Increase of the mitotic index of colonic mucosa after cholecystectomy

Biomarkers of Colorectal Cancer Risk Decrease 6 months After Roux-en-Y Gastric Bypass Surgery

PURPOSE

The impact of weight loss on obesity-related colorectal cancer (CRC) risk is not well defined. Previous studies have suggested that Roux-en-Y gastric bypass (RYGB) surgery may have an unexpected adverse impact on CRC risk. This study aimed to investigate the impact of RYGB on biomarkers of CRC risk.

MATERIALS AND METHODS

Rectal mucosal biopsies and blood were obtained from patients undergoing RYGB (n = 22) and non-obese control participants (n = 20) at baseline and at a median of 6.5 months after surgery. Markers of systemic inflammation and glucose homeostasis were measured. Expression of pro-inflammatory genes and proto-oncogenes in the rectal mucosa was quantified using qPCR. Crypt cell proliferation state of the rectal mucosa was assessed by counting mitotic figures in whole micro-dissected crypts.

RESULTS

At 6.5 months post-surgery, participants had lost 29 kg body mass and showed improvements in markers of glucose homeostasis and in systemic inflammation. Expression of pro-inflammatory genes in the rectal mucosa did not increase and COX-1 expression fell significantly (P = 0.019). The mean number of mitoses per crypt decreased from 6.5 to 4.3 (P = 0.028) after RYGB.

CONCLUSION

RYGB in obese adults led to lower rectal crypt cell proliferation, reduced systemic and mucosal markers of inflammation and improvements in glucose regulation. These consistent findings of reduced markers of tumourigenic potential suggest that surgically induced weight loss may lower CRC risk.

Tissue-specific DNA methylation loss during ageing and carcinogenesis is linked to chromosome structure, replication timing and cell division rates

DNA methylation is an epigenetic mechanism known to affect gene expression and aberrant DNA methylation patterns have been described in cancer. However, only a small fraction of differential methylation events target genes with a defined role in cancer, raising the question of how aberrant DNA methylation contributes to carcinogenesis. As recently a link has been suggested between methylation patterns arising in ageing and those arising in cancer, we asked which aberrations are unique to cancer and which are the product of normal ageing processes. We therefore compared the methylation patterns between ageing and cancer in multiple tissues. We observed that hypermethylation preferentially occurs in regulatory elements, while hypomethylation is associated with structural features of the chromatin. Specifically, we observed consistent hypomethylation of late-replicating, lamina-associated domains. The extent of hypomethylation was stronger in cancer, but in both ageing and cancer it was proportional to the replication timing of the region and the cell division rate of the tissue. Moreover, cancer patients who displayed more hypomethylation in late-replicating, lamina-associated domains had higher expression of cell division genes. These findings suggest that different cell division rates contribute to tissue- and cancer type-specific DNA methylation profiles.

Increased colorectal epithelial cell proliferation and crypt fission associated with obesity and roux-en-Y gastric bypass

BACKGROUND AND AIMS

The relationship between obesity, weight reduction, and future risk of colorectal cancer is not well understood. Therefore, we compared mucosal biomarkers in normal weight individuals [body mass index (BMI), 18.5-24.9 kg/m(2)] with those in morbidly obese patients (BMI >40 kg/m(2)) before and 6 months after Roux-en-Y gastric bypass (RYGB).

METHODS

Rectal epithelial cell mitosis, crypt area, and crypt branching were measured following whole crypt microdissection. Apoptosis was measured by immunohistochemistry for neo-cytokeratin 18 on fixed tissue sections. Serum levels of C-reactive protein and cytokines were assayed in combination with quantification of mucosal proinflammatory gene expression by real-time RT-PCR.

RESULTS

Twenty-six morbidly obese patients (mean BMI, 54.4 kg/m(2)) had significantly increased mitosis, crypt area, and crypt branching (all P < 0.01) compared with 21 age- and sex-matched normal weight individuals (mean BMI, 22.5 kg/m(2)). Morbidly obese patients underwent a mean excess weight loss of 41.7% at a mean of 26 weeks after RYGB. Surprisingly, this was associated with a further increase in mitosis and decreased apoptosis of epithelial cells. At the same time, lower levels of serum C-reactive protein and interleukin-6 following RYGB were accompanied by a reduction in mucosal IL-6 protein content but elevated mucosal expression of other proinflammatory genes such as cyclooxygenase-1 and cyclooxygenase-2.

CONCLUSIONS

Mucosal biomarkers, accepted as indicators of future colorectal cancer risk, are increased in morbidly obese patients compared with normal weight controls. The hyperproliferative state that exists 6 months after RYGB may have important implications for long-term colorectal cancer risk in bariatric surgery patients.

p53 and mdm2 expression in colorectal carcinoma: a correlative analysis with clinical staging and histological parameters

Colorectal carcinoma (CRC) is rare in the Indian subcontinent. The two-hit carcinogenic theory has been well established from the turn of this century, in which p53 is described as a late marker in colorectal carcinogenesis, and murine double minute 2 (mdm2) has not yet been correlated with colorectal carcinoma. With the recent introduction of anti-mdm2 oligonucleotides, it is apparent that if its role can be established in colorectal carcinogenesis, the DNA conservation of the wild p53 strain would be achieved therapeutically because mdm2 conserves the wild p53 strain. We studied 32 cases with adequate number of controls and found a positive correlation (P = .001) between these proteins. These proteins were expressed in tumor adjacent to the hyperplastic mucosa, dysplastic mucosa, and aberrant crypt foci, unlike in studies in the West. The expression of these proteins was correlated with aggressive tumor behavior. All these indicate significant diagnostic, therapeutic, and prognostic roles for these proteins.

Risk of colorectal cancer and other cancers in patients with gall stones

BACKGROUND

The occurrence of gall stones has repeatedly been associated with an increased risk for cancer of the colon, but risk associated with cholecystectomy remains unclear.

AIMS

To evaluate the hypothesis in a nationwide cohort of more than 40,000 gall stone patients with complete follow up including information of cholecystectomy and obesity.

PATIENTS

In the population based study described here, 42,098 patients with gall stones in 1977-1989 were identified in the Danish Hospital Discharge Register.

METHODS

These patients were linked to the Danish Cancer Registry to assess their risks for colorectal and other cancers during follow up to the end of 1992.

RESULTS

The analysis showed a modest increase in the number of cancers at all sites combined (n = 3940; RR, 1.07; 95% confidence intervals (CI), 1.0 to 1.1). A weak association was found for cancer of the colon (n = 360; RR, 1.09; 95% CI 1.0 to 1.2), which remained unchanged when analysed by sex, anatomical subsite, and duration of follow up. Multivariate analysis with adjustment for cholecystectomy and clinically defined obesity did not change these estimates to any significant extent. Excess risks were found for cancers of the pancreas and the small intestine. A non-significant increased risk for breast cancer was seen in women five years after initial discharge for gall stones.

CONCLUSION

A borderline significant association was seen between gall stones and cancer of the colon, and for cancer of pancreas and small intestine as well as for breast cancer in women.

Recent advances in the management of gallstones

Demands for less invasive, more cost-effective therapy have revolutionized the management of gallstones over the past 10 years. There are no reliable methods of permanently reversing the pathophysiologic defects that cause gallstones. Open cholecystectomy (OC), the gold standard for managing symptomatic cholelithiasis, has been largely replaced by laparoscopic cholecystectomy (LC), which has the advantages of a minimal hospital stay and quicker return to work. Other adjunctive therapies, limited in applicability to selected patients, include oral bile acid therapy (BAT), dissolutional agents, and extracorporeal shock wave lithotripsy. Choledocholithiasis (CDL), formerly managed exclusively with surgical common duct exploration, is increasingly treated with therapeutic biliary endoscopy. Methods of laparoscopic common bile duct exploration are being developed. Optimal algorithms for applying these techniques to patients undergoing LC are evolving. In a sense, the solution to all, or certainly most, gallstones now can be seen through a scope.

Cholecystectomy and colorectal cancer in China

Colorectal cancer is a major public health problem in China: 79,800 new cases are estimated to occur each year, which ranks it among the five most common tumours in China. Although the association between cholecystectomy and colorectal cancer has been studied elsewhere, few studies have been conducted in the Chinese population, characterized by a lower fat intake, and low colorectal cancer incidence. We conducted this hospital-based case-control study to explore this association. The study included a total of 503 incident cases with pathologically diagnosed colorectal cancer in Drum Tower Hospital at Nanjing in China from 1965 to 1986, and 2188 healthy controls who had annual routine physical examinations at the same hospital. Diagnosis of cholelithiasis was confirmed by ultrasonography or X-ray cholecystography, and the information on cholecystectomy was obtained by checking medical charts for both cases and controls. The prevalence of cholelithiases was 5.8% for cases and 6.1% for controls (P > 0.05). Eight cases (1.6%) and 18 controls (0.8%) had a history of previous cholecystectomy. The period between cases' cholecystectomy and diagnosis of colorectal cancer ranged from 2.5 to 23 years, and the mean interval was 8.9 years. The crude odds ratio for patients having previous cholecystectomy is 1.95 (95% CI: 0.84-4.51) compared with controls. The odds ratio for female patients with previous cholecystectomy was 2.79 (95% CI: 1.03-7.59). When subsites were analysed, a significant association between right colon cancer and cholecystectomy was noted: the odds ratio was 6.2 (95% CI: 2.24-16.9), and that for females was even higher 8.61 (95% CI: 2.44-3.04) with statistical significance.(ABSTRACT TRUNCATED AT 250 WORDS)

A meta-analysis of cholecystectomy and risk of colorectal cancer

BACKGROUND

Over 60 studies have addressed the hypothesis that the risk of colorectal cancer is increased following cholecystectomy; these studies have yielded inconsistent findings. The aim of the present study was to quantitatively summarize the results from the collective studies.

METHODS

A meta-analysis of the published studies addressing the relation between cholecystectomy and colorectal cancer was conducted.

RESULTS

The combined results from 33 case-control studies showed an association between cholecystectomy and risk of colorectal cancer (pooled relative risk [RR] = 1.34; 95% confidence interval [CI] = 1.14-1.57), particularly when limited to the proximal colon (RR = 1.88; 95% CI = 1.54-2.30). In most studies, the risk was stronger when the first 5-15 years following the surgery were excluded. The results from 6 cohort studies, with follow-up to approximately 15 years postcholecystectomy, were generally null (RR = 0.97; 95% CI = 0.82-1.14). A more limited body of evidence suggests that cholelithiasis is related to an elevated risk of proximal colon cancer.

CONCLUSIONS

Because the risks varied substantially by study design and because time since cholecystectomy or potentially confounding factors were often not considered, we could not firmly quantitate this risk. However, the findings are consistent with other evidence that suggests some characteristic of bile acid metabolism increases the risk of cancer of the proximal colon.

Cholecystectomy and colorectal cancer

BACKGROUND

An increased risk of large bowel cancer, especially of the right colon, following cholecystectomy has been reported in some studies but contradicted in others. The aim of this study was to settle this question by creating a cohort of cholecystectomy patients that was large enough and with a sufficient follow-up time to detect even weak associations.

METHODS

A population-based cohort consisting of 62,615 patients who underwent cholecystectomy was followed up for the occurrence of colorectal cancer up to 23 years.

RESULTS

There were 633 colorectal cancers versus 637.9 expected (standardized incidence ratio [SIR] = 0.99; 95% confidence interval [CI] = 0.92-1.07). Analyses of an extensive number of subgroups including sex, age at operation, duration of follow-up, underlying diagnosis, type of operation, and different cancer sites did not show any association. However, for cancer of the right colon among women, the risk was increased (SIR = 1.24; 95% CI = 1.03-1.48) most prominent 15 years or more after operation (SIR = 1.54; 95% CI = 1.03-2.22).

CONCLUSIONS

Overall, there is no excess risk of colorectal cancer following cholecystectomy, but consistent with some earlier reports, we observed an increased risk among women for right-sided colon cancer 15 years or more after operation.

Cholecystectomy and colorectal cancer: evidence from a cohort study on diet and cancer

The association between cholecystectomy and subsequent risk for colorectal carcinoma was investigated in a prospective cohort study on diet and cancer (n = 120,852), which is being conducted in the Netherlands from 1986 onwards among 120,852 men and women, aged 55 to 69. After a follow-up period of 3.3 years, 478 incident cases of colorectal cancer (258 men and 220 women) were identified in the cohort, 64 of whom reported at baseline to have undergone previous gall-bladder surgery (21 men and 43 women). After adjustment for age and familial history of large-bowel cancer, the relative rate (RR) for colorectal cancer in subjects who had undergone cholecystectomy compared with those who had not was 1.81 in men (p = 0.02) and 1.47 in women (p = 0.05). Additional adjustment for parity. Quetelet index, alcohol intake and other dietary variables resulted in a RR of 1.78 in men and 1.51 in women. In women, the highest RR was detected in the right colon (RR = 1.89), whereas in men, no site within the large bowel accounted specifically for the increased relative rate. In both men and women, the rate appeared to increase from approximately 6 years after cholecystectomy onward. According to the TNM stage of the disease, cholecystectomized patients were not detected at an earlier stage than the other patients. It is concluded that in this study the positive association between colorectal cancer and cholecystectomy cannot be explained by detection bias or ascertainment bias and is not confounded by risk factors for gallstone disease or dietary factors.

Gallstones and colorectal cancer--there is a relationship, but it is hardly due to cholecystectomy

The prevalence of gallstone disease in 145 consecutive patients with colorectal cancer was compared with gallstone prevalence in 4,159 subjects randomly selected from a population. The group of patients had a significantly higher prevalence of gallstone disease than the population (odds ratio = 1.59; 95 percent confidence limits 1.04-2.45), whereas cholecystectomies occurred with equal frequency in the two groups. There was a nonsignificant trend toward more right-sided cancers in patients with gallstones than in patients without. These results, together with available literature, give substantial evidence for an association between gallstones and colorectal cancer, an association which is not due to cholecystectomy being a predisposing factor to colorectal cancer. Sporadic findings of an association between cholecystectomy and colorectal cancer can be explained by the above relationship.

Faecal bile acid excretion in children with inflammatory bowel disease

Faecal bile acid excretion and intestinal transit time were studied in 18 children with inflammatory bowel disease in clinical remission and with normal stools: 16 with ulcerative colitis, two with Crohn's colitis, mean age 14 years (range 10-17 years). Five healthy children, mean age 12.4 years (range 10-17 years), were studied as control subjects. Most patients were taking sulphasalazine, but none were taking steroids. Transit time was determined by carmine and did not differ between groups. Faeces were collected for 72 hours, and faecal water was prepared by centrifugation of faeces at 15,000 x g for two hours. Bile acids in total faeces and faecal water were studied using capillary gas-liquid chromatography-mass spectrometry. Faecal excretion of total bile acids, unconjugated bile acids, and glycine and taurine conjugates were significantly increased in patients as was faecal water excretion of total bile acids, particularly the taurine conjugates and cholic and chenodeoxycholic acids. Total concentrations of bile acids in faeces and faecal water were two to five times higher in patients. The children with inflammatory bowel disease in clinical remission had high excretion and concentration rates of bile acids, especially taurine conjugates, in both total faeces and faecal water, a finding of considerable interest in the pathogenesis of malignancy in these diseases.

Cholecystectomy as a risk factor for colorectal adenomatous polyps and carcinoma

Multiple studies have suggested a possible relationship between prior cholecystectomy and the occurrence of subsequent colorectal carcinoma. This relationship has been particularly noticed among female patients and for right-sided lesions of the colon. In the current study, the authors undertook a case-control study among patients who underwent colonoscopy in three private practices in New York City between April 1986 and March 1988. Over this period, 302 adenomatous polyp cases, 106 colon cancer cases, and 507 controls were interviewed regarding their prior history of cholecystectomy. Overall, no significant association was observed between cholecystectomy and either colorectal adenomatous polyps or cancer. Cholecystectomy does not appear to be a significant risk factor for colorectal neoplasia.

Cholecystectomy and right colon cancer in Puerto Rico

A case-control study was undertaken to evaluate the possible relationship between cholecystectomy and right colon cancer. Two hundred patients with adenocarcinoma of the cecum or ascending colon (diagnosed between 1984 and 1989) were compared with 200 matched neighborhood controls. Cholecystectomy history was obtained through interviews using structured questionnaires and subsequently validated from hospital records. A statistically significant association (odds ratio = 2.14) was found between right colon cancer and a history of prior cholecystectomy. The altered bile metabolism which occurs after removal of the gallbladder may have a carcinogenic effect on the right colon. Dietary habits of the colon cancer patients in our study were consistent with prior reports in the literature, showing that this group has a lower intake of vegetables and cereal fiber than the control population.

The relationship between cholecystectomy and colon cancer: an Iowa study

The relationship between cholecystectomy and subsequent development of colon cancer was investigated in a case-control study of 165 patients with histologically proven adenocarcinoma of the colon. These patients were from a community in Iowa where incidence of colon cancer was considered to be higher than average in the United States. The relative risk of developing colon cancer after cholecystectomy was shown to be 2.11 (P = .009) for the entire series and 2.91 (P = .002) for the female group. There was a difference of frequency in developing colon cancer after cholecystectomy between the right- and left-sided colons; the relative risk of the right versus the left colon cancer was 2.31 (P = .019). The other factors, including blood group, red cell indices, obesity, serum cholesterol, colonic diverticula, and co-existence of hyperplastic or adenomatous polyp disclosed no significant relation to colon cancer developed after cholecystectomy.

Cholelithiasis in childhood: a follow-up study

Fifteen children with cholelithiasis who were treated at the Royal Hospital for Sick Children, Glasgow between 1973 and 1985 are reviewed. Ten patients had idiopathic gallstones and five had gallstones in association with hereditary spherocytosis. All patients have been followed up for between 4 months and 12 years (mean 4.1 years): ultrasonography has been carried out on 13. Fourteen patients underwent surgery of whom only seven had symptoms from their gallstones. Nine patients had cholecystostomy and removal of gallstones, four patients had cholecystectomy (one had negative exploration of the common bile duct in addition) and one patient with choledocholithiasis underwent choledochotomy with transduodenal sphincterotomy. One patient did not have surgery; she has remained asymptomatic and ultrasound examination confirms that she still has a solitary gallstone in her gallbladder. Clinical review with ultrasonography shows that cholecystostomy with removal of gallstones appears to be an acceptable alternative to cholecystectomy.

Cholecystectomy and adenomatous polyps of the colon in women

The relationship between prior cholecystectomy and colon cancer in women has been a subject of recent research interest. No study has yet reported on cholecystectomy and adenomatous polyps, a precursor lesion for most colon cancers. This pilot case-control study interviewed 245 women who had undergone colonoscopy between 1983 and 1985 at Columbia-Presbyterian Medical Center with a structured telephone-administered questionnaire. Fifty-six were colon cancer cases, 105 were adenomatous polyp (AP) cases, and 84 were controls (without colonic neoplasia). Adjusted for age and educational attainment, the odds ratio for prior cholecystectomy among colon cancer cases compared to controls was 1.79 (95% confidence limits, 0.59 to 5.44) and 2.26 for right-sided colon cancer cases (95% confidence limits, 0.61 to 8.42). Despite a lack of statistical power, these estimates are consistent with earlier reports. The odds ratio for adenomatous polyp cases was 1.02 (95% confidence limits, 0.40 to 2.64), suggesting no association between prior cholecystectomy and adenomatous polyps. These preliminary findings are currently being explored in a large-scale case-control study.