Epidemiology of colorectal cancer

Metabolic syndrome and risk of subsequent colorectal cancer

The metabolic syndrome and visceral obesity have an increasing prevalence and incidence in the general population. The actual prevalence of the metabolic syndrome is 24% in US population and between 24.6% and 30.9% in Europe. As demonstrated by many clinical trials (NAHANES III, INTERHART) the metabolic syndrome is associated with an increased risk of both diabetes and cardiovascular disease. In addition to cardiovascular disease, individual components of the metabolic syndrome have been linked to the development of cancer, particularly to colorectal cancer. Colorectal cancer is an important public health problem; in the year 2000 there was an estimated total of 944,717 incident cases of colorectal cancer diagnosed world-wide. This association is sustained by many epidemiological studies. Recent reports suggest that individuals with metabolic syndrome have a higher risk of colon or rectal cancer. Moreover, the clusters of metabolic syndrome components increase the risk of associated cancer. The physiopathological mechanism that links metabolic syndrome and colorectal cancer is mostly related to abdominal obesity and insulin resistance. Population and experimental studies demonstrated that hyperinsulinemia, elevated C-peptide, elevated body mass index, high levels of insulin growth factor-1, low levels of insulin growth factor binding protein-3, high leptin levels and low adiponectin levels are all involved in carcinogenesis. Understanding the pathological mechanism that links metabolic syndrome and its components to carcinogenesis has a major clinical significance and may have profound health benefits on a number of diseases including cancer, which represents a major cause of mortality and morbidity in our societies.

Regulation of the apoptosis-inducing kinase DRAK2 by cyclooxygenase-2 in colorectal cancer

Background:

Cyclooxygenase-2 (COX-2) is over-expressed in colorectal cancer (CRC), rendering tumour cells resistant to apoptosis. Selective COX-2 inhibition is effective in CRC prevention, although having adverse cardiovascular effects, thus focus has shifted to downstream pathways.

Methods:

Microarray experiments identified genes regulated by COX-2 in HCA7 CRC cells. In vitro and in vivo regulation of DRAK2 (DAP kinase-related apoptosis-inducing kinase 2 or STK17β, an apoptosis-inducing kinase) by COX-2 was validated by qRT-PCR.

Results:

Inhibition of COX-2 induced apoptosis and enhanced DRAK2 expression in HCA7 cells (4.4-fold increase at 4 h by qRT-PCR, P=0.001), an effect prevented by co-administration of PGE₂. DRAK2 levels were suppressed in a panel of human colorectal tumours (n=10) compared to normal mucosa, and showed inverse correlation with COX-2 expression (R=−0.68, R²=0.46, P=0.03). Administration of the selective COX-2 inhibitor rofecoxib to patients with CRC (n=5) induced DRAK2 expression in tumours (2.5-fold increase, P=0.01). In vitro silencing of DRAK2 by RNAi enhanced CRC cell survival following COX-2 inhibitor treatment.

Conclusion:

DRAK2 is a serine–threonine kinase implicated in the regulation of apoptosis and is negatively regulated by COX-2 in vitro and in vivo, suggesting a novel mechanism for the effect of COX-2 on cancer cell survival.

Effects of a probiotic soy product and physical exercise on formation of pre-neoplastic lesions in rat colons in a short-term model of carcinogenic

Purpose

In this study the influence of moderate or intense physical exercise, alone or in combination with the consumption of a soya product fermented with Enterococcus faecium, on the development of colon cancer induced chemically in rats with 1,2-dimethylhydrazine (DMH), was investigated.

Methods

Eighty male Wistar SPF rats were randomly allocated to 8 groups (n = 10). One week after the start of the program of product ingestion and/or physical activity, all animals except the controls (group I) were injected subcutaneously with 50 mg/kg b.w. of 1,2-dimethylhydrazine (DMH). This procedure was repeated at the end of the second week. At the end of the 6-week experiment, all the animals were euthanized; the colons were removed and numbers of ACF was estimated.

Results

Twenty-four days after the induction of pre-neoplastic lesions, it was evident that the formation of ACF was not significantly reduced by the ingestion of the fermented product, by intense or moderate physical activity or by a combination of these factors, in comparison with the positive control group of rats (p < 0.05). On the other hand, the performance of intense exercise, on its own, increased the number of ACF.

Conclusion

The results reported in this article show that consumption of the fermented soy product described here and the practice of physical exercise (intense or moderate) were incapable, separately or combined, of inhibiting the formation of ACF in DMH-induced rats. The intense physical exercise led to an increased number of foci in the colons of these rats and, probably, to greater susceptibility to colorectal cancer.

Young-age onset of colorectal cancer in Israel

AIM

The study was conducted to investigate the differences in clinical-pathological, ethnic, and demographic presentations and the expression of mismatch repair proteins in a cohort of young-onset (</=50 years) versus late-onset Israeli patients (>50 years) with colorectal cancer.

MATERIALS AND METHODS

Clinical, demographic, and histopathological data of patients with colorectal cancer were collected retrospectively from medical records and pathology reports.

RESULTS

Ninety patients, 50 years of age or younger with a mean age of 42 years were compared with a group of 190 patients above 50 years of 50 (see Table 1). Sixty percent of the young-onset patients were females, compared to 40% in the older age group (P = 0.02). Twenty-one percent of the young-onset patients were Arabs as compared to 2% of older-onset patients (P = 0.001). Younger patients displayed a higher percentage of mucinous cancers and a higher percentage of diagnosis at an advanced stage of disease; 40% of young-onset versus 31% of older-onset patients presented Duke's stages C and D (P = 0.02).

CONCLUSIONS

Younger age of onset colorectal cancer in our cohort of Israeli patients is associated with higher percentage of Arab patients, mucinous cancers, female gender, and advanced stage at diagnosis.

Proneoplastic effects of PGE2 mediated by EP4 receptor in colorectal cancer

Background

Prostaglandin E₂ (PGE₂) is the major product of Cyclooxygenase-2 (COX-2) in colorectal cancer (CRC). We aimed to assess PGE₂ cell surface receptors (EP 1–4) to examine the mechanisms by which PGE₂ regulates tumour progression.

Methods

Gene expression studies were performed by quantitative RT-PCR. Cell cycle was analysed by flow cytometry with cell proliferation quantified by BrdU incorporation measured by enzyme immunoassay. Immunohistochemistry was employed for expression studies on formalin fixed paraffin embedded tumour tissue.

Results

EP4 was the most abundant subtype of PGE₂ receptor in HT-29 and HCA7 cells (which show COX-2 dependent PGE₂ generation) and was consistently the most abundant transcript in human colorectal tumours (n = 8) by qRT-PCR (ANOVA, p = 0.01). G0/G1 cell cycle arrest was observed in HT-29 cells treated with SC-236 5 μM (selective COX-2 inhibitor) for 24 hours (p = 0.02), an effect abrogated by co-incubation with PGE₂ (1 μM). G0/G1 arrest was also seen with a specific EP4 receptor antagonist (EP4A, L-161982) (p = 0.01). Treatment of HT-29 cells with either SC-236 or EP4A caused reduction in intracellular cAMP (ANOVA, p = 0.01). Early induction in p21^WAF1/CIP1 expression (by qRT-PCR) was seen with EP4A treatment (mean fold increase 4.4, p = 0.04) while other genes remained unchanged. Similar induction in p21^WAF1/CIP1 was also seen with PD153025 (1 μM), an EGFR tyrosine kinase inhibitor, suggesting EGFR transactivation by EP4 as a potential mechanism. Additive inhibition of HCA7 proliferation was observed with the combination of SC-236 and neutralising antibody to amphiregulin (AR), a soluble EGFR ligand. Concordance in COX-2 and AR localisation in human colorectal tumours was noted.

Conclusion

COX-2 regulates cell cycle transition via EP4 receptor and altered p21^WAF1/CIP1 expression. EGFR pathways appear important. Specific targeting of the EP4 receptor or downstream targets may offer a safer alternative to COX-2 inhibition in the chemoprevention of CRC.

Comparison of blood neoangiogenesis and lymphatic vascularization in colorectal adenomas from patients with and without concomitant colorectal cancer

Blood and lymphatic vessel proliferation is essential for tumor growth and progression. Most colorectal carcinomas develop from adenomas (adenoma-carcinoma sequence) in a process due to accumulation of molecular genetic alterations. About 5% of adenomatous polyps are expected to become malignant, but data on the differential angiogenic patterns of these lesions in patients with and without concomitant cancer are missing. The aim of the present study is to compare the angiogenic and lymphatic patterns of adenomatous polyps from patients with and without sporadic cancer. Thirty adenomatous polyps (15 from patients with another principal malignant lesion, and 15 from patients without cancer) were submitted to immunohistochemical staining for CD105 (marker for neoangiogenesis) and D2-40 (marker for lymphatic endothelium). Microvessel density and total vascular area were determined by computer image analysis to quantify the immunostained and total areas, and to assess the number of microvessels. Adenomas from patients with carcinoma showed significantly higher values of total vascular area determined by immunostaining for CD105 (cutoff value = 4386 microm(2); P = 0.019) and of lymphatic microvessel density determined by immunostaining with D2-40 (cutoff value = 11.5; P = 0.041) when compared with those from patients without cancer. The present data indicate a significant increase in blood microvascular area and in lymphatic microvascular counts in adenomas removed from patients with cancer.

Cyclooxygenase as a target for chemoprevention in colorectal cancer: lost cause or a concept coming of age?

COX-2 is upregulated at an early stage in colorectal carcinogenesis and generates prostaglandins, which promote cancer cell proliferation, impair apoptosis and enhance angiogenesis, promoting tumour growth and metastasis. There are ample data from animal models and human studies to demonstrate enhanced tumour progression associated with COX-2 activity in cancer cells. Conversely, NSAIDs including aspirin inhibit COX-2 and, therefore, have anti-neoplastic properties. There has been sustained interest in COX-2 as a chemopreventive target in colorectal cancer (CRC) and although both aspirin and COX-2 selective NSAIDs have demonstrated efficacy, adverse effects have limited their widespread adoption. In particular, evidence of the cardiovascular effects of COX-2 selective inhibitors has led to questioning of the suitability of COX-2 as a target for chemoprevention. This review examines the basis for targeting COX-2 in CRC chemoprevention, evaluates the efficacy and safety of the approach and examines future strategies in this area.

Diet and epigenetics in colon cancer

Over the past few years, evidence has accumulated indicating that apart from genetic alterations, epigenetic alterations, through e.g. aberrant promoter methylation, play a major role in the initiation and progression of colorectal cancer (CRC). Even in the hereditary colon cancer syndromes, in which the susceptibility is inherited dominantly, cancer develops only as the result of the progressive accumulation of genetic and epigenetic alterations. Diet can both prevent and induce colon carcinogenesis, for instance, through epigenetic changes, which regulate the homeostasis of the intestinal mucosa. Food-derived compounds are constantly present in the intestine and may shift cellular balance toward harmful outcomes, such as increased susceptibility to mutations. There is strong evidence that a major component of cancer risk may involve epigenetic changes in normal cells that increase the probability of cancer after genetic mutation. The recognition of epigenetic changes as a driving force in colorectal neoplasia would open new areas of research in disease epidemiology, risk assessment, and treatment, especially in mutation carriers who already have an inherited predisposition to cancer.

Analysis of urinary nucleosides as potential tumor markers in human colorectal cancer by high performance liquid chromatography/electrospray ionization tandem mass spectrometry

BACKGROUND

Increased levels of modified nucleosides have been observed in urine from patients suffering from several cancers. In this study, we evaluated whether urinary nucleosides can serve as potential tumor markers for colorectal cancer by high performance liquid chromatography-electrospray/tandem mass spectrometry (HPLC/ESI-MS/MS).

METHODS

A simple and specific method based on HPLC/ESI-MS/MS was developed to determine the urinary nucleosides from patients with colorectal cancer. We studied the excretion patterns of nucleosides in urine from 26 patients with colorectal cancer and 18 healthy controls.

RESULTS

The LC/MS/MS approach with selective reaction monitoring (SRM) allowed for the sensitive determination of nucleosides in human urine samples with colorectal cancer. The mean levels of 5 urinary nucleosides (adenosine, cytidine, N(2),N(2)-dimethylguanine, 8-hydroxy-2'-deoxyguanosine and uridine) were significantly higher in the patients with colorectal cancer than in the healthy adults.

CONCLUSIONS

The results indicate that urinary nucleosides determined by LC/MS/MS may be useful as biological markers for colorectal cancer. Our findings suggest that LC/MS/MS is a highly specific and sensitive method for rapidly screening a large number of nucleoside that may be useful as markers for cancer in humans.

A summary measure of pro- and anti-oxidant exposures and risk of incident, sporadic, colorectal adenomas

Despite compelling basic science evidence, the search for causal associations linking specific pro- and anti-oxidants to presumably oxidative stress-related neoplasms, such as colorectal adenoma, has produced inconsistent results. We developed an oxidative balance score (OBS) to characterize the pro-oxidant and anti-oxidant exposures of 2,305 participants in a case-control study of colorectal adenoma that used both endoscopy-confirmed and community controls. Twelve lifestyle medical and dietary factors with known pro- or anti-oxidant properties were considered. Each high anti-oxidant exposure and low pro-oxidant exposure was awarded one or two points depending on the level of exposure, and the points for each OBS component were summed. We observed a significant inverse association between OBS (continuous variable) and colorectal adenoma in the analyses with either community, or endoscopy controls (each p-trend < 0.01). When the OBS was treated as an ordinal variable and a score of <or=3 points was used as the referent category, in the analyses with the endoscopy controls the adjusted odds ratios for scores of 4-6, 7-9, 10-12, 13-15, and 16+, were 0.42, 0.32, 0.22, 0.20, and 0.19, respectively, with all 95% confidence intervals excluding 1.0. The corresponding analysis for community controls showed a similar trend. Our findings are in line with the basic science evidence supporting the role of oxidative stress in colorectal neoplasia.

Hyperglycemia and hypertriglyceridemia may associate with the adenoma-carcinoma transition in colorectal epithelial cells

BACKGROUND AND AIM

Epidemiological studies have suggested the positive correlation between hyperlipidemia and/or hyperglycemia and colorectal cancer risk.

METHODS

We retrospectively examined the association between fasting blood sugar (BS) or triglycerides (TG) and the presence of colorectal adenoma, carcinoma in situ and invasive cancer in 867 patients who received total colonoscopy by medical health check.

RESULTS

An increased TG level, but not a BS level, was significantly associated with the increased risk of adenoma, although with non-independent multivariate analysis. In contrast, an elevated BS level was identified as an independent risk factor for invasive cancer in 93 patients with carcinoma lesions with an odds ratio of 1.74 (P < 0.05).

CONCLUSION

Our data suggest that hypertriglyceridemia and hyperglycemia may correlate with the development of adenoma and invasive cancer, respectively. The effectiveness of strict BS control in patients with hypertriglyceridemia for the prevention of the invasive colorectal carcinoma deserves further studies.

Bevacizumab, Capecitabine, and Oxaliplatin As Neoadjuvant Therapy for Patients With Potentially Curable Metastatic Colorectal Cancer

Purpose

Patients with colorectal cancer (CRC) and liver metastases have a poor prognosis, but can benefit from perioperative chemotherapy and disease resection. Bevacizumab improves outcomes in patients with metastatic CRC; however, its impact on surgical complications and hepatic regeneration after liver resection remains to be determined.

Patients and Methods

Fifty-six patients with metastatic CRC with liver metastases potentially curable by resection were eligible for this single-center, nonrandomized phase II trial. Eligibility criteria defined patients at high risk of early recurrence. Patients received biweekly bevacizumab plus capecitabine and oxaliplatin for six cycles. The sixth cycle of therapy did not include bevacizumab, resulting in 5 weeks between the last administration of bevacizumab and surgery.

Results

Objective response to neoadjuvant chemotherapy was achieved in 41 patients (73%). Fifty-two patients underwent liver resection including 11 with synchronous primary tumor resection. No increased intraoperative bleeding events or wound-healing complications were observed and only three patients (6%) required perioperative blood transfusions. Further surgery was necessary in a single patient. Postoperative liver function and regeneration were normal in all but one patient. No postoperative mortality occurred and morbidity was encountered in 11 patients (20%). The mean length of postoperative hospitalization was 9 days (± 4.0).

Conclusion

These data suggest that bevacizumab can be safely administered until 5 weeks before liver resection in patients with metastatic CRC without increasing the rate of surgical or wound healing complications or severity of bleeding. To our knowledge, they are also the first to show that neoadjuvant bevacizumab does not affect liver regeneration after resection.

Priorities for women's health from the Global Burden of Disease study

Women's health is increasingly recognized as a global health priority. It is essential to address not only sexual and reproductive health, but also other health issues that occur throughout life. This paper uses the 2005 estimates of morbidity and mortality from the WHO Global Burden of Disease study and a review of the literature to identify key areas of concern for women by age group and world region. The leading causes of death in women aged between 15 and 44 years include infectious diseases such as HIV/AIDS, tuberculosis, maternal health conditions, and injuries. The leading causes of death in women aged 45 years and older include cardiovascular diseases, chronic obstructive pulmonary disease, and other noncommunicable conditions. Neuropsychiatric and sensory disorders are a major cause of disability for both age groups. An understanding of the key regional and age-specific priorities for women's health will facilitate the development of appropriate interventions and policies to reduce disease burden.

Irinotecan/Fluorouracil Combination in First-Line Therapy of Older and Younger Patients With Metastatic Colorectal Cancer: Combined Analysis of 2,691 Patients in Randomized Controlled Trials

Purpose

Uncertainty exists about whether elderly patients benefit to the same extent as younger patients from combination therapy with irinotecan in the first-line treatment of metastatic colorectal cancer (CRC).

Patients and Methods

Combined analysis was carried out with source data from the fluorouracil (FU)/folinic acid (FA) and the irinotecan/FU/FA arms of four first-line, phase III trials of CRC to investigate the efficacy and safety of combination and monotherapy in elderly (age ≥ 70 years; n = 599) compared with younger (age < 70 years; n = 2,092) patients.

Results

Response rates were improved with irinotecan-based combination therapy compared with FU/FA in patients both younger than 70 years and ≥ 70 years (46.6% v 29.0% P < .0001; and 50.5% v 30.3%, P < .0001, respectively). With irinotecan/FU/FA, progression-free survival was better for both younger (hazard ratio [HR], 0.77; 95% CI, 0.70 to 0.85; P < .0001) and elderly patients (HR, 0.75; 95% CI, 0.61 to 0.90; P = .0026). In younger patients, overall survival was improved with combination therapy (HR, 0.83; 95% CI, 0.75 to 0.92; P = .0003). The same trend was observed in elderly patients (HR, 0.87; 95% CI, 0.72 to 1.05; P = .15). There was no significant interaction between treatment arm and age in the regression analysis. The expected differences in toxicity between combination and monotherapy in elderly and younger patients were observed. A significant interaction between treatment and age (cutoff, 70 years) for vomiting and hepatotoxicity was not confirmed by analysis that used age as a continuous variable.

Conclusion

Patients older than 70 years of age who were selected for inclusion in phase III trials derived similar benefits as younger patients from irinotecan-containing chemotherapy, and the risk of toxicity was similar.

Intestinal protozoa are hypothesized to stimulate immunosurveillance against colon cancer

Colon cancer in humans results in considerable morbidity and mortality throughout most of the world. During the twentieth century, there was a rapid rise in colon cancer within modernizing countries that has not been adequately explained, although the role of diet has been widely explored. Previously, we showed that the presence of the endemic Eimeria spp. protozoan in intestinal tissues is associated with regions of low tumorigenesis in the large and small bovine intestine and that an Eimeria surface protein is a potent activator of dendritic cells and a useful immunomodulator, with anti-cancer and anti-viral properties. Therefore, we hypothesize that the persistent presence of such an intestinal protozoan enhances immunosurveillance by elevating the intestinal alert status and that the loss of these organisms could lead to a higher incidence of colon cancer. Preliminary support of this hypothesis derives from the observations that domestic animals, known to maintain this protozoan, have very low colon cancer incidence. We propose that this also may occur in human populations that use human excrement (night soil) as a fertilizer, a practice that serves to complete the life cycle of this type of microbe. We examine some evidence for this hypothesis in Japan's mortality patterns, where we show that colon cancer increased after the cessation of night soil use, but before the change to a western diet. We conclude that this hypothesis, a variation of the hygiene hypothesis, is worth further consideration and continued elaboration.

Referring patients to specialists: a structured vignette survey of Australian and British GPs

BACKGROUND

In Australia and in the United Kingdom (UK) access to specialists is sanctioned by General Practitioners (GPs). It is important to understand how practitioners determine which patients warrant referral.

METHODS

A self-administered structured vignette postal survey of General Practitioners in Western Australia and the United Kingdom. Sixty-four vignettes describing patients with colorectal symptoms were constructed encompassing six clinical details. Nine vignettes, chosen at random, were presented to each individual. Respondents were asked if they would refer the patient to a specialist and how urgently. Logistic regression and parametric tests were used to analyse the data

RESULTS

We received 260 completed questionnaires. 58% of 'cancer vignettes' were selected for 'urgent' referral. 1632/2367 or 69% of all vignettes were selected for referral. After adjusting for clustering the model suggests that 38.4% of the variability is explained by all the clinical variables as well as the age and experience of the respondents. 1012 or 42.8 % of vignettes were referred 'urgently'. After adjusting for clustering the data suggests that 31.3 % of the variability is explained by the model. The age of the respondents, the location of the practice and all the clinical variables were significant in the decision to refer urgently.

CONCLUSION

GPs' referral decisions for patients with lower bowel symptoms are similar in the two countries. We question the wisdom of streaming referrals from primary care without a strong evidence base and an effective intervention for implementing guidelines. We conclude that implementation must take into account the profile of patients but also the characteristics of GPs and referral policies.

Câncer ano-reto-cólico: aspectos atuais II - câncer colorretal - fatores de riscos e prevenção

O câncer colorretal é curável e passível de prevenção. A chave para o alcance desses objetivos é relativamente simples e pode ser aplicada em escala populacional. Basta, para tanto, que sejamos capazes de conscientizar os médicos, independente da sua área especial de atuação, e proporcionar às pessoas o mais fácil alcance às informações médicas expressas em termos simples sobre a profilaxia e o diagnóstico precoce dessa neoplasia maligna, sobretudo, destacando os fatores protetores e os de riscos, principalmente os que são suscetíveis de ser modificados.

Trends in colorectal cancer mortality by ethnicity and socio-economic position in New Zealand, 1981-99: one country, many stories

BACKGROUND

Ethnicity and socio-economic position are important determinants of colorectal cancer (CRC) mortality. In this paper, we determine trends in colorectal cancer mortality by ethnicity and socio-economic position in New Zealand.

METHODS

Cohort studies of the entire New Zealand population for 1981-84, 1986-89, 1991-94 and 1996-99 (linking Census and mortality datasets) allowed direct determination of trends in CRC mortality by income and education. For ethnicity, we used routine unlinked Census and mortality data, but with correction factors applied for undercounting of Mâori and Pacific deaths.

RESULTS

ETHNICITY: CRC mortality trends varied markedly. There were small (10-20%) decreases among non-Mâori non-Pacific people, a 50% increase among Mâori, and up to 10-fold increase among Pacific people. By 1996-99, all three ethnic groups had similar CRC mortality. SOCIO-ECONOMIC POSITION: For females, differences in CRC mortality by education and income increased over time e.g. poor females had a 40% higher CRC mortality than rich females in 1996-99, compared with no difference in 1981-84 (p for trend 0.04). In men, increases in inequality were seen by income but not education.

CONCLUSION

The observed ethnic trends probably reflect differential trends in exposure to etiological risk factors. Social inequalities in colorectal cancer mortality appear to be increasing.

The surgeon's role in cancer prevention. The model in colorectal carcinoma

Cancer Prevention is an emerging field, capturing the old traditional concept of anticipating the development of a major disease and preventing its full impact by early detection, treatment, or aborting the tumorigenic process by a "molecular vaccine" and alleviating the full impact of the disease. Surgeons are important clinician scientists who can carry this discipline forward and develop its full potential in the clinics and in the community. Advances in molecular biology, genetics, and other technologies have permitted seminal understanding of the carcinogenic pathways and identification of targets and intermediate end points in neoplasia. In this review, we will see that we have the means of preventing significant numbers of colorectal carcinomas (CRC).

Results after change of treatment policy for rectal cancer – report from a single hospital in China

BACKGROUND

Great changes have occurred in the management of rectal cancer. This study presents the outcome of total mesorectal excision (TME) for rectal cancer in a single Chinese institution and evaluates TME's role in the comprehensive management of rectal cancer.

METHODS

We reviewed the data of rectal cancer patients surgically treated by three colorectal surgeons from January 2000 to August 2004. Patients who received surgical resection for rectal cancer from January 1996 to December 1999, before the introduction of TME, were chosen as controls. Data regarding characteristics of patients and tumors, surgical procedures, postoperative complications, and results of follow-up were collected for analysis.

RESULTS

Three hundred and seventy-seven patients with rectal cancer were enrolled in our study, with 175 patients in the TME group and 202 as controls. Mortality and morbidity rates were 1% and 14% in TME patients and 1% and 31% in controls, respectively. The TME group had a shorter operation time and hospital stay, and less bleeding, wound and urinary complications. The local recurrence (LR) rate was 6% and 12% in the TME and the control groups, respectively (P<0.05). With a median follow-up of 35 months, the actuarial 5-year survival rate was 66%. Consistent with the univariate analysis result, multivariate analysis demonstrated that TNM stage, tumor grade, age, and surgeons were independent prognostic factors. TME was not an independent prognostic factor for patients' survival.

CONCLUSIONS

TME is a safe and efficient option in reducing LR. However, it is not an independent predictor for patients' survival. In addition to the standardized usage of TME, further knowledge on the molecular mechanism of cancer is needed.

Hypothesis: oxidative stress score as a combined measure of pro-oxidant and antioxidant exposures

PURPOSE

To explore the hypothesis that a combination of several risk factors acting through the same pathway may produce an overall large increase in risk even in the presence of weak associations with each individual factor.

METHODS

Using oxidative stress pathway as an example, we propose an oxidative stress score (OSS), where high and low pro-oxidant exposures expressed as continuous variables are assigned values of 0 and 1, while high and low antioxidant exposures are assigned values of 1 and 0, respectively. Dichotomous variables for pro-oxidant and antioxidant exposures are scored in a similar fashion. All individual scores are then summed to calculate the overall OSS, where higher and lower values indicate a shift toward antioxidant and pro-oxidant exposures, respectively.

RESULTS

We illustrate this approach by using data from two previously-conducted case-control studies: a colonoscopy-based colorectal adenoma study, and a population-based prostate cancer study. In this pilot illustration we found a substantial decrease in risk associated with a high OSS for both prostate cancer and colorectal adenoma. By contrast, analyses for individual OSS components demonstrated no discernible pattern.

CONCLUSIONS

Our exploratory analyses serve as a demonstration of a method and warrant further confirmation on a larger scale.

Synchronous rectal adenocarcinoma and anal canal adenocarcinoma

It is difficult to distinguish a rectal carcinoma with anal metastases from coexistent synchronous anorectal carcinomas. The therapeutic strategy for rectal and anal carcinoma is so different that it should be clearly identified. Here, we report on the case of a 63-year-old man who presented with an upper-third rectal adenocarcinoma. Five months after resection, he developed an adenocarcinoma in the anal canal. The histological slides of both tumors were reviewed and immunohistochemical studies for cytokeratins (CKs) 7 and 20 were performed. The index tumor demonstrated CK 7-/CK 20+ and the second showed CK7+/CK20+. For this reason, we believe the present case had synchronous adenocarcinomas arising from anal canal and the rectum separately. It is very important to differentiate the anorectal lesions pathologically because of the impact on the therapeutic options available, especially for the lesion arising in the anal canal.

Role of BRAF-V600E in the serrated pathway of colorectal tumourigenesis

There is increasing evidence for an alternative pathway of sporadic colorectal tumourigenesis that is associated with DNA microsatellite instability (MSI), due to methylation and loss of expression of the mismatch repair gene MLH1. Recent studies have highlighted a serrated pathway of colorectal cancer (CRC) in which serrated polyps with activating mutations in BRAF progress to CRCs with MSI following methylation and silencing of MLH1. The present study provides a novel mechanistic experimental model for these clinical observations. We investigated the role of BRAF activating mutation (BRAF-V600E) in colorectal tumourigenesis by studying the effects of forced expression of BRAF-V600E in the 'normal' colon epithelial NCM460 cell line and by targeting endogenous BRAF-V600E in MSI-High (MSI-H) colon cancer cell lines. The findings indicate that BRAF mutation in colon epithelial cells contributes to a gain in resistance towards apoptotic stimuli, which is likely to be an important characteristic of pre-malignant serrated lesions. BRAF-V600E also plays a role in the development and maintenance of transformed and invasive phenotypes in colon epithelial cells. Our findings also suggest that BRAF mutation potentiates promoter hypermethylation of the MLH1 gene promoter. Together, these results highlight BRAF as a potential target for therapeutic intervention in sporadic MSI-H colorectal cancers.

Physical activity and colon cancer risk among women in the California Teachers Study

BACKGROUND

Existing data suggest that physical activity reduces colon cancer risk, but the association is not consistently observed in women. One potential explanation for this inconsistency is that hormone therapy, which is associated with lower colon cancer risk, acts as a modifier of the physical activity/colon cancer relationship.

METHODS

Participants in the California Teachers Study (N = 120,147), a prospective cohort of female teachers and administrators residing in California, ages 22 to 84 years at baseline and with no prior history of colon cancer were eligible for study. Between 1996 and 2002, 395 patients were diagnosed with invasive colon cancer. The relative risks (RR) associated with lifetime (high school through age 54 years or current age) and recent (past 3 years) strenuous and moderate recreational physical activity were estimated using Cox proportional hazards regression models.

RESULTS

Combined lifetime moderate and strenuous recreational physical activity was only modestly associated with colon cancer risk in the cohort [>or=4 versus <or=0.5 h/wk/y: RR, 0.75; 95% confidence interval, 0.57-1.00; P(trend) = 0.23]. Lifetime physical activity reduced colon cancer risk among postmenopausal women who had never taken hormone therapy (>or=4 versus <or=0.5 h/wk/y: RR, 0.51; 95% confidence interval, 0.31-0.85; P(trend) = 0.02). Postmenopausal women with histories of hormone therapy use had lower colon cancer risk, but their risk was not associated with physical activity. The likelihood ratio test for interaction between hormone use and lifetime moderate plus strenuous physical activity was of borderline statistical significance (P = 0.05). We observed no effect modification by age, body mass index, smoking status, menopausal status, or folate intake.

CONCLUSIONS

Lifetime recreational physical activity may protect against colon cancer among postmenopausal women who have never used hormone therapy. Among hormone therapy users, who have lower risk of colon cancer, recreational physical activity does not seem to provide any additional benefit. With declining rates of hormone therapy use, physical activity offers one possible means for reducing women's colon cancer risk.

Effect of diabetes mellitus on the epidemiology and outcomes of colon cancer

OBJECTIVES

To assess the effect of diabetes mellitus (DM) on the pathogenesis and outcomes from colon cancer.

METHODS

A retrospective chart review was conducted on 1853 patients with colon cancer.

RESULTS

A higher percentage of males than females with colon cancer had DM (16.2% vs 11.3%; p < 0.01). Males had a slightly lower risk of dying from colon cancer (RR - 0.88; p=0.08). There was no difference in the median age of diagnosis of colon cancer in patients with and without DM, but a larger proportion of patients with diabetes mellitus were >or=70 yr at diagnosis (50% vs 43%) (p=0.0004). No significant relationship was noted between stage of colon cancer or survival and presence of DM.

CONCLUSIONS

DM did not affect either the stage at diagnosis, or outcomes from colon cancer. More males with colon cancer tended to have DM and a larger proportion of patients with DM were >or=70 yr at the time of diagnosis.

Effect of diabetes mellitus on the epidemiology and outcomes of colon cancer

OBJECTIVES

To assess the effect of diabetes mellitus (DM) on the pathogenesis and outcomes from colon cancer.

METHODS

A retrospective chart review was conducted on 1853 patients with colon cancer.

RESULTS

A higher percentage of males than females with colon cancer had DM (16.2% vs 11.3%; p < 0.01). Males had a slightly lower risk of dying from colon cancer (RR - 0.88; p=0.08). There was no difference in the median age of diagnosis of colon cancer in patients with and without DM, but a larger proportion of patients with diabetes mellitus were >or=70 yr at diagnosis (50% vs 43%) (p=0.0004). No significant relationship was noted between stage of colon cancer or survival and presence of DM.

CONCLUSIONS

DM did not affect either the stage at diagnosis, or outcomes from colon cancer. More males with colon cancer tended to have DM and a larger proportion of patients with DM were >or=70 yr at the time of diagnosis.

Do older adults using NSAIDs have a reduced risk of colorectal cancer?

BACKGROUND AND OBJECTIVES

Colorectal cancer (CRC) is primarily a disease of older adults. Although NSAIDs are thought to protect from CRC, and long-term use of NSAIDs is common in the elderly, little is known about the impact of NSAID use on CRC risk at advanced age. We specifically reviewed current evidence regarding the effects of NSAIDs on CRC risk in individuals aged > or =65 years, a rapidly growing age group.

STUDY DESIGN

We searched all articles in PubMed published before August 2005. Studies were included if a subgroup analysis of older adults (> or =65 years of age) was performed, or if long-term use of NSAIDs for > or =5 years and CRC risk was investigated. From the selected studies, relevant information, including sample characteristics and association with CRC risk, was extracted and compared.

RESULTS

Altogether 19 studies were identified. Only four studies specifically considered NSAID use in people > or =65 years of age; of these, two showed risk reduction for CRC comparable to that seen in younger age groups or in all age groups. The most informative observational studies found decreasing relative risk of CRC with increasing duration of NSAID use, suggesting substantial risk reduction after 10-20 years of regular use.

CONCLUSIONS

The available data on long-term effects of NSAID use in elderly people are sparse but predominantly indicate risk reduction for CRC comparable to that seen in younger age groups or all ages. Whether and to what degree initiating NSAID use in old age prevents CRC is essentially unknown. In light of the potential adverse effects of NSAIDs, including recent data on adverse cardiovascular outcomes, more information is needed on the minimum effective dose of NSAIDs and the duration of use required in order to evaluate individual risks and benefits in older adults.

The T/G mutation in exon 8 of hMSH2 gene in the sporadic colon cancer patients

The DNA mismatch repair (MMR) system guards against genomic instability, therefore the mutations in the human MMR genes cause the majority of the hereditary nonpolyposis colorectal cancer (HNPCC) and a small percentage of the sporadic colon cancer. hMSH2 is one of MMR genes involved in the correction of mispairing during replication and its mutations are associated with both--microsatellite instability and the hereditary and sporadic colon tumourgenesis. The aim of this study was to analyse the T/G mutation (codon 458) in exon 8 of hMSH2 gene in the sporadic colon cancer cells. We also examined the relationship between the T/G mutation of hMSH2 gene, and the selected prognostic factors such as Dukes' stage, histological grade and lymph node metastasis. We analysed samples of tumour from 75 patients with sporadic colorectal cancers. The mutation in the hMSH2 gene ware determined by the RFLP-PCR. We found T/G mutation in exon 8 of hMSH2 gene in 5 patients (6,7%). There was no statistically significant difference between this mutation and selected clinical parameters. The results of our studies revealed that mutations of hMSH2 gene may lead to development of colorectal cancer. No dependence between the mutation of hMSH2 gene and clinical parameters, suggests that the mutation of hMSH2 gene may have a critical significance for the first steps of carcinogenesis in colon epithelial.

Duration of adjuvant chemotherapy for colon cancer and survival among the elderly

PURPOSE

In randomized trials, patients with stage III colon cancer who received 6 months of fluorouracil (FU)-based adjuvant chemotherapy had better survival than patients who did not. However, little is known about the predictors of, or the survival associated with, duration of chemotherapy in the community.

PATIENTS AND METHODS

The linked Surveillance, Epidemiology, and End Results-Medicare database was used to identify individuals > or = 65 years of age diagnosed with stage III colon cancer between 1995 and 1999. We used logistic and Cox proportional hazards regression models to analyze factors associated with early discontinuation of FU-based chemotherapy among these elderly colon cancer patients.

RESULTS

Among 1,722 patients who received 1 to 7 months of FU-based chemotherapy, older age, being unmarried, and having comorbid conditions were associated with receiving less than 5 months of treatment. Among the 1,579 patients who survived > or = 8 months, the 1,091 (69.1%) who received 5 to 7 months of treatment had lower overall (hazard ratio [HR], 0.59; 95%, CI 0.49 to 0.71) and colon cancer-specific (HR, 0.53; 95% CI, 0.43 to 0.66) mortality than the 488 (30.9%) who received 1 to 4 months of treatment.

CONCLUSION

More than 30% of elderly patients who initiated FU-based chemotherapy for stage III colon cancer and survived for at least 8 months discontinued treatment early. Mortality rates among such patients were nearly twice as high as among patients who completed 5 to 7 months of treatment. If the association we observed between duration of treatment and survival is confirmed, additional investigation is warranted to determine whether dose-intensity, cumulative dose, or other factors related to receipt of full adjuvant treatment are responsible.

Benefit-risk assessment of irinotecan in advanced colorectal cancer

Irinotecan exerts its cytotoxic activity through inhibition of the nuclear enzyme topoisomerase I. It has been approved in most countries worldwide for treatment of patients with advanced colorectal cancer (CRC). Activity is seen in previously untreated patients and in patients refractory to fluorouracil treatment, whether it is given alone or in combination with other cytotoxic drugs. Irinotecan was first developed in patients refractory to fluorouracil. Activity in terms of tumour responses and patient benefit was seen in several phase II trials that used either a weekly or a three-weekly schedule. In two randomised trials (irinotecan vs best supportive care, and irinotecan vs an infused fluorouracil-based regimen), irinotecan prolonged median survival by approximately 2.5 months without any deterioration in quality-of-life. It was later studied in previously untreated patients with advanced CRC in combination with fluorouracil/folinic acid (leucovorin). In three large randomised trials, median time to tumour progression was prolonged by approximately 2.5 months and overall survival by about 2.5 months compared with fluorouracil/folinic acid alone. Tumour responses were also seen more frequently in the irinotecan arm (35-40% vs 20%). Again, quality-of-life scores were not deteriorated by the addition of irinotecan. Irinotecan has many acute adverse effects. The most prominent and dose limiting being diarrhoea and neutropenia. With irinotecan monotherapy, diarrhoea was seen in 80% of patients and severe grade 3 to 4 diarrhoea occurred in 30-40% of the patients. The severity of diarrhoea can be diminished by preventive actions. Less risk of diarrhoea is generally seen when irinotecan is combined with fluorouracil. Neutropenia is generally short-lived, but may be severe if diarrhoea is also present. This has been noticed particularly when irinotecan has been given in combination with a bolus fluorouracil/folinic acid regimen. Other toxicities include acute cholinergic-like symptoms, nausea and vomiting, and alopecia. In spite of these adverse effects, irinotecan has been accepted as an important first-line treatment for patients with advanced CRC, in combination with, preferably, an infused fluorouracil-based regimen, and has been approved for use as monotherapy in the second-line indication.

The potential for improved outcome in patients with hepatic metastases from colon cancer: a population-based study

AIMS

Reports from specialized centres suggest that 20-25% of patients with hepatic metastases from colorectal cancer have resectable disease, with 5-year survival rates of 30-40%, and that an additional 13-38% may become resectable after chemotherapy. The purpose of this study was to assess the potential for improvement in outcome for patients with hepatic metastases from colon cancer in an unselected population.

PATIENTS AND METHODS

All patients diagnosed with colon cancer in the Stockholm/Gotland region between 1 January 1996 and 31 December 1999 were identified and followed until 31 December 2002. Treatment and outcome in patients with hepatic metastases was analyzed and CT-scans and MR images of the liver were reviewed to re-evaluate resectability.

RESULTS

In 2280 patients with colon cancer, hepatic metastases were diagnosed in 537 patients. Only 21 of these patients underwent a hepatic resection. Retrospective evaluation of liver images indicated that 10% of the patients had potentially resectable hepatic disease.

CONCLUSION

The rate of potentially resectable liver metastases from colon cancer in a population is lower than suggested from hospital-based series. With structured management programs including follow-up routines and multidisciplinary treatment protocols the proportion of patients amenable for liver resection may be increased. In this study preoperative chemotherapy might have increased the resectability rate to at the most 17%. To significantly improve prognosis for patients with hepatic metastases from colon cancer more effective treatment modalities are needed.

MR colonography: baseline appearance of the unprepared rectosigmoid

A retrospective review of 100 routine pelvic MR examinations was conducted to evaluate the appearance of the unprepared rectosigmoid colon, with the aim of informing future strategies for minimal preparation MR colonography. All examinations were reviewed by two observers in consensus, and included matched-location axial T1 weighted and T2 weighted fat suppressed fast spin echo (FSFSE) images. Analysis revealed that the overall appearance of the faecal material in the colon could simulate tumour in 80% of T1 weighted and 17% of T2 weighted images. By matching the images from the two sequences for each patient the faeces had an overall appearance that would mimic tumour in only 7% of cases. However, luminal tumour-mimicking foci of signal occurred frequently, present in 91% of T1 weighted and 85% of T2 weighted studies. The results indicate that if bowel-cleansing regimens are to be avoided for MR colonography, effective strategies such as dietary restriction and use of oral contrast agents will be required to reduce luminal signal on T2 weighting and eliminate polyp-mimicking foci. The results also suggest that T2 weighted strategies should be further investigated and that combination with T1 weighted imaging may improve discrimination of lesions from normal faecal material.

Perceived psychologic stress and colorectal cancer mortality: findings from the Japan Collaborative Cohort Study

OBJECTIVE

The purpose of this research was to examine the relationship between perceived psychologic stress and colorectal cancer mortality in a prospective large-scale study.

METHODS

Between the years 1988 and 1990, 32,153 men and 45,854 women aged 40 to 79 years were enrolled. Participants completed a self-administered questionnaire that addressed demographic, lifestyle, and psychosocial characteristics. Subjects were subsequently followed for mortality until the end of 1999. Perceived psychologic stress was assessed using the question "Do you feel stress during your daily life?" The 4 possible responses, ranging from "little or none" (1) to "extreme" (4), were dichotomized as low (1 or 2) or high (3 or 4) stress. Relative risks (RRs) with 95% confidence intervals (CIs) for colon and rectal cancer according to the perceived level of stress were estimated using Cox's proportional hazard model.

RESULTS

During the follow-up period (average, 9.6 years), 193 colon cancer deaths (96 men and 97 women) and 127 rectal cancer deaths (88 men and 39 women) were confirmed within the study group. Women who reported high stress had a 1.64-fold higher risk of colon cancer mortality (multivariate-adjusted RR, 1.64; 95% CI, 1.01-2.66) compared with those reporting low stress. There was no significant association between perceived stress and female rectal cancer or male colon and rectal cancer mortality.

CONCLUSIONS

Perceived psychologic stress was weakly associated with increased mortality from colon cancer in women. No positive or inverse association was found in men. Further studies are needed to confirm our results.

Screening of patients at average risk for colon cancer

Both the incidence and the mortality from colorectal cancer can be substantially reduced by primary and secondary prevention. There are many screening tests for colorectal cancer, and any test should result in a reduction in colorectal cancer incidence and mortality. If the age-eligible population undergoes these screening tests, the burden of colorectal cancer should be substantially reduced. The scientific evidence related to secondary prevention, specifically screening of individuals at average risk for colorectal cancer, is presently reviewed.

Colon stenting: a review

Up to 85% of patients who present with colonic obstruction have a colorectal cancer. Between 7% and 29% of these patients present with total or partial intestinal obstruction. Only 20% of these patients presenting with acute colonic obstruction due to malignancy survive 5 years. Emergent surgical intervention in patients with colonic obstruction is associated with significant morbidity and mortality rates. Only 40% of patients with obstructive carcinoma of the left colon can be treated with surgical resection without the need for a colostomy. The use of a temporary or permanent colostomy has a significant impact on quality of life. The decompressive effect seen with colonic stenting is a durable, simple, and effective palliative treatment of patients with advanced disease. Stent deployment provides an effective solution to acute colonic obstruction and allows surgical treatment of the patient in an elective and more favorable condition. In addition, colonic stenting reduces costs and avoids the need for a colostomy.

Colorectal cancers with microsatellite instability display mRNA expression signatures characteristic of increased immunogenicity

Background

Colorectal cancers displaying high-degree microsatellite instability (MSI-H) have an improved prognosis compared to microsatellite stable (MSS) cancers. The observation of pronounced lymphocytic infiltrates suggests that MSI-H cancers are inherently more immunogenic. We aimed to compare the gene expression profiles of MSI-H and MSS cancers to provide evidence for an activated immune response in the former.

Results

We analysed tissue from 133 colorectal cancer patients with full consent and Local Ethics Committee approval. Genomic DNA was analysed for microsatellite instability in BAT-26. High-quality RNA was used for microarray analysis on the Affymetrix^® HG-U133A chip. Data was analysed on GeneSpring software version 6.0. Confirmatory real-time RT-PCR was performed on 28 MSI-H and 26 MSS cancers. A comparison of 29 MSI-H and 104 MSS cancers identified 2070 genes that were differentially expressed between the two groups [P < 0.005]. Significantly, many key immunomodulatory genes were up-regulated in MSI-H cancers. These included antigen chaperone molecules (HSP-70, HSP-110, Calreticulin, gp96), pro-inflammatory cytokines (Interleukin (IL)-18, IL-15, IL-8, IL-24, IL-7) and cytotoxic mediators (Granulysin, Granzyme A). Quantitative RT-PCR confirmed up-regulation of HSP-70 [P = 0.016], HSP-110 [P = 0.002], IL-18 [P = 0.004], IL-8 [0.002] and Granulysin [P < 0.0001].

Conclusions

The upregulation of a large number of genes implicated in immune response supports the theory that MSI-H cancers are immunogenic. The novel observation of Heat Shock Protein up-regulation in MSI-H cancer is highly significant in light of the recognised roles of these proteins in innate and antigen-specific immunogenicity. Increased mRNA levels of pro-inflammatory cytokines and cytotoxic mediators also indicate an activated anti-tumour immune response.

Dysregulation of E-cadherin by oncogenic ras in intestinal epithelial cells is blocked by inhibiting MAP kinase

BACKGROUND

Mutations in oncogenic Ras contribute to colorectal tumorigenesis. Loss of the cell adhesion protein E-cadherin is associated with tumor invasion and metastasis.

METHODS

Expression of oncogenic Ras was induced in intestinal epithelial cells. Changes in cell morphology, E-cadherin protein expression, and E-cadherin localization were examined by light microscopy, Western blot, and immunofluorescence respectively. Expression of E-cadherin in human colorectal tumors was examined by immunohistochemistry.

RESULTS

Induction of oncogenic Ras results in an epithelial to mesenchymal transformation with loss of membranous E-cadherin expression and mis-localization to the cytoplasm. Removal of Ras stimulus or blockade of the MAP kinase pathway allowed reversion to a normal cellular phenotype and return of E-cadherin to the cell membrane. Loss of or decreased expression of E-cadherin was observed in seven of eight colorectal tumors.

CONCLUSIONS

Oncogenic Ras contributes to malignant transformation and altered E-cadherin expression in intestinal epithelial cells. Similar dysregulation of E-cadherin is found in human colorectal tumors. Ras effects on E-cadherin are critical to malignant transformation in our in-vitro model and may be an important event in human colorectal tumors.

Training and quality assurance for rectal cancer: 20 years of data is enough

Rectal cancer is a common disease with a high rate of mortality. During the past 20 years, substantial improvements have been made in the surgical, pathological, radiological, and oncological approaches used to treat this disease, but there is good evidence for continuing suboptimum performances among the teams that treat patients with colorectal cancers. Studies involving more than 4000 patients show that large reductions in local recurrences and a 20% increase in survival can be achieved with high-quality surgical and pathological training in total mesorectal excision. New developments in radiology and oncology may further increase this benefit.

Gene therapy for colorectal cancer

Colorectal cancer is an important public health problem worldwide. Gene therapy has therapeutic potential for patients with advanced or recurrent colorectal cancer, incurable by conventional treatments. To date, many strategies of gene therapy have been explored, including mutant gene correction, prodrug activation, immune stimulation and genetically-modified oncolytic viruses. Although the preclinical results of gene therapy for colorectal cancer have shown promise, gene therapy is still at an early stage of clinical development and has not yet shown a significant therapeutic benefit for patients. The main obstacles for introduction of gene therapy to patients are poor targeting selectivity of the vectors and inefficient gene transfer. As the science supporting tumour-selective vectors evolves, gene therapy may expand rapidly in the clinical practice of colorectal cancer treatment.