Increase of colon and rectal cancer incidence rates in Japan: trends in incidence rates in Miyagi Prefecture, 1959-1997

Association between being breastfed in infancy and adult colorectal cancer risk among Japanese men and women

It has been postulated that being breastfed in infancy affects not only health status in childhood but also disease risk in adulthood. To investigate the association of being breastfed with the risks of adult colorectal cancer and benign tumor, we conducted a case-control study including 1190 colorectal cancer and 1585 benign tumor cases and 5301 controls, admitted to a single hospital in Miyagi Prefecture, Japan, between 1997 and 2013. History of having been breastfed was assessed using a self-administered questionnaire, and odds ratios (ORs) were estimated using unconditional logistic regression. There was no association between being breastfed and colorectal cancer risk (breastfed versus formula-only fed, OR = 1.21; 95% CI 0.87-1.67). There was also no association with the risk of benign tumor (OR = 1.04). On the other hand, analyses stratified by sex and birth year found heterogeneous associations. Women born after 1950 who had been breastfed tended to have increased risks of colorectal cancer (OR = 1.58) and benign tumor (OR = 1.51) relative to those who had been formula-only fed, although not statistically significant. In men born after 1950, being breastfed was associated with a significantly decreased risk of benign tumor (OR = 0.57; 95% CI 0.33-0.98).

Associations of cigarette smoking, alcohol drinking and body mass index with survival after colorectal cancer diagnosis by anatomic subsite: a prospective patient cohort study in Japan

BACKGROUND

Cigarette smoking, alcohol drinking and obesity are known to be risk factors for colorectal cancer. These factors may affect survival after diagnosis, but evidence has been inconsistent. We investigated subsite-specific associations between prediagnosis smoking, alcohol drinking and body mass index and survival in colorectal cancer.

METHODS

Subjects were 1300 patients (colon 778; rectum 502; concurrent 20) with histologically confirmed colorectal cancer diagnosed during 1997-2013 at a single institution in Japan. Histories of smoking and alcohol drinking, height and prediagnosis weight were assessed using a self-administered questionnaire. Using Cox proportional hazards model, hazard ratios and 95% confidence intervals of mortality were estimated.

RESULTS

During a median follow-up period of 6.7 years, 479 deaths were documented. Ever-smoking was associated with an increased risk of all-cause death among patients with colon cancer (hazard ratio: 1.47; 95% confidence interval: 1.07-2.02 compared with never-smoking). According to colon subsite, this increased risk was clear in patients with proximal colon cancer (hazard ratio: 2.09; 95% confidence interval: 1.28-3.40). There was no association between smoking and rectal cancer survival. Alcohol drinking was not associated with survival for either colon or rectal cancer. Among patients with rectal cancer, higher body mass index was associated with a lower risk of all-cause (Ptrend = 0.0006) and disease-specific death (Ptrend = 0.02). For colon cancer, lower body mass index tended to be associated with a higher risk of all-cause death (Ptrend = 0.05).

CONCLUSIONS

The results indicate that lifestyles identified as risk factors for colorectal cancer may impact differently on patient survival according to anatomic subsite.

Risk of Colorectal Carcinoma May Predispose to the Genetic Variants of the GST, CYP450, and TP53 Genes Among Nonsmokers in the Saudi Community

PURPOSE

Colorectal carcinoma (CRC) represents a considerable public health burden in Saudi Arabia. Several candidate genes and genetic variants have been associated with morbidity and mortality among patients with CRC. We explored whether allelic variants of the GSTM1, GSTT1, CYP450 (rs4646903 and rs1048943), and TP53 (rs1042522) genes predisposed nonsmoking Saudi individuals to increased risk for CRC.

PATIENTS AND METHODS

DNA from buccal cells of 158 participants (80 with CRC and 78 healthy controls) were analyzed for five SNPs using conventional PCR and TaqMan genotyping assays. The SNPStats software was utilized to choose the best interactive inheritance mode for selected SNPs (https://www.snpstats.net).

RESULTS

The mean age of diagnosis was 62.4±13.5 years (range, 40-83 years), with those aged 71-80 years and those aged 40-50 years accounting for the most diagnoses (35.7% and 28.6% of diagnosis, respectively). The GSTM1 and TP53 rs1042522 SNPs were associated with CRC (OR= 3.7; P< 0.0001, and OR= 1.6; P= 0.033, respectively). A plausible contribution to CRC was observed for the GSTM1 and TP53 rs1042522 SNPs (x ² _Yates= 14.7; P= 0.00013, and x ² _Yates= 11.2; P= 0.0008, respectively), while the GSTT1 null variant did not affect risk. Heterozygosity in the CYP450 (rs4646903 and rs1048943 SNPs) was associated with a significant risk for CRC. The GSTM1/GSTT1 and CYP450 rs4646903/rs1048943 SNP pairs were in linkage disequilibrium, and the associations were statistically significant (P= 0.01 and P= 4.6x10^‒7, respectively).

CONCLUSION

The GSTM1 and TP53 rs1042522 variants can increase the development of CRC in Saudi nonsmokers. Even the presence of one copy of a variant allele in the CYP1A1 gene can predispose CRC risk. Additional studies should also examine other SNP combinations with lifestyle factors that may help prevent, rather than facilitate, colorectal tumorigenesis.

An age-period-cohort analysis of mortality rates for stomach, colorectal, liver, and lung cancer among prefectures in Japan, 1999-2018

BACKGROUND

Although change in the birth cohort effect on cancer mortality rates is known to be highly associated with the decreasing rates of age-standardized cancer mortality rates in Japan, the differences in the trends of cohort effect for representative cancer types among the prefectures remain unknown. This study aimed to investigate the differences in the decreasing rate of cohort effects among the prefectures for representative cancer types using age-period-cohort (APC) analysis.

METHODS

Data on stomach, colorectal, liver, and lung cancer mortality for each prefecture and the population data from 1999 to 2018 were obtained from the Vital Statistics in Japan. Mortality data for individuals aged 50 to 79 years grouped in 5-year increments were used, and corresponding birth cohorts born 1920-1924 through 1964-1978 were used for analysis. We estimated the effects of age, period, and cohort on each type of mortality rate for each prefecture by sex. Then, we calculated the decreasing rates of cohort effects for each prefecture. We also calculated the mortality rate ratio of each prefecture compared with all of Japan for cohorts using the estimates.

RESULTS

As a result of APC analysis, we found that the decreasing rates of period effects were small and that there was a little difference in the decreasing rates among prefectures for all types of cancer among both sexes. On the other hand, there was a large difference in the decreasing rates of cohort effects for stomach and liver cancer mortality rates among prefectures, particularly for men. For men, the decreasing rates of cohort effects in cohorts born between 1920-1924 and 1964-1978 varied among prefectures, ranging from 4.1 to 84.0% for stomach cancer and from 20.2 to 92.4% for liver cancers, respectively. On the other hand, the differences in the decreasing rates of cohort effects among prefectures for colorectal and lung cancer were relatively smaller.

CONCLUSIONS

The decreasing rates of cohort effects for stomach and liver cancer varied widely among prefectures. It is possible that this will influence cancer mortality rates in each prefecture in the future.

A review of nutrition and dietary interventions in oncology

The complex cellular mechanisms and inter-related pathways of cancer proliferation, evasion, and metastasis remain an emerging field of research. Over the last several decades, nutritional research has prominent role in identifying emerging adjuvant therapies in our fight against cancer. Nutritional and dietary interventions are being explored to improve the morbidity and mortality for cancer patients worldwide. In this review, we examine several dietary interventions and their proposed mechanisms against cancer as well as identifying limitations in the currently available literature. This review provides a comprehensive review of the cancer metabolism, dietary interventions used during cancer treatment, anti metabolic drugs, and their impact on nutritional deficiencies along with a critical review of the following diets: caloric restriction, intermittent fasting, ketogenic diet, Mediterranean diet, Japanese diet, and vegan diet.

Global trends in colorectal cancer mortality: projections to the year 2035

Colorectal cancer (CRC) is the third most common cancer worldwide and the fourth most common cause of cancer death. Predictions of the future burden of the disease inform health planners and raise awareness of the need for cancer control action. Data from the World Health Organization (WHO) mortality database for 1989-2016 were used to project colon and rectal cancer mortality rates and number of deaths in 42 countries up to the year 2035, using age-period-cohort (APC) modelling. Mortality rates for colon cancer are predicted to continue decreasing in the majority of included countries from Asia, Europe, North America and Oceania, except Latin America and Caribbean countries. Mortality rates from rectal cancer in general followed those of colon cancer, however rates are predicted to increase substantially in Costa Rica (+73.6%), Australia (+59.2%), United States (+27.8%), Ireland (+24.2%) and Canada (+24.1%). Despite heterogeneous trends in rates, the number of deaths is expected to rise in all countries for both colon and rectal cancer by 60.0% and 71.5% until 2035, respectively, due to population growth and ageing. Reductions in colon and rectal cancer mortality rates are probably due to better accessibility to early detection services and improved specialized care. The expected increase in rectal cancer mortality rates in some countries is worrisome and warrants further investigations.

Prognostic impact of tumor location in colon cancer: the Monitoring of Cancer Incidence in Japan (MCIJ) project

BACKGROUND

Colorectal cancer (CRC) is globally one of the most common cancers. Although studies have found a significant prognostic impact of cancer location for right-sided colon cancers compared with those of the left-side, evidence is lacking in a Japanese population. Therefore, we investigated 5-year net survival in colon cancer by tumor site in a Japanese population.

METHODS

Diagnoses obtained between 2006 and 2008 in 21 population-based cancer registries from the Monitoring of Cancer Incidence in Japan (MCIJ) project were used. Colon cancer patients were categorized as having right-sided (C18.0-18.4) or left-sided colon cancer (C18.5-C18.7). We calculated the 5-year net survival for subjects diagnosed from 2006 until 2008 by anatomical subsite according to sex, age groups, tumor stage at diagnosis. We applied the excess mortality model to calculate excess hazard ratios (EHRs) and 95% confidential intervals (CIs) with and without adjustment for age, sex and cancer stages to evaluate the effect of location of colon cancer.

RESULTS

This study analyzed a total of 62,350 colon cancer subjects. Five-year net survivals for subjects with left- and right-sided colon cancer were 74.0% (95% CI, 73.4-74.7%) and 70.4% (95% CI, 69.7-71.0%), respectively. Compared with left-sided colon cancers, the EHR for right-sided colon cancers was 1.20 (95% CI, 1.16-1.25) after adjustment for age, sex and stage.

CONCLUSION

Our study found that the net survival for right-sided colon cancer was significantly lower than that for left-sided colon cancer. The anatomical site of cancer in the colon might be an important stratification factor in future studies of colon cancer.

A population-based age-period-cohort study of colorectal cancer incidence comparing Asia against the West

BACKGROUND

Colorectal cancer (CRC) is the third most common cancer worldwide but incidence varied widely. Despite the role of genetics, CRC is also sensitive to macro-environmental factors. Few studies have ever compared across different countries/regions to suggest possible macro-environmental risk factors of CRC. We estimated the effects of age, period and cohort on the changes of incidence of colorectal cancer across different countries/regions.

METHODS

Poisson regression age-period-cohort (APC) models were conducted to estimate the age, period and cohorts effects on CRC incidence across the West (i.e., the UK, the US and Australia) and Asia (i.e. Japan, Hong Kong, Shanghai, Singapore and India). We maximized the length of the study period according to each country's data availability.

RESULTS

Western populations show upward inflections for their 1950s-1960s cohorts, while Asian populations (except India) show downward inflections for their 1950s cohorts. Japanese population also shows upward inflections for its 1960s cohorts, similar to the Western populations. There are apparent upward inflections towards the more recent cohorts for Hong Kong, Shanghai and Singapore; nevertheless, the confidence intervals are wider towards the more recent cohorts.

CONCLUSION

Our findings imply an increasing risk of CRC in both Western and Asian populations as their younger cohorts reach older ages. These findings are consistent with the life course argument that macro-environmental changes associated with socio-economic development have specific effects that extend over the life course. Actions that pertain to altering lifestyle-related exposures over the life course are of great importance in combating young CRC risks in the future.

A Dose-Response Meta-analysis of Coffee Consumption and Colorectal Cancer Risk in the Japanese Population: Application of a Cubic-Spline Model

BACKGROUND

A recent meta-analysis compared the relative risks of colorectal cancer between the highest and lowest levels of coffee consumption in the Japanese population. However, this analysis did not define the risks with respect to specific exposure values when considering levels of coffee consumption per day in the study population.

METHODS

We conducted a two-stage random-effects dose-response meta-analysis of the association between coffee consumption and colorectal cancer among the Japanese. This was performed by modeling coffee consumption using restricted cubic splines to be able to examine a potential nonlinear relation.

RESULTS

We identified a total of 26 studies from seven articles, which were distributed separately according to sex and colon/rectum cancers. Data from 14 cohort studies showed that the pooled relative risks for colorectal cancers were less than 1.0 in cases with coffee consumption of 1-3 cups/day and 1.0 in cases with consumption of 4 cups/day or more, although these results were not statistically significant. Data from 12 case-control studies showed that the pooled odds ratios for cancer risk were significantly less than 1.0 in cases with coffee consumption of 1-6 cups/day.

CONCLUSIONS

Findings from this meta-analysis indicate that moderate coffee consumption may not be associated or may be weakly inversely associated with the risk of colorectal cancer in the Japanese population.

Urinary Polyamine Biomarker Panels with Machine-Learning Differentiated Colorectal Cancers, Benign Disease, and Healthy Controls

Colorectal cancer (CRC) is one of the most daunting diseases due to its increasing worldwide prevalence, which requires imperative development of minimally or non-invasive screening tests. Urinary polyamines have been reported as potential markers to detect CRC, and an accurate pattern recognition to differentiate CRC with early stage cases from healthy controls are needed. Here, we utilized liquid chromatography triple quadrupole mass spectrometry to profile seven kinds of polyamines, such as spermine and spermidine with their acetylated forms. Urinary samples from 201 CRCs and 31 non-CRCs revealed the N₁,N₁₂-diacetylspermine showing the highest area under the receiver operating characteristic curve (AUC), 0.794 (the 95% confidence interval (CI): 0.704–0.885, p < 0.0001), to differentiate CRC from the benign and healthy controls. Overall, 59 samples were analyzed to evaluate the reproducibility of quantified concentrations, acquired by collecting three times on three days each from each healthy control. We confirmed the stability of the observed quantified values. A machine learning method using combinations of polyamines showed a higher AUC value of 0.961 (95% CI: 0.937–0.984, p < 0.0001). Computational validations confirmed the generalization ability of the models. Taken together, polyamines and a machine-learning method showed potential as a screening tool of CRC.

Coffee consumption and the risk of colorectal cancer by anatomical subsite in Japan: Results from the HERPACC studies

Consumption of coffee, a popular beverage worldwide, has been associated with lower colorectal cancer (CRC) risk. Although CRC exhibits different biological characteristics by anatomical subsite, the possibly heterogeneous impact of coffee on CRC by anatomical subsite has remained unclear. Here, we conducted two case-control studies to examine the association between coffee consumption and CRC risk as well as risk by anatomic subsite among Japanese using data from the Hospital-based Epidemiological Research Program at Aichi Cancer Center I and II (HERPACC-I and II). Subjects were enrolled in HERPACC-I between 1988 and 2000 and in HERPACC-II between 2001 and 2005. Coffee consumption was measured with a self-administered questionnaire. A conditional logistic regression model was used to calculate odds ratios (ORs) of CRC with coffee consumption, adjusted for potential confounders of age, smoking, alcohol drinking, red meat intake, BMI, exercise, family history of CRC, and diabetes mellitus history. We estimated summary ORs by pooling study-specific ORs with a fixed effects model. In total, 2,696 CRC cases and 13,480 non-cancer outpatients as controls were included. Overall, compared to non-drinkers, ORs of less than 1 cup/day, 1-2 cups/day and 3 or more cups/day for CRC were 0.88 (95% CI: 0.77-1.00), 0.90 (95% CI: 0.80-1.01) and 0.78 (95% CI: 0.65-0.92), respectively (trend-p = 0.009). Subsite-specific analysis revealed a significant inverse linear trend between coffee consumption and distal colon cancer (p-trend = 0.048), and a tendency toward a lower risk of rectal cancer (p-trend = 0.068). These findings suggest that coffee consumption might impact the prevention of CRC, especially distal colon cancer.

Colorectal cancer incidence in 5 Asian countries by subsite: An analysis of Cancer Incidence in Five Continents (1998-2007)

Colorectal cancer is the fourth most common cancer in Asia. However, the trends in colorectal cancer incidence by subsite have not been analyzed across Asian countries. We used the most recent, high quality data from 6 cancer registries for two 5-year periods, 1998-2002 and 2003-2007, from Cancer Incidence in Five Continents to estimate colorectal cancer incidence by subsite in 5 Asian countries. Cases with overlapping lesions or otherwise unspecified colon cancer were re-distributed as proximal or distal colon cancer. Age-standardized incidence rates (ASRs) per 100,000 population and incidence rate ratios from 1998 to 2002 to 2003-2007 were calculated for each subsite. For 2003-2007, men in Miyagi, Japan, had the highest ASR for cancer in the proximal colon, distal colon and rectum. Men of Jewish ancestry in Israel had a high ASR for proximal and distal colon cancer, but the lowest ASR for rectal cancer. The proportion of rectal cancer was highest among Korean men (51.39%) and lowest among Israeli women (26.6%). From 1998-2002 to 2003-2007, rectal cancer incidence did not significantly change in most registries, except for men in Miyagi, Japan, and both sexes in Korea. However, during the same period cancer incidence in the proximal and distal colon increased in most registries. In conclusion, there was substantial variation in subsite distributions of colorectal cancer in Asian registries and increases in overall incidence of colorectal cancer could be attributed to increases in colon cancer.

Comparison of plasma levels of obesity-related biomarkers among Japanese populations in Tokyo, Japan, São Paulo, Brazil, and Hawaii, USA

Although Japanese in Japan and the USA are high-risk populations for colorectal cancer, the prevalence of obesity, one of the established risk factors for this disease, is low in these populations compared with other high-risk populations. To understand this inconsistency, we compared plasma obesity-related biomarkers in cross-sectional studies carried out in Tokyo, São Paulo, and Hawaii. We measured plasma levels of insulin-like growth factor-I (IGF-I), insulin-like growth factor-binding protein (IGFBP)-1, IGFBP-3, C-peptide, adiponectin, leptin, tumor necrosis factor-α, and interleukin-6 by immunoassay and total C-reactive protein, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides using a clinical chemistry autoanalyzer. A total of 299 participants were included in the present analysis, comprising 142 Japanese in Tokyo, 79 Japanese Brazilians in São Paulo, and 78 Japanese Americans in Hawaii. We found significantly lower plasma levels of C-peptide and IGF-I in Japanese in Tokyo than in Japanese Americans, and lower levels of leptin and triglycerides and higher levels of adiponectin, IGFBP-3, and high-density lipoprotein cholesterol in Japanese in Tokyo than in the other two populations. We also observed a significantly higher plasma IGFBP-1 level in Japanese Brazilians, and lower plasma levels of total cholesterol and low-density lipoprotein in Japanese Americans than in the other two populations. We observed significant differences in obesity-related biomarkers between the three Japanese populations. If our results are confirmed, the risk of colorectal cancer predicted on the basis of these biomarkers would be lowest for Japanese in Tokyo, followed by Japanese Brazilians and Japanese Americans.

Increasing Incidence of Colorectal Cancer, Starting at a Younger Age for Rectal Compared to Colon Cancer in Brunei Darussalam

BACKGROUND

Colorectal cancer (CRC) is the most common gastrointestinal malignancy and is a significant cause of mortality. Its incidence is generally increasing in Asia. Reports from the West have indicated that the incidence of rectal cancer is increasing in the younger population. This study assessed the time trend of CRC in Brunei Darussalam specifically assessing the different age groups at which the incidences start to increase.

MATERIALS AND METHODS

The National Cancer registry was reviewed (1991 to 2014). The age standardized rate (ASR) and the age specific incidence rates (ASIRs) for three time periods (1991-1998), (1999-2006) and (2007-2014) were calculated.

RESULTS

The mean age of diagnosis was 59.3±14.6 years old, incidences being slightly higher amongst men (57.6%) and Malays (67.1%). The most common tumor type was adenocarcinoma (96.4%). Rectal cancers accounted for 35.2% (n=372/1,056) of all cancers of the large bowel; more men were affected than women. The proportion of rectal cancer was also high among the indigenous group. In the three time periods, the ASR for CRC increased from 16 per 100,000 (1991-1998) to 19.6 per 100,000 (1999-2006) and 24.3 per 100,000 (2007-2014). The ASIRs for CRC increased markedly between the time periods 1998-2006 and 2007-2014, beginning in the 40-44 years age group. For rectal cancers, the ASIRs started to increase in the 25-29 age group onward whereas for colon cancers, the increase was observed at a later age, starting from the 45-49 age group.

CONCLUSIONS

Our study showed an increase in the incidence of CRC including in the younger age groups. The increase was seen earlier in rectal cancer compared to colon cancer. These data mirror the trends reported from the West.

Recent Decrease in Colorectal Cancer Mortality Rate is Affected by Birth Cohort in Korea

BACKGROUND

Colorectal cancer mortality has started to decrease in several developed countries in Asia. The current study aimed to present the long-term trends in colorectal cancer mortality in Korea using joinpoint analysis and age-period-cohort modeling.

MATERIALS AND METHODS

The number of colorectal cancer deaths and the population for each 5-year age group were obtained from Statistics Korea for the period 1984-2013 for adults 30 years and older. Joinpoint regression analysis was conducted to determine changes in trends in age-standardized mortality rates, and age-period-cohort analysis was performed to describe trends in colorectal cancer mortality using the intrinsic estimator method.

RESULTS

In men, the age-standardized mortality rate for colorectal cancer increased from 1984 to 2003, and the mortality rates stabilized thereafter, whereas the mortality rate of colorectal cancer in women has decreased since 2004. The age-specific mortality rate of colorectal cancer increased in both men and women over time, whereas decreases in the age-specific mortality rate in younger cohorts were observed. In the age-period-cohort analysis, old age and recent period were associated with higher mortality for both men and women. The birth cohort born after 1919 showed reduced colorectal cancer mortality in both men and women.

CONCLUSIONS

Our study showed a recent decreasing trend in colorectal cancer mortality in women and a stable trend in men after 2003-2004. These changes in colorectal cancer mortality may be attributed to birth cohort effects.

Factors Determining Colorectal Cancer: The Role of the Intestinal Microbiota

The gastrointestinal tract, in particular the colon, holds a complex community of microorganisms, which are essential for maintaining homeostasis. However, in recent years, many studies have implicated microbiota in the development of colorectal cancer (CRC), with this disease considered a major cause of death in the western world. The mechanisms underlying bacterial contribution in its development are complex and are not yet fully understood. However, there is increasing evidence showing a connection between intestinal microbiota and CRC. Intestinal microorganisms cause the onset and progression of CRC using different mechanisms, such as the induction of a chronic inflammation state, the biosynthesis of genotoxins that interfere with cell cycle regulation, the production of toxic metabolites, or heterocyclic amine activation of pro-diet carcinogenic compounds. Despite these advances, additional studies in humans and animal models will further decipher the relationship between microbiota and CRC, and aid in developing alternate therapies based on microbiota manipulation.

Rice, bread, noodle and cereal intake and colorectal cancer in Japanese men and women: the Japan Public Health Center-based prospective Study (JPHC Study)

Background:

Colorectal cancer (CRC) incidence rate increased rapidly in Japan between the 1950s and 1990s. We examined the association between rice intake and CRC risk in comparison with bread, noodles and cereal among Japanese adults enrolled in the Japan Public Health Center-based prospective Study.

Methods:

A total of 73 501 Japanese men and women were followed-up from 1995 to 1999 until the end of 2008 for an average of 11 years. During 801 937 person-years of follow-up, we identified 1276 incident cases of CRC. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) of CRC for rice, noodle, bread and cereal intake were calculated by Cox proportional hazards model.

Results:

Overall, no significant association was observed for the highest quartile of rice intake compared with the lowest and the risk of CRC and its subsites in men (HR, 0.77; 95% CI, 0.56–1.07) and women (HR, 1.10; 95% CI, 0.71–1.68). However, a non-significant inverse trend was observed between rice intake and rectal cancer in men. No clear patterns of association were observed in bread, noodle and cereal intake.

Conclusion:

Our findings suggest that the consumption of rice does not have a substantial impact on the risk of CRC in the Japanese population.

A birth cohort analysis of the incidence of ascending and descending colon cancer in the United States, 1973-2008

OBJECTIVES

There is evidence indicating that the trends in colorectal cancer (CRC) incidence rates in the United States differ according to CRC subsites, including for ascending cancer which has shown a different pattern from the overall trends. We investigated the time trends for ascending and descending colon cancer in the United States by race and gender to identify the specific components that may account for the incidence trends.

METHODS

Using data from the National Cancer Institute's Surveillance, Epidemiology, and End Results program for 1973-2008, we conducted age-period-cohort modeling to evaluate birth cohort patterns and evaluate age-period-cohort effects on incidence trends of colon cancer over time.

RESULTS

A clear birth cohort pattern was observed for both ascending and descending colon cancer, and the incidence rates of ascending colon cancer in the more recent birth cohorts were higher compared to earlier cohorts particularly for black males and females. This increase was most obvious in the younger age groups and appeared to accelerate, especially for black females. For descending colon cancer, the study suggested an increase in the birth cohort slope in the later birth cohorts for all gender and race groups, after a period of decline in earlier birth cohorts.

CONCLUSION

The increase in incidence rates of both ascending and descending colon cancer in more recent birth cohorts for blacks suggests the need for targeted public health strategies to increase CRC screening. Further, additional etiological studies are warranted to evaluate factors responsible for the observed trends in more recent birth cohorts, including differences by subsites, race, and/or gender.

Validation of a quantitative FFQ for a study of diet and risk of colorectal adenoma among Japanese Brazilians

OBJECTIVE

To assess the validity of a 161-item quantitative FFQ (QFFQ) that was developed to evaluate dietary risk factors for a colorectal adenoma case–control study.

DESIGN

A cross-sectional validation study of the QFFQ against 4 d food diary using Pearson correlation coefficients, cross-classification, weighted k statistics and Bland–Altman plotting.

SETTING

Two hospitals in Sa˜o Paulo, Brazil.

SUBJECTS

Ninety-seven healthy Japanese-Brazilian adults (40–75 years) were recruited. One participant was excluded from the analysis due to unusual energy intake report.

RESULTS

Mean daily nutrient intakes from the QFFQ were higher than from the food diary. The mean Pearson correlation coefficient for nutrient intakes between the QFFQ and the average of the 4 d food diary was 0?43, and increased to 0?45 after correcting correlations for attenuation due to residual day-to-day variation in the food diary measurements. Adjustment for total energy and further adjustment for age and gender decreased the correlation; however, 77% of observations remained in the same or adjacent quartiles with a mean weighted k of 0?22. Bland–Altman plots on loge-transformed data showed no linear trend between the differences and means for energy, fat, protein, total folate and vitamin C. Compared with the food diary, the QFFQ showed consistently reasonable performance for dietary fibre, total folate, retinol, riboflavin and vitamin C.

CONCLUSIONS

This investigation supports the relative validity of the QFFQ as a method for assessing long-term dietary intake. The instrument will be a useful tool in the analysis of diet–adenoma associations in the case–control study.

Common variant in 6q26-q27 is associated with distal colon cancer in an Asian population

BACKGROUND AND AIM

Colorectal cancer (CRC) is a multifactorial disease with both environmental and genetic factors contributing to its development. The incidence of CRC is increasing year by year in Japan. Patients with CRC in advanced stages have a poor prognosis, but detection of CRC at earlier stages can improve clinical outcome. Therefore, identification of epidemiologial factors that influence development of CRC would facilitate the prevention or early detection of disease.

METHODS

To identify loci associated with CRC risk, we performed a genome-wide association study (GWAS) for CRC and sub-analyses by tumour location using 1583 Japanese CRC cases and 1898 controls. Subsequently, we conducted replication analyses using a total of 4809 CRC cases and 2973 controls including 225 Korean subjects with distal colon cancer and 377 controls.

RESULTS

We identified a novel locus on 6q26-q27 region (rs7758229 in SLC22A3, p = 7.92 × 10⁻⁹, OR of 1.28) that was significantly associated with distal colon cancer. We also replicated the association between CRC and SNPs on 8q24 (rs6983267 and rs7837328, p = 1.51 × 10⁻⁸ and 7.44 × 10⁻⁸, ORs of 1.18 and 1.17, respectively). Moreover, we found cumulative effects of three genetic factors (rs7758229, rs6983267, and rs4939827 in SMAD7) and one environmental factor (alcohol drinking) which appear to increase CRC risk approximately twofold.

CONCLUSIONS

We found a novel susceptible locus in SLC22A3 that contributes to the risk of distal colon cancer in an Asian population. These findings would further extend our understanding of the role of common genetic variants in the aetiology of CRC.

Genome-wide association studies may be misinterpreted: genes versus heritability

Much of the literature on genome-wide association studies (GWAS) is based on the premise that an important proportion of common diseases is heritable and that this proportion is likely to be due to genetic variants detectable with extensive scans of the DNA. Heritability is estimated from family studies, including twin studies and is based on the comparison of the variation in disease among different members of particular families. Since there is a wide gap between the population variation in disease explained by the results of GWAS (usually <10% for common diseases) and estimates of heritability (often >50%), the question arises as to how to explain these differences. However, the premise for this question is based on two sources of misunderstanding: (i) confusion between variation and causation and (ii) confusion between heritability and genetic determination. As we show with a number of examples, variation is not causation and heritability is not genetic determination. Therefore, heritability studies do not provide valid estimates of the proportion of disease cases that are attributable to genetic factors. Such estimates in turn cannot be used to estimate the proportion of cases that are due to environmental factors.

Colorectal cancer prevention through dietary and lifestyle modifications

Several studies indicate that Western dietary and lifestyle factors are responsible for the high incidence of colorectal cancer in industrialized countries. Diets rich in red and processed meat, refined starches, sugar, and saturated and trans-fatty acids but poor in fruits, vegetables, fiber, omega-3 fatty acids and whole grains are closely associated with an increased risk of colorectal cancer. Other main features of the western lifestyle, such as excess body mass and sedentary behaviours, are also strongly associated with higher risk of developing this cancer. Modifications of the western diet, notably increasing consumption of foods from plant origin and reducing that of red meat intake, and maintenance of physical activity and appropriate body mass could substantially reduce colorectal cancer incidence and mortality.

Colorectal cancer screening in evolution: Japan and the USA

Colorectal cancer (CRC) is one of the most common cancers in both Japan and the USA. Age-adjusted incidence of CRC has been in decline in the USA since 1985, while rates in Japan have been increasing. The decline in the USA is commonly attributed to CRC screening programs but there is little direct evidence to support this assertion. The current screening recommendations in the USA cover several options including colonoscopy and computerized tomographic colonography (CTC). The Japanese CRC screening program is centered on fecal immunochemistry testing (FIT). The US government Medicare program's approval of colonoscopy as a primary screening test has lead to a large increase in the number of patients undergoing the procedure. However, the benefit achieved from this change in screening program emphasis is not clear. Simulation models demonstrate that a screening program centered on FIT achieves 94% of the benefit that an all-colonoscopy program is able to accomplish but at a lower cost per life year gained. Clinical studies of colonoscopy have failed to demonstrate the 76-90% declines in CRC incidence predicted by the National Polyp Study published in 1993. A potential reason for this failure is the quality of colonoscopy performance. Until more compelling data becomes available demonstrating the utility of colonoscopy as a primary screening modality, there is little incentive to alter the proven cost-effective approach to CRC screening currently in practice in Japan.

Calorie restriction and cancer prevention: metabolic and molecular mechanisms

An important discovery of recent years has been that lifestyle and environmental factors affect cancer initiation, promotion and progression, suggesting that many malignancies are preventable. Epidemiological studies strongly suggest that excessive adiposity, decreased physical activity, and unhealthy diets are key players in the pathogenesis and prognosis of many common cancers. In addition, calorie restriction (CR), without malnutrition, has been shown to be broadly effective in cancer prevention in laboratory strains of rodents. Adult-onset moderate CR also reduces cancer incidence by 50% in monkeys. Whether the antitumorigenic effects of CR will apply to humans is unknown, but CR results in a consistent reduction in circulating levels of growth factors, anabolic hormones, inflammatory cytokines and oxidative stress markers associated with various malignancies. Here, we discuss the link between nutritional interventions and cancer prevention with focus on the mechanisms that might be responsible for these effects in simple systems and mammals with a view to developing chemoprevention agents.

Trends in colorectal cancer incidence in Norway 1962-2006: an interpretation of the temporal patterns by anatomic subsite

There have been rapid increases in the incidence of colorectal cancer in Norway since the 1960s, and rates rank among the highest worldwide. The primary objectives are to describe trends in left- and right-sided colon cancer and rectal cancer by calendar period and birth cohort and to generate hypotheses as to the etiological factors in operation. Although the age-adjusted incidence rates of both colon and rectal cancer increased in Norway in both sexes up to the 1980s, subsite- and age-specific analyses reveal a deceleration in the rate of increase thereafter, apparent in the rates of both left-sided colon and rectal cancer. Overall trends in incidence of right-sided colon cancer continue to increase in both sexes. Rates in both left- and right-sided colon cancers have tended to stabilize or decrease among successive generations born after 1950, however, while incidence rates of rectal cancer appear to be increasing in recent generations. The all-ages rates are thus in keeping with the commonly reported "left to right shift" of colon cancer, although standardization masks important observations. The cohort patterns provide further evidence that factors earlier in life are important, and while the complex etiology makes interpretation difficult, modifications in diet, obesity and physical activity in Norway are likely among the drivers of the trends in one or more of the colorectal subsites examined. In summary, the recent downturn in the disease at younger ages provides some reason for optimism, although possible increases in rectal cancer among recent birth cohorts are of concern.

Clinical value of 18F-FDG PET/CT in assessing suspicious relapse after rectal cancer resection

AIM: To evaluate the value of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in the restaging of resected rectal cancer.

METHODS: From January 2007 to Sep 2008, 21 patients who had undergone curative surgery resection for rectal carcinoma with suspicious relapse in conventional imaging or clinical findings were retrospectively enrolled in our study. The patients underwent 28 PET/CT scans (two patients had two scans, one patient had three and one had four scans). Locoregional recurrences and/or distant metastases were confirmed by histological analysis or clinical and imaging follow-up.

RESULTS: Final diagnosis was confirmed by histopathological diagnosis in 12 patients (57.1%) and by clinical and imaging follow-up in nine patients (42.9%). Eight patients had extrapelvic metastases with no evidence of pelvic recurrence. Seven patients had both pelvic recurrence and extrapelvic metastases, and two patients had pelvic recurrence only. ¹⁸F-FDG PET/CT was negative in two patients and positive in 19 patients. ¹⁸F-FDG PET/CT was true positive in 17 patients and false positive in two. The accuracy of ¹⁸F-FDG PET/CT was 90.5%, negative predictive value was 100%, and positive predictive value was 89.5%. Five patients with perirectal recurrence underwent ¹⁸F-FDG PET/CT image guided tissue core biopsy. ¹⁸F-FDG PET/CT also guided surgical resection of pulmonary metastases in three patients and monitored the response to salvage chemotherapy and/or radiotherapy in four patients.

CONCLUSION: ¹⁸F-FDG PET/CT is useful for evaluating suspicious locoregional recurrence and distant metastases in the restaging of rectal cancer after curative resection.

Evaluation of bowel cancer registration data in England, 1996-2004

Background:

The National Health Service (NHS) bowel cancer screening programme (BCSP) was initiated across England in April 2006. To determine the feasibility of using national cancer registration data to assess the impact of the BCSP on stage-specific incidence, we studied trends in the incidence rates of colon (ICD10 C18) and rectosigmoid junction and rectum (ICD10 C19–C20) cancers and the completeness of data on Dukes stage in England.

Methods:

Data were obtained from all nine cancer registries for the period 1996–2004, before the introduction of the BCSP, in men and women aged 50–79 years.

Results:

Overall, incidence rates declined by 1% per year in the 9 years before the introduction of the BCSP (P<0.001). Dukes stage was recorded for 60% of all registrations but this varied between regions and over time. Only four registries had completeness of 74% or more. Registrations with unknown Dukes stage decreased from 1996 to 2000, and then increased during 2001–2004 affecting trends in stage-specific incidence.

Conclusion:

To study the impact of the BCSP on stage-specific incidence, regional variations in data completeness need to be addressed.

Cutoff value determines the performance of a semi-quantitative immunochemical faecal occult blood test in a colorectal cancer screening programme

Background:

The cutoff of semi-quantitative immunochemical faecal occult blood tests (iFOBTs) influences colonoscopy referrals and detection rates. We studied the performance of an iFOBT (OC-Sensor) in colorectal cancer (CRC) screening at different cutoffs.

Methods:

Dutch screening participants, 50–75 years of age, with average CRC risk and an iFOBT value ⩾50 ng ml⁻¹ were offered colonoscopy. The detection rate was the percentage of participants with CRC or advanced adenomas (⩾10 mm, ⩾20% villous, high-grade dysplasia). The number needed to scope (NNTScope) was the number of colonoscopies to be carried out to find one person with CRC or advanced adenomas.

Results:

iFOBT values ⩾50 ng ml⁻¹ were detected in 526 of 6157 participants (8.5%) and 428 (81%) underwent colonoscopy. The detection rate for advanced lesions (28 CRC and 161 with advanced adenomas) was 3.1% (95% confidence interval: 2.6–3.5%) and the NNTScope was 2.3. At 75 ng ml⁻¹, the detection rate was 2.7%, the NNTScope was 2.0 and the CRC miss rate compared with 50 ng ml⁻¹ was <5% (N=1). At 100 ng ml⁻¹, the detection rate was 2.4% and the NNTScope was <2. Compared with 50 ng ml⁻¹, up to 200 ng ml⁻¹ CRC miss rates remained at 16% (N=4).

Conclusions:

Cutoffs below the standard 100 ng ml⁻¹ resulted in not only higher detection rates of advanced lesions but also more colonoscopies. With sufficient capacity, 75 ng ml⁻¹ might be advised; if not, up to 200 ng ml⁻¹ CRC miss rates are acceptable compared with the decrease in performed colonoscopies.

International trends in colorectal cancer incidence rates

BACKGROUND

Previous studies have documented significant variations in colorectal cancer incidence rates and trends regionally and across countries. However, no study has examined the worldwide pattern using the most recently updated incidence data from the IARC.

METHODS

We obtained sex-specific colorectal cancer incidence for 1953-57 through 1998-2002 by cancer registry from Cancer Incidence in Five Continents (CI5) databases. For 51 cancer registries with long-term incidence data, we assessed the change in the incidence rates over the past 20 years by calculating the ratio of the incidence rates in 1998-2002 to that in 1983-87.

RESULTS

Colorectal cancer incidence rates for both males and females statistically significantly increased from 1983-87 to 1998-2002 for 27 of 51 cancer registries considered in the analysis, largely confined to economically transitioning countries including Eastern European countries, most parts of Asia, and select countries of South America. These increases were more prominent for men than for women. We also observed substantial variations in colorectal cancer incidence trends within countries such as Japan. Similarly, trends in Israel and Singapore varied significantly according to ethnicity. The United States is the only country where colorectal cancer incidence rates declined in both males and females.

CONCLUSIONS

Colorectal cancer incidence rates continue to increase in economically transitioning countries, with incidence rates among men in the Czech Republic and Slovakia exceeding the peak incidence observed in the United States and other long-standing developed nations. Targeted prevention and early detection programs could help reverse the trend in these countries.

Clinical predictors of colorectal polyps and carcinoma in a low prevalence region: Results of a colonoscopy based study

AIM: To estimate the prevalence of colorectal cancer (CRC) in patients with long lasting colonic symptoms undergoing total colonoscopy; and to establish clinical features predicting its occurrence.

METHODS: This prospective study was carried out in Imam Hospital, Tabriz University of medical sciences, Iran. Continuous patients with long lasting lower gastrointestinal tract symptoms who had the criteria of a colonoscopy were included. The endoscopist visualized the caecum documented by a photo and/or a specimen from terminal ileum.

RESULTS: Four hundred and eighty consecutive symptomatic patients [mean age (SD): 42.73 (16.21)] were included. The prevalence of colorectal neoplasia was 15.3% (34 subjects) and 37.7% (181 subjects) had a completely normal colon. Adenomatous polyps were detected in 56 (11.7%) patients, in 12.3% of men and 10.9% of women. The mean age of the patients with a polyp was significantly higher than the others (49.53 ± 14.16 vs 41.85 ± 16.26, P = 0.001). Most of the adenomatous polyps were left sided and tubular; only 22.5% of polyps were more than 10 mm. Cancer was detected in 16 (3.6%) of our study population, which was mostly right sided (57.2%). The mean age of patients with cancer was significantly higher than the others (60.25 ± 8.26 vs 42.13 ± 16.08, P < 0.005) and higher than patients with polyps [60.25 (8.26) vs 49.53 (1.91) (P < 0.0005)]. None of the symptoms (diarrhea, abdominal pain, rectal bleeding, constipation, altering diarrhea and constipation, history of cancer, known irritable bowel disease, history of polyp and fissure or family history of cancer) were predictors for cancer or polyps, but the age of the patient and unexplained anemia independently predicted cancer.

CONCLUSION: Less advanced patterns and smaller sizes of adenomas in Iran is compatible with other data from Asia and the Middle East, but in contrast to western countries. Prevalence of colonic neoplasia in our community seems to be lower than that in western population. Colonic symptoms are not predictors for polyps or cancer but unexplained anemia and elder age can predict CRC.

Q&A on diagnosis, screening and follow-up of colorectal neoplasia

The impressive and brisk evolution of medical science prevents many physicians from a thorough update on all the research fields. Colorectal cancer diagnosis, screening and follow-up is well known to require a multi-disciplinary approach, as it is faced by several specialties such as primary care physicians, gastroenterologists, non-gastroenterologist internists, radiologists and surgeons. To address this issue in a mutual perspective, we focused on the main points of the epidemiology, diagnosis, screening and follow-up of colorectal neoplasia by using a simple "Question & Answers" structure.

Translational approaches to addressing complex genetic pathways in colorectal cancer

Colorectal cancer (CRC) is among the most prevalent cancers worldwide and represents a major public health challenge in the developed world. From the perspective of translational investigation, scientists have enormous opportunity to elucidate the molecular genetic mechanisms that contribute to CRC pathogenesis because most cancers develop from adenomatous precursor lesions. The process of adenoma growth and transformation is accompanied by cumulative mutations in dominant genetic pathways that confer a growth advantage. Although this developmental process permits interrogation of informative pathways before the development of cancer, only a few adenomas progress to CRC. Accordingly, a major challenge for clinical translational investigators is to identify the molecular signatures that indicate increased likelihood for adenoma progression. By corollary, these molecular signatures include mutations in high penetrance alleles, which include the Adenomatous Polyposis Coli (APC) gene as well as other alleles in the Wnt/beta-catenin signaling pathway that specify increased genetic susceptibility to CRC. Interactions between these high penetrance alleles and other modifier genes as well as with environmental factors are of particular importance to understand the complex network of events that lead to CRC. This brief review will highlight 3 areas where important questions concerning genetic and environmental risk factors have fueled translational investigation into possible pathways that lead to CRC.

Dietary lipids and cancer

For many years, epidemiological studies continued to suggest that high fat diets are linked to an increased incidence of certain cancers. However, whether the oncogenic properties of fat are associated with their quantity rather than the quality has become debatable. Epidemiological studies have been suggesting that n-6 polyunsaturated fatty acids (n-6 PUFA) and saturated fats are more likely to increase the incidence of cancer, whereas monounsaturated fatty acids (MUFA) and n-3 polyunsaturated fatty acids (n-3 PUFA) are more likely to prevent or decrease the chance of carcinogenesis. A firm conclusion cannot be drawn yet because of insufficient research. This paper reviews the current knowledge of the effects of saturated fats, different types of unsaturated fats, and fat-soluble vitamins on the etiology of cancer.