hMLH1 and hMSH2 genes were 5.28% and 10.78%, respectively (p<0.01). Somatic mutations in hMLH1 and hMSH2 genes were 6.73% and 11.70%, respectively (p = 0.02). In LS CRC, both germline and somatic mutation frequencies of hMLH1/hMSH2 gene were 28.57%. The most prevalent germline mutation site in hMSH2 gene was c.1168 CTT>TTT (3.90%), a polymorphism. Somatic mutation frequency of hMLH1/hMSH2 gene was significantly different in proximal, distal colon and rectal cancer (p = 0.03). Our findings elucidate the mutation spectrum and frequency of hMLH1 and hMSH2 genes in sporadic and LS CRC, and their relationships with clinicopathological characteristics of CRC.

Meat intake, cooking methods and risk of proximal colon, distal colon and rectal cancer: The Norwegian Women and Cancer (NOWAC) cohort study

Red and processed meat intake is an established risk factor for colorectal cancer (CRC), but epidemiological evidence by subsite and sex is still limited. In the population-based Norwegian Women and Cancer cohort, we examined associations of meat intake with incident proximal colon, distal colon and rectal cancer, in 84,538 women who completed a validated food frequency questionnaire (FFQ) during 1996-1998 or 2003-2005 (baseline or exposure update) at age 41-70 years, with follow-up by register linkages through 2009. We also examined the effect of meat cooking methods in a subsample (n = 43,636). Multivariable hazard ratios (HRs) were estimated by Cox regression. There were 459 colon (242 proximal and 167 distal), and 215 rectal cancer cases with follow-up ≥ 1 (median 11.1) year. Processed meat intake ≥60 vs. <15 g/day was associated with significantly increased cancer risk in all subsites with HRs (95% confidence interval, CI) of 1.69 (1.05-2.72) for proximal colon, 2.13 (1.18-3.83) for distal colon and 1.71 (1.02-2.85) for rectal cancer. Regression calibration of continuous effects based on repeated 24-hr dietary recalls, indicated attenuation due to measurement errors in FFQ data, but corrected HRs were not statistically significant due to wider CIs. Our study did not support an association between CRC risk and intake of red meat, chicken, or meat cooking methods, but a high processed meat intake was associated with increased risk of proximal colon, distal colon and rectal cancer. The effect of processed meat was mainly driven by the intake of sausages.

RE: Physical Activity and Risks of Proximal and Distal Colon Cancers: A Systematic Review and Meta-Analysis

RE: Physical Activity and Risks of Proximal and Distal Colon Cancers: A Systematic Review and Meta-Analysis

Trends in colorectal incidence by anatomic subsite from 1985 to 2005: a population-based study

Conflicting results on the shift of right-left ratio in colon cancer incidence have been reported. We examine incidence trends by subsite in a population-based study. Colorectal cancer cases diagnosed in the 1985-2005 period were identified through the Tuscany Cancer Registry. Colon subsite was defined as proximal and distal; gender, age at diagnosis, histology, and stage were analyzed. Average annual incidence and age-specific rates according to subsite were calculated. A total of 21,160 colorectal cancer cases were extracted; in 18,311 cases, the subsite was identified: 6,916 rectal, 5,239 proximal, and 6,156 distal. A larger proportion of distal colon cancers presented as early stage when compared with proximal. Incidence of rectal and distal colon cancer remained stable, while proximal colon cancer incidence increased. Proximal colon cancer incidence rate increased through the period. Temporal variations in the incidence rate by subsite could suggest different carcinogenic pathways of right- and left-sided colon cancer.

Diabetes and Sex-specific Colorectal Cancer Risks in Newfoundland and Labrador: A Population-based Retrospective Cohort Study

Studies on the relationship between diabetes and colorectal cancer (CRC) are inconsistent. It is also unclear whether CRC risk elevation for individuals with diabetes is similar for males and females. Using data from Newfoundland and Labrador (NL), the province with the highest CRC incidence and diabetes prevalence in Canada, we assessed and compared the risk elevation of CRC for males and females with diabetes, overall and by anatomic subsite.A population-based retrospective cohort study including a study sample of 122,228 individuals aged ≥30 years was conducted using administrative health databases over a 10.5-year period (October 1, 1996 to March 31, 2007). Hazard ratios were estimated using Cox proportional hazard models.In comparison with non-diabetes counterparts, both males and females with diabetes were at a significantly elevated risk of overall CRC, with corresponding hazard ratios of 1.38 and 1.52, respectively. For males, diabetes significantly increased the risk of proximal and distal colon cancers, but not of rectal cancer. For females, diabetes significantly increased the risk of proximal colon and rectal cancers, but not of distal colon cancer. The results suggest that there is a stronger association between diabetes and CRC for females than for males, and the association did not change after adjusting for overweight/obesity.Diabetes led to a greater risk of CRC in both the male and female population in NL. Risk was subsite-specific and varied by sex. Future research should examine reasons for the observed diabetes-associated CRC risk to support CRC prevention strategies among the diabetes population.

Diabetes and sex-specific colorectal cancer risks in Newfoundland and Labrador: a population-based retrospective cohort study.

Studies on the relationship between diabetes and colorectal cancer (CRC) are inconsistent. It is also unclear whether CRC risk elevation for individuals with diabetes is similar for males and females. Using data from Newfoundland and Labrador (NL), the province with the highest CRC incidence and diabetes prevalence in Canada, we assessed and compared the risk elevation of CRC for males and females with diabetes, overall and by anatomic subsite. A population-based retrospective cohort study including a study sample of 122,228 individuals aged ≥30 years was conducted using administrative health databases over a 10.5-year period (October 1, 1996 to March 31, 2007). Hazard ratios were estimated using Cox proportional hazard models. In comparison with non-diabetes counterparts, both males and females with diabetes were at a significantly elevated risk of overall CRC, with corresponding hazard ratios of 1.38 and 1.52, respectively. For males, diabetes significantly increased the risk of proximal and distal colon cancers, but not of rectal cancer. For females, diabetes significantly increased the risk of proximal colon and rectal cancers, but not of distal colon cancer. The results suggest that there is a stronger association between diabetes and CRC for females than for males, and the association did not change after adjusting for overweight/obesity. Diabetes led to a greater risk of CRC in both the male and female population in NL. Risk was subsite-specific and varied by sex. Future research should examine reasons for the observed diabetes-associated CRC risk to support CRC prevention strategies among the diabetes population.

Antioxidants and prevention of gastrointestinal cancers

Gastrointestinal cancers account for 20% of all incident cancers in the United States. Much work has been done to understand the role dietary factors play in the prevention of gastrointestinal cancers, yet evidence regarding the potential preventive effect of antioxidants is conflicting. This review highlights the recent studies investigating the associations between dietary antioxidants and cancers of the gastrointestinal tract. In-vitro and in-vivo studies in animals continue to support the hypothesis that antioxidants reduce the risk of gastrointestinal cancers. Results in human populations are not as supportive. Antioxidant nutrients and fruits and vegetables do not seem to confer protection against colorectal cancer, and certain antioxidants were found to increase the risk of distal colon cancer. Individual antioxidants also do not help prevent pancreatic cancer. Total antioxidant intake and plant-based foods seem promising for stomach cancer prevention, while vitamin C lowers the risk of esophageal cancer. Preventive effects for stomach and esophageal cancers were often limited to or stronger in smokers. Evidence is scarce regarding antioxidants and liver cancer. Antioxidants do not aid in the prevention of gastrointestinal cancers in the general population; however, they may act as chemopreventive agents for stomach and esophageal cancers, especially in high-risk populations.

Physical Activity, Occupational Sitting Time, and Colorectal Cancer Risk in the Netherlands Cohort Study

We investigated occupational energy expenditure and sitting time in the longest held job (in men only), nonoccupational physical activity, and former sports participation in relation to colorectal cancer endpoints. The Netherlands Cohort Study includes 120,852 participants who completed a self-administered questionnaire in 1986 when they were aged 55-69 years. By 2002, 1,819 male and 1,366 female colorectal cancer cases were available for case-cohort analyses. In men, higher occupational energy expenditure levels and fewer occupational sitting hours were associated with decreased hazard ratios for colon cancer, particularly distal colon cancer (occupational energy expenditure of ≥12 vs. <8 kJ/minute, hazard ratio (HR) = 0.71, 95% confidence interval (CI): 0.52, 0.97; P for trend = 0.01; occupational sitting hours of <2 vs. 6-8 hours/day, HR = 0.63, 95% CI: 0.48, 0.83; P for trend = 0.001). The median duration of the longest held job for male subcohort members was 29 years. Nonoccupational physical activity was inconsistently associated with colorectal cancer endpoints in men, and it was inversely associated with colon cancer in women, particularly distal colon cancer (>90 vs. ≤30 minutes/day, HR = 0.69, 95% CI: 0.50, 0.96; P for trend = 0.06), and rectal cancer (>90 vs. ≤30 minutes/day, HR = 0.59, 95% CI: 0.39, 0.90; P for trend = 0.02). In conclusion, regular long-term physical activity and fewer sitting hours may protect against colon cancer, particularly distal colon cancer; results for rectal cancer were mixed.

Dietary polyphenols and colorectal cancer risk: The Fukuoka colorectal cancer study

To investigate the associations between dietary intake of polyphenols and colorectal cancer. The study subjects were derived from the Fukuoka colorectal cancer study, a community-based case-control study. The study subjects were 816 cases of colorectal cancer and 815 community-based controls. The consumption of 148 food items was assessed by a computer-assisted interview. We used the consumption of 97 food items to estimate dietary intakes of total, tea and coffee polyphenols. The Phenol-Explorer database was used for 92 food items. Of the 5 foods which were not listed in the Phenol-Explorer Database, polyphenol contents of 3 foods (sweet potatoes, satoimo and daikon) were based on a Japanese study and 2 foods (soybeans and fried potatoes) were estimated by ORAC-based polyphenol contents in the United States Department of Agriculture Database. Odds ratios (OR) and 95%CI of colorectal cancer risk according to quintile categories of intake were obtained by using logistic regression models with adjustment for age, sex, residential area, parental history of colorectal cancer, smoking, alcohol consumption, body mass index 10 years before, type of job, leisure-time physical activity and dietary intakes of calcium and n-3 polyunsaturated fatty acids. There was no measurable difference in total or tea polyphenol intake between cases and controls, but intake of coffee polyphenols was lower in cases than in controls. The multivariate-adjusted OR of colorectal cancer according to quintile categories of coffee polyphenols (from the first to top quintile) were 1.00 (referent), 0.81 (95%CI: 0.60-1.10), 0.65 (95%CI: 0.47-0.89), 0.65 (95%CI: 0.46-0.89) and 0.82 (95%CI: 0.60-1.10), respectively (P trend = 0.07). Similar, but less pronounced, decreases in the OR were also noted for the third and fourth quintiles of total polyphenol intake. Tea polyphenols and non-coffee polyphenols showed no association with colorectal cancer risk. The site-specific analysis, based on 463 colon cancer cases and 340 rectal cancer cases, showed an inverse association between coffee polyphenols and colon cancer. The multivariate-adjusted OR of colon cancer for the first to top quintiles of coffee polyphenols were 1.00 (referent), 0.92 (95%CI: 0.64-1.31), 0.75 (95%CI: 0.52-1.08), 0.69 (95%CI: 0.47-1.01), and 0.68 (95%CI: 0.46-1.00), respectively (P trend = 0.02). Distal colon cancer showed a more evident inverse association with coffee polyphenols than proximal colon cancer. The association between coffee polyphenols and rectal cancer risk was U-shaped, with significant decreases in the OR at the second to fourth quintile categories. There was also a tendency that the OR of colon and rectal cancer decreased in the intermediate categories of total polyphenols. The decrease in the OR in the intermediate categories of total polyphenols was most pronounced for distal colon cancer. Intake of tea polyphenols was not associated with either colon or rectal cancer. The associations of coffee consumption with colorectal, colon and rectal cancers were almost the same as observed for coffee polyphenols. The trend of the association between coffee consumption and colorectal cancer was statistically significant. The present findings suggest a decreased risk of colorectal cancer associated with coffee consumption.

What Should Be Done to Increase Survival in Patients With Colorectal Cancer?

See Article on Page 144-150 As a result of its rapid increase, colorectal cancer (CRC) in Korea was the third most common cancer in 2010. The age-standardized incidence rate of CRC was 20.4 (per 100,000) in 1999 and increased to 35.9 in 2010 (annual percentage changes, 5.9%). In 2010, 25,782 new CRC cases (15,612 men and 9,918 women) were diagnosed [1]. The article used the Korea Central Cancer Registry (226,352 cases) to show that the 5-year relative survival rates had improved between 1993 and 2010 (55.4% for 1993-1995 and 72.6% for 2006-2010) [2]. The rapid increase in CRC incidence is mainly attributed to the increase in colon cancer, especially distal colon cancer, and may be explained by a transition of risk factors for subsites or by the effect of CRC screening. The survival improvement may be due to an increase in early detection, refinement of surgical technique, new chemotherapy agents, and a multidisciplinary approach. CRC screening is a common denominator of the rapid increase in the incidence rate and the improved survival. CRC screening programs were introduced in 2004 as a part of the National Cancer Screening Program for Medical Aid recipients and National Health Insurance beneficiaries in the lower income bracket. Fecal occult blood test (FOBT) is provided free of charge as a primary modality for men and women aged 50 years or older. FOBT-positive individuals are provided follow-up by either colonoscopy or double-contrast barium enema. The participation rate was only 10.5% in 2004, but it increased to 21.1% in 2008 [3]. We colorectal surgeons still have a long way to go before we achieve our goal of complete healing of CRC. An expansion of an adherent to CRC screening program and an extension to surveillance colonoscopy without FOBT are the crux of the matter.

Subsite-Specific Dietary Risk Factors for Colorectal Cancer: A Review of Cohort Studies

Objective. A shift in the total incidence from left- to right-sided colon cancer has been reported and raises the question as to whether lifestyle risk factors are responsible for the changing subsite distribution of colon cancer. The present study provides a review of the subsite-specific risk estimates for the dietary components presently regarded as convincing or probable risk factors for colorectal cancer: red meat, processed meat, fiber, garlic, milk, calcium, and alcohol. Methods. Studies were identified by searching PubMed through October 8, 2012 and by reviewing reference lists. Thirty-two prospective cohort studies are included, and the estimates are compared by sex for each risk factor. Results. For alcohol, there seems to be a stronger association with rectal cancer than with colon cancer, and for meat a somewhat stronger association with distal colon and rectal cancer, relative to proximal colon cancer. For fiber, milk, and calcium, there were only minor differences in relative risk across subsites. No statement could be given regarding garlic. Overall, many of the subsite-specific risk estimates were nonsignificant, irrespective of exposure. Conclusion. For some dietary components the associations with risk of cancer of the rectum and distal colon appear stronger than for proximal colon, but not for all.

Data on the Characteristics and the Survival of Korean Patients With Colorectal Cancer From the Korea Central Cancer Registry

PurposeThe incidence rates of colorectal cancer (CRC) in Korea have been increasing during the past decade. Therefore, it is important to understand the characteristics, including survival, of Korean CRC patients. The aim of this study was to use the nationwide cancer registry to evaluate the characteristics of Korean CRC, focusing on the survival, according to tumor location, sex, and specific age groups.MethodsUsing the Korea Central Cancer Registry (KCCR), we analyzed a total of 226,352 CRC cases diagnosed from 1993 to 2010. The five-year relative survivals were compared for the proximal colon, the distal colon, and the rectum. Survival rates were compared between men and women and between patients of young age (less than 40 years old) and patients of advanced age (70 years old or older).ResultsThe 5-year survival rates were improved in all subsites between 1993 and 2010. Distal colon cancer showed favorable survival compared to proximal colon or rectal cancer. Females demonstrated worse survival for local or regional cancers, and this difference was significant in for patients in their seventies. Young patients (<40 years old) showed better survival rates for overall and proximal colon cancer comparable to those for older patients (≥40 years old), but advanced age patients (≥70 years old) had worse survivals for all tumor subsites compared to their younger counterparts (<70 years old). These trends were similar in distant CRC.ConclusionKorean CRC has certain distinct characteristics of survival according to tumor location, sex, and age. Despite the limitations of available data, this study contributes to a better understanding of survival differences in Korean CRC.

Bisphosphonates Are Associated With Reduced Risk of Colorectal Cancer: A Systematic Review and Meta-analysis

Colorectal cancer (CRC) is the third most common cancer worldwide. Several preclinical and observational studies have shown that bisphosphonates may have chemopreventive effects against CRC. We performed a systematic review and meta-analysis of all studies evaluating the effect of bisphosphonates on the risk of CRC. We conducted a systematic search of Medline, Embase, and Web of Science through August 2012 and manually reviewed the literature. Studies were included if they met the following criteria: (1) evaluated and clearly defined exposure to bisphosphonates, (2) reported CRC outcomes, and (3) reported relative risks or odds ratio (OR) or provided sufficient data for their estimation. Summary OR estimates with 95% confidence intervals (CIs) were estimated using the random-effects model. Statistical heterogeneity was assessed with the Cochran's Q and I(2) statistic. We analyzed data from 6 population-based observational studies reporting 20,001 cases of CRC in 392,106 patients. A meta-analysis of these studies showed a statistically significant 17% reduction in CRC incidence with bisphosphonate use (unadjusted OR, 0.83; 95% CI, 0.76-0.90), with borderline heterogeneity across studies (Cochran's Q, P = .16; I(2) = 37%). This effect persisted after correcting for multiple covariates in individual studies (adjusted OR, 0.85; 95% CI, 0.74-0.98). When the analysis was restricted to women only, use of bisphosphonates was associated with a 16% reduction in CRC incidence, which bordered on statistical significance (n = 5 studies; adjusted OR, 0.84; 95% CI, 0.70-1.01). This chemopreventive effect of bisphosphonates was observed for proximal and distal colon cancers, as well as rectal cancer, independently. Based on meta-analysis, bisphosphonate use is associated with a modest, but statistically significant, reduction in CRC risk.

Increasing trend of colorectal cancer incidence in Korea, 1999-2009.

PurposeThis study was conducted in order to demonstrate changing trends in colorectal cancer incidence according to sex, age group, and anatomical location in the Korean population.Materials and MethodsData from the Korea Central Cancer Registry between 1999 and 2009 were analyzed. Annual percent changes (APCs) of sex- and age-specific incidence rates for cancer of the proximal colon (International Statistical Classification of Diseases and Related Health Problems, 10th revision [ICD-10] code C18.0-18.5), distal colon (C18.6-18.7), and rectum (C19-20), and male-to-female incidence rate ratios (IRR) were calculated.ResultsThe age-standardized incidence rate (ASR) of colorectal cancer was 27 (per 100,000) in 1999 and increased to 50.2 in 2009 among men (APC, 6.6%). The ASR for women was 17.2 in 1999 and 26.9 in 2009 (APC, 5.1%). The rectum was the most common site of cancer among both men and women during 1999 and 2009. However, the distal colon had the highest APC (10.8% among men and 8.4% among women), followed by the proximal colon (7.9% among men and 6.6% among women), and rectum (5.2% among men and 2.4% among women). The proportion of rectal cancer decreased from 51.5% in 1999 to 47.1% in 2009 among men, and from 50.5% to 42.8% among women. An increase in the male-to-female IRR was observed for distal colon cancer and rectal cancer, whereas the IRR for proximal colon cancer was stable.ConclusionThe rapid increase in colorectal cancer incidence is mainly attributed to the increase in colon cancer, especially distal colon cancer, and may be explained by a transition of risk factors for subsites or by the effect of colorectal cancer screening.

Physical activity and the risk of proximal colon and distal colon cancers: A systematic review and meta-analysis

Physical activity and the risk of proximal colon and distal colon cancers: A systematic review and meta-analysis

A pooled analysis of smoking and colorectal cancer: timing of exposure and interactions with environmental factors.

Considerable evidence suggests that cigarette smoking is associated with a higher risk of colorectal cancer (CRC). What is unclear, however, is the impact of quitting smoking on risk attenuation and whether other risk factors for CRC modify this association. We conducted a pooled analysis of eight studies, including 6,796 CRC cases and 7,770 controls, to evaluate the association between cigarette smoking history and CRC risk and to investigate potential effect modification by other risk factors. Current smokers [OR, 1.26; 95% confidence interval (CI), 1.11-1.43] and former smokers (OR, 1.18; 95% CI, 1.09-1.27), relative to never smokers, showed higher risks of CRC. Former smokers remained at higher CRC risk, relative to never smokers, for up to about 25 years after quitting. The impact of time since quitting varied by cancer subsite: The excess risk due to smoking decreased immediately after quitting for proximal colon and rectal cancer but not until about 20 years post-quitting for distal colon cancer. Furthermore, we observed borderline statistically significant additive interactions between smoking status and body mass index [BMI; relative excess risk due to interaction (RERI]), 0.15; 95% CI, -0.01 to 0.31; P = 0.06] and significant additive interaction between smoking status and fruit consumption (RERI, 0.16; 95% CI, 0.01-0.30; P = 0.04). CRC risk remained increased for about 25 years after quitting smoking, and the pattern of decline in risk varied by cancer subsite. BMI and fruit intake modified the risk associated with smoking. These results contribute to a better understanding of the mechanisms through which smoking impacts CRC etiology.