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.

Dysfunction of fronto-limbic brain circuitry in depression

BACKGROUND

depression is characterized by a stable negative bias toward emotional stimuli. This bias is associated with abnormal activities in emotion-processing regions (such as the amygdala) and cognitive-control regions (such as the dorsolateral prefrontal cortex [DLPFC]). However, it remains unclear whether the emotion-processing and cognitive-control regions affect negative cognitive bias independently or reciprocally.

EXPERIMENTAL PROCEDURE

a functional magnetic resonance imaging (fMRI) study of 16 depressed patients and 16 matched control subjects was conducted during an emotion-interference task.

RESULTS

the accuracies were significantly lower in the depressed group than in the control group when subjects attended to the happy and the neutral faces. Compared with control participants, depressed patients showed abnormal activity in bilateral amygdala and the right DLPFC. In addition, a significant correlation was found between the right amygdala and the right DLPFC when subjects observed the happy faces.

CONCLUSIONS

the results suggest that the dysfunction in positive emotion-processing and cognitive-control regions may reciprocally affect negative cognitive bias. Additionally, altered positive emotional interference processing in the fronto-limbic brain circuitry might be another cause of negative cognitive bias that finally leads to depression.

Oral uracil-tegafur plus leucovorin vs fluorouracil bolus plus leucovorin for advanced colorectal cancer: a meta-analysis of five randomized controlled trials

AIM

The aim of this study was to evaluate systematically the efficacy and safety of oral uracil-tegafur (UFT) plus leucovorin (LV) compared with infusional fluorouracil (5-FU) plus LV for advanced colorectal cancer.

METHOD

Eligible studies were identified from Medline, Embase and the Cochrane Library. The end-points included overall survival and overall tumour response rate, and toxicity including leucopenia, febrile neutropenia, stomatitis/mucositis and diarrhoea.

RESULTS

Five randomized controlled trials were identified. Pooled data demonstrated no difference in overall survival between the oral UFT plus LV regimen and the 5-FU bolus plus LV regimen [hazard ratio 1.013; 95% confidence interval (CI) 0.911-1.127].The fixed-effect pooled estimate for overall tumour response rate showed no significant difference between the two regimens (relative risk 0.893; 0.672-1.187). Grade 3-4 leucopenia [odds ratio (OR) 0.126; 955 CI 0.048-0.326], grade 1-4 leucopenia (OR 0.089; 95% CI 0.067-0.119) and grade1-4 febrile neutropenia (OR 0.020; 95% CI 0.004-0.102) were significantly less prominent in the oral UFT regimens. For nonhaematological toxicities, grade 3-4 stomatitis/mucositis (OR 0.075; 95% CI 0.039-0.146), grade 3-4 infection (OR 0.484; 95% CI 0.310-0.758), grade 1-4 infection (OR 0.672; 95% CI 0.547-0.826, P < 0.001), grade 1-4 diarrhoea (OR 0.743; 95% CI 0.626-0.881) were also less likely to happen in patients in the oral UFT plus LV regimen, while there was no significant difference between the two treatment regimens with respect to grade 1-4 stomatitis/mucositis (OR 0.278; 95% CI 0.053-1.456) and grade 3-4 (OR 1.174; 95% CI 0.983-1.403) diarrhoea.

CONCLUSION

Oral UFT or 5-FU bolus combined with LV results in similar overall survival and tumour response rates for advanced colorectal cancer. The former treatment regimen is greatly superior in terms of toxicity, especially haematological toxicity.

A meta-analysis of randomized controlled trials comparing antibacterial therapy with placebo in Crohn's disease

BACKGROUND

Antibacterial therapy has been investigated in several randomized, clinical trials compared with placebo for the management of Crohn's disease. Evidences for the efficacy of intervention are increasingly required.

OBJECTIVES

To conduct a meta-analysis of randomized trials to compare the effects of antibacterial therapy versus placebo in patients with Crohn's disease.

SEARCH STRATEGY

A systematic literature search of Pubmed, EMBASE, Cochrane Library (April 1966 to July 2009) was conducted using specific search terms.

SELECTION CRITERIA

Eligible studies were randomized controlled trials comparing antibacterial (antimycobacterial and broad-spectrum antibiotic) therapy with placebo.

DATA COLLECTION AND ANALYSIS

Studies were reviewed to determine the number of participants, mean follow-up, and the odds ratios (OR) for primary end point of clinical remission and clinical response were also abstracted. The meta-analysis was performed using a fixed-effects model or a randomized-effects model according to the degree of heterogeneity.

RESULTS

Eleven randomized placebo-controlled clinical trials with 668 participants (364 patients in the treatment group and, 304 patients in the placebo group) were identified. Antimycobacterial agents were used in four of the trials and broad-spectrum antibiotics were used in the other seven trials. Pooled analysis showed no significant differences in the rates of clinical remission [OR = 1.28, 95% confidence interval (CI): 0.87-1.90, P = 0.214] and clinical response (OR = 1.52, 95% CI: 0.91-2.55, P = 0.108) after receiving antibacterial treatment for 3 months or longer.

CONCLUSION

In this meta-analysis, no evidence of benefit for antibiotics in patients with Crohn's disease was found.

Abstract P3-08-03: Defects in BRCA1 Contribute to Global Differential Allele-Specific Expression

Differential allele-specific expression (DASE) has been shown to contribute to phenotypic variability in humans and more recently to the pathogenesis of cancer. DASE is associated with X-chromosome inactivation and genomic imprinting and is relatively common among non-imprinted autosomal genes. The DASE phenotype can also be transmitted by Mendelian inheritance. We have previously reported that nonsense-mediated mRNA decay (NMD) of mutant BRCA1 as well as other epigenetic mechanisms can lead to DASE of BRCA1 and enhanced susceptibility to breast cancer. BRCA1 has been implicated in many cellular processes including DNA repair, cell-cycle-checkpoint control, protein ubiquitination, and chromatin remodeling. Importantly, cells carrying a deleterious BRCA1 mutation exhibit increased genome instability, therefore, we hypothesize that defects in BRCA1 lead not only to DASE of itself, but increase genome-wide DASE and thus contribute to increased breast cancer susceptibility. To test this hypothesis, we employed a genome-wide ASE assay (Illumina Human Omni1-Quad BeadChip) using primary mammary epithelial cells [3 BRCA1 wild-type vs. 3 BRCA1 mutant carrying (2800delAA, 4154delA and R1751X)]. As shown in Table 1, cells carrying a BRCA1 mutation had significantly more DASE events as compared to wild-type cell (P&lt;10-7). In addition, we identified 351 genes demonstrating DASE that were unique to the BRCA1 mutant cells. The cellular functions of these genes are wideranging, including DNA repair, cell cycle control, lipid metabolism and protein degradation. In summary, this study provides the first evidence that mutant BRCA1 can lead to global DASE, which in turn may contribute to the development of breast cancer in mutation carriers. This work was supported in part by the Eileen Stein-Jacoby Fund and a grant from the Congressionally Directed Medical Research Programs, Department of Defense, W81XWH-08-1-0361 (XC).

Table 1. BRCA1 mutations increase the global DASE in PMECs

t; A DASE event is defined as that the Log-ratio of allele-specific expression level of one gene is more than 1 or less than -1, i.e. the expression level from one allele is at least 50% less than the level of another allele

Meta-analysis of the colon J-pouch vs transverse coloplasty pouch after anterior resection for rectal cancer

PURPOSE

To evaluate the outcome of colonic J-pouches (CJP) and transverse colonic pouches (TCPs) after anterior resection for rectal cancer.

METHOD

Trials were located through Medline, Embase, the Cochrane Central Register of Controlled Trials, VIP and CNKI. Main end-points included functional outcomes, postoperative complications and anorectal physiological outcomes.

RESULTS

Of 120 articles, 34 compared CJP and TCP. Of these only six were randomized controlled trials (RCT), which fulfilled the inclusion criteria. These six included 648 patients, including 326 in the CJP group and 322 in the TCP group. There were no differences in the incidences of anastomotic leak [odds ratio 0.50, 95% confidence interval (CI) 0.21-1.18], chest infection (0.43, 0.09-2.00), wound infection (0.87, 0.33-2.30), anastomotic stricture (1.30, 0.44-3.84), fistula (0.64, 0.18-2.31).There were no difference in functional outcomes such as stool frequency [weighted mean difference (WMD) of -0.01, -0.30-0.27 at 6 months].There was no difference for anorectal physiology but heterogeneity existed: resting pressure (0.39, -1.76 to 2.55; 3.09, -0.04 to 6.23; 4.15, 2.21-6.094, at preoperation, 6 and 12 months,); squeeze pressure (-15.02, -46.14 to 16.10; -15.04, -37.04 to 6.97;0.83, -7.70 to 9.37 at preoperation, 6 and 12 months);(Neo)rectal threshold volume(8.49, 5.18-11.81; 27.13, -5.08 to 59.35, at preoperation and 6 months); Maximal (neo) rectal volume (-14.05, -36.60 to 8.50; 23.37, 2.65-44.09; -0.54, -0.91 to -0.18, at preoperation, 6 and at 12 months).

CONCLUSIONS

Transverse colonic pouch has similar results as CJP. As it is a safe, feasible, simple, technically easy and time-saving surgical procedure, TCP is a good candidate for wider clinical application.