Clinicopathological characteristics of colon cancer diagnosed at primary health care institutions.

BACKGROUND/AIMS: The purpose of this study was to evaluate the clinicopathologic characteristics of colon cancers detected at the SOK Sokpeynhan Internal Medical Network, a nationwide system of primary health care institutions. METHODS: We analyzed 579 colon cancer patients diagnosed using colonoscopy at the SOK network from January 2011 through December 2012. Cancers from the rectum to the splenic flexure were classified as left colon cancer. Patients over 65 were classified as senior. RESULTS: The mean age (±SD) of subjects was 60.9±10.5 years and 61.1% were men. More than one quarter (28.2%) of patients were asymptomatic. The prevalence of left colon cancer was higher (77.9%) than that for right colon cancer. The most frequent macroscopic and histologic types were depressed (58.9%) and moderately differentiated adenocarcinoma (52.2%), respectively. Asymptomatic subjects displayed protruding or well differentiated adenocarcinoma, while symptomatic patients were more likely to display depressed or moderately differentiated adenocarcinoma (P<0.05). The mean age of the right colon cancer group was higher than that for the left colon cancer group (P<0.05). Among symptomatic patients, the most frequent symptoms were bloody stool for patients with left colon cancer and abdominal discomfort for patients with right colon cancer (P<0.05). The prevalence of depressed cancer was higher in older subjects as compared to younger subjects (P<0.05). The prevalence of right colon cancer tended to increase with age, although this difference did not achieve statistical significance (P>0.05). CONCLUSIONS: Study results indicated an increase of colon cancer amongst younger demographics in recent years. The effectiveness of colonoscopy screening was also evident, as asymptomatic patients demonstrated frequent findings of well differentiated adenocarcinomas. Study results also suggested a need for closer examination of older patients, as right colon cancer tended to increase with age.

[Clinicopathologic characteristics of superficial gastric cancer diagnosed at primary health care institutions in 2011].

BACKGROUND/AIMS: Stomach cancer is prevalent in Korea. The purpose of this study was to evaluate the characteristics of superficial gastric cancers detected at SOK Sokpeynhan Internal Medical Network, the nationwide primary health care institutions. METHODS: We prospectively analysed the clinicopathologic and endoscopic characteristics of 218 superficial gastric cancer patients diagnosed using gastric endoscopy at SOK network from January 2011 through December 2011. RESULTS: The mean age was 58.5 years old and male to female ratio was 1.7 : 1. Asymptomatic patients were most common (45.0%). The macroscopic classification revealed that simple types (63.8%) were more common than complex types (36.2%). The most common type was IIc (28.4%) and other types were as follows; IIb (16.1%), IIb+IIc (13.3%), IIa (10.6%), III (9.2%), IIa+IIc (7.3%), IIc+IIa (6.0%), IIc+IIb (5.0%). The most commonly involved sites were the body (53.1%) and greater curvature (32.6%) of the stomach. The size of lesion was less than 1 cm (69.3%) and less than 5 mm (33.5%) in diameter. The most common pathologic type was tubular adenocarcinoma (75.7%). Helicobacter pylori infection rate was 50.2%. Fifty five percent of the cases were diagnosed via endoscopy of National Health Insurance Corporation screenings. CONCLUSIONS: Superficial gastric cancers in 2011 at primary health care SOK network were different from those of previous reports. Type IIc was most common but type IIb was more prevalent and the body and greater curvature of the stomach were the most commonly involved sites. Therefore, careful observation of the proximal gastric mucosa and mucosal color change is needed.

p53 mutations and microsatellite instabilities in the subtype of intestinal metaplasia of the stomach.

To investigate the potential implication of the subtype of intestinal metaplasia in the progression to the gastric carcinoma, we analyzed the mutations of the p53 gene and microsatellite instability (MSI) both in the complete type (type I) and in the sulphomucin-secreting incomplete type (type III) intestinal metaplasia located adjacent to the gastric carcinoma. p53 mutations were observed in 13.3% of type I, in 6.6% of type III intestinal metaplasia, and in 40% of gastric carcinoma. The difference between p53 mutations observed in type I and type III intestinal metaplasia was not statistically significant. No identical mutation of the p53 gene was found in the intestinal metaplasia and carcinoma specimens from the patients. There was no case of intestinal metaplasia showing MSI. In gastric carcinomas, MSI was observed in six cases (40%). The cases harboring BAT-26 instability did not have the mutation of the p53 gene. These data suggest that intestinal metaplasia adjacent to gastric carcinoma, irrespective of its subtype, do not have the genetic alterations as showing in their carcinoma tissues.

The effect of the repeated subcultures of Helicobacter pylori on adhesion, motility, cytotoxicity, and gastric inflammation.

In vitro subcultures of bacteria can lead to genetic and phenotypic changes. This study aimed at investigating the effect of repeated subcultures on the adhesion, motility, cytotoxicity, and gastric inflammation caused by Helicobacter pylori. H.pylori SS1 strain was subcultured 64 times on agar plates containing Brucella broth and 5% bovine calf serum. The adhesion, motility, cytotoxicity, and gastric inflammation produced in Mongolian gerbils were compared between the first and 64th subcultured strain. The adhesion rates, following 3 hr exposure of AGS cells to either the first strain or the 64th-transferred strain, were 21% and 12%, respectively. The motility of the 64th-transferred strain decreased significantly when compared to the 1st strain (9.1 mm vs. 15.1 mm). The cytotoxicity index tended to be higher in the first strain than in the 64th-transferred strain (73.7% vs. 69.2%). The initial infection rate on the gerbils showed no difference between the two strains. However, chronic gastric inflammation of the first strain-infected gerbils was somewhat more severe than that of the 64th-transferred strain-infected gerbils. Therefore, the use of repeatedly subcultured strains of H. pylori in virulence experiments can lead to different results from those of the original strain.

Effects of selective cyclooxygenase-2 inhibitor and non-selective NSAIDs on Helicobacter pylori-induced gastritis in Mongolian gerbils.

BACKGROUND: It is still a point of controversy whether Helicobacter pylori-infected patients are more likely to develop mucosal damage while taking NSAIDs. Selective cyclooxygenase (COX-2) inhibitors may be associated with less severe gastric mucosal damage than conventional NSAIDs, but this association is undefined in H. pylori-induced gastritis. The aim of this study was to evaluate the effects of selective COX-2 and nonselective NSAIDs on H. pylori-induced gastritis. METHODS: After intragastric administration of indomethacin, NS-398 or vehicle alone, once daily for 5 days in H. pylori-infected and uninfected Mongolian gerbils, we evaluated gastric mucosal damage, inflammatory cell infiltration and prostaglandin E2 (PGE2) concentration. We investigated whether H. pylori infection induced the COX-2 expression. RESULTS: In H. pylori-uninfected groups, the indomethacin-treated group showed the highest mucosal damage score and the lowest PGE2 concentration. There was no difference in mucosal damage scores and PGE2 concentration between NS-398 and vehicle-alone treated group. In H. pylori-infected groups, there was no difference in mucosal damage scores, irrespective of the type of drugs administered. The indomethacin-treated group showed the lowest PGE2 concentration, similar to that of the NS-398 and vehicle-alone treated groups, both without H. pylori infection. Gastric neutrophil and monocyte infiltration scores were higher in H. pylori-infected groups than in uninfected groups. However, there was no difference in these scores according to the type of drugs administered, within H. pylori-infected or uninfected groups. COX-2 protein expression was observed in H. pylori-infected Mongolian gerbils but not in uninfected ones. CONCLUSIONS: Our animal study showed that H. pylori infection induced COX-2 expression and increased prostaglandin concentration. Administration of NSAIDs decreased the prostaglandin concentration, but did not increase mucosal damage in H. pylori-induced gastritis. Selective COX-2 inhibitors, instead of conventional NSAIDs, had no beneficial effect on preventing mucosal damage in H. pylori-induced gastritis.