Statin use is associated with a reduced incidence of colorectal adenomatous polyps

MicroRNA‑192 acts as a tumor suppressor in colon cancer and simvastatin activates miR‑192 to inhibit cancer cell growth

Colon cancer is one of the most common malignant tumors worldwide. Understanding the underlying molecular mechanisms is crucial for the development of therapeutic strategies for the treatment of patients with colon cancer. In the present study, a novel tumor suppressive microRNA, miR‑192, was demonstrated to be markedly downregulated in colon cancer cells compared with normal colon cells. By overexpressing miR‑192 in colon cancer HCT‑116 cells, the results of the present study revealed that miR‑192 inhibits cell proliferation, migration and invasion. Bioinformatics were used to determine the target gene of miR‑192 and Ras‑related protein Rab‑2A (RAB2A) was identified as a downstream target of miR‑192. Following the determination of the role of the miR‑192‑RAB2A pathway in colon cancer, small molecules that may regulate miR‑192 were screened and the results demonstrated that simvastatin is an activator of miR‑192. Furthermore, simvastatin upregulated miR‑192 and inhibited the expression of downstream targets of miR‑192, which subsequently led to suppressed proliferation, migration and invasion of colon cancer cells. In conclusion, the present study identified a novel colon cancer cell suppressor, as well as a small‑molecule activator of the tumor suppressor miR‑192, which may represent a therapeutic strategy for the treatment of patients with colon cancer.

Parameters of Glucose and Lipid Metabolism Affect the Occurrence of Colorectal Adenomas Detected by Surveillance Colonoscopies

PURPOSE

Limited data are available regarding the associations between parameters of glucose and lipid metabolism and the occurrence of metachronous adenomas. We investigated whether these parameters affect the occurrence of adenomas detected on surveillance colonoscopy.

MATERIALS AND METHODS

This longitudinal study was performed on 5289 subjects who underwent follow-up colonoscopy between 2012 and 2013 among 62171 asymptomatic subjects who underwent an initial colonoscopy for a health check-up between 2010 and 2011. The risk of adenoma occurrence was assessed using Cox proportional hazards modeling.

RESULTS

The mean interval between the initial and follow-up colonoscopy was 2.2±0.6 years. The occurrence of adenomas detected by the follow-up colonoscopy increased linearly with the increasing quartiles of fasting glucose, hemoglobin A1c (HbA1c), insulin, homeostasis model assessment of insulin resistance (HOMA-IR), and triglycerides measured at the initial colonoscopy. These associations persisted after adjusting for confounding factors. The adjusted hazard ratios for adenoma occurrence comparing the fourth with the first quartiles of fasting glucose, HbA1c, insulin, HOMA-IR, and triglycerides were 1.50 [95% confidence interval (CI), 1.26-1.77; p(trend)<0.001], 1.22 (95% CI, 1.04-1.43; p(trend)=0.024), 1.22 (95% CI, 1.02-1.46; p(trend)=0.046), 1.36 (95% CI, 1.14-1.63; p(trend)=0.004), and 1.19 (95% CI, 0.99-1.42; p(trend)=0.041), respectively. In addition, increasing quartiles of low-density lipoprotein-cholesterol and apolipoprotein B were associated with an increasing occurrence of adenomas.

CONCLUSION

The levels of parameters of glucose and lipid metabolism were significantly associated with the occurrence of adenomas detected on surveillance colonoscopy. Improving the parameters of glucose and lipid metabolism through lifestyle changes or medications may be helpful in preventing metachronous adenomas.

Statin use and the risk of colorectal adenoma: A meta-analysis

BACKGROUND

Although statin use has been reported to reduce the risk of colorectal cancer beyond its cholesterol-lowering effects, the benefit of statins against colorectal adenoma has not been fully clarified. We aimed to investigate the association between statin use and the risk of colorectal adenoma.

METHODS

We conducted a systematic literature search on MEDLINE, EMBASE, and the Cochrane Library using the primary keywords "adenoma," "polyp," "colorectal," "colon," "rectal," "rectum," "neoplasia," "neoplasm," "statin," "3-hydroxy-3-methylglutaryl-coenzyme A," and "HMG-CoA." Studies were included if they evaluated the association between statin use and adenoma and reported relative risks (RRs) or odds ratios or provided data for estimation. Pooled estimates were calculated using the random-effects model.

RESULTS

Six studies including 13 239 patients were analyzed. The median proportion of patients with any adenoma was 29.7% (range, 20.9-38.4%) in patients taking statins and 31.2% (range, 19.6-63.4%) in patients not taking statins across included studies. The median proportion of patients with advanced adenoma in those taking statins was 7.7% (range, 3.1-27.2%), whereas that in patients not taking statins was 11.3% (range, 3.5-32.4%). On meta-analysis, statin use did not significantly affect the risk of any adenoma (pooled RR = 0.901; 95% confidence interval [CI], 0.735-1.104); however, it was associated with a lower risk of advanced adenoma (pooled RR = 0.833; 95% CI, 0.750-0.925).

CONCLUSIONS

Statin use seems to be associated with a reduced risk of advanced adenoma, but not any adenoma. Statins may prevent neoplastic progression of adenomas rather than the development of adenomas.

Concomitant Statin Use Has a Favorable Effect on Gemcitabine-Erlotinib Combination Chemotherapy for Advanced Pancreatic Cancer

PURPOSE

Erlotinib-gemcitabine combined chemotherapy is considered as the standard treatment for unresectable pancreatic cancer. This study aimed to determine the clinical factors associated with response to this treatment.

MATERIALS AND METHODS

This retrospective study included 180 patients with unresectable pancreatic cancer who received ≥2 cycles of gemcitabine-erlotinib combination therapy as first-line palliative chemotherapy between 2006 and 2014. "Long-term response" was defined as tumor stabilization after >6 chemotherapy cycles.

RESULTS

The median progression-free survival (PFS) and overall survival (OS) were 3.9 and 8.1 months, respectively. On univariate analysis, liver metastasis (p=0.023) was negatively correlated with long-term response. Locally advanced stage (p=0.017), a history of statin treatment (p=0.01), and carcinoembryonic antigen levels <4.5 (p=0.029) had a favorable effect on long-term response. On multivariate analysis, a history of statin treatment was the only independent favorable factor for long-term response (p=0.017). Prognostic factors for OS and PFS were significantly correlated with liver metastasis (p=0.031 and 0.013, respectively). A history of statin treatment was also significantly associated with OS after adjusting for all potential confounders (hazard ratio, 0.48; 95% confidence interval, 0.26-0.92; p=0.026).

CONCLUSION

These results suggest that statins have a favorable effect on "long-term response" to gemcitabine-erlotinib chemotherapy in unresectable pancreatic cancer patients. Statins may have a chemoadjuvant role in stabilizing long-term tumor growth.

Blood Lipid Concentrations and Colorectal Adenomas: A Systematic Review and Meta-Analysis of Colonoscopy Studies in Asia, 2000-2014

It is unclear whether dyslipidemia is associated with risk of colorectal neoplasia. The incidence of both conditions is increasing in Asia, motivating a number of new studies from this region. We performed a systematic literature search of Asian colonoscopy-based studies that collected blood lipid concentrations at the time of endoscopy. Persons found to have colorectal adenoma were considered cases, and those found to be adenoma-free were considered controls. Seventeen studies published between 2000 and 2014 met inclusion criteria, collectively enrolling 17,387 cases and 30,427 controls. Mean differences and adjusted odds ratios were summarized with random-effects meta-analyses. Compared with controls, cases had higher total cholesterol (mean difference (MD) = 2.4 mg/dL, 95% confidence interval (CI): 0.2, 4.6), higher low-density lipoprotein cholesterol (MD = 1.3 mg/dL, 95% CI: 0.1, 2.6), higher triglyceride (MD = 16.4 mg/dL, 95% CI: 11.2, 21.5), and lower high-density lipoprotein (HDL) cholesterol (MD = -2.1 mg/dL, 95% CI: -2.7, -1.6) concentrations. Based on adjusted odds ratios, associations for 40-mg/dL-higher triglyceride levels (odds ratio = 1.13, 95% CI: 1.05, 1.21) and 10-mg/dL-higher HDL cholesterol levels (odds ratio = 0.96, 95% CI: 0.92, 1.00) achieved statistical significance. Persons with adenoma were more likely to have unfavorable cholesterol profiles at the time of colonoscopy than those without adenoma. The most convincing evidence for an association between dyslipidemia and colorectal neoplasia was observed for hypertriglyceridemia.

Reduced Risk of Barrett's Esophagus in Statin Users: Case-Control Study and Meta-Analysis

BACKGROUND

Use of statins has been associated with a reduced incidence of esophageal adenocarcinoma in population-based studies. However there are few studies examining statin use and the development of Barrett's esophagus.

AIM

The purpose of this study was to examine the association between statin use and the presence of Barrett's esophagus in patients having their first gastroscopy.

METHODS

We have performed a case-control study comparing statin use between patients with, and without, an incident diagnosis of non-dysplastic Barrett's esophagus. Male Barrett's cases (134) were compared to 268 male age-matched controls in each of two control groups (erosive gastro-esophageal reflux and dyspepsia without significant upper gastrointestinal disease). Risk factor and drug exposure were established using standardised interviews. Logistic regression was used to compare statin exposure and correct for confounding factors. We performed a meta-analysis pooling our results with three other case-control studies.

RESULTS

Regular statin use was associated with a significantly lower incidence of Barrett's esophagus compared to the combined control groups [adjusted OR 0.62 (95 % confidence intervals 0.37-0.93)]. This effect was more marked in combined statin plus aspirin users [adjusted OR 0.43 (95 % CI 0.21-0.89)]. The inverse association between statin or statin plus aspirin use and risk of Barrett's was significantly greater with longer duration of use. Meta-analysis of pooled data (1098 Barrett's, 2085 controls) showed that statin use was significantly associated with a reduced risk of Barrett's esophagus [pooled adjusted OR 0.63 (95 % CI 0.51-0.77)].

CONCLUSIONS

Statin use is associated with a reduced incidence of a new diagnosis of Barrett's esophagus.

Metformin use and risk of colorectal adenoma after polypectomy in patients with type 2 diabetes mellitus

BACKGROUND

Existing literature suggests that metformin, the most commonly used biguanide, may lower colorectal cancer risk. Because most colorectal cancers originate in precancerous adenomas, we examined whether metformin use lowered colorectal adenoma risk after polypectomy in patients with type-2 diabetes.

METHODS

Retrospective cohort study of 40- to 89-year-old Kaiser Permanente Northern California patients who had type 2 diabetes, and ≥1 adenoma detected at baseline colonoscopy during 2000 to 2009 and a repeat colonoscopy 1 to 10 years from baseline adenoma diagnosis through 2012. Cox models evaluated the association between metformin use during follow-up and subsequent adenoma diagnoses, controlling for age, race/ethnicity, sex, body mass index, and repeat examination indication.

RESULTS

Study included 2,412 patients followed for a median of 4.5 years; cumulatively, 1,117 (46%) patients had ≥1 adenoma at repeat colonoscopy. Compared with patients not receiving diabetes medications (n = 1,578), metformin-only use (n = 457) was associated with lower adenoma recurrence risk [adjusted HR, 0.76; 95% confidence interval (CI), 0.65-0.89], and the association was stronger with increasing total metformin dose [quartile (Q) 1: HR, 0.90; 95% CI, 0.72-1.12; Q2: HR, 0.89; 95% CI, 0.70-1.12; Q3: HR, 0.80; 95% CI, 0.63-1.01; Q4: HR, 0.50; 95% CI, 0.42-0.60, Ptrend < 0.001]. Findings were unchanged in sensitivity analyses, including evaluating only outcomes during the 3- to 10-year period from baseline.

CONCLUSION

Our study suggests a potential benefit of metformin use in lowering the risk of subsequent adenomas after polypectomy in patients with type 2 diabetes.

IMPACT

Metformin may lower colorectal cancer risk by reducing the formation of precancerous lesions, reinforcing the potential additional benefits of its use.

Use of Cyclo-Oxygenase Inhibitors Is Not Associated with Clinical Relapse in Inflammatory Bowel Disease: A Case-Control Study

Patients with inflammatory bowel disease (IBD) often have associated conditions, for which anti-inflammatory medication with cyclo-oxygenase (COX) inhibitors may be helpful. The current evidence is conflicting regarding the role of COX-inhibitors in causing relapse in IBD. This case-control study examined the association between the use of COX inhibitors and relapse of IBD. Logistic regression was used to analyse the relationship between COX-inhibitors and IBD relapse. Overall COX inhibitor use (combined non-steroidal anti-inflammatory drugs (NSAIDs) and selective COX-2 agents) had a negative association with relapse of IBD (adjusted OR 0.26, 95% CI 0.09-0.80). This negative association was confined to ulcerative colitis (UC) (adjusted OR = 0.06, 95% CI 0.01-0.50) and no association was found in Crohn's disease (CD) patients (adjusted OR 1.25, 95% CI 0.18-7.46). The significant negative association between UC relapse and medication use was also seen with non-specific NSAIDs. Selective COX-2 inhibitor use was rare but non-significantly more common in stable patients. There was no association between low-dose aspirin or paracetamol use and relapse of CD or UC. We conclude that COX-inhibitor use was not associated with an increased risk of relapse in UC or CD, and may be protective in UC. Where indicated, NSAIDs should not be withheld from IBD patients.

Prevalence of colorectal neoplasm in Chinese patients with high-risk coronary artery disease classified by the Asia-Pacific Colorectal Screening score

OBJECTIVE

The aim of this study was to investigate the prevalence of colorectal neoplasms in patients coronary artery disease (CAD) with or without a family history of colorectal cancer (CRC).

METHODS

In this cross-sectional study, individuals with suspected CAD in the absence of cancer-related symptoms underwent coronary angiography for the first time, and were divided into CAD and non-CAD groups. Colonoscopy was performed in individuals at high-risk tier based on their Asia-Pacific colorectal screening (APCS) score. Their waist circumference (WC), height and body weight were measured.

RESULTS

There were 634 of 1157 individuals at a high risk of developing advanced colorectal neoplasms, 91.0% (577/634) of whom were male smokers. The proportion of CAD patients in the high-risk tier was 81.5% (517/634), while the prevalences of adenomas (32.1% vs 22.2%, P < 0.05) and advanced adenomas (14.7% vs 8.5%, P < 0.05) were significantly higher in the CAD group than in the non-CAD group. After 83 individuals with a family history of CRC were excluded, only the prevalence of adenomas was still significantly higher in the CAD group than in the non-CAD group (25.5% vs 16.0%, P < 0.01). Body mass index (BMI) ≥ 25 kg/m(2) was correlated with the occurrence of adenomas (OR 2.133, 95% CI 1.219-3.730, P = 0.008) in CAD patients.

CONCLUSIONS

Even in the absence of family history of CRC, CAD patients at a high risk of developing advanced colorectal neoplasms classified by the APCS score still showed a remarkably high prevalence of colorectal adenomas. Moreover, the association between the occurrence of adenomas and CAD was stronger in overweight (BMI ≥ 25 kg/m(2)) individuals.

Novel prospects of statins as therapeutic agents in cancer

Statins are well known competitive inhibitors of hydroxymethylglutaryl-CoA reductase enzyme (HMG-CoA reductase), thus traditionally used as cholesterol-lowering agents. In recent years, more and more effects of statins have been revealed. Nowadays alterations of lipid metabolism have been increasingly recognized as a hallmark of cancer cells. Consequently, much attention has been directed toward the potential of statins as therapeutic agents in the oncological field. Accumulated in vitro and in vivo clinical evidence point out the role of statins in a variety of human malignancies, in regulating tumor cell growth and anti-tumor immune response. Herein, we summarize and discuss, in light of the most recent observations, the anti-tumor effects of statins, underpinning the detailed mode of action and looking for their true significance in cancer prevention and treatment, to determine if and in which case statin repositioning could be really justified for neoplastic diseases.

Colorectal polyps and polyposis syndromes

A polyp is defined as any mass protruding into the lumen of a hollow viscus. Colorectal polyps may be classified by their macroscopic appearance as sessile (flat, arising directly from the mucosal layer) or pedunculated (extending from the mucosa through a fibrovascular stalk). Colorectal polyps may also be histologically classified as neoplastic or as non-neoplastic (hyperplastic, hamartomatous, or inflammatory). The neoplastic polyps are of primary importance because they harbor a malignant potential, which represents a stage in the development of colorectal cancer. For this reason, it is essential to identify these polyps at a sufficiently early stage, when a simple outpatient procedure to remove them can interrupt the development of colorectal cancer and prevent disease and death. When invasive carcinoma arises in a polyp, careful consideration must be given to ensuring the adequacy of treatment. Although most neoplastic polyps do not evolve into cancer, it is well accepted that the majority of colorectal carcinomas evolve from adenomatous polyps; the sequence of events leading to this transformation is referred to as the adenoma-to-carcinoma sequence. The presence of a systemic process that promotes the development of multiple gastro-intestinal polyps is termed 'polyposis'. Hereditary gastro-intestinal polyposis syndromes account for approximately 1% of all cases of colorectal cancer and are associated with a broad spectrum of extra-colonic tumors. Early detection and accurate classification of these syndromes are essential, in order to initiate a surveillance program for the early detection of cancer. Several polyposis syndromes have been described, each having its own genetic basis and characteristic polyp distribution, clinical presentation, and malignancy risk. Diagnostic modalities and treatment options for neoplastic polyps-as well as the most prevalent polyposis syndromes-are reviewed below.

Beyond aspirin-cancer prevention with statins, metformin and bisphosphonates

Cancer risk reduction using pharmacological means is an attractive modern preventive approach that supplements the classical behavioural prevention recommendations. Medications that are commonly used by large populations to treat a variety of common, non-cancer-related, medical situations are an attractive candidate pool. This Review discusses three pharmacological agents with the most evidence for their potential as cancer chemopreventive agents: anti-hypercholesterolaemia medications (statins), an antidiabetic agent (metformin) and antiosteoporosis drugs (bisphosphonates). Data are accumulating to support a significant negative association of certain statins with cancer occurrence or survival in several major tumour sites (mostly gastrointestinal tumours and breast cancer), with an augmented combined effect with aspirin or other non-steroidal anti-inflammatory drugs. Metformin, but not other hypoglycaemic drugs, also seems to have some antitumour growth activity, but the amount of evidence in human studies, mainly in breast cancer, is still limited. Experimental and observational data have identified bisphosphonates as a pharmacological group that could have significant impact on incidence and mortality of more than one subsite of malignancy. At the current level of evidence these potential chemopreventive drugs should be considered in high-risk situations or using the personalized approach of maximizing individual benefits and minimizing the potential for adverse effects with the aid of pharmacogenetic indicators.