Gender differences in colorectal cancer: implications for age at initiation of screening

Sex- and gender-specific disparities in colorectal cancer risk

Colorectal cancer is one of the most common causes of cancer morbidity both in men and in women. However, females over 65 years old show higher mortality and lower 5-year survival rate of colorectal cancer compared to their age-matched male counterparts. The objective of this review is to suggest gender-based innovations to improve colorectal cancer outcomes in females. Women have a higher risk of developing right-sided (proximal) colon cancer than men, which is associated with more aggressive form of neoplasia compared to left-sided (distal) colon cancer. Despite differences in tumor location between women and men, most of scientific researchers do not consider sex specificity for study design and interpretation. Also, colorectal cancer screening guidelines do not distinguish females from male, which may explain the higher frequency of more advanced neoplasia when tumors are first detected and false negative results in colonoscopy in females. Moreover, socio-cultural barriers within females are present to delay screening and diagnosis. Few studies, among studies that included both men and women, have reported sex-specific estimates of dietary risk factors which are crucial to establish cancer prevention guidelines despite sex- and gender-associated differences in nutrient metabolism and dietary practices. Furthermore, anti-cancer drug use for colorectal cancer treatment can cause toxicity to the reproductive system, and gender-specific recurrence and survival rates are reported. Therefore, by understanding sex- and gender-related biological and socio-cultural differences in colorectal cancer risk, gender-specific strategies for screening, treatment and prevention protocols can be established to reduce the mortality and improve the quality of life.

Sex- and gender-specific disparities in colorectal cancer risk

Colorectal cancer is one of the most common causes of cancer morbidity both in men and in women. However, females over 65 years old show higher mortality and lower 5-year survival rate of colorectal cancer compared to their age-matched male counterparts. The objective of this review is to suggest gender-based innovations to improve colorectal cancer outcomes in females. Women have a higher risk of developing right-sided (proximal) colon cancer than men, which is associated with more aggressive form of neoplasia compared to left-sided (distal) colon cancer. Despite differences in tumor location between women and men, most of scientific researchers do not consider sex specificity for study design and interpretation. Also, colorectal cancer screening guidelines do not distinguish females from male, which may explain the higher frequency of more advanced neoplasia when tumors are first detected and false negative results in colonoscopy in females. Moreover, socio-cultural barriers within females are present to delay screening and diagnosis. Few studies, among studies that included both men and women, have reported sex-specific estimates of dietary risk factors which are crucial to establish cancer prevention guidelines despite sex- and gender-associated differences in nutrient metabolism and dietary practices. Furthermore, anti-cancer drug use for colorectal cancer treatment can cause toxicity to the reproductive system, and gender-specific recurrence and survival rates are reported. Therefore, by understanding sex- and gender-related biological and socio-cultural differences in colorectal cancer risk, gender-specific strategies for screening, treatment and prevention protocols can be established to reduce the mortality and improve the quality of life.

Colorectal cancer screening and prevention in women

Colorectal cancer (CRC) is one of the leading cancers and cause of cancer deaths in American women and men. Females and males share a similar lifetime cumulative risk of CRC however, substantial differences in risk factors, tumor biology, and effectiveness of cancer prevention services have been observed between them. This review distills the evidence documenting the unique variation observed between the genders relating to CRC risk factors, screening and prevention. Consistent evidence throughout the world demonstrates that women reach equivalent levels of adenomas and CRC as men but it occurs nearly a decade later in life than in their male counterparts. Women have a higher proportion of tumors which are hypermethylated, have microsatellite instability and located in the proximal colon suggesting the serrated pathway may be of greater consequence in them than in men. Other CRC risk factors such as smoking, diet and obesity have been shown to have disparate effects on women which may related to interactions between estrogen exposure, body fat distribution, and the biologic underpinnings of their tumors. There is data showing the uptake, choice, and efficacy of different CRC screening methods in women is dissimilar to that in men. The mortality benefit from FOBT, sigmoidoscopy, and protection from interval CRC by colonoscopy appears to be lower in women than men. A greater understanding of these gender idiosyncrasies will facilitate an personalized approach to CRC prevention and should ultimately lead to a reduced burden of disease.

Gender- and site-specific differences of colorectal neoplasia relate to vitamin D

BACKGROUND

The effect of vitamin D on colorectal adenomas may vary with regard to gender, localisation and histological type of the lesion.

AIM

To define the role of vitamin D and gender in a Caucasian cohort of subjects undergoing screening colonoscopy after consideration of established risk factors.

METHODS

One thousand five hundred and thirty-two subjects (813 males, 58.8 ± 9.7 years; 719 females, 59.7 ± 10.7 years) were allocated to tertiles of 25-hydroxyvitamin D3 [25(OH)D3 ] serum concentrations. The number, localisation, size and histology of the detected colonic lesions were recorded.

RESULTS

Among men, no association was found between vitamin D and the total number, size and histological stage of adenomas at any site. In female subjects, less women with adenomas were found in the highest vitamin D tertile (N = 42/239; 17.2%) as compared to the low vitamin D group (N = 60/240; 25.0%; P = 0.035). In particular, the number of women with adenomas in the proximal colon was significantly lower in the highest tertile (N = 21/239, 8.8%) compared to the low vitamin D group (N = 41/240; 17.1%; P = 0.007). The rates at other sites were not different. The inverse association of vitamin D serum concentrations with the presence of adenomas in the proximal colon was maintained after adjustment for potential confounders. In 80 women on vitamin D supplementation, the rate of adenomas was lower compared to those not on supplementation (3/80; 3.8%; vs. 90/719; 12.5%; P = 0.016).

CONCLUSIONS

A potential preventive effect of vitamin D on colorectal adenomas was found in the proximal colon in women. This observation is supported by further decrease of lesions in the proximal colon of women on vitamin D supplementation.

BRAF V600E mutation and KRAS codon 13 mutations predict poor survival in Chinese colorectal cancer patients

Background

Mutations in KRAS, BRAF and PIK3CA are the most common somatic alterations found in the colorectal cancer (CRC) patients from Western countries; but their prevalence and prognostic value have not been adequately assessed in Asian patients. The aim of this study was to determine the mutation frequencies of these genes in Chinese CRC patients and to investigate their impact on prognosis.

Methods

The sequences of exon 2 of KRAS, exon 15 of BRAF and exons 9 and 20 of PIK3CA were evaluated by PCR and direct sequencing using DNA extracted from formalin-fixed paraffin-embedded (FFPE) tissues from primary CRC tumors of 214 patients (colon/rectum: 126/88).

Results

KRAS, BRAF and PIK3CA mutations were identified in 44.9% (96/214), 4.2% (9/214) and 12.3% (26/212) CRCs, respectively. The most frequent mutations in KRAS, BRAF and PIK3CA were G12D, V600E and H1047R, respectively. All BRAF and 80.8% PIK3CA mutations were from colon cancer patients. BRAF V600E was associated with advanced TNM (P < 0.001), more distant metastases (P = 0.025), and worse overall survival (OS, P < 0.001; multivariate HR = 4.2, P = 0.004) in colon cancer patients. Compared with KRAS wt/BRAF wt CRC patients (N = 109), those with KRAS codon 13 mutations (N = 25) had significantly worse OS (P = 0.016; multivariate HR = 2.7, P = 0.011), whereas KRAS codon 12-mutated cases were not significantly associated with survival. Among the three most common KRAS mutations, G13D (N = 23) showed significant association with poor OS (P = 0.024; multivariate HR = 2.6, P = 0.016) compared with KRAS wt/BRAF wt patients.

Conclusion

Our findings indicate that PI3K/RAS-RAF signaling pathway genes are frequently mutated in Chinese CRC patients, but have different characteristics than found in Western patients. BRAF V600E is an independent prognostic factor for Chinese patients. Our finding that KRAS codon 13 mutations (in particular G13D) are associated with inferior survival in BRAF wild-type CRCs in Chinese patients was not reported thus far. Our data emphasizes the importance of prospective evaluation of molecular features in CRC patients, because a single mutation type may represent a distinct biologic effect and clinical implication.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-802) contains supplementary material, which is available to authorized users.

The utility of Apc-mutant rats in modeling human colon cancer

Prior to the advent of genetic engineering in the mouse, the rat was the model of choice for investigating the etiology of cancer. Now, recent advances in the manipulation of the rat genome, combined with a growing recognition of the physiological differences between mice and rats, have reignited interest in the rat as a model of human cancer. Two recently developed rat models, the polyposis in the rat colon (Pirc) and Kyoto Apc Delta (KAD) strains, each carry mutations in the intestinal-cancer-associated adenomatous polyposis coli (Apc) gene. In contrast to mouse models carrying Apc mutations, in which cancers develop mainly in the small intestine rather than in the colon and there is no gender bias, these rat models exhibit colonic predisposition and gender-specific susceptibility, as seen in human colon cancer. The rat also provides other experimental resources as a model organism that are not provided by the mouse: the structure of its chromosomes facilitates the analysis of genomic events, the size of its colon permits longitudinal analysis of tumor growth, and the size of biological samples from the animal facilitates multiplexed molecular analyses of the tumor and its host. Thus, the underlying biology and experimental resources of these rat models provide important avenues for investigation. We anticipate that advances in disease modeling in the rat will synergize with resources that are being developed in the mouse to provide a deeper understanding of human colon cancer.

Early colon screening of adult patients with cystic fibrosis reveals high incidence of adenomatous colon polyps

BACKGROUND AND GOALS

Cystic fibrosis (CF) is associated with increased incidence of gastrointestinal cancer. Increasing overall life expectancy of CF patients predicts emergence of colon cancer as a significant clinical problem in the adult CF population. The primary aim of this study was to estimate the incidence of adenomatous colon polyps in patients with CF during systematic screening by colonoscopy.

STUDY

This is a single-center series of 45 CF patients aged 40 years and above (mean age, 47 y) undergoing colonoscopic screening. A fraction of these patients (9/45) had history of organ transplantation. Results from transplant and nontransplant patients were analyzed separately.

RESULTS

Adult CF patients have a high incidence of adenomatous polyps identified by colonoscopy. In addition, positive examinations are characterized by multiple polyps and common features of advanced pathology. The incidence of adenomatous colon polyps is greater in male patients, although the 1 patient in this cohort found to have colorectal cancer was female.

CONCLUSIONS

CF has features of a hereditary colon cancer syndrome. Increasing life expectancy of CF patients suggests that earlier colon screening in this population may be warranted. Optimal criteria for initiation of screening and frequency of surveillance should be subject of further studies.

Race, ethnicity, and sex affect risk for polyps >9 mm in average-risk individuals

BACKGROUND & AIMS

Colorectal cancer risk differs based on patient demographics. We aimed to measure the prevalence of significant colorectal polyps in average-risk individuals and to determine differences based on age, sex, race, or ethnicity.

METHODS

In a prospective study, colonoscopy data were collected, using an endoscopic report generator, from 327,785 average-risk adults who underwent colorectal cancer screening at 84 gastrointestinal practice sites from 2000 to 2011. Demographic characteristics included age, sex, race, and ethnicity. The primary outcome was the presence of suspected malignancy or large polyp(s) >9 mm. The benchmark risk for age to initiate screening was based on white men, 50-54 years old.

RESULTS

Risk of large polyps and tumors increased progressively in men and women with age. Women had lower risks than men in every age group, regardless of race. Blacks had higher risk than whites from ages 50 through 65 years and Hispanics had lower risk than whites from ages 50 through 80 years. The prevalence of large polyps was 6.2% in white men 50-54 years old. The risk was similar among the groups of white women 65-69 years old, black women 55-59 years old, black men 50-54 years old, Hispanic women 70-74 years old, and Hispanic men 55-59 years old. The risk of proximal large polyps increased with age, female sex, and black race.

CONCLUSIONS

There are differences in the prevalence and location of large polyps and tumors in average-risk individuals based on age, sex, race, and ethnicity. These findings could be used to select ages at which specific groups should begin colorectal cancer screening.

Incidence of colorectal adenomas: birth cohort analysis among 4.3 million participants of screening colonoscopy

BACKGROUND

Most colorectal cancers develop from adenomas. We aimed to estimate sex- and age-specific incidence rates of colorectal adenomas and to assess their potential implications for colorectal cancer screening strategies.

METHODS

Sex- and age-specific incidence rates of colorectal adenomas were derived by a birth cohort analysis using data from 4,322,085 screening colonoscopies conducted in Germany and recorded in a national database in 2003-2012. In addition, cumulative risks of colorectal cancer among colonoscopically neoplasm-free men and women were estimated by combining adenoma incidence rates with previously derived adenoma-colorectal cancer transition rates.

RESULTS

Estimated annual incidence in percentage (95% confidence interval) in age groups 55-59, 60-64, 65-69, 70-74, and 75-79 was 2.4 (2.2-2.6), 2.3 (2.1-2.6), 2.4 (2.1-2.6), 2.2 (1.8-2.5), and 1.8 (1.2-2.3) among men, and 1.4 (1.3-1.5), 1.5 (1.4-1.7), 1.6 (1.4-1.8), 1.6 (1.3-1.8), and 1.2 (0.8-1.6) among women. Estimated 10- and 15-year risks of clinically manifest colorectal cancer were 0.1% and 0.5% or lower, respectively, in all groups assessed.

CONCLUSIONS

Annual incidence rates of colorectal adenomas are below 2.5% and 2% among men and women, respectively, and show little variation by age.

IMPACT

Risk of clinically manifest colorectal cancer is expected to be very small within 10 years and beyond after negative colonoscopy for men and women at all ages. The use of rescreening after a negative screening colonoscopy above 60 years of age may be very limited.

Age- and sex-specific spatio-temporal patterns of colorectal cancer mortality in Spain (1975-2008)

In this paper, space-time patterns of colorectal cancer (CRC) mortality risks are studied by sex and age group (50-69, ≥70) in Spanish provinces during the period 1975-2008. Space-time conditional autoregressive models are used to perform the statistical analyses. A pronounced increase in mortality risk has been observed in males for both age-groups. For males between 50 and 69 years of age, trends seem to stabilize from 2001 onward. In females, trends reflect a more stable pattern during the period in both age groups. However, for the 50-69 years group, risks take an upward trend in the period 2006-2008 after the slight decline observed in the second half of the period. This study offers interesting information regarding CRC mortality distribution among different Spanish provinces that could be used to improve prevention policies and resource allocation in different regions.

Characteristics of colorectal polyps and cancer; a retrospective review of colonoscopy data in iran

BACKGROUND Early diagnosis and endoscopic resection of adenomatous polyps is the main approach for screening and prevention of colorectal cancer (CRC). We aimed to assess polyp detection rate (PDR) and to characterize demographic, clinical, and pathological features of colorectal polyps in an Iranian population. METHODS We retrospectively analyzed the data from 5427 colonoscopies performed during 2007-2012 at Masoud Clinic, the main endoscopy center associated with Sasan Alborz Biomedical Research Center, in Tehran, Iran. RESULTS Our sample included 2928 (54%) women and 2499 (46%) men, with the mean age of 48.3 years (SD=16.1). The most common reasons for colonoscopy included screening in 25.0%, and gastrointestinal bleeding in 15.2%. Cecal intubation was successful in 86% of patients. The quality of bowel preparation was fair to excellent in 78.1% (n=4235) of colonoscopies. Overall PDR was 42.0% (95% CI: 40.6-43.3). The PDR in men (51.1%, 95% CI: 49.1-53.1) was significantly higher than women (34.2%, 95% CI: 32.4-35.9, p<0.001). Polyps were more frequently observed in patients after the 6(th) decade of life (F=3.2; p=0.004). CRC was detected in 2.9% (73/2499) of men and 1.9% (57/2928) of women (p=0.02). The mean age for patients with cancer was significantly higher than that for individuals with polyps, 60.9 (SD=13.4) year vs. 56.9 (SD=13.7) year, respectively (p=0.001). Almost 82.8% of the lesions were precancerous with tubular type predominance (62.3%) followed by tubulo-villous (10.3%), villous (6.6%), and serrated (3.6%). Hyperplastic/inflammatory polyps comprised 17.2% of lesions. CONCLUSION Distal colon was more prone to develop polyps and cancer than proximal colon in our series. These findings provide a great infrastructure for next preventive programs and have implications for colorectal cancer screening at population-level.

Tests and investigations for colorectal cancer screening

Worldwide, colorectal (CRC) is the third most common form of cancer, after lung and breast cancer, and the fourth most common cause of cancer death, although in developed countries CRC incidence is higher and it accounts for an even higher proportion of cancer deaths. Successful treatment of early-stage CRC confers substantial survival advantage, and there is now overwhelming evidence that screening average-risk individuals for CRC reduces the incidence and disease-specific mortality. In spite of considerable research for new biomarkers for CRC, the detection of blood in faeces remains the most effective screening tool. The best evidence to date for population-based CRC screening comes from randomised-controlled trials that used a guaiac-based faecal occult blood test (gFOBt) as the first-line screening modality, whereby test-positive individuals are referred for follow-up investigations, usually colonoscopy. A major innovation in the last ten years or so has been the development of other more analytically sensitive and specific screening techniques for blood in faeces. The faecal immunochemical test for haemoglobin (FIT) confers substantial benefits over gFOBt in terms of analytical sensitivity, specificity and practicality and FIT are now recommended for CRC screening by the European guidelines for quality assurance in colorectal cancer screening and diagnosis. The challenge internationally is to develop high quality CRC screening programmes for which uptake is high. This is especially important for developing countries witnessing an increase in the incidence of CRC as populations adopt more westernised lifestyles. This review describes the tests available for CRC screening and how they are being used worldwide. The reader will gain an understanding of developments in CRC screening and issues that arise in choosing the most appropriate screening test (or tests) for organised population-based screening internationally and optimising the performance of the chosen test (or tests). Whilst a wide range of literature has been cited, this is not a systematic review. The authors provide FOBT CRC screening for a population of 14.6 million in the south of England and the senior author (SPH) was the lead author of the European guidelines for quality assurance in colorectal cancer screening and diagnosis and leads the World Endoscopy Organization Colorectal Cancer Committee's Expert Working Group on 'FIT for Screening'.

A computational model for genetic and epigenetic signals in colon cancer

Cancer, a class of diseases, characterized by abnormal cell growth, has one of the highest overall death rates world-wide. Its development has been linked to aberrant genetic and epigenetic events, affecting the regulation of key genes that control cellular mechanisms. However, a major issue in cancer research is the lack of precise information on tumour pathways; therefore, the delineation of these and of the processes underlying disease proliferation is an important area of investigation. A computational approach to modelling malignant system events can help to improve understanding likely "triggers", i.e. initiating abnormal micro-molecular signals that occur during cancer development. Here, we introduce a network-based model for genetic and epigenetic events observed at different stages of colon cancer, with a focus on the gene relationships and tumour pathways. Additionally, we describe a case study on tumour progression recorded for two gene networks on colon cancer, carcinoma in situ. Our results to date showed that tumour progression rate is higher for a small, closely-associated network of genes than for a larger, less-connected set; thus, disease development depends on assessment of network properties. The current work aims to provide improved insight on the way in which aberrant modifications characterize cancer initiation and progression. The framework dynamics are described in terms of interdependencies between three main layers: genetic and epigenetic events, gene relationships and cancer stage levels.

Screening and Primary prevention of Colorectal Cancer: a Review of sex-specific and site-specific differences

Background

Colorectal cancer (CRC) is the second commonest cancer in England. Incidence rates for colorectal adenomas and advanced colorectal neoplasia are higher in men than in women of all age groups. The male-to-female ratio for CRC incidence rates differs for different parts of the large bowel.

Objective

To summarize the current evidence on colorectal screening and prevention, focussing on potential differences in benefits between sexes and colorectal sites.

Methods

(i), We reviewed the evidence from randomized controlled trials (RCTs) of the impact of different screening approaches on CRC incidence and mortality, overall, for each sex separately, and for subsites of the large bowel. (ii) We reviewed studies comparing detection parameters for faecal immunochemical tests for haemoglobin (FIT) with guaiac FOBt (gFOBt). (iii) The role of aspirin in CRC prevention in the general population was reviewed using evidence from RCTs, with specific emphasis on the differences observed between sexes and lesion site.

Results

(i) Our intention-to-treat random-effects meta-analysis showed that once-only flexible sigmoidoscopy (FS) screening performed on average-risk individuals aged 55 + decreased CRC incidence by 18% and mortality by 28%, but sex-specific results were lacking. (ii) Modern quantitative FIT were superior to qualitative gFOBt in average-risk population screening in their ability to discriminate between individuals with and without colorectal neoplasia. Some recent FIT studies suggest varying operating characteristics in men and women. (iii) Evidence of an effect of aspirin on the incidence of CRC (in particular, proximal disease) in both sexes aged 40 and over at average-risk of CRC is emerging.

Conclusions

We encourage researchers of CRC screening and prevention to publish their results by sex where possible. Pilot studies should be undertaken before implementation of quantitative FIT in a national screening programme to establish the appropriate threshold. Finally, individual risk assessment for CRC and non-CRC events, will be necessary to make an informed decision on whether a patient should receive aspirin chemoprevention.

Long-term mortality after screening for colorectal cancer

BACKGROUND

In randomized trials, fecal occult-blood testing reduces mortality from colorectal cancer. However, the duration of the benefit is unknown, as are the effects specific to age and sex.

METHODS

In the Minnesota Colon Cancer Control Study, 46,551 participants, 50 to 80 years of age, were randomly assigned to usual care (control) or to annual or biennial screening with fecal occult-blood testing. Screening was performed from 1976 through 1982 and from 1986 through 1992. We used the National Death Index to obtain updated information on the vital status of participants and to determine causes of death through 2008.

RESULTS

Through 30 years of follow-up, 33,020 participants (70.9%) died. A total of 732 deaths were attributed to colorectal cancer: 200 of the 11,072 deaths (1.8%) in the annual-screening group, 237 of the 11,004 deaths (2.2%) in the biennial-screening group, and 295 of the 10,944 deaths (2.7%) in the control group. Screening reduced colorectal-cancer mortality (relative risk with annual screening, 0.68; 95% confidence interval [CI], 0.56 to 0.82; relative risk with biennial screening, 0.78; 95% CI, 0.65 to 0.93) through 30 years of follow-up. No reduction was observed in all-cause mortality (relative risk with annual screening, 1.00; 95% CI, 0.99 to 1.01; relative risk with biennial screening, 0.99; 95% CI, 0.98 to 1.01). The reduction in colorectal-cancer mortality was larger for men than for women in the biennial-screening group (P=0.04 for interaction).

CONCLUSIONS

The effect of screening with fecal occult-blood testing on colorectal-cancer mortality persists after 30 years but does not influence all-cause mortality. The sustained reduction in colorectal-cancer mortality supports the effect of polypectomy. (Funded by the Veterans Affairs Merit Review Award Program and others.).

Gender medicine: a task for the third millennium

Gender-specific medicine is the study of how diseases differ between men and women in terms of prevention, clinical signs, therapeutic approach, prognosis, psychological and social impact. It is a neglected dimension of medicine. In this review we like to point out some major issues in five enormous fields of medicine: cardiovascular diseases (CVDs), pharmacology, oncology, liver diseases and osteoporosis. CVDs have been studied in the last decades mainly in men, but they are the first cause of mortality and disability in women. Risk factors for CVD have different impacts in men and women; clinical manifestations of CVD and the influence of drugs on CVD have lot of gender differences. Sex-related differences in pharmacokinetics and pharmacodynamics are also emerging. These differences have obvious relevance to the efficacy and side effect profiles of various medications in the two sexes. This evidence should be considered for drug development as well as before starting any therapy. Gender disparity in cancer incidence, aggressiveness and prognosis has been observed for a variety of cancers and, even if partially known, is underestimated in clinical practice for the treatment of the major types of cancer. It is necessary to systematize and encode all the known data for each type of tumor on gender differences, to identify where this variable has to be considered for the purposes of the prognosis, the choice of treatment and possible toxicity. Clinical data suggest that men and women exhibit differences regarding the epidemiology and the progression of certain liver diseases, i.e., autoimmune conditions, genetic hemochromatosis, non-alcoholic steatohepatitis and chronic hepatitis C. Numerous hypotheses have been formulated to justify this sex imbalance including sex hormones, reproductive and genetic factors. Nevertheless, none of these hypothesis has thus far gathered enough convincing evidence and in most cases the evidence is conflicting. Osteoporosis is an important public health problem both in women and men. On the whole, far more epidemiologic, diagnostic and therapeutic studies have been carried out in women than in men. In clinical practice, if this disease remains underestimated in women, patients' and physicians' awareness is even lower for male osteoporosis, for which diagnostic and therapeutic strategies are at present less defined. In conclusion this review emphasizes the urgency of basic science and clinical research to increase our understanding of the gender differences of diseases.

Sex differences in colorectal cancer survival: population-based analysis of 164,996 colorectal cancer patients in Germany

Risk of colorectal cancer (CRC) is considerably higher in men compared to women; however, there is inconclusive evidence of sex differences in CRC prognosis. We aimed to assess and explain sex differences in 5-year relative survival using standard and model-based period analysis among 164,996 patients diagnosed with CRC from 1997 to 2006 and reported to 11 German cancer registries covering a population of 33 million inhabitants. Age-adjusted 5-year relative survival was higher in women (64.5% vs. 61.9%, P<0.0001). A substantial survival advantage of women was confirmed in multivariate analysis after adjusting for CRC stage and subsite in subjects under 65 years of age (relative excess risk, RER 0.86, 95% CI 0.82-0.90), but not in older subjects (RER 1.01, 95% CI 0.98-1.04); this pattern was similar in the 1st and in the 2nd to 5th year after diagnosis. The survival advantage of women varied by CRC stage and age and was most pronounced for localized disease (RERs 0.59-0.88 in various age subgroups) and in patients under 45 years of age (RERs 0.59, 0.72 and 0.76 in patients with localized, regional or advanced disease, respectively). On the contrary, sex differences in survival did not vary by location of CRC. In conclusion, our large population-based study confirmed a survival advantage of female compared to male CRC patients, most notably in young and middle aged patients and patients with localized disease. The effect of sex hormones, either endogenous or through hormonal replacement therapy, might be the most plausible explanation for the observed patterns.

Reduced expression of steroid sulfatase in primary colorectal cancer

Colorectal cancer (CRC) is considered an estrogen-dependent malignancy, and intratissue estrogen concentration can be controlled by steroid sulfatase (STS). Little is known about changes in the expression of STS during the development of CRC. Therefore, we analysed the STS mRNA levels in primary colonic adenocarcinoma tissues and adjacent histopathologically unchanged colonic mucosa from patients who underwent radical colon resection (n=90). We found a statistically significant decrease in STS transcript levels in CRC (P=0.0453). Moreover, we found that sodium butyrate (NaBu) significantly upregulated STS transcript levels in DLD-1 and HCT116 CRC cells. Our results suggest that STS expression can be decreased in the process of large intestinal carcinogenesis. Moreover, we observed that NaBu might increase STS expression in CRC cells.

Assessment of adenoma detection rate benchmarks in women versus men

BACKGROUND

Current guidelines suggest screening adenoma detection rates (ADRs) of 15% for average-risk women and 25% for average-risk men.

OBJECTIVE

Determine average-risk screening ADRs and the prevalence of adenomas by location, size, shape, and degree of dysplasia in each sex.

DESIGN

Post hoc analysis of prospectively collected data.

SETTING

Academic center, ambulatory center.

PATIENTS

A total of 864 average-risk patients.

INTERVENTION

Screening colonoscopy.

MAIN OUTCOME MEASUREMENTS

By using a prospectively collected colonoscopy database, we determined the ADRs for each sex and compared them to current medical society guidelines. In patients with adenomas detected, we compared the percentage of proximally located, large, and advanced-pathology adenomas between sexes.

RESULTS

The overall average-risk screening ADR was 33.7% for both sexes combined. Average risks for women and men were significantly higher than guidelines (women: 25.4% vs 15%; P = .0003; men: 41.2% vs 25%; P < .0001). The ADR remained significantly higher for men versus women (P < .0001). Overall advanced-pathology adenoma detection was 12.2% for both sexes combined. There was a significantly higher advanced-pathology ADR for men (15.3%) versus women (8.7%) (P = .003). There was no significant difference between the sexes when age was considered in both advanced-pathology and average-risk ADRs.

LIMITATIONS

Data from the study focused on improving ADRs in an academic setting.

CONCLUSION

The ADR in our study was higher than current benchmarks for both sexes. In patients with at least one adenoma, advanced-pathology adenomas were detected equally among men and women. Although the benefits of achieving supra-benchmark ADRs are unknown, high ADRs may lead to more effective colonoscopy.

Cancer of the colon and rectum: potential effects of sex-age interactions on incidence and outcome

Background

Sex differences in epidemiological, clinical and pathological characteristics of colorectal cancer have been under intensive investigation for the last three decades. Given that most of the sex-related differences reported were also age-related, this study sought to determine the potential effect of a sex-age interaction on colorectal cancer development and progression.

Material/Methods

Statistical data on sex- and age-specific colon or rectal cancer incidence, disease stage and survival for white persons were derived from the United States Surveillance, Epidemiology and End Results (SEER) Program. Age-specific incidence rates in 2002–2006 were analyzed by 5-year age groups (45–49, 50–54, 55–59, 60–64, 65–69, 70–74, 75–79, 80–84 years) in men and women. Sex differences were measured by calculating rate differences (RD) and rate ratios (RR). Equivalent analyses for a similar time period were performed for stage distribution and 5-year relative survival.

Results

Age-specific incidence rates were higher for men, for all life-time periods. However, the magnitude of the male predominance was age-dependent. The RR and RD did not remain constant over time: they increased gradually with age, peaked at 70–74 years, and declined thereafter. The distribution of stage at diagnosis was similar between men and women, but women seemed to have better survival, until the age of 64 years for colon cancer and 74 years for rectal cancer.

Conclusions

There seem to be significant age-related sex differences in the incidence of colorectal cancer, and maybe also in its prognosis.

The modifying effect of patient location on stage-specific survival following colorectal cancer using geosurvival models

Colorectal cancer (CRC) is the third leading cause of cancer death in the US, and stage at diagnosis is the primary prognostic factor. To date, the interplay between geographic place and individual characteristics such as cancer stage with CRC survival is unexplored. We used a Bayesian geosurvival statistical model to evaluate whether the spatial patterns of CRC survival at the census tract level varies by stage at diagnosis (in situ/local, regional, distant), controlling for patient characteristics, surveillance test use, and treatment using linked 1991-2005 SEER-Medicare data of patients ≥ 66 years old in two US metropolitan areas. The spatial pattern of survival varied by stage at diagnosis for both cancer sites and registries. Significant spatial effects were identified in all census tracts for colon cancer and the majority of census tracts for rectal cancer. Geographic disparities appeared to be highest for distant-stage rectal cancer. Compared to those with in situ/local stage in the same census tracts, patients with distant-stage cancer were at most 7.73 times and 4.69 times more likely to die of colon and rectal cancer, respectively. Moreover, frailty areas for CRC at in situ/local stage more likely have a higher relative risk at regional stage, but not at distant stage. We identified geographic areas with excessive risk of CRC death and demonstrated that spatial patterns varied by both cancer type and cancer stage. More research is needed to understand the moderating pathways between geographic and individual-level factors on CRC survival.

Impact of family history of gastric cancer on colorectal neoplasias in young Japanese

AIM

The aim of this study was to elucidate risk factors for the development of colorectal neoplasia in the young population. In particular, we focused on the family history of gastric cancer.

METHOD

Young Japanese subjects aged 30-49 years old who underwent colonoscopy for the first time from August 2007 to August 2008 were included in this study. A total of 300 unselected consecutive patients (mean age 40.5 years) were eligible for analysis, and family history of colorectal cancer and gastric cancer, sex, age, body mass index, positivity of faecal occult blood test and the presence of symptoms were evaluated. Risk factors for developing colorectal adenoma and/or carcinoma were assessed.

RESULTS

Colorectal neoplasias were detected in 83 (27.7%) cases. Two were found to have invasive carcinoma. Univariate and multivariate analyses revealed that family history of gastric cancer (OR 2.09, 95% CI 1.12-3.92, P = 0.02) was an independent risk factor for the development of colorectal neoplasia, as well as male sex (OR 1.89, 95% CI 1.10-3.27, P = 0.02), older age (OR 2.05, 95% CI 1.18-3.55, P = 0.01) and positive faecal occult blood test (OR 1.99, 95% CI 1.14-3.48, P = 0.02).

CONCLUSION

In the young population under 50 years of age, a family history of gastric cancer is an independent risk factor for the development of colorectal neoplasia.

Evaluation of the appropriate age range of colorectal cancer screening based on the changing epidemiology in the past 20 years in taiwan

Introduction. According to the recommendation of the United States Preventative Services Task Force, most countries provide average-risk screening for colorectal cancers (CRCs) between the ages of 50 and 75 years. However, the age range of screening should be modified because of an increasing life span. Methods. Totally 124,314 CRC cases were registered in Taiwan Cancer Registry from 1988 to 2007. The 20-year study period was divided into four 5-year increments. We divided the patients into four age groups (under age 50, age 50–74, age 74–84, and over age 85) in each increment to determine whether there were changes in the age distribution. Results. In the subgroup of patients under age 50, the number of CRC cases increased, but they accounted for a decreasing proportion of the total CRCs. In the 50–74 age group, the proportion of CRC cases also dropped. In contrast, the proportion increased in the 75–84 age group. Therefore, 43.63% of CRC patients would not be delegated to screen in the period of 2003–2007 if the CRC screening were restricted in the 50–74 age group. Conclusions. CRC screening for healthy individuals aged over 75 years is necessary.

A retrospective observational study examining the characteristics and outcomes of tumours diagnosed within and without of the English NHS Bowel Cancer Screening Programme

Background:

Colorectal cancer is common in England and, with long-term survival relatively poor, improving outcomes is a priority. A major initiative to reduce mortality from the disease has been the introduction of the National Health Service (NHS) Bowel Cancer Screening Programme (BCSP). Combining data from the BCSP with that in the National Cancer Data Repository (NCDR) allows all tumours diagnosed in England to be categorised according to their involvement with the BCSP. This study sought to quantify the characteristics of the tumours diagnosed within and outside the BCSP and investigate its impact on outcomes.

Methods:

Linkage of the NCDR and BCSP data allowed all tumours diagnosed between July 2006 and December 2008 to be categorised into four groups; screen-detected tumours, screening-interval tumours, tumours diagnosed in non-participating invitees and tumours diagnosed in those never invited to participate. The characteristics, management and outcome of tumours in each category were compared.

Results:

In all, 76 943 individuals were diagnosed with their first primary colorectal cancer during the study period. Of these 2213 (2.9%) were screen-detected, 623 (0.8%) were screening-interval cancers, 1760 (2.3%) were diagnosed in individuals in non-participating invitees and 72 437 (94.1%) were diagnosed in individuals not invited to participate in the programme due to its ongoing roll-out over the time period studied. Screen-detected tumours were identified at earlier Dukes’ stages, were more likely to be managed with curative intent and had significantly better outcomes than tumours in other categories.

Conclusion:

Screen-detected cancers had a significantly better prognosis than other tumours and this would suggest that the BCSP should reduce mortality from colorectal cancer in England.

The effect of polyp location and patient gender on the presence of dysplasia in colonic polyps

OBJECTIVE:

There is increasing evidence of significant clinical and biological differences between proximal and distal colorectal polyps, as well as possible differences based on patient gender. There is a need to optimize and individualize screening strategies. We studied the potential influence of gender and of polyp location on the presence of dysplasia in colon polyps.

METHODS:

We used a prospective database on adenoma detection to identify patients. The primary outcome was the presence of dysplasia in colonic polyps. Covariates include age, gender, race, lesion size and site, and use of aspirin. Multivariate logistic regression analysis was used to analyze the relationship between the primary outcome and covariates. Results were reported as odds ratios (ORs), 95% confidence intervals (CIs), and P-values.

RESULTS:

A total of 2,400 patients (50.5% females and 49.5% males) completed colonoscopy for various indications. A total of 3,045 polyps were removed in 1,237 patients. Of those polyps, 54% (n=1,636) were on the right compared with 46% (n=1,409) in the left colon. The proportion of adenomas was significantly greater on the right colon when compared with the left: 69.4% vs. 39.3% (P=<0.0001). Multivariate logistic regression analysis showed that the right colon did have a significant association with dysplasia when controlling for age, gender, polyp size, and use of aspirin (OR=3.1 (95% CI: 2.3–4), P=<0.0001). Female gender was associated with decreased odds of finding dysplasia (OR=0.6 (95% CI: 0.46–0.78), P=0.03).

CONCLUSION:

Patient characteristics (male gender) as well procedure findings (increase polyp size and right-sided lesions) are associated with increased odds of dysplasia.

The importance of blood loss during colon cancer surgery for long-term survival: an epidemiological study based on a population based register

OBJECTIVE

This study tested the hypothesis that the amount of blood loss during surgery for colonic cancer influences long-term survival.

BACKGROUND

The perioperative blood loss during surgery for colorectal cancer relates to the risk for complications and early mortality.

METHODS

All patients who underwent surgery for colon cancer between 1997 and 2003 in the health-care region of Uppsala/Örebro were prospectively registered at the regional oncological center. Data on patients who underwent radical surgery for stages I to III disease were analyzed. Patients who died within 6 months after surgery were excluded. Hazard ratios were calculated with uni- and multivariate Cox proportional hazard regression. Because of covariation, blood loss, blood transfusion, and complications were tested in separate multivariate analyses.

RESULTS

Blood loss of 250 mL or more during surgery, male gender, occurrence of complications, age more than 75 years, and stage III disease were risk factors for overall mortality in the uni- and multivariate analyses. Perioperative blood transfusion was shown to be a risk factor in the univariate analysis only.

CONCLUSIONS

The results support the hypothesis that degree of blood loss during surgery for colon cancer is a factor that influences long-term survival.

Gender differences in colorectal cancer incidence in the United States, 1975-2006

BACKGROUND

Gender differences have been documented among patients diagnosed with colorectal cancer (CRC). It is still not clear, however, how these differences have changed over the past 30 years and if these differences vary by geographic areas. We examined trends in CRC incidence between 1975 and 2006.

METHODS

The study population consisted of 373,956 patients ≥40 years diagnosed with malignant CRC between 1975 and 2006 who resided in one of the nine Surveillance, Epidemiology and End Results (SEER) regions of the United States. Age-adjusted incidence rates over time were reported by gender, race, CRC subsite, stage, and SEER region.

RESULTS

Overall, CRC was diagnosed in roughly equal numbers of men (187,973) and women (185,983). Men had significantly higher age-adjusted CRC incidence rates across all categories of age, race, tumor subsite, stage, and SEER region. Gender differences in CRC age-adjusted incidence rates widened slightly from 1975 to 1988, reached a peak in 1985-1988, and have narrowed over time since 1990. The largest gap and decline in CRC incidence rates between men and women were observed among those ≥80 years (p<0.001), followed by those 70-79 and then 60-69 years. Gender differences in CRC incidence rates for the 40-49 and 50-59 age categories were small and increased only slightly over time (p=0.003).

CONCLUSIONS

Higher CRC age-adjusted incidence among men than among women has persisted over the past 30 years. Although gender differences narrowed in the population ≥60 years, especially from 1990 to 2006, gender gaps, albeit small ones, in those younger than 60 increased over time. Future studies may need to examine the factors associated with these differences and explore ways to narrow the gender gap.

Gender differences in colorectal cancer during the past 20 years in Taiwan

PURPOSE

Gender differences in colorectal cancer (CRC) incidence have been previously reported. We designed this population-based study to determine if this gender difference was restricted to specific patient subgroups.

METHODS

Using the Taiwan Cancer Registry database, we identified a total of 124,314 CRCs registered from 1988 to 2007. We compared the incidence of CRCs by gender in all CRCs, in colon and rectal cancers considered separately, and in right-sided versus left-sided colon cancers.

RESULTS

In individuals aged 50 years and older, the incidence of CRCs was lower in females compared with males. For right-sided colon cancers, the incidence in both genders was similar. Because the proportion of right-sided colon cancer accounted for only one fourth of the total CRCs, its influence on the incidence of total CRCs is reduced.

CONCLUSIONS

Although the incidence of total CRCs is male dominant, the actual gender difference in CRC incidence in Taiwan is limited to the left side of the colon.

Effect of butyrate on aromatase cytochrome P450 levels in HT29, DLD-1 and LoVo colon cancer cells

Epidemiological studies suggest that colonic production of butyrate and estrogen may be involved in human susceptibility to colorectal cancer (CRC). Estrone (E1) can be produced by the aromatase pathway during the conversion of androstenedione (A) to E1. Therefore, we studied the effect of sodium butyrate (NaBu) on the CYP19A1 transcript and protein levels and on the conversion of A to E1 in HT29, DLD-1 and LoVo CRC cells. We found that NaBu significantly downregulated CYP19A1 transcript and protein levels, a phenomenon that was associated with reduced conversion of A to E1 in HT29, DLD-1 and LoVo cells. Our studies demonstrated that, although butyrate exhibited a protective role in CRC development, this compound may reduce aromatase activity and the production of E1 in colon cancer cells.

Nonpolypoid colorectal neoplasms: gender differences in prevalence and malignant potential

OBJECTIVE

Colonoscopy may fail to prevent colorectal cancer, especially in the proximal colon and in women. Nonpolypoid colorectal neoplasms may potentially explain some of these post-colonoscopy cancers. In the present study, we aimed to examine the prevalence and malignant potential of nonpolypoid colorectal neoplasms in a large population, with special attention to gender and location.

METHODS

We performed a cross-sectional study of all consecutive patients undergoing elective colonoscopy at a single academic medical center. The endoscopists were familiarized on the detection and treatment of nonpolypoid lesions. Advanced histology was defined by the presence of high-grade dysplasia or early cancer.

RESULTS

We included 2310 patients (53.9% women, mean age 58.4 years) with 2143 colorectal polyps. Prevalences of colorectal neoplasms and nonpolypoid colorectal neoplasms were lower in women than in men (20.9% vs. 33.7%, p < 0.001 and 3.0% vs. 5.5%, p = 0.002). In women, nonpolypoid colorectal neoplasms were significantly more likely to contain advanced histology than polypoid ones (OR 2.89, 95% CI 1.24-6.74, p = 0.01), while this was not the case in men (OR 0.91, 95% CI 0.40-2.06, p = 0.83). Proximal neoplasms with advanced histology were more likely to be nonpolypoid than distal ones (OR 4.68, 95% CI 1.54-14.2, p = 0.006).

CONCLUSION

Nonpolypoid mechanisms may play an important role in colorectal carcinogenesis, in both women and men. Although women have fewer colorectal neoplasms than men, they have nonpolypoid colorectal neoplasms, which frequently contain advanced histology.

Decreased expression of 17β-hydroxysteroid dehydrogenase type 1 is associated with DNA hypermethylation in colorectal cancer located in the proximal colon

BACKGROUND

The importance of 17β-estradiol (E2) in the prevention of large bowel tumorigenesis has been shown in many epidemiological studies. Extragonadal E2 may form by the aromatase pathway from androstenedione or the sulfatase pathway from estrone (E1) sulfate followed by E1 reduction to E2 by 17-β-hydroxysteroid dehydrogenase (HSD17B1), so HSD17B1 gene expression may play an important role in the production of E2 in peripheral tissue, including the colon.

METHODS

HSD17B1 expression was analyzed in colorectal cancer cell lines (HT29, SW707) and primary colonic adenocarcinoma tissues collected from fifty two patients who underwent radical colon surgical resection. Histopathologically unchanged colonic mucosa located at least 10-20 cm away from the cancerous lesions was obtained from the same patients. Expression level of HSD17B1 using quantitative PCR and western blot were evaluated. DNA methylation level in the 5' flanking region of HSD17B1 CpG rich region was assessed using bisulfite DNA sequencing and HRM analysis. The influence of DNA methylation on HSD17B1 expression was further evaluated by ChIP analysis in HT29 and SW707 cell lines. The conversion of estrone (E1) in to E2 was determined by electrochemiluminescence method.

RESULTS

We found a significant decrease in HSD17B1 transcript (p = 0.0016) and protein (p = 0.0028) levels in colorectal cancer (CRC) from the proximal but not distal colon and rectum. This reduced HSD17B1 expression was associated with significantly increased DNA methylation (p = 0.003) in the CpG rich region located in the 5' flanking sequence of the HSD17B1 gene in CRC in the proximal but not distal colon and rectum. We also showed that 5-dAzaC induced demethylation of the 5' flanking region of HSD17B1, leading to increased occupation of the promoter by Polymerase II, and increased transcript and protein levels in HT29 and SW707 CRC cells, which contributed to the increase in E2 formation.

CONCLUSIONS

Our results showed that reduced HSD17B1 expression can be associated with DNA methylation in the 5' flanking region of HSD17B1 in CRC from the proximal colon.

Colorectal cancer screening and prevention in women

Colorectal cancer (CRC) is the third most common cause of cancer in women. Screening for CRC increases early detection of cancer and premalignant polyps and decreases morbidity from this disease. However, adherence to the screening guidelines continues to remain inadequate both at the physician and patient levels. Several factors are of special importance to women. Presence of prior gynecological malignancies may increase the risk of CRC in women. Furthermore, new studies have shown other factors such as obesity and smoking to increase the risk of CRC in women. This article highlights issues unique to women with regards to CRC and outlines special considerations for determining screening intervals in women, identifies factors that make screening more difficult in women, and reviews studies that identify preventative strategies which, together with screening, may reduce the burden of CRC.

Role of endoglin and VEGF family expression in colorectal cancer prognosis and anti-angiogenic therapies

Colorectal cancer (CRC) is one of the cancer models and most of the carcinogenic steps are presently well understood. Therefore, successful preventive measures are currently used in medical practice. However, CRC is still an important public health problem as it is the third most common cancer and the fourth most frequent cause of cancer death worldwide. Nowadays, pathologic stage is a unique and well-recognized prognostic indicator, however, more accurate indicators of the biologic behavior of CRC are expected to improve the specificity of medical treatment. Angiogenesis plays an important role in the growth and progression of cancer but its role as a prognostic factor is still controversial. Probably the most important clinical implication of tumor angiogenesis is the development of anti-angiogenic therapy. The goal of this review is to critically evaluate the role of angiogenic markers, assessed by either endoglin-related microvessel density or expression of vascular endothelial growth factor family members in the CRC setting and discuss the role of these angiogenic markers in anti-angiogenic therapies.

Issues related to colorectal cancer and colorectal cancer screening practices in women

Studies have shown that colorectal cancer (CRC) incidence is equal between men and women. However, several studies have demonstrated lower adenoma detection rates in women than in men. Many questions arise about differences in adenomas, CRC, and screening practices between men and women: should screening be the same for both sexes, are there differences in risk factors in the formation of colon cancer, should special groups of women be screened differently from the general population, are colonoscopies tolerated differently in women and why, and what determines if a woman will undergo colonoscopy? This article reviews these issues.

Risk of advanced colorectal neoplasia according to age and gender

Background

Colorectal cancer (CRC) is one of the leading causes of cancer related morbidity and death. Despite the fact that the mean age at diagnosis of CRC is lower in men, screening by colonoscopy or fecal occult blood test (FOBT) is initiated at same age in both genders. The prevalence of the common CRC precursor lesion, advanced adenoma, is well documented only in the screening population. The purpose of this study was to assess the risk of advanced adenoma at ages below screening age.

Methods and Findings

We analyzed data from a census of 625,918 outpatient colonoscopies performed in adults in Bavaria between 2006 and 2008. A logistic regression model to determine gender- and age-specific risk of advanced neoplasia was developed. Advanced neoplasia was found in 16,740 women (4.6%) and 22,684 men (8.6%). Male sex was associated with an overall increased risk of advanced neoplasia (odds ratio 1.95; 95% confidence interval, CI, 1.91 to 2.00). At any age and in any indication group, more colonoscopies were needed in women than in men to detect advanced adenoma or cancer. At age 75 14.8 (95% CI, 14.4–15.2) screening, 18.2 (95% CI, 17.7–18.7) diagnostic, and 7.9 (95% CI, 7.6–8.2) colonoscopies to follow up on a positive FOBT (FOBT colonoscopies) were needed to find advanced adenoma in women. At age 50 39.0 (95% CI, 38.0–40.0) diagnostic, and 16.3 (95% CI, 15.7–16.9) FOBT colonoscopies were needed. Comparable numbers were reached 20 and 10 years earlier in men than in women, respectively.

Conclusions

At any age and independent of the indication for colonoscopy, men are at higher risk of having advanced neoplasia diagnosed upon colonoscopy than women. This suggests that starting screening earlier in life in men than in women might result in a relevant increase in the detection of asymptomatic preneoplastic and neoplastic colonic lesions.

Butyrate induces expression of 17β-hydroxysteroid dehydrogenase type 1 in HT29 and SW707 colorectal cancer cells

Epidemiological studies have revealed that butyrate and 17β-estradiol (E2) may decrease the incidence of colorectal cancer (CRC). In peripheral tissue, E2 can be produced locally by 17β-hydroxysteroid dehydrogenase 1 (HSD17B1) estrone (E1) reduction. Using quantitative real-time polymerase chain reaction and western blotting analysis, we found that sodium butyrate significantly upregulates HSD17B1 long and short transcripts and protein levels in HT29 and SW707 CRC cells. Chromatin immunoprecipitation analysis showed that upregulation of these transcript levels correlated with an increase in binding of Polymerase II to proximal and distal promoters of HSD17B1. Moreover, we observed that upregulation of HSD17B1 protein levels was associated with increased conversion of E1 to E2 in HT29 and SW707 CRC cells. Since sodium butyrate increases the conversion of E1 to E2, our findings may support the validity of butyrate in the prophylaxis of CRC incidence.

Inequalities in participation in an organized national colorectal cancer screening programme: results from the first 2.6 million invitations in England

BACKGROUND

An organized, population-based, colorectal cancer screening programme was initiated in England in 2006 offering biennial faecal occult blood testing (FOBT) to adults aged 60-69 years. Organized screening programmes with no associated financial costs to the individual should minimize barriers to access for lower socio-economic status (SES) groups. However, SES differences in uptake were observed in the pilot centres of the UK programme, so the aim of this analysis was to identify the extent of inequalities in uptake by SES, ethnic diversity, gender and age in the first 28 months of the programme. Design Cross-sectional analysis of colorectal cancer screening uptake data.

METHODS

Between October 2006 and January 2009, over 2.6 million adults aged 60-69 years were mailed a first FOBT kit by the five regional screening hubs. Uptake was defined as return of a test kit within 13 weeks. We used multivariate generalized linear regression to examine variation by area-based socioeconomic deprivation, area-based ethnicity, gender and age.

RESULTS

Uptake was 54%, but showed a gradient across quintiles of deprivation, ranging from 35% in the most deprived quintile to 61% in the least deprived. Multivariate analyses confirmed an independent effect of deprivation, with stronger effects in women and older people. The most ethnically diverse areas also had lower uptake (38%) than other areas (52-58%) independent of SES, age, gender and regional screening hub. Ethnic disparities were more pronounced in men but equivalent across age groups. More women than men returned a kit (56 vs 51%), but there was also an interaction with age, with uptake increasing with age in men (49% at 60-64 years; 53% at 65-69 years) but not women (57 vs 56%).

CONCLUSIONS

Overall uptake rates in this organized screening programme were encouraging, but nonetheless there was low uptake in the most ethnically diverse areas and a striking gradient by SES. Action to promote equality of uptake is needed to avoid widening inequalities in cancer mortality.

Sex differences in performance of fecal occult blood testing

OBJECTIVES

Immunological and guaiac-based fecal occult blood tests (iFOBTs and gFOBTs) are widely used for early detection of colorectal cancer (CRC). We aimed to assess potential sex differences in performance of iFOBTs and gFOBT in the screening setting.

METHODS

The sensitivity, specificity, and positive and negative predictive values for detection of advanced colorectal neoplasms (CRC or advanced adenoma) were assessed by sex for a range of cutpoints of a quantitative iFOBT (RIDASCREEN Hemoglobin), six qualitative iFOBTs, and a gFOBT (HemOccult) among 1,157 male and 1,167 female participants of the German screening colonoscopy program (mean age: 63.0 and 62.0 years, respectively).

RESULTS

The prevalence of advanced colorectal neoplasms was much higher among men (13.5%) than among women (7.5%). At any cutpoint of the quantitative iFOBT, and for all qualitative iFOBTs and the gFOBT, the sensitivity and positive predictive value were substantially higher, and specificity and negative predictive value were substantially lower among men than among women. At the cutpoint of 2 μg/g stool given by the manufacturer of the quantitative iFOBT, sensitivity, specificity, and the positive and negative predictive values were 47.6, 85.0, 33.0, and 91.3% among men, and 30.7, 89.5, 19.3, and 94.1% among women (P value for sex differences 0.001, 0.002, 0.004, and 0.019, respectively). Sex differences in predictive values were mostly explained by sex differences in the prevalence of advanced colorectal neoplasms.

CONCLUSIONS

There are major sex differences in the performance of fecal occult blood testing, which might require careful attention in the interpretation of test results, and in the design, modeling, and evaluation of CRC screening strategies.

Male sex and smoking have a larger impact on the prevalence of colorectal neoplasia than family history of colorectal cancer

BACKGROUND & AIMS

Screening recommendations for colorectal cancer (CRC) commonly take family history but no other risk factors into account. We compared and assessed risk factors of colorectal polyps in a large population undergoing screening colonoscopy.

METHODS

We conducted a population-based cross-sectional study that included 3349 subjects, 55 years or older (mean ages of men and women, 63.6 and 63.4 years, respectively), who underwent colonoscopy for the first time within the nationwide colonoscopy screening program in Germany. We calculated prevalences of colorectal polyps and estimated multivariate prevalence ratios (PRs) and population attributable fractions (PAFs).

RESULTS

Overall, 654 subjects had hyperplastic polyps (20%), 675 had non-advanced adenomas (20%), 343 had advanced adenomas (10%), and 40 had CRC (1%). Risk factor prevalences and adjusted PRs were higher for male gender and smoking than for family history of CRC. PAFs for prevalence of non-advanced and advanced neoplasia were highest for male gender (23% and 23%, respectively), followed by smoking (7% and 9%, respectively), and family history of CRC (2% and 4%, respectively).

CONCLUSIONS

Male gender and smoking have a larger impact on the prevalence of colorectal neoplasia than family history, suggesting an extensive evaluation of additional risk stratification in population-based screening, particularly by sex.

Is gender related to the stage of colorectal cancer at initial presentation in young patients?

BACKGROUND

The incidence of colorectal cancer (CRC) in young adults is rising, and young age is a predictor of poor survival. The purpose of this study was to examine factors leading to increased mortality in patients ≤ 50 years of age, and to examine this population for characteristics that could lead to benefit from CRC screening.

METHODS

Charts of patients 50 years of age and under, diagnosed with CRC from 1998 through 2007, at our community teaching hospital, were reviewed retrospectively. Demographics, social and family history, staging, treatment and death were evaluated. Mann Whitney, Fisher Exact, and χ(2) tests were used with P <0.05 considered statistically significant.

RESULTS

Forty-five young patients with CRC were identified. Twenty-five patients were female and 20 male; the mean age was 43.6 y. Most patients presented with rectal bleeding. Right-sided cancers had a higher presenting stage (P < 0.05). Men had both a higher presenting stage (P = 0.35) and a higher incidence of smoking compared with women (P = 0.001). Female patients were more likely to have left-sided CRC (65%) compared with men (35%). Ninety-six percent of patients underwent surgical resection; 14 patients died.

CONCLUSIONS

CRC in young adults is not common, but is often advanced when discovered. Diagnostic efforts should be aggressive in young patients who have rectal bleeding, especially young male smokers. Sigmoidoscopy is not adequate for comprehensive diagnosis of CRC in young patients, as the majority have right-sided colon cancers, which often result in subsequent presentation of the disease at a higher stage, risk, and mortality rate.

Targeting risk groups for screening

Currently colorectal cancer (CRC) screening guidelines are based on age and to some extent on family history of screenees only. Potentially CRC screening could be also customised according to gender, race, ethnicity, smoking habits, presence of obesity, diabetes and metabolic syndrome. The factors that could be individually modified are: choice of screening test, age of initiation of screening and screening intervals. Gender is probably the easiest factor to be included. One of the professional societies has already included the race into guidelines in order to lower the age of starting screening in African-Americans. Targeting persons at higher than average-risk aims at optimising the use of available resources. However, an important drawback of such approach exists; it is the risk of making guidelines too complex and incomprehensible for both eligible screenees and physicians.

Sex differences in epidemiological, clinical and pathological characteristics of colorectal cancer

Sex significantly influences the clinical and pathological characteristics of colorectal cancer (CRC). These include differences in incidence and mortality rates, clinical presentations including age, emergency surgery for complications from CRC, screening participation rates, site, stage and treatment utilization, histopathology and survival. Environmental, behavioral and biological factors contribute to the differential risk. Recent advances in the molecular biology of CRC, specifically in microsatellite status, estrogen hormone and estrogen receptor beta, have led to greater understanding of the effect of estrogen in colorectal carcinogenesis. Estrogen may preferentially protect against microsatellite unstable cancers through its effect on selected molecular targets; however, the exact pathways have not been elucidated. Recognition of important sex disparities in these areas may lead to the implementation of specific measures to diminish these differences and facilitate equitable distribution of health resources. Identifying specific molecular targets on CRC that interact with estrogen may stimulate research to improve the overall outcomes of all patients with CRC.

Gender disparities in metastatic colorectal cancer survival

PURPOSE

Previous studies have shown that estrogen prevents colon cancer in postmenopausal women, indicating a role in colorectal cancer carcinogenesis and tumor progression. We investigated the interactions between sex, age, ethnicity, and year of diagnosis on overall survival (OS) in patients with metastatic colorectal cancer (MCRC).

EXPERIMENTAL DESIGN

We screened 52,882 patients with MCRC from 1988 to 2004, using the Surveillance Epidemiology and End Results registry. Age at diagnosis, sex, ethnicity, tumor location, year of diagnosis, OS, and cancer-specific survival were evaluated using Cox proportional hazards model. The models were adjusted for marital status, tumor site, tumor differentiation, and treatment with radiation and/or surgery.

RESULTS

We observed that younger women (18-44 years old) with MCRC lived longer than younger men (17 months versus 14; P < 0.0001, log-rank test). In contrast, older women (55 years and older) had significantly worse OS than older men (7 months versus 9; P < 0.0001, log-rank test). In multivariate analysis, we found that gender discrepancies have widened in recent years; young women diagnosed after 2000 have improved cancer-specific survival, compared to men (hazard ratio, 0.778; 95% confidence interval, 0.669-0.904), but those diagnosed before 2000 benefit less (hazard ratio, 0.931; 95% confidence interval, 0.821-1.056).

CONCLUSION

As one of the largest data sets analyzed to establish that younger women with MCRC survive longer than younger men, hormonal status not only seems to play an important role in the development and pathogenesis of colorectal cancer but also may be of prognostic significance. These data warrant further studies to determine the role of estrogen in colorectal cancer.

Individualizing colonoscopy screening by sex and race

BACKGROUND

There is increasing discussion whether colorectal cancer (CRC) screening guidelines should be individualized by sex and race.

OBJECTIVES

To determine individualized colonoscopic screening guidelines by sex and race for the average-risk population and to compare the cost-effectiveness of this approach with that of uniform guidelines for all.

DESIGN

We used the MISCAN-Colon microsimulation model to estimate life expectancy and lifetime CRC screening and treatment costs in a U.S. cohort of black and white men and women at average risk for CRC. We compared the base-case strategy of no screening and 3 competing colonoscopy strategies: (1) the currently recommended "uniform 10-yearly colonoscopy from age 50 years," (2) a shorter interval "uniform 8-yearly colonoscopy from age 51 years," and (3) "individualized screening according to sex and race."

RESULTS

The base-case strategy of no screening was the least expensive, yet least effective. The uniform 10-yearly colonoscopy strategy was dominated. The uniform 8-yearly colonoscopy and individualized strategies both increased life expectancy by 0.0433 to 0.0435 years per individual, at a cost of $15,565 to $15,837 per life-year gained. In the individualized strategy, blacks began screening 6 years earlier, with a 1-year shorter interval compared with whites. The individualized policies were essentially the same for men and women, because the higher CRC risk in men was offset by their shorter life expectancy. The results were robust for changes in model assumptions.

CONCLUSIONS

The improvements in costs and effects of individualizing CRC screening on a population level were only marginal. Individualized guidelines, however, could contribute to decreasing disparities between blacks and whites. The acceptability and feasibility of individualized guidelines, therefore, should be explored.

Gender as a risk factor for advanced neoplasia and colorectal cancer: a systematic review and meta-analysis

BACKGROUND & AIMS

Studies have reported higher rates of advanced colorectal neoplasia in men than in women. We performed a meta-analysis to provide a quantitative pooled risk estimate of the association between gender and advanced colorectal neoplasia.

METHODS

We conducted a systematic review to identify studies of average risk and asymptomatic individuals undergoing screening colonoscopy. We also included studies of subjects with a family history of colorectal neoplasia. We used random effects models to evaluate pooled relative risk estimates and performed heterogeneity and publication bias analyses. The primary outcome measure was relative risk of advanced neoplasia in men compared with women. A secondary outcome measure was relative risk for colorectal cancer.

RESULTS

Seventeen studies consisting of 18 different populations were included, comprising 924,932 men and women. The pooled relative risk estimate for advanced neoplasia for men compared with women was 1.83 (95% confidence interval [CI], 1.69 -1.97). This positive association between gender and advanced neoplasia was significant across all age groups from 40 to older than 70 years. In 5 studies, the relative risk estimate for cancer for men compared with women was 2.02 (95% CI, 1.53-2.66). Significant heterogeneity was found for the overall analysis and for studies reporting on cancer but not for studies thate xcluded subjects with a family history or for those analyses grouped by age.

CONCLUSIONS

This meta-analysis provides strong evidence that men are at greater risk for advanced colorectal neoplasia across all age groups. This might inform decisions to create sex-specific colorectal cancer screening recommendations.