Colorectal cancer: another complication of diabetes mellitus?

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

BACKGROUND

Poor diet increases the risk of both colorectal cancer and type 2 diabetes. We investigated the role of diet in the association between diabetes and colorectal cancer.

METHODS

We analyzed data from 484,020 individuals, aged 50-71 years who participated in the prospective National Institutes of Health-AARP Diet and Health Study and were cancer free at baseline (1995-1996). History of diabetes was self-reported. Diet quality was measured with the Healthy Eating Index-2005 (HEI-2005), using a self-administered food-frequency questionnaire. Cox regression models were constructed to estimate the hazard ratios (HR) and 95% confidence intervals (CI) of first primary incident colorectal cancer, overall and by anatomical location.

RESULTS

During an average follow-up of 9.2 years, we identified 7,598 new cases of colorectal cancer. After controlling for non-dietary confounders, diabetes was associated with increased risk of colorectal cancer (HR 1.27, 95% CI: 1.18, 1.36). Further adjustment for diet quality did not attenuate this association. Diabetes was associated with a HR of 1.23 (95% CI: 1.07, 1.40) in individuals with good diet (quartile 4 of HEI-2005) and 1.58 (95% CI: 1.34, 1.86) in those with poor diet (quartile 1 of HEI-2005), compared to those with no diabetes and good diet. Moreover, diabetes was associated with a stronger risk of proximal than distal colon cancer (HR: 1.33 vs. HR: 1.20), while poor diet was associated with a weaker risk of proximal colon cancer (HR: 1.18 vs. HR: 1.46).

CONCLUSION

Diabetes and poor diet, independently and additively are associated with the increased risk of colorectal cancer.

Impact of diabetes on overall and cancer-specific mortality in colorectal cancer patients

PURPOSE

Diabetes is associated with increased risk of developing colorectal cancer (CRC), but its effect on overall and cancer-specific mortality in CRC patients has been little investigated. The aim of this study was to assess the influence of diabetes on overall and cancer-specific mortality in Italian CRC patients.

METHODS

Cases of adult (≥15 years) CRC, diagnosed in 2003-2005, most followed-up to the end of 2008, were randomly selected from the Italian Cancer Registries database. Diabetic status, sex, age, tumor stage, subsite, treatment, morphology, and grade were obtained by consultation of patient clinical records. Poisson multivariable regression models, adjusted for potential confounding variables, were used to estimate hazard ratios (HRs) for all-cause and CRC-specific mortality, according to diabetic status.

RESULTS

A total of 1,039 CRC cases with known fasting glucose or diabetic status, archived in 7 cancer registries, was analyzed. Compared to non-diabetics, diabetics (specific diagnosis or glucose ≥126 mg/dl) were older and less likely to receive adjuvant therapy. Diabetics were at higher risk of all-cause death [HR 1.41; 95 % confidence interval (CI) 1.18-1.70] and CRC death (HR 1.36; 95 % CI 1.11-1.67), with no differences by sex or subsite.

CONCLUSIONS

Diabetes was significantly associated with increased overall and CRC-specific mortality. Our findings indicate that diabetes is a negative prognostic factor for CRC and suggest that in patients with CRC, diabetes prevention and treatments that stabilize the condition and control its complications might reduce mortality. Further studies are required to ascertain the mechanisms linking diabetes to greater mortality in CRC patients.

Prediabetes is associated with a high-risk colorectal adenoma

BACKGROUND

Type 2 diabetes mellitus is associated with an increased risk of colorectal neoplasia. However, association between prediabetes and colorectal adenoma has not been reported.

AIMS

The aim of this study was to evaluate the relationship between prediabetes and the presence of colorectal adenomas.

METHODS

Consecutive prediabetic subjects who underwent screening colonoscopy were enrolled at Kyung Hee University Hospital in Gangdong, Seoul, Korea, between June 2006 and May 2012. Non-prediabetic subjects were separately pooled from the database of the Center for Health Promotion between January 2012 and May 2012. Prediabetes was defined according to the recommendations of the American Diabetes Association. The prevalence of colorectal adenomas and their characteristics were compared between prediabetic and non-prediabetic groups.

RESULTS

The prevalence of colorectal adenoma was higher in prediabetic subjects than in non-prediabetic subjects (39.6 vs. 30.6 %, respectively, p = 0.019). Prediabetic subjects had more multiple and high-risk adenomas than the control group in non-matched analysis (p = 0.000, respectively). In age-matched analysis, the prevalence of multiple and high-risk adenomas were significantly higher in a prediabetic group than those in a control group (44.4 vs. 28.4 %, p = 0.034; 51.9 vs. 34.6 %, p = 0.026, respectively). Furthermore, prediabetes (odds ratio = 2.198; 95 % confidence interval = 1.042-4.637; p = 0.039) was found to be an independent risk factor for a high-risk adenoma by multivariate analysis.

CONCLUSIONS

The prevalence of multiple and high-risk colorectal adenomas is significantly higher in the prediabetic subjects than those in the control group. Furthermore, prediabetes was found to be an independent risk factor for a high-risk colorectal adenoma.

Insulin receptor membrane retention by a traceable chimeric mutant

Background

The insulin receptor (IR) regulates glucose homeostasis, cell growth and differentiation. It has been hypothesized that the specific signaling characteristics of IR are in part determined by ligand-receptor complexes localization. Downstream signaling could be triggered from the plasma membrane or from endosomes. Regulation of activated receptor's internalization has been proposed as the mechanism responsible for the differential isoform and ligand-specific signaling.

Results

We generated a traceable IR chimera that allows the labeling of the receptor at the cell surface. This mutant binds insulin but fails to get activated and internalized. However, the mutant heterodimerizes with wild type IR inhibiting its auto-phosphorylation and blocking its internalization. IR membrane retention attenuates AP-1 transcriptional activation favoring Akt activation.

Conclusions

These results suggest that the mutant acts as a selective dominant negative blocking IR internalization-mediated signaling.

The shape of the placental surface at birth and colorectal cancer in later life

OBJECTIVES

Many chronic diseases, including certain cancers, may originate through variations in the supply of nutrients to the fetus. These variations change gene expression and permanently set the structure and function of the body, a process known as programming. Fetal nutrition depends on the mother's metabolism and nutritional reserves, and on the placenta's ability to transfer nutrients from mother to baby. In this study, we examine how colorectal cancer is related to maternal and placental characteristics.

METHODS

We ascertained 275 cases of colorectal cancer among the 20,431 people in the Helsinki Birth Cohort, who were born during 1924-1944 and whose body size at birth was recorded, together with the shape and size of the placenta.

RESULTS

Hazard ratios for colorectal cancer increased as the placental surface became longer and more oval. The hazard ratio was 2.3 (95% CI 1.2-4.7) among people in whom the difference between the length and breadth of the surface exceeded 6 cm, compared with those in whom there was no difference. Colorectal cancer was unrelated to other placental measurements or to body size at birth.

CONCLUSION

An oval placental surface at birth is associated with later colorectal cancer. The shape of the placental surface is determined by events at around 8-12 weeks gestation. We speculate that, if the spiral arteries open prematurely, the surface becomes more oval and the fetus is at risk of oxidative damage at a time when the colon is differentiating.

Diabetes mellitus and the occurrence of colorectal cancer: an updated meta-analysis of cohort studies

BACKGROUND

Recently, it has been found that diabetes patients have a higher incidence of colorectal cancer than the general population, but epidemiological studies examining a potential relationship between the two have produced inconsistent conclusions. Thus, we set out to perform a meta-analysis of cohort studies to evaluate the association between diabetes and colorectal cancer.

MATERIALS AND METHODS

Using "diabetes," "colorectal cancer," and associated key words, we performed a systematic review of published cohort studies in multiple databases, including MEDLINE, EMBASE, ISI Web of Knowledge databases, OVID, CNKI, CBMD ISC, WANFANG, and CQVIP. We then applied stringent inclusion and exclusion criteria to identify which studies to include in our analysis. STATA version 12.0 software (StataCorp., College Station, TX) was used to conduct statistical analysis, including consolidated statistics calculations, tests for heterogeneity, and publication bias evaluations.

RESULTS

We obtained a total of 532 potential articles. In accordance with our inclusion and exclusion criteria, we selected 29 articles for the meta-analysis. The analysis of extracted information indicated that diabetes is a risk factor for the development of colorectal cancer (relative risk 1.22, 95% confidence interval 1.19-1.26). Subgroup analyses by control populations, regions, gender, follow-up time, and colorectal cancer site also support this finding.

CONCLUSIONS

The risk of individuals with diabetes to develop colorectal cancer is 1.22 times higher than that of individuals without diabetes. The positive association remains consistent for both men and women and for studies carried out in North America, Europe, and Asia, as well as for different follow-up times.

Selenium supranutrition: are the potential benefits of chemoprevention outweighed by the promotion of diabetes and insulin resistance?

Selenium was considered a toxin until 1957, when this mineral was shown to be essential in the prevention of necrotic liver damage in rats. The hypothesis of selenium chemoprevention is principally formulated by the observations that cancer incidence is inversely associated with selenium status. However, recent clinical and epidemiological studies demonstrate a role for some selenoproteins in exacerbating or promoting other disease states, specifically type 2 diabetes, although other data support a role of selenium in stimulating insulin sensitivity. Therefore, it is clear that our understanding in the role of selenium in glucose metabolism and chemoprevention is inadequate and incomplete. Research exploring the role of selenium in individual healthcare is of upmost importance and possibly will help explain how selenium is a double-edged sword in the pathologies of chronic diseases.

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

OBJECTIVE

Studies on the relationship between diabetes and colorectal cancer (CRC) are inconsistent. It is also unclear whether CRC risk elevation for individuals with diabetes is similar for males and females. Using data from Newfoundland and Labrador (NL), the province with the highest CRC incidence and diabetes prevalence in Canada, we assessed and compared the risk elevation of CRC for males and females with diabetes, overall and by anatomic subsite.

METHODS

A population-based retrospective cohort study including a study sample of 122,228 individuals aged ≥30 years was conducted using administrative health databases over a 10.5-year period (October 1, 1996 to March 31, 2007). Hazard ratios were estimated using Cox proportional hazard models.

RESULTS

In comparison with non-diabetes counterparts, both males and females with diabetes were at a significantly elevated risk of overall CRC, with corresponding hazard ratios of 1.38 and 1.52, respectively. For males, diabetes significantly increased the risk of proximal and distal colon cancers, but not of rectal cancer. For females, diabetes significantly increased the risk of proximal colon and rectal cancers, but not of distal colon cancer. The results suggest that there is a stronger association between diabetes and CRC for females than for males, and the association did not change after adjusting for overweight/obesity.

CONCLUSIONS

Diabetes led to a greater risk of CRC in both the male and female population in NL. Risk was subsite-specific and varied by sex. Future research should examine reasons for the observed diabetes-associated CRC risk to support CRC prevention strategies among the diabetes population.

Perioperative exercise for chronic liver injury patients with hepatocellular carcinoma undergoing hepatectomy

BACKGROUND

The aim of this study was to examine the outcomes of exercise therapy in patients with hepatocellular carcinoma who underwent hepatectomy.

METHODS

Fifty-one patients with hepatocellular carcinoma were randomized to diet therapy alone (n = 25) or to exercise in addition to diet therapy (n = 26). Exercise at the anaerobic threshold of each patient was started 1 month preoperatively, resumed from 1 week postoperatively, and continued for 6 months.

RESULTS

Whole body mass and fat mass in the exercise group compared with the diet group were significantly decreased at 6 months postoperatively. Fasting serum insulin and the homeostasis model assessment score were also significantly decreased. At 6 months, anaerobic threshold and peak oxygen consumption were significantly increased, while serum insulin and insulin resistance were significantly improved in a high-frequency exercise subgroup compared with a low-frequency group.

CONCLUSIONS

Perioperative exercise therapy for patients with hepatocellular carcinoma with liver dysfunction may improve insulin resistance associated with hepatic impairment and suggests a benefit to the early resumption of daily exercise after hepatectomy.

Diabetes mellitus and cancer risk: review of the epidemiological evidence

Diabetes mellitus and cancer are diseases of epidemic proportions across the globe. These diseases are influenced by many factors, both genetic and environmental. A possible association between diabetes and cancer risk has long been speculated. Increased incidence of several cancers has been observed in diabetes patients, notably pancreatic, hepatic, colorectal, breast, urinary tract, and endometrial cancers. In contrast, a decreased incidence of prostate cancer is observed in diabetes patients, implying a protective effect. Precise knowledge of the complex associations and interactions between these two conditions is of great importance for their prevention and treatment. Multiple potential mechanisms have been proposed, but they have tended to be site-specific. Possible common mechanisms for a biological link between diabetes and cancer include hyperinsulinemia, hyperglycemia, and inflammation. Today, 366 million people live with diabetes globally, and this figure is expected to increase. Thus, if diabetes is associated with even a small increase in cancer risk, this may have important consequences at the population level. The aim of this review is to summarize recent epidemiological evidence of an association between diabetes and total cancer and specific sites of cancer, and to consider causal associations between these diseases.

Diabetes mellitus and the incidence and mortality of colorectal cancer: a meta-analysis of 24 cohort studies

AIM

The incidence and mortality of colorectal cancer (CRC) were quantified in persons with and without diabetes mellitus (DM).

METHOD

Medline and Embase were searched for articles published before July 2010. Cohort studies that evaluated incidence and mortality of DM and CRC were included. The initial search identified 1887 titles, of which 24 articles met the inclusion criteria. We defined the relative risk (RR) as the metric of choice; 95% confidence intervals (CIs) were calculated with a random-effects model.

RESULTS

There was an increase in the RR of developing CRC in persons with DM compared with those without DM (RR 1.28; 95% CI 1.19-1.39), without heterogeneity between studies (P(heterogeneity) = 0.13). The association between duration of DM and CRC incidence was stronger in the 11-15-year group (RR 1.51; 95% CI 1.12-2.03) than in the <10-year group (RR 1.05; 95% CI 0.90-1.22) and the >15-year group (RR 1.25; 95% CI 0.80-1.94), and there was significant heterogeneity among subgroups (P(heterogeneity) = 0.01). In studies reporting standardized incidence ratios (SIRs), there was an increased incidence of CRC with DM (RR 1.27; 95% CI 1.14-1.42; P(heterogeneity) = 0.09), and the association was stronger among men (RR 1.47; 95% CI 1.15-1.86) than women (RR 1.08; 95% CI 1.00-1.17); there was significant heterogeneity among gender (P(heterogeneity) = 0.01).

CONCLUSION

This meta-analysis suggests that individuals with DM have a significant increase in risk of developing CRC.

Genomic instability in patients with type 2 diabetes mellitus on hemodialysis

Objective

A previous study by our research group evaluated the levels of DNA damage using the comet assay in hemodialysis patients with type 2 diabetes mellitus. The same blood samples were also evaluated using the cytochalasin B micronucleus assay. A comparison of the results of the two assays is presented here.

Methods

Whole blood samples were collected from 22 type 2 diabetes mellitus patients on hemodialysis and from 22 control subjects. Samples were collected from patients early in the morning on Mondays, before the first weekly hemodialysis session. The cytokinesis-block micronucleus assay (CBMN) was used to evaluate genomic instability.

Results

The frequencies of micronuclei and nuclear buds were higher in patients than in controls (p-value = 0.001 and p-value < 0.001, respectively). There was a correlation between the frequency of micronuclei and DNA damage with the results of the comet assay (p-value < 0.001). The difference in the frequency of micronuclei and nuclear buds between patients and controls was more pronounced in the group with higher median comet values than in the group with lower comet values.

Conclusion

Our results suggest that the increased rates of DNA damage as measured by the comet assay and influenced by the weekly routine therapy of these patients has a mutagenic effect, thereby increasing the risk of cancer in this group.

Nutrition, metabolism and colorectal cancer

Colorectal cancer and myocardial infarction are associated at population level and in autoptic studies. Furthermore, they share many blood variables: cholesterol, triglycerides and HDL cholesterol, fructosamine, glycated haemoglobin and glycated apolipoprotein B. These blood variables are intermediates between dietary, mainly saturated fats and high glycemic index and load diets, and colorectal cancer and myocardial infarction. Blood intermediate variables can be used in dietary trials as outcomes, and even to throw light on the pathogenesis of both diseases.

Age- and sex-specific risks of colorectal cancers in diabetic patients

Diabetes has been reported to increase the risk of colorectal neoplasm in most but not all studies. However, the data on age- and sex-specific incidence rates and relative risks associated with diabetes are limited. We carried out this population-based cohort study to investigate the overall sex- and age-specific risks of colorectal cancer in association with diabetes. Diabetic patients (n = 615,532) and age- and sex-matched control individuals (n = 614,871), selected from the claim datasets, were followed up from 2000 to 2006. The rates of admission due to colon and rectum cancers were estimated using the person-years approach, and the age- and sex-specific hazard ratio (HR) for both the malignancies were determined using the Cox regression model. The overall incidence rate of colon cancer was 9.94 per 10,000 patient-years for the diabetic patients, as opposed to 7.84 per 10,000 patient-years for the control-group patients. The corresponding observation for rectal cancer was 7.16 and 6.28 per 10,000 patient-years. Diabetic patients aged ≥ 45 years had significantly high HRs for developing colon cancer (1.20-1.45-fold). We also noted a significantly high HR of rectal cancer in diabetic men (1.18-fold) aged ≥ 45 years, but not in diabetic women. In conclusion, diabetes may significantly increase the risk of colorectal cancer, especially in patients aged 45-64 years. Diabetologists should keep this relationship in mind while treating middle-aged diabetic men and should also advise these patients to undergo regular screening tests for colorectal cancer.

Disease-specific mortality among stage I-III colorectal cancer patients with diabetes: a large population-based analysis

AIMS/HYPOTHESIS

The aim of our study was to investigate overall and disease-specific mortality of colorectal cancer patients with diabetes.

METHODS

In this population-based study, we included all colorectal cancer patients, newly diagnosed with stage I-III cancer, between 1997 and 2007 in the registration area of the Eindhoven Cancer Registry. Stage of cancer, cancer treatment and comorbidities were actively collected by reviewing hospital medical records. Data on patients with and without diabetes were linked to Statistics Netherlands to assess vitality, date of death and underlying cause of death. Follow-up of all patients was completed until 1 January 2009.

RESULTS

We included 6,974 patients with colon cancer and 3,888 patients with rectal cancer, of whom 820 (12%) and 404 (10%), respectively, had diabetes at the time of cancer diagnosis. During follow-up, death occurred in 611 (50%) of 1,224 cancer patients with diabetes and 3,817 (40%) of 9,638 cancer patients without diabetes. Multivariate Cox regression analyses, adjusted for age, sex, socioeconomic status, stage, lymph nodes examined, adjuvant therapy and year of diagnosis, showed that overall mortality was significantly higher for colon (HR 1.12, 95% CI 1.01, 1.25) and rectal (HR 1.21, 95% CI 1.03, 1.41) cancer patients with diabetes than for those without. Disease-specific mortality was only significantly increased for rectal cancer patients (HR 1.30, 95% CI 1.06, 1.60).

CONCLUSIONS/INTERPRETATION

Diabetes at the time of rectal cancer diagnosis was independently associated with an increased risk of colorectal cancer mortality compared with no diabetes, suggesting a specific interaction between diabetes and rectal cancer. Future in-depth studies including detailed diabetes- and cancer-related variables should elucidate pathways.

Diabetes and cancer (2): evaluating the impact of diabetes on mortality in patients with cancer

In this paper we address methodological aspects of aetiological importance in the link between diabetes and mortality in patients with cancer. We identified nine key points on the cancer pathway at which confounding may arise-cancer screening use, stage at diagnosis, cancer treatment selection, cancer treatment complications and failures, peri-treatment mortality, competing risks for long-term mortality, effects of type 2 diabetes on anti-cancer therapies, effects of glucose-lowering treatments on cancer outcome and differences in tumour biology. Two types of mortality studies were identified: (1) inception cohort studies that evaluate the effect of baseline diabetes on cancer-related mortality in general populations, and (2) cohorts of patients with a cancer diagnosis and pre-existing type 2 diabetes. We demonstrate, with multiple examples from the literature, that pre-existing diabetes affects presentation, cancer treatment, and outcome of several common cancer types, often to varying extents. Diabetes is associated with increased all-cause mortality in cancer patients, but the evidence that it influences cancer-specific mortality is inconsistent. In the absence of data that address the potential biases and confounders outlined in the above framework, we caution against the reporting of cancer-related mortality as a main endpoint in analyses determining the impact of diabetes and glucose-lowering medications on risk of cancer.

Diabetes mellitus and the incidence of colorectal cancer: an updated systematic review and meta-analysis

AIM

The purpose of this study was to determine whether diabetes mellitus is associated with an increased risk of colorectal cancer.

METHODS

Relevant studies were identified in MEDLINE and EMBASE (up until November 1st, 2011). Inclusion criteria were original, peer-reviewed publications, with case-control and cohort studies (for studies on diabetes mellitus and colorectal cancer). Summary relative risks with 95% confidence intervals were calculated with a random-effects model.

RESULTS

Twenty-four studies including eight case-control and 16 cohort studies, with a total of 3,659,341 participants, were included in this updated systematic review and meta-analysis, and all involved diabetes mellitus and colorectal cancer risk. Meta-analysis of the 24 included studies indicated that diabetes was associated with an increased risk of colorectal cancer, compared with no diabetes (summary RR of colorectal cancer incidence = 1.26, 95% CI = 1.20-1.31), without heterogeneity between studies (P(heterogeneity) = 0.296). Sub-group analyses found that these results were consistent between case-control and cohort studies and among studies conducted in different areas. The association between diabetes and colorectal cancer incidence did not differ significantly by sex and sub-sites. Insulin therapy was also positively associated with risk of colorectal cancer (summary RR = 1.61, 95% CI 1.18-1.35), with evidence of heterogeneity between studies (P(heterogeneity) = 0.014).

CONCLUSIONS

Our findings further support a relationship between diabetes and increased risk of colon and rectal cancer in both women and men, and insulin therapy for diabetes may increase this risk.

Diabetes mellitus is an independent risk factor for colorectal cancer

BACKGROUND

Epidemiological studies have suggested positive associations between diabetes and colorectal cancer. However, the findings were inconsistent, especially regarding specific sex or cancer subsite.

AIMS

To conduct a systematic review with meta-analysis to examine the association of diabetes mellitus with risk of colorectal cancer and to investigate whether the association is dependent on sex, cancer subsite, race/ethnicity, or duration of diabetes.

METHODS

Relevant studies were identified by searching Pubmed to May 12, 2011. The reference lists of identified articles were also reviewed. Two authors independently selected the studies and extracted relevant data. The study quality was assessed.

RESULTS

Thirty-nine studies (28 cohort studies and 11 case-control studies) were included in the final analysis. Compared with non-diabetic subjects, the pooled risk estimate of colorectal cancer for diabetic subjects was 1.29 (95% CI = 1.23-1.35). The subgroup analyses revealed that the risk was significantly increased for both genders, for every cancer subsite, and for both short duration and long duration of diabetes. Exposure to diabetes increased the risk of colorectal cancer for White and Asian, whereas there was no evidence of such an association either among Black or native Hawaiians.

CONCLUSIONS

Our results confirmed that subjects with diabetes are at modestly increased risk of developing colorectal cancer.

The impact on clinical outcome of high prevalence of diabetes mellitus in Taiwanese patients with colorectal cancer

BACKGROUND

Both colorectal cancer (CRC) and diabetes mellitus (DM) are important public health problems worldwide. As there are controversies about survival impact on CRC patients with preexisting DM, the purpose of the present study is to evaluate the incidence and the survival impact of preexisting DM on the long-term outcomes of patients with CRC in Taiwan.

METHODS

From January 2002 to December 2008, 1,197 consecutive patients with histologically proven primary CRC, who received surgical treatment at a single institution, were enrolled. The clinicopathologic features between these patients with and without DM were retrospectively investigated. Moreover, we intended to analyze the impact of DM on overall survival (OS) and cancer-specific survival (CSS) rates.

RESULTS

Of 1,197 CRC patients, 23.6% of patients had either a reported history of DM or were currently taking one or more diabetes-controlling medications. CRC patients with DM were significantly older than those without DM (P <0.001), and had a higher incidence of cardiac disease and higher body mass index than those without DM (both P<0.001). There were no significant differences in gender, tumor size, tumor location, histological type, AJCC/UICC cancer stage, vascular invasion, perineural invasion, comorbidity of pulmonary disease or renal disease, and OS, and CSS between two groups. Additionally, DM patients had a higher incidence of second malignancy than patients without DM (9.54% vs 6.01%, P=0.040).

CONCLUSIONS

A considerably high prevalence of DM in CRC patients but no significant impact of DM on survival was observed in the single-institution retrospective study, regardless of cancer stages and tumor locations. Therefore, treatment strategies for CRC patients with DM should be the same as patients without DM.

Diabetes and cancer I: risk, survival, and implications for screening

Type 2 diabetes mellitus (DM) and cancer are common diseases that are frequently diagnosed in the same individual. An association between the two conditions has long been postulated. Here, we review the epidemiological evidence for increased risk of cancer, decreased cancer survival, and decreased rates of cancer screening in diabetic patients. The risk for several cancers, including cancers of the pancreas, liver, colorectum, breast, urinary tract, and endometrium, is increased in patients with DM. In a pooled risk analysis weighting published meta-analytic relative risk (RR) for individual cancer by differences in their incidence rates, we found a population RR of 0.97 (95 % CI, 0.75-1.25) in men and 1.29 (95 % CI, 1.16-1.44) in women. All meta-analyses showed an increased relative risk for cancer in diabetic men, except studies of prostate cancer, in which a protective effect was observed. The relationship between diabetes and cancer appears to be complex, and at present, a clear temporal relationship between the two conditions cannot be defined. DM also impacts negatively on cancer-related survival outcomes and cancer screening rates. The overwhelming evidence for lower cancer screening rates, increased incidence of certain cancers, and poorer prognosis after cancer diagnosis in diabetic patients dictates a need for improved cancer care in diabetic individuals through improved screening measures, development of risk assessment tools, and consideration of cancer prevention strategies in diabetic patients. Part two of this review focuses on the biological and pharmacological mechanisms that may account for the association between DM and cancer.

Systematic review and meta-analysis of insulin therapy and risk of cancer

Recent epidemiological studies suggest that treatment with insulin may promote cancer growth. The present systematic review and meta-analysis of published observational studies was conducted to assess the risk of cancer during treatment with insulin. A search of online database through January 2011 was performed and examined the reference lists of pertinent articles, limited to observational studies in humans. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated with a random-effects model. Fifteen studies (five case-control and ten cohort studies) were included, with 562,043 participants and 14,085 cases of cancer. Insulin treatment was associated with an increased risk of overall cancer [summary RR (95% CI)=1.39 (1.14, 1.70)]. Summary RR (9% CI) for case-control studies was 1.83 (0.99, 3.38), whereas RR for cohort studies was 1.28 (1.03, 1.59). These results were consistent between studies conducted in the USA and in Europe. For studies that included combined type 1 and 2 diabetes, the summary estimate was stronger than studies including only type 2 diabetes mellitus. The association between insulin treatment and cancer was stronger for pancreatic cancer [summary RR (95% CI)=4.78 (3.12, 7.32)] than for colorectal cancer [1.50 (1.08, 2.08)]. Insulin treatment was not associated with breast, prostate, and hepatocelluar cancer, and their effect estimates were not statistically significant. Our findings support an association between insulin use and increased risk of overall, pancreatic, and colorectal cancer.

The association of diabetes mellitus with liver, colon, lung, and prostate cancer is independent of hypertension, hyperlipidemia, and gout in Taiwanese patients

Studies have shown an association between diabetes and cancer in Western countries; but this, as well as the influence of associated metabolic factors, must be confirmed by a prospective study in other population groups. This study aimed to investigate whether the strong association of cancer and diabetes is independent from the influence of hypertension, dyslipidemia, and gout in the Taiwanese population. A total of 985,815 study subjects were identified from the National Health Insurance in 1997 and followed up from 1998 to 2009. The demographic characteristics between patients with diabetes and cancer, including age, sex, hypertension, dyslipidemia, and gout, were analyzed using the χ(2) test. Cox proportional hazard regression models were used to determine the independent effects of diabetes on the risks of cancer. A total of 104,343 diabetic patients were followed up from 1998 to 2009. After adjusting for sex, age, hypertension, dyslipidemia, and gout, the incidences of cancer at any site and in the liver, colon, lungs, and prostate in diabetic patients were independently higher, with risk ratios of 1.56 (95% confidence interval [CI], 1.43-1.71), 1.67 (95% CI, 1.39-2.01), 1.75 (95% CI, 1.49-2.06), 1.54 (95% CI, 1.26-1.88), and 1.56 (95% CI, 1.19-2.04), respectively. Only breast cancer did not show any clinical significance. There was an increased incidence of cancer at any site in the diabetic patients compared with nondiabetic subjects. The most common cancers were liver, colon, lung, breast, and prostate cancer; and except for breast cancer, their incidences increased independently of hypertension, dyslipidemia, and gout in patients with diabetes.

The complex dual diagnosis of diabetes and cancer

Diabetes and cancer are two of the top three killers in the United States. As the number of people surviving cancer increases, more patients will be living with both cancer and diabetes. This integrative review of the literature will provide an overview of diabetes, cancer, and the complex interactions between the two. A literature search was conducted and three main areas were identified that warrant additional discussion: the relationship between glucocorticoids and hyperglycemia, glucose control in the management of diabetes in patients with cancer, and an increased risk of certain cancers with the comorbid condition of diabetes. The hope is that, through additional research, evidence-based practice guidelines can be developed to direct the care of these challenging comorbid conditions. To provide holistic care to patients, diabetes and cancer management must be incorporated into healthcare curricula and should be an essential part of clinical diabetes educator certification.

Is diabetes mellitus an independent risk factor for colon cancer and rectal cancer?

OBJECTIVES

Diabetes mellitus (DM) has been associated with an increased risk of colorectal cancer (CRC). The American College of Gastroenterology Guidelines for Colorectal Cancer Screening 2008 recommend that clinicians be aware of an increased CRC risk in patients with smoking and obesity, but do not highlight the increase in CRC risk in patients with DM. To provide an updated quantitative assessment of the association of DM with colon cancer (CC) and rectal cancer (RC), we conducted a meta-analysis of case-control and cohort studies. We also evaluated whether the association varied by sex, and assessed potential confounders including obesity, smoking, and exercise.

METHODS

We identified studies by searching the EMBASE and MEDLINE databases (from inception through 31 December 2009) and by searching bibliographies of relevant articles. Summary relative risks (RRs) with 95% confidence intervals (CIs) were calculated with fixed- and random-effects models. Several subgroup analyses were performed to explore potential study heterogeneity and bias.

RESULTS

DM was associated with an increased risk of CC (summary RR 1.38, 95% CI 1.26-1.51; n=14 studies) and RC (summary RR 1.20, 95% CI 1.09-1.31; n=12 studies). The association remained when we limited the meta-analysis to studies that either controlled for smoking and obesity, or for smoking, obesity, and physical exercise. DM was associated with an increased risk of CC for both men (summary RR 1.43, 95% CI 1.30-1.57; n=11 studies) and women (summary RR 1.35, 95% CI 1.14-1.53; n=10 studies). For RC, there was a significant association between DM and cancer risk for men (summary RR 1.22, 95% CI 1.07-1.40; n=8 studies), but not for women (summary RR 1.09, 95% CI=0.99-1.19; n=8 studies).

CONCLUSIONS

These data suggest that DM is an independent risk factor for colon and rectal cancer. Although these findings are based on observational epidemiological studies that have inherent limitations due to diagnostic bias and confounding, subgroup analyses confirmed the consistency of our findings across study type and population. This information can inform risk models and specialty society CRC screening guidelines.

Diabetes mellitus and incidence and mortality of colorectal cancer: a systematic review and meta-analysis of cohort studies

Increasing evidence suggests that a history of diabetes mellitus (DM) may be associated with an increased risk of colorectal cancer (CRC). To provide a quantitative assessment of the association between DM and risk of CRC, We evaluated the relation between DM and incidence and mortality of CRC in a systematic review of cohort studies. Full publications of cohort studies were identified in MEDLINE, EMBASE and Science Citation Index Expanded, through February 28, 2011. Summary relative risks (SRRs) with 95% confidence intervals (CIs) were summarized using a random-effects model. Between-study heterogeneity was assessed using the Cochran's Q and I2 statistics. A total of 41 cohort studies (35 articles) were included in this systematic review. Combining 30 cohort studies which presented results on diabetes and CRC incidence, diabetes was associated with an increased incidence of CRC (SRRs 1.27, 95% CI: 1.21-1.34), with evident heterogeneity among studies (P=0.002, I2=48.4%). Subgroup analysis and meta-regression analysis by controlling the confounders showed that the increased incidence of CRC was independent of geographic locations, sex, family history of colorectal cancer, smoking, physical activity and body mass index. Diabetes was also positively associated with CRC mortality (SRR 1.20, 95% CI: 1.03-1.40), with evidence of heterogeneity between studies (P<0.001, I2=81.4%). Results from this systematic review support that compared to non-diabetic individuals, diabetic individuals have an increased risk of CRC.

Type 2 diabetes mellitus and colorectal cancer: meta-analysis on sex-specific differences

Although there is consent concerning a higher risk for colorectal cancer (CRC) amongst patients with type 2 diabetes mellitus (T2DM), there remains uncertainty regarding potential sex differences in the strength of this association. We reviewed and summarised epidemiological studies assessing the sex-specific association of T2DM with the risk for CRC. All relevant studies published until 14th February 2011 were identified by a systematic search of MEDLINE, EMBASE, BIOSIS Previews and ISI Web of Knowledge databases and cross-referencing. We included observational studies that reported relative risk (RR) or odds ratio (OR) estimates with 95% confidence intervals (CIs) for the association between T2DM and CRC. Two authors independently extracted data and assessed study quality of each study in a standardised manner. Study-specific estimates were pooled for both sexes separately using random-effects models. A total of 29 eligible studies were used for meta-analysis. Overall estimates of relative risk (RR) were very similar amongst men (RR=1.29; 95%-confidence interval (CI): 1.19-1.140) and women (RR=1.34; 95%-CI: 1.22-1.47). In both men and women, risk estimates from case-control studies were slightly higher than those from cohort studies. Overall, T2DM is associated with a moderate increase in CRC risk in both men and women.

Nonalcoholic fatty liver disease: an independent risk factor for colorectal neoplasia

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of insulin resistance (IR), and IR is associated with an increased risk of colorectal carcinoma (CRC). Increased echogenicity suggesting NAFLD is a frequent incidental finding on ultrasound examination. We aimed to systematically evaluate whether NAFLD is an independent risk factor for colonic neoplasia.

PATIENTS AND METHODS

One thousand two hundred and eleven patients (603 males, 60.6 ± 9.6 years; 608 females, 61.1 ± 10.3 years) who underwent screening colonoscopy according to national screening recommendations for CRC were evaluated in a cross-sectional study. Colorectal adenomas were classified as tubular adenoma, advanced adenoma (villous features, size ≥ 1 cm or high-grade dysplasia) or carcinoma. NAFLD was diagnosed by increased echogenicity on ultrasound examination after serological exclusion of infectious, immunological, hereditary or alcoholic aetiology.

RESULTS

Nonalcoholic fatty liver disease was diagnosed in 367 (60.8%) males and in 265 (43.5%) females. The total rate of adenomas was increased in subjects with NAFLD (243/367 vs. 107/236 in males, P = 0.010; 94/265 vs. 78/343 in females; P = 0.014). In particular, more tubular adenomas (127/367 vs. 56/236; P = 0.006), adenomas of the rectum (40/367 vs. 8/236; P = 0.004) and more cancers (6/367 vs. 1/236; P < 0.001) were observed in males with NAFLD. In females with NAFLD, more tubular adenomas (59/265 vs. 48/343; P = 0.011) and adenomas of the proximal colon (51/265 vs. 40/343; P = 0.041) were observed. Multivariate regression analyses demonstrated an independent association of colorectal adenomas with hepatic steatosis after adjustment for age, sex, body mass index and glucose intolerance (OR 1.47; 95% CI 1.079-2.003; P = 0.015).

CONCLUSION

Patients with NAFLD undergoing screening colonoscopy reveal significantly more CRC precursor lesions and early CRC compared with subjects without NAFLD. This elevated risk is independent from other manifestations of IR. These findings suggest that detecting fatty liver on ultrasound should heighten the awareness for referral to screening colonoscopy.

Type 2 diabetes and cancer: what is the connection?

Epidemiological studies have demonstrated an association between type 2 diabetes and cancer. Type 2 diabetes is characterized by insulin resistance and hyperinsulinemia. Hyperinsulinemia may lead to cancer through insulin's effect on its cognate receptor and the insulin-like growth factor system. The effects of insulin and insulin-like growth factor I on cancer development and progression have been demonstrated in animal and human studies. Type 2 diabetes has been positively associated with cancers of the breast, colon, and pancreas. An inverse relationship has been observed between type 2 diabetes and prostate cancer, and this may be due to lower testosterone levels in men with type 2 diabetes. Medications used to treat type 2 diabetes may affect cancer cells directly or indirectly by affecting serum insulin levels. Hyperinsulinemia may be an important risk factor for cancer as well as a target for cancer therapy.

Basal insulin treatment in type 2 diabetes

Insulin glargine is the first 24-h recombinant DNA insulin analog introduced to the market. Substitution of glycine for asparagine and addition of two arginine residues raise the isoelectric point of insulin glargine and result in microprecipitates, delaying absorption from subcutaneous tissue. This delayed absorption result in fairly flat 24-h insulin concentration profiles with no discernible peak. Large, multicenter, randomized, controlled trials in patients with type 2 diabetes show that although NPH insulin and insulin glargine are equally effective in lowering glycosylated hemoglobin (A1c) and fasting blood glucose, there is a clear advantage of insulin glargine over NPH insulin in reducing nocturnal and overall hypoglycemia. Lower risk of hypoglycemia with glargine was also consistently demonstrated by trials comparing insulin glargine and premixed analog insulins. These studies also showed greater reduction in A1c with twice-daily premixed insulins compared with glargine, when insulin glargine was administered without mealtime insulin coverage. Insulin glargine was also compared with another insulin analog, insulin detemir. Trials showed that both insulin analogs are equally effective in lowering A1c and have comparable risk of hypoglycemia. Trials comparing insulin glargine with glucagon-like peptide-1 agonists showed comparable significant reductions in A1c with both regimens. Insulin glargine is well tolerated, has low immunogenicity, reduced risks for acute myocardial infarction, and a lower risk of hypoglycemia compared with NPH insulin in individuals with type 2 diabetes.

Metabolic syndrome and its association with colorectal cancer: a review

Currently, significant amount of epidemiologic evidence is present to suggest that metabolic syndrome increases the risk of developing colorectal cancer. This evidence is based on studies of the evaluate determinants of the metabolic syndrome (obesity), clinical consequences of metabolic syndrome (type 2 diabetes and hypertension) and serum component of metabolic syndrome (hypertriglyceridemia, hyperglycemia and low high-density lipoprotein cholesterol), as well as markers of hyperinsulinemia. Although the exact pathogenesis of this relationship is unknown, it seems that hyperinsulinemia may play a pivotal role in increasing CRC risk.

Defining the molecular nexus of cancer, type 2 diabetes and cardiovascular disease

The metabolic syndrome is characterized by a state of metabolic dysfunction resulting in the development of several chronic diseases that are potentially deadly. These metabolic deregulations are complex and intertwined and it has been observed that many of the mechanisms and pathways responsible for diseases characterizing the metabolic syndrome such as type 2 diabetes and cardiovascular disease are linked with cancer development as well. Identification of molecular pathways common to these diverse diseases may prove to be a critical factor in disease prevention and development of potential targets for therapeutic treatments. This review focuses on several molecular pathways, including AMPK, PPARs and FASN that interconnect cancer development, type 2 diabetes and cardiovascular disease. AMPK, PPARs and FASN are crucial regulators involved in the maintenance of key metabolic processes necessary for proper homeostasis. It is critical to recognize and identify common pathways deregulated in interrelated diseases as it may provide further information and a much more global picture in regards to disease development and prevention. Thus, this review focuses on three key metabolic regulators, AMPK, PPARs and FASN, that may potentially serve as therapeutic targets.

Diabetes mellitus and increased risk of cancer: focus on metformin and the insulin analogs

Type 2 diabetes mellitus has been associated with an increased risk of hepatic, pancreatic, colon, endometrial, breast, and bladder cancer. Although a mechanism of action for the increased risk has been postulated, no definitive evidence has been completely elucidated in the medical literature. Results of recently released studies documented the use of specific antidiabetic drugs with increased rates of cancer. The insulin analog glargine was the focus of four observational studies published in 2009 that outlined an increase in the rates of cancer associated with its use. In contrast, the use of metformin has been shown to possibly decrease the rate of specific cancers when used in the treatment of type 2 diabetes. These data regarding cancer risk and antidiabetic drugs are contradictory and at this time are inconclusive. Until results of long-term randomized prospective studies are available to elucidate a correlation with cancer and insulin, we must continue treating diabetes in order to avert the long-term complications of the disease.

Diabetes mellitus negatively impacts survival of patients with colon cancer, particularly in stage II disease

PURPOSE

This retrospective study aimed to determine the effects of diabetes on overall survival (OS) and cancer-specific survival (CSS) in patients with newly diagnosed colon cancers, with particular focus on the impact of diabetes on survival at each stage of colon cancer.

METHODS

From January 1999 to January 2008, 2762 consecutive patients diagnosed with colon cancer in Taipei Veterans General Hospital were enrolled. The general characteristics as well as presence of diabetes prior to colon cancer diagnosis were identified. Cox proportional hazard analyses were used for prognostic factors determination; and survival was analyzed using the Kaplan-Meier method with log-rank test.

RESULTS

A total of 469 patients (17%) had diabetes at diagnosis of colon cancer. Patients with diabetes had baseline characteristics comparable to those without diabetes with the exception that the patients with diabetes were older (>65 years). Diabetes significantly and negatively impacted OS and CSS in multivariate analyses. After adjusting for possible confounding factors, the prognostic impact of diabetes on OS and CSS was particularly significant in patients with stage II colon cancer.

CONCLUSIONS

Diabetes is a poor prognostic factor in patients with newly diagnosed colon cancer, and it may directly impact the tumor behavior of stage II disease. Further study is required to elucidate the underlying pathophysiologic mechanisms.

Type 2 diabetes increases and metformin reduces total, colorectal, liver and pancreatic cancer incidences in Taiwanese: a representative population prospective cohort study of 800,000 individuals

BACKGROUND

Metformin protection against cancer risk in Orientals is uncertain. We examined the possible metformin effect on total, esophageal, gastric, colorectal (CRC), hepatocellular (HCC) and pancreatic cancers in a Taiwanese cohort.

METHODS

A representative sample of 800,000 was drawn from the Taiwanese National Health Insurance data of 2000. A cohort of 480,984 participants 20 years or older, diabetes-cancer-free on 1st January 2000 was formed and categorized as four groups by DM and metformin usage status. Eligible incident cancer events had to occur one year after the index date until the end of 2007. The Cox proportional-hazards model evaluated relative risk of cancer for treated DM patients with or without metformin. The covariates included age, gender, other oral anti-hyperglycemic medication, Charlson comorbidity index (CCI) score and metformin exposure dosage and duration.

RESULTS

With diabetes but no anti-hyperglycemic medication, cancer incidence density increased at least 2-fold for total, CRC and HCC. On metformin, total, CRC and HCC incidences decreased to near non-diabetic levels but to varying degrees depending on gender and cancer type (CRC in women, liver in men). Adjustment for other oral anti-hyperglycemic agents usage and CCI made the benefit of metformin more evident [hazard ratios (95% confidence intervals): total 0.12 (0.08-0.19), CRC 0.36 (0.13-0.98), liver 0.06 (0.02-0.16), pancreas 0.15 (0.03-0.79)]. There was a significant gender interaction with metformin in CRC which favored women. Metformin dosage for a significant decrease in cancer incidence was ≤ 500 mg/day.

CONCLUSIONS

Metformin can reduce the incidences of several gastroenterological cancers in treated diabetes.

Effect of diabetes mellitus on outcomes of colorectal cancer

Purpose

Many studies have revealed that diabetes mellitus (DM) increases a person's lifetime risk of colorectal cancer and that DM is associated with a worse outcome of colon cancer, but this association is controversial. In this study, we intended to examine the relationship between DM and the long-term outcomes of colorectal cancer.

Methods

A retrospective analysis was conducted on 657 patients who underwent surgery due to colorectal cancer between 1997 and 2004 at Korea Cancer Center Hospital. The operations were done by a single surgeon. With a median follow-up of 4.7 years, we analyzed differences in recurrence-free survival (RFS) and overall survival (OS) between patients with DM and those without DM.

Results

Of the 657 patients, 374 (57%) were males and 67 (10%) had DM. There was no difference in age at diagnosis, sex and pathologic stage of colorectal cancer according to the presence of DM. There were no difference in the RFS and the OS of colon cancer between the patients with DM and those without DM. At 5 years, the RFS was 71.3% in diabetic patients vs. 70.4% in non-diabetic patients (P = 0.480), and the OS was 68.8% in diabetic patients vs. 75.0% in non-diabetic patients (P = 0.498). There was no difference in the median survival between the groups (9.6 years in the diabetic group vs. 10.6 years in the non-diabetic group; P = 0.495).

Conclusion

In this study, we did not find any relation between the presence of DM and either the recurrence or the survival in cases of colorectal cancer. More studies to elucidate whether the influence of DM is directly related to a higher rate of cancer recurrence or survival are needed.

Insulin glargine and cancer risk: an opinion statement of the Endocrine and Metabolism Practice and Research Network of the American College of Clinical Pharmacy

Diabetes mellitus has reached epidemic proportions worldwide, eliciting extensive research on both the disease process and its treatment. Regardless of diabetes type, the progressive nature of the disease makes insulin the long-term mainstay of diabetes management. Recently, the insulin analog glargine was reported in several epidemiologic studies to be associated with an increased risk of cancer. Inconsistent study results and media attention have caused much angst and concern to health care professionals and the general population. A clear understanding of the current evidence is needed to adequately develop a patient-oriented risk:benefit assessment. Members of the Endocrine and Metabolism Practice and Research Network of the American College of Clinical Pharmacy evaluated available evidence to provide guidance and discussion on the risk of cancer with insulin glargine use. We believe the current link between insulin glargine and cancer is tenuous but merits further evaluation. An independent analysis of all available glargine clinical trial data should be performed, and a vigorous postmarketing safety study of glargine should be conducted. Until more substantial data are available, however, neither the choice of initial insulin therapy nor insulin maintenance regimens should be influenced by the current information linking insulin glargine to cancer.

Efficacy and safety of sodium phosphate for colon cleansing in type 2 diabetes mellitus

OBJECTIVES

The need for colonoscopy is common among diabetic patients. However, there are no standards per se for bowel preparation in patients with type 2 diabetes. In this study, we evaluated the efficacy, safety, and tolerability of sodium phosphate (NaP), and the quality of bowel cleansing in relation to glycemic control and late complications.

METHODS

A total of 50 consecutive type 2 diabetic patients and 50 non-diabetic patients underwent bowel preparation by NaP. Fasting blood glucose, sodium (Na), potassium (K), calcium (Ca), phosphorus (P), magnesium, and creatinine levels were measured on the procedure day. Patients were given a tolerability questionnaire regarding symptoms.

RESULTS

With regard to bowel preparation quality, optimal bowel cleansing was achieved in 35 (70%) diabetic and 47 (94%) non-diabetic patients (P = 0.002). Abdominal pain or discomfort during and an hour after the procedure was similar in both groups (P >0.05). The changes in Na, K, Ca, P and creatinine levels after NaP use did not reach statistical significance between the groups (P >0.05). In the diabetic patients, there was a significant correlation between the quality of bowel cleansing and mean age, duration of diabetes mellitus, level of hemoglobin A1c (HbA1c), fasting blood glucose level, and diabetic late complications (P <0.05).

CONCLUSION

These data suggest that NaP is safe and tolerable in diabetic patients, but the quality of bowel cleansing is worse than in non-diabetic patients. These observations support the concept that the quality of bowel cleansing in those with type 2 diabetes is closely related to the duration and regulation of the disease and the presence of late complications.

Associations of diabetes mellitus with site-specific cancer mortality in the Asia-Pacific region

BACKGROUND

Owing to the increasing prevalence of obesity and diabetes in Asia, and the paucity of studies, we examined the influence of raised blood glucose and diabetes on cancer mortality risk.

MATERIALS AND METHODS

Thirty-six cohort Asian and Australasian studies provided 367, 361 participants (74% from Asia); 6% had diabetes at baseline. Associations between diabetes and site-specific cancer mortality were estimated using time-dependent Cox models, stratified by study and sex, and adjusted for age.

RESULTS

During a median follow-up of 4.0 years, there were 5992 deaths due to cancer (74% Asian; 41% female). Participants with diabetes had 23% greater risk of mortality from all-cause cancer compared with those without: hazard ratio (HR) 1.23 [95% confidence interval (CI) 1.12, 1.35]. Diabetes was associated with mortality due to cancer of the liver (HR 1.51; 95% CI 1.19, 1.91), pancreas (HR 1.78; 95% CI 1.20, 2.65), and, less strongly, colorectum (HR 1.32; 95% CI 0.98, 1.78). There was no evidence of sex- or region-specific differences in these associations. The population attributable fractions for cancer mortality due to diabetes were generally higher for Asia compared with non-Asian populations.

CONCLUSION

Diabetes is associated with increased mortality from selected cancers in Asian and non-Asian populations.

Diabetes and risk of incident colorectal cancer in a prospective cohort of women

OBJECTIVE

To determine whether accounting for the time dynamics of diabetes exposure will change the risk estimates for colorectal cancer.

METHODS

We analyzed data from the 45, 516 women enrolled in the BCDDP follow-up cohort study. We used proportional hazards regression to obtain multivariable-adjusted risk estimates for incident colorectal cancer for prevalent diabetes at baseline and diabetes as a time-dependent variable.

RESULTS

Subjects with diabetes had a statistically significant increased risk of colorectal cancer compared to subjects without diabetes (RR = 1.60, 95% CI 1.18-2.18). When we defined exposure as duration of diabetes exposure at cohort exit, we found that in the first 4 years after diagnosis risk was essentially the same as in those never having had a diagnosis of diabetes. For those who had been diagnosed between 4 and 8 years previously, however, we observed a RR of 2.36 (95% CI 0.96-5.79), while longer duration of exposure was associated with smaller and then no change in risk compared to those without a diagnosis of diabetes.

CONCLUSIONS

These results are consistent with the theory that hyperinsulinemia can explain, at least in part, the association of diabetes with colorectal cancer, but in a time-dependent manner.

Colorectal cancer outcomes, recurrence, and complications in persons with and without diabetes mellitus: a systematic review and meta-analysis

BACKGROUND

Diabetes mellitus increases the risk of incident colorectal cancer, but it is less clear if pre-existing diabetes mellitus influences mortality outcomes, recurrence risk, and/or treatment-related complications in persons with colorectal cancer.

METHODS

We performed a systematic review and meta-analysis comparing colorectal cancer mortality outcomes, cancer recurrence, and treatment-related complications in persons with and without diabetes mellitus. We searched MEDLINE and EMBASE through October 1, 2008, including hand-searching references of qualifying articles. We included studies in English that evaluated diabetes mellitus and cancer treatment outcomes, prognosis, and/or mortality. The initial search identified 8,208 titles, of which 15 articles met inclusion criteria. Each article was abstracted by one author using a standardized form and re-reviewed by another author for accuracy. Authors graded quality based on pre-determined criteria.

RESULTS

We found significantly increased short-term perioperative mortality in persons with diabetes mellitus. In the meta-analysis of long-term mortality, persons with diabetes mellitus had a 32% increase in all-cause mortality compared to those without diabetes mellitus (95% CI: 1.24, 1.41). Although data on other outcomes are limited, available studies suggest that pre-existing diabetes mellitus predicts increased risk of some post-operative complications as well as 5-year cancer recurrence. In contrast, there is little evidence that diabetes confers increased risk for long-term cancer-specific mortality.

CONCLUSIONS

Patients with colorectal cancer and pre-existing diabetes mellitus have an increased risk of short- and long-term mortality. Future research should determine whether improvements in prevention and treatment of diabetes mellitus will improve outcomes for colorectal cancer patients.

The association of diabetes with colorectal cancer risk: the Multiethnic Cohort

Background:

Diabetics have been found to have a greater risk of colorectal cancer than non-diabetics.

Methods:

We examined whether this relationship differed by ethnic group, cancer site or tumour stage in a population-based prospective cohort, including 3549 incident colorectal cancer cases identified over a 13-year period (1993–2006) among 199 143 European American, African American, Native Hawaiian, Japanese American and Latino men and women in the Multiethnic Cohort.

Results:

Diabetics overall had a significantly greater risk of colorectal cancer than did non-diabetics (relative risk (RR)=1.19, 95% confidence interval (CI)=1.09–1.29, P-value (P)<0.001). Positive associations were observed for colon cancer, cancers of both the right and left colon, and cancers diagnosed at a localised and regional/distant stage. The association with colorectal cancer risk was significantly modified by smoking status (P_Interaction=0.0044), with the RR being higher in never smokers (RR=1.32, 95% CI=1.15–1.53, P<0.001) than past (RR=1.19, 95% CI=1.05–1.34, P=0.007) and current smokers (RR=0.90, 95% CI=0.70–1.15, P=0.40).

Conclusion:

These findings provide strong support for the hypothesis that diabetes is a risk factor for colorectal cancer.

Clinical usefulness of glycosylated hemoglobin as a predictor of adenomatous polyps in the colorectum of middle-aged males

OBJECTIVE

We investigated the clinical usefulness of HbA1c in screening an average-risk group <50 years of age who need colonoscopy for colorectal cancer (CRC) screening.

METHODS

Eight hundred nineteen asymptomatic males who underwent colonoscopy for CRC screening with blood chemistries between January 2006 and December 2006 were enrolled. The ages of the subjects ranged from 40 to 59.

RESULTS

Subjects in their 50 s had significantly more adenomatous polyps than subjects in their 40 s (32.7% vs. 26.0%, p < 0.05). The incidence of adenomatous polyp increased with increasing quartiles of HbA1C as follows: first quartile (19.9%, HbA1c 4.0-5.0), second quartile (27.8%, HbA1c 5.1-5.3), third quartile (32.7%, HbA1c 5.4-5.5), and fourth quartile (34.9%, HbA1c = 5.6-8.8)(p = 0.008). When combining quartile of HbA1c and age (40 s vs. 50 s) according to HbA1C levels, the odds ratio for adenomatous polyp in subjects in their 40 s with HbA1c <5.4% was significantly lower than that in subjects in their 50 s. However, the odds ratio for adenomatous polyp in subjects in their 40 s with HbA1c > or =5.4% was similar to that in subjects in their 50 s with average risk for CRC.

CONCLUSIONS

An elevated HbA1c may be useful as a clinical predictor of adenomatous polyps in male subjects <50 years of age who have average risk for CRC.

Impact of diabetes mellitus on the prognosis of patients with oral squamous cell carcinoma: a retrospective cohort study

BACKGROUND

Diabetes mellitus (DM) is a prevalent chronic metabolic disease reported to affect the treatment outcomes of malignancies. This study explores the impact of diabetes on the prognosis of oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

Clinicopathological characteristics and survival in terms of overall survival (OS), recurrence-free survival (RFS), and cancer-specific survival (CSS) of patients with OSCC who underwent surgical intervention at the Taipei Veterans General Hospital between 2002 and 2005 were stratified by diabetic status and compared.

RESULTS

Patients with DM tend to have a lower OS, RFS, and CSS compared with nondiabetics (adjusted hazard ratio [HR] = 2.22, 2.42, and 2.16, respectively) even in less aggressive tumor stages (stage I and II). In advanced tumors, diabetic patients who were not prescribed adjuvant therapy had a significantly higher recurrence rate than nondiabetic patients (HR = 2.66). However, there was no significant difference in treatment outcome in patients with locally advanced tumors amenable to receive adjuvant therapy, even with the delayed initiation of adjuvant therapy in the DM group (49.1 +/- 22.3 days vs. 40.0 +/- 16.6 days, P = .04). DM was also associated with a higher frequency of perineural invasion (adjusted odds ratio [OR] = 2.53).

CONCLUSION

DM status could be a prognostic factor for OSCC, particularly for its effect in the survival and perineural invasion. Although diabetes-associated comorbidities may impair decision making toward less aggressive therapeutic modality, adjuvant treatment may be essential for DM patients to improve their survival.

Diabetes and risk of incident cancer: a large population-based cohort study in Israel

Type 2 diabetes mellitus has been associated with an increased risk of a variety of cancers in observational studies, but few have reported the relationship between diabetes and cancer risk in men and women separately. The main goal of this retrospective cohort study was to evaluate the sex-specific risk of incident overall and site-specific cancer among people with DM compared with those without, who had no reported history of cancer at the start of the follow-up in January 2000. During an average of 8 years of follow-up (SD = 2.5), we documented 1,639 and 7,945 incident cases of cancer among 16,721 people with DM and 83,874 free of DM, respectively. In women, DM was associated with an adjusted hazard ratio of 1.96 (95% CI: 1.53-2.50) and 1.41 (95% CI: 1.20-1.66) for cancers of genital organs and digestive organs, respectively. A significantly reduced HR was observed for skin cancer (0.38; 95% CI: 0.22-0.66). In men with DM, there was no significant increase in overall risk of cancer. DM was related with a 47% reduction in the risk of prostate cancer. These findings suggest that the nature of the association between DM and cancer depends on sex and specific cancer site.

Impact of diabetes mellitus on treatment outcomes in patients with nasopharyngeal cancer

BACKGROUND AND PURPOSE

To determine the influence of diabetes mellitus on stages and long-term outcomes among patients with nasopharyngeal cancer.

MATERIAL AND METHODS

The study summarized 37 patients who were diagnosed as having diabetes mellitus and nasopharyngeal cancer and treated by radiotherapy between January 1999 and December 1999. With a median follow-up of 34.6 mo, we analyzed differences in RFS, MFS, DFS, and OS between the diabetes and the non-diabetes group.

RESULTS

37 patients were involved in our study. According to the Chinese Fuzhou staging system for NPC, which was modified in 1992, 2 patients belong to stage I, 9 stage II, 17 stage III, and 6 stage IV. The 4-yr RFS of diabetes group and non-diabetes group was 52.1% vs 68.2%, the 4-yr MFS was 73.0% vs 72.0%, the 4-yr DFS was 35.1% vs 65.1%, and the OS was 67.6% vs 75.7%. The Wilcoxon (Gehan) test showed there was no significant difference between the two groups of RFS, MFS, and OS, while the diabetes group had a worse DFS than non-diabetes group (Wilcoxon p = 0.0047).

CONCLUSIONS

Patients with diabetes had a worse DFS than non-diabetes, but statistic tests did not show significant differences in RFS, MFS, and OS; further studies should be continue to find out the results in the future.