Diet, lifestyle, and colon cancer

Diet and lifestyle modification offers means of reducing risk of developing colon cancer. Current data suggest that consuming a Western style diet, that is, one high in meat, refined grains, and sugar and low in vegetables and fiber, may contribute to risk of colon cancer. There also are data to support a reduction in colon cancer risk from consuming high levels of calcium and folate. Energy balance and maintaining an appropriate body weight have been associated with a reduced risk of colon cancer. An important part of the energy balance equation is physical activity. High levels of physical activity have consistently been identified as being associated with a reduced risk of colon cancer. It is estimated that 13% of colon cancer can be attributed to being physically inactive, 12% of colon cancer can be attributed to eating a Western style diet, and 8% of colon cancer can be attributed to having a first degree relative with colorectal cancer.     

Bacteria, inflammation, and colon cancer

INTRODUCTION Our relationship with the colonic bacterial flora has long been viewed as a symbiotic one. We provide a nutrient- rich habitat, while the bacteria play important roles in the development of the mucosal immune system, the maintenance of a phys…     

Myoelectric spiking activity of right colon,left colon,and rectosigmoid of healthy humans

The tip of an intraluminal probe was positioned in the cecum, and before and after a standard meal (>800 kcal), the rapid myoelectrical activity of the right, the left, and the rectosigmoid colon in six healthy subjects was recorded. In each colonic site, we recorded two different patterns of spike bursts: Short spike bursts and long spike bursts, as previously described. We observed no difference in either the duration or the amplitude of the two kinds of spike bursts among the three different parts of the colon. Before the meal, the number of long spike bursts was lower in the right than in the left colon (P<0.01) and than in the rectosigmoid (P<0.01). After the meal, a significant activity increase in long spike bursts lasted 20 min in the right colon (P<0.001), 100 min in the left colon, and in the rectosigmoid (P<0.001–P<0.05). This activity was always significantly less intense in the right colon than in the two other sites (P<0.001–P<0.01) and was less marked in the left colon than in the rectosigmoid (P 0.01–P<0.05). The short spike burst activity remained unchanged. These results provide evidence for the heterogeneity of motility in the different parts of the colon, with a relative hypomotility of the right colon compared to the left colon and the rectosigmoid in the healthy human.Prof. Robert Tournut died on January 2, 1987.     

The colon,anorectum, and spinal cord patient

As humans have become more mechanized, the number of persons sustaining spinal cord injuries resulting in quadriplegia or paraplegia has increased. Because colorectal function is modulated by a combination of neural, hormonal, and luminal influences, many of the normal regulatory mechanisms remain intact in patients with spinal cord injuries. Management of these patients, however, requires an understanding of altered function in the denervated hindgut. The foregut and midgut are innervated by parasympathetic fibers in the vagus and sympathetic fibers from the lower six thoracic vertebra. In contrast, the hindgut is innervated by parasympathetic fibers arising from the sacral plexus and sympathetic fibers from the lumbar spinal column. Consequently, in most spinal cord injuries, the foregut and midgut remain normally innervated whereas the hindgut looses input from cerebral and spinal cord sources. In high cord lesions this results in decreased colonic motility. In low cord injuries there is loss of inhibitory influences that normally down-regulate left colonic and rectosigmoid sphincter activity. This increased motility causes a loss of left colonic compliance and increases left colonic transit, thus leading to chronic constipation. At the same time in both high and low cord injuries, reflex activity of the anorectum is left unregulated by cerebral input. Once stimulated by distention, the rectum spontaneously evacuates its contents. Thus, fecal impaction and incontinence in these patients principally results from loss of inhibitory influences on rectosigmoid sphincter activity and on rectal reflex activity     

Gut microbiota,dysbiosis and colon lavage

Gut microbial dysbiosis is considered an alteration of diversity and abundance of intestinal microbes, which contributes to the onset of many disorders. Several factors cause dysbiosis, depending on life-style (nutrition, stress, environment, smoking, physical activity) or particular diseases (inflammatory, autoimmune, chronic diseases). Drugs (i.e. antibiotics, anticancer drugs), as well as medical and surgical procedures, can often cause dysbiosis. Mechanical bowel preparations (MBP) and the so called "bowel cleansing" have an immediate impact on intestinal microbial composition. Whether these "acute" changes may lead to any clinical consequences is still unknown. It is tempting to speculate that such dysbiosis fostering events, at least in patients already presenting abdominal complaints, such as irritable bowel syndrome (IBS), or inflammatory bowel disease (IBD) patients, may drive additional or more severe symptoms. Recently, the possibility of using probiotic supplementation has been addressed in the literature, with the purpose to counteract intestinal dysfunctional changes observed in relation to a dysbiotic state. Whereas probiotics are recognized to be effective and safe in restoring gut microbiota dysbiosis, preliminary evidence suggest that this approach may prove helpful even in case of transient dysbiotic states related to colonoscopy bowel preparation.     

Adenosquamous carcinoma of the colon, rectum, and anus

PURPOSE: There have been 49 cases of adenosquamous carcinoma of the colon, rectum, and anus reported in the English literature. We have reviewed 145 cases of adenosquamous carcinoma to better define epidemiologic and survival characteristics of this extremely rare colon carcinoma. METHODS: The National Cancer Institute's Surveillance, Epidemiology, and End Results program public use CD-ROM file for the years 1973 through 1992 were reviewed. This represents approximately 9.5 percent of the United States population. Adenosquamous carcinomas arising in the colon, rectum, and anus were identified using the International Classification of Diseases-O codes. The Astler-Coller tumor classification was used for staging. Two-tailed Student'st-test, Mantel-Haenszel chi-squared tests, and generalized Wilcoxon's tests were used for comparisons of means, proportions, and actuarial survival rates, respectively. Survival curves were calculated by the Kaplan-Meier method. RESULTS: One hundred forty-five cases of adenosquamous carcinoma were identified, representing 0.06 percent of all colorectal malignancies. The mean age of patients was 67 years. Eighty-four percent of patients were Caucasians, 15 percent were Afro-Americans, and 1 percent were other races. Afro-Americans were diagnosed at a significantly younger age (median age, 62 years;P=0.03). Fifty-three percent of the carcinomas were located in the sigmoid colon, rectum, and anus, 28 percent in the right colon, and the rest in the middle segment. Seventy-four percent of distal cases were staged A through C, compared with 44 percent of proximal cases. Patients with adenosquamous carcinoma of the sigmoid colon, rectum, and anus survived longer than all other patients (P=0.001). Patients with adenosquamous carcinoma Stages A and B₁ had survival rates similar to patients with comparably staged adenocarcinomas. Fifty percent of the patients, including most of the patients with D stage, died in the first year. Patients with Stages B₂, C, and D adenosquamous carcinomas had a significantly shorter survival than the comparably staged adenocarcinomas (P0.02). The overall adjusted five-year survival rate was 30.7 percent. In those patients who survived more than 24 months, the five-year survival was 84 percent. CONCLUSIONS: The survival rates for patients with adenosquamous carcinoma Stages A and B₁ are similar to patients with comparably staged colorectal adenocarcinomas. However, we found that patients with colorectal and anal adenosquamous carcinomas staged B₂ through D have significantly poorer survival than patients with comparably staged adenocarcinomas, supporting the previous reports of a poor prognosis associated with adenosquamous carcinomas.     

Pathophysiology, clinical presentation, and management of colon cancer

Colon cancer is believed to arise from two types of precursor polyps via two distinct pathways: conventional adenomas by the conventional adenoma-to-carcinoma sequence and serrated adenomas according to the serrated adenoma-to-carcinoma theory. Conventional adenomas arise from mutation of the APC gene; progression to colon cancer is a multistep process. The fundamental genetic defect in serrated adenomas is unknown. Environmental factors can increase the risk for colon cancer. Advanced colon cancer often presents with symptoms, but early colon cancer and premalignant adenomatous polyps commonly are asymptomatic, rendering them difficult to detect and providing the rationale for mass screening of adults over age 50.     

Diverticula,diverticulosis and diverticulitis of the colon

Summary Solitary diverticula, diverticulosis, and diverticulitis are defined and discussed as separate clinical entities. Diverticula of the “true” and “false” varieties are differentiated from each other with respect to their embryologic and physiopathologic characteristics. The diagnosis of diverticulosis and diverticulitis is discussed. The problem of colonic hemorrhage in the elderly patient with diverticulosis and hypertensive cardiovascular disease is presented. The cause of bleeding in diverticulosis and diverticulitis is discussed. A one-stage resection of the sigmoid flexure for diverticulitis is described and illustrated.     

Primary sclerosing cholangitis, inflammatory bowel disease, and colon cancer

The prevalence of inflammatory bowel disease (IBD) in patients with PSC differs in various part of the world. Ulcerative colitis (UC) is most common, but 1 to 14% of all primary sclerosing cholangitis (PSC) patients have Crohn disease with colonic involvement. Many PSC patients without clinical symptoms of IBD have colonoscopic and histological findings compatible with IBD, and the subclinical phase may last several years before onset of symptoms of active colitis. The characteristics of UC in patients with PSC are different from those in UC patients without PSC. The colitis is usually substantial, the clinical course of the colitis is quiescent, and rectal sparing is common. Moreover, PSC patients with UC have a higher risk of developing colorectal dysplasia/carcinoma than UC patients without PSC. In patients having an ileal pelvic pouch with ileal anal anastomosis, PSC is a risk factor for development of pouchitis. It is important that all PSC patients with UC are included in colonoscopic surveillance programs.