胆囊切除与大肠癌

大肠癌是常见的恶性肿瘤之一，国外对大肠癌与胆囊病关系的研究已达到分子生物学水平。在国内虽然大肠癌发病率相对较低，但随着饮食结构的改变，大肠癌的发病率也逐年升高。但大肠癌的病因尚未明确，可能与饮食习惯、遗传素质、大肠腺瘤病、慢性黏膜炎症等有关。1978首次报道胆囊切除术可增加大肠癌的发病率，引起人们对两者之间关系的关注。     

Cyclooxygenase-2 Expression in Colorectal Adenomas

PURPOSE: Cyclooxygenase-2 is an important target for nonsteroidal anti-inflammatory drugs in suppressing colorectal tumorigenesis. To evaluate the role of cyclooxygenase-2 in sporadic colorectal adenoma, we correlated cyclooxygenase-2 expression in adenomas with other adenoma characteristics. METHODS: Cyclooxygenase-2 expression was evaluated immunohistochemically in 95 endoscopically resected colorectal adenomas. RESULTS: Cyclooxygenase-2 was expressed mainly in the cytoplasm of adenoma cells, where it was seen in 74 percent (70/95) of adenomas. Expression was related significantly to grade of dysplasia (P < 0.001) and tumor size (P = 0.028). Multivariate logistic regression analysis showed cyclooxygenase-2 expression in adenoma cells to be independently associated with grade of dysplasia (P = 0.001). CONCLUSION: Observed associations suggest that cyclooxygenase-2 plays an important role in progression of the adenoma-to-carcinoma sequence.     

Moderate Alcohol Consumption Protects Against Colorectal Adenomas in Smokers

Background Although some studies have shown an association between alcohol consumption and colorectal adenomas, the effect of moderate alcohol consumption is not well defined, nor is the interaction between alcohol and smoking. Aim To investigate the relationship between different levels of alcohol consumption and colorectal adenomas and to determine whether smoking modifies this relationship. Methods Eligible patients who underwent a complete colonoscopy were included (179 cases and 466 controls). Alcohol consumption was obtained from a lifestyle questionnaire. Patients were divided into three groups: (1) Abstainers: 0 drinks/week; (2) Moderate drinkers: > 0 to <7 drinks/week; (3) Heavy drinkers: > 7 drinks/week. Odds ratios (OR) were calculated using logistic regression, controlling for gender, age, body mass index, use of non-steroidal anti-inflammatory medications. Results were stratified by the number of years smoked. Results The proportion of patients with adenomas was 29.6% in abstainers, 22.1% in moderate drinkers, and 36.7% in heavy drinkers. The relationship between alcohol consumption and colorectal adenomas varied significantly by smoking history. For individuals who had never smoked, heavy drinkers were at significantly increased odds of having an adenoma compared to moderate drinkers (OR 3.08; 95% CI: 1.50–6.32), while no difference was seen for abstainers (OR 0.99; 95% CI: 0.52–1.89). Similarly, among individuals who had smoked 1–14 years, heavy drinkers were at increased odds of having an adenoma compared to moderate drinkers (OR 2.61; 95% CI: 1.04–6.51), and no difference was seen for abstainers (OR 1.02; 95% CI: 0.33–3.10). Somewhat unexpectedly, among individuals who had smoked for 15 or more years, abstainers were at increased odds of having an adenoma compared to moderate drinkers (OR 2.04; 95% CI: 0.91–4.59), while heavy drinkers were not at increased odds of having an adenoma (OR 0.73; 95% CI: 0.27–1.97). Conclusions Consumption of less than seven alcohol drinks per week does not increase the risk of having a colorectal adenoma. We found evidence in this study that moderate alcohol consumption among long-term smokers may potentially decrease the risk of an adenoma compared to abstainers.     

胆囊切除与结直肠息肉相关性的研究

背景：胆囊切除已被认为是结直肠癌的危险因素之一,但胆囊切除与结直肠息肉的关系一直未受到重视。目的：探讨胆囊切除与结直肠息肉的相关性。方法：连续收集经结肠镜排除恶性肿瘤、炎症性肠病、家族性腺瘤性息肉病等疾病的患者425例,根据既往有无胆囊切除史分为胆囊切除组（n=63）和对照组（n=362）,对两组患者结直肠息肉的发生率、内镜下息肉表现和组织学类型进行分析。结果：胆囊切除组结直肠息肉发生率高于对照组（46.0%对37.8%）,但差异无统计学意义（P=0.219）。两组患者息肉的部位和形态均无明显差异（P=0.753,P=0.127）;但胆囊切除患者腺瘤性息肉的发生危险显著高于对照组（OR=1.79,P=0.006）。亚组分析示胆囊切除史≥10年的结直肠息肉发生率与胆囊切除史〈10年无明显差异（P=0.11）。结论：胆囊切除并未增加结直肠息肉发生的危险性,但腺瘤性息肉的发生率显著增高,因此对胆囊切除患者应重视早期结直肠癌和腺瘤性息肉的筛查。     

Alcohol and Cigarette Smoking and the Risk of Colorectal Adenomas

Whether alcohol and tobacco can be considered as risk factors for the occurrence of adenomas remains inconclusive. A case–control study was carried out to examine these factors while taking into account possible confounding factors. One hundred eighty-two patients with colorectal adenomas and similar numbers of hospital and population controls were compared as to intake of alcohol and various nutrients including smoking and drug intake. There was a positive association between cigarette smoking and adenoma risk compared with hospital controls, the RR being 2.3 (1.1–4.6). Overall alcohol intake was no risk factor in hospital controls, but drinking liquor was associated with an increased risk, the RR being 4.1 (1.3–13.4) and was especially marked in males [RR 10.2 (2.3–46.2)]. Compared with population controls, there was no increased RR associated with smoking or alcohol intake. None of the risk factors was positively associated with disease risk in those with small or large adenomas. These findings suggest that alcohol and tobacco play no major role in the formation or growth of adenomas.     

Lack of Relationship between Cholecystectomy and Colorectal Cancer

To study the postulated relationship between prior cholecystectomy and occurrence of subsequent colorectal cancer, we examined the prevalence of cholecystectomy in all patients with histologically confirmed colorectal cancer registered during 1966–75 in the city of Malmö. In addition, we studied the frequency of colon cancer in all females autopsied in 1978–79 with a previous cholecystectomy. Of all 1061 cases of colon cancer diagnosed during the 1966–75 period. 94 (8.9%) had undergone cholecystectomy, as compared with 106 (10.0%) in the age-matched controls. In the female subgroup (n = 503) the corresponding figure for cholecystectomy was 58 (11.5%), as compared with 70 (13.9%) in the controls. The incidence of right-sided colon cancer among the 58 females with previous cholecystectomy did not differ from that of age-matched controls (28.6 and 28.1%, respectively). The incidence of colon cancer among 305 females with a prior cholecystectomy autopsied during 1978–79 was 24 (7 right-sided), as compared with 22 (8 right-sided) in age-matched controls without gallbladder disease. Gastric cancer was more frequent (p < 0.01) in cholecystectomized women than in controls. These results refute the suggested relationship between cholecystectomy and development of colon cancer in any location.     

Colorectal flat neoplasia

BACKGROUND AND AIMS: An attempt has been made to evaluate the clinicopathological characteristics of flat colorectal neoplastic lesions, and analyse the factors associated with the malignancy. PATIENTS AND METHODS: A total of 115 flat neoplastic lesions, > or = 5 mm in size, diagnosed in 87 patients by colonoscopy, were investigated. RESULTS: The rectum was the most common location. Almost half (49.6%) of the flat neoplasms were small (5-10 mm), 27.8% were 11-20 mm and the remainder (22.6%) larger than 20 mm. The surface was smooth in 55.7%, granular in 20.0% and nodular in 24.3%. Histologically, the flat lesions were tubular, tubulovillous and villous adenomas in 69.6%, 20.9% and 5.2%, respectively. Five lesions (4.3%) were composed of carcinomas without adenoma. High-grade dysplasia, intramucosal carcinoma and invasive carcinoma were diagnosed in 9.6%, 7.8% and 6.1% of all flat neoplasms, respectively. Univariate analysis demonstrated that the location, size, surface pattern and histologic type of the flat lesions were factors associated with malignancy. However, in multivariate analysis, the size of the flat lesions was the only significant risk factor for malignant transformation. CONCLUSIONS: Flat neoplastic lesions of the colorectum have a relatively high rate of malignancy, and size is the most important factor associated with malignancy.     

Colorectal Adenomas and Diet

It has been postulated that high intakes of animal fat and protein and low intakes of fiber, calcium, and antioxidants increase the risk of colorectal cancer. Whether specific types of protein such as that from red meat are important, and whether vegetables might be key protective factors will also be considered in this study. Dietary intake over the past year was studied according to the diet history method by means of a case-control study in 184 cases and matched controls. After adjustment for energy, relative weight, and social class, no associations were found for fat or protein in comparison with either control group. Unexpectedly, carbohydrate intake was inversely related with adenoma risk, the RR being 0.29 (0.10-0.81) for quintile 5 versus 1 in comparison with hospital controls. None of the antioxidants showed a significant protective effect except beta-carotene intake in comparison with hospital controls, the RR being 0.24 (0.11-0.50) for the highest versus the lowest quintile. There was, however, a statistically significant positive association between adenomas and meat consumption with the RR for the highest versus the lowest quintile. There was, however, a statistically significant positive association between adenomas and meat consumption with the RR for the highest versus the lowest quintile of intake being 3.6 (1.7-7.5) in comparison with hospital controls and 4.4 (1.6-12.1) in comparison with population controls. Our data support the protective role for carbohydrate intake and of beta-carotene intake in the etiology of colorectal adenomas and show a strong increased risk for developing adenomas in those with high meat intake.     

Risk factors associated with missed colorectal flat adenoma: A multicenter retrospective tandem colonoscopy study

AIM: To determine the miss rate for colorectal flat adenomas during colonoscopy and the risk factors. METHODS: Flat adenomas are frequently missed during colonoscopy. However, the risk factors that influence their miss rates are unclear. This was a multicenter, retrospective study in which patients diagnosed with colorectal adenomas at a diagnostic colonoscopy and followed within 3 mo by a second therapeutic colonoscopy were pooled out from the established database. The “per-patient” and “per-adenoma” adenoma miss rates (AMR) for overall adenomas and flat adenomas, and patient-, adenoma-, and procedure-related risk factors potentially associated with the “per-adenoma” AMR for flat adenomas were determined. RESULTS: Chromoscopy and high-definition colonoscopy were not taken under consideration in the study. Among 2093 patients with colorectal adenomas, 691 (33.0%) were diagnosed with flat adenomas, 514 with concomitant protruding adenomas and 177 without. The “per-patient” AMR for flat adenomas was 43.3% (299/691); the rates were 54.3% and 11.3%, respectively, for those with protruding adenomas and those without (OR = 9.320, 95%CI: 5.672-15.314, χ² = 99.084, P < 0.001). The “per-adenoma” AMR for flat adenomas was 44.3% (406/916). In multivariate analysis, older age, presence of concomitant protruding adenomas, poor bowel preparation, smaller adenoma size, location at the right colon, insufficient experience of the colonoscopist, and withdrawal time < 6 min were associated with an increased “per-adenoma” AMR for flat adenomas. The AMR for flat adenomas was moderately correlated with that for overall adenomas (r = 0.516, P < 0.0001). The AMR for flat adenomas during colonoscopy was high. CONCLUSION: Patient’s age, concomitant protruding adenomas, bowel preparation, size and location of adenomas, proficiency of the colonoscopist, and withdrawal time are factors affecting the “per-adenoma” AMR for flat adenomas.     

糖尿病与结直肠癌患病危险关系的调查分析

目的:了解糖尿病(DM)与结直肠癌患病的关系,明确糖尿病相关因素对结直肠癌发病的影响.方法:采用病例对照的方法分析同时期住院的结直肠癌(n=364)与非肿瘤患者(n=733)与糖尿病相关因素的关系及差异.对比分析两组患者的糖尿病患病情况、糖尿病家族史、结直肠癌家族史、并发病情况、吸烟、饮酒等生活行为以及血脂水平等方面的差异.结果:结直肠癌组糖尿病患者患结直肠癌的危险度是非糖尿病患者的1.72倍,有糖尿病家族史者患结直肠癌的危险度也明显增加(OR=1.64);有结直肠癌家族史的糖尿病患者患结直肠癌的风险度(OR=3.23)高于无结直肠癌家族史的糖尿病患者(OR=1.57);但通过进一步分层分析表明无论患者有无结直肠癌家族史,结直肠癌组糖尿病患者所占比例均高于对照组.多因素回归分析显示:年龄、性别、糖尿病家族史、冠心病、高血压、吸烟、饮酒及血脂对结直肠癌没有显著影响;糖尿病及结直肠癌家族史对结直肠癌患病具有显著影响(OR=2.99,P＜0.01;OR=1.79,P＜0.01).结论:糖尿病与结直肠癌患病存在一定的相关性,糖尿病增加了患结直肠癌的风险性,其是结直肠癌患病的独立危险因素.     

胆汁酸与大肠癌相关性的荟萃分析

目的 为了阐明粪便中总胆汁酸和单一胆汁酸的浓度是否与大肠癌的发生有关,我们对目前所有相关文献进行了荟萃分析.方法 检索以下电子数据库:Pubmed、Embase、the Cochrane Controlled Trials Register、the Science Citation Index和中文科技期刊数据库.根据纳入标准,纳入有关评价粪便胆汁酸和大肠癌/腺瘤关系的观察性试验.文献必需报道了患者和对照组的粪便中总胆汁酸、鹅脱氧胆酸、脱氧胆酸或石胆酸的浓度.我们计算加权均数差(weighted mean difference,WMD)和95%可信区间(95%confidence interval,CI).通过漏斗图肉眼观察是否存在发表偏倚,并做Begg和Egger检验进一步验证.结果 我们检索到了20个病例对照研究或队列研究(共1226例).无论是固定效应模型,还是随机效应模型,对所有研究进行汇总后均未发现粪便中总胆汁酸和大肠癌/腺瘤存在联系(WMD0.61,95% CI 0.35～1.57)mg/g冻干粪).相比对照组,大肠癌/腺瘤巾鹅脱氧胆酸、脱氧胆酸和石胆酸的浓度显著增加,分别为WMD 0.16、0.40、0.32,95% CI 0.00～0.32,0.18～0.61,0.12～0.53 mg/g冻干粪.然而初级胆汁酸和次级胆汁酸浓度却并无差异.结论 粪便中总胆汁酸与大肠癌/腺瘤无关联,但鹅脱氧胆酸和石胆酸可能涉及大肠癌的发生,脱氧胆酸则可能同大肠癌和大肠腺瘤都存在联系.     

Immunohistochemical Expression of Matrix Metalloproteinase-7 in Human Colorectal Adenomas Using Specified Automated Cellular Image Analysis System: A Clinicopathological Study

Background/Aim:

To evaluate the immunohistochemical expression of matrix metalloproteinase-7 (MMP-7) in colorectal adenomas, and to correlate this expression with different clinicopathological parameters.

Patients and Methods:

The study was retrospectively designed. Thirty three paraffin blocks from patients with colorectal adenoma and 20 samples of non-tumerous colonic tissue taken as control group were included in the study. MMP-7 expression was assessed by immunohistochemistry method. The scoring of immunohistochemical staining was conducted utilizing a specified automated cellular image analysis system (Digimizer).

Results:

The frequency of positive immunohistochemical expression of MMP-7 was significantly higher in adenoma than control group (45.45% versus 10%) (P value < 0.001). Strong MMP-7 staining was mainly seen in adenoma cases (30.30%) in comparison with control (0%) the difference is significant (P < 0.001). The three digital parameters of MMP-7 immunohistochemical expression (Area (A), Number of objects (N), and intensity (I)) were significantly higher in adenoma than control. Mean (A and I) of MMP-7 showed a significant correlation with large sized adenoma (≥ 1cm) (P < 0.05), also a significant positive correlation of the three digital parameters (A, N, and I) of MMP-7 expression with villous configuration and severe dysplasia in colorectal adenoma had been identified (P < 0.05).

Conclusion:

MMP-7 plays an important role in the growth and malignant conversion of colorectal adenomas as it is more likely to be expressed in advanced colorectal adenomatous polyps with large size, severe dysplasia and villous histology. The use of automated cellular image analysis system (Digmizer) to quantify immunohistochemical staining yields more consistent assay results, converts semi-quantitative assay to a truly quantitative assay, and improves assay objectivity and reproducibility.     

Hyperplastic Polyposis and the Risk of Colorectal Cancer

PURPOSE Hyperplastic polyps are usually considered to be an innocent finding with little or no potential to progress to colorectal cancer. However, recent literature suggests that some of these polyps may be morphologically and genetically distinct and lead to microsatellite unstable colorectal cancers. The purpose of this study was to define the cancer risk associated with hyperplastic polyposis.METHODS All patients with hyperplastic polyposis diagnosed by a single colorectal surgeon at a university hospital were followed prospectively. The diagnosis of hyperplastic polyposis was made by the presence of more than 20 hyperplastic polyps distributed throughout the colon and/or a hyperplastic polyp at least 1 cm in size in diameter in the right colon. Patient demographics, family history, size, location, and distribution of polyps and the development of colorectal cancer were noted.RESULTS Thirteen patients who met the criteria for hyperplastic polyposis were identified and followed prospectively. All of these patients had at least 30 polyps distributed throughout the colon, often > 100. Nine of 13 also had a hyperplastic polyp at least 1 cm in size, usually in the right colon. Of particular note, 7 of 13 patients (54 percent) were diagnosed with colorectal cancer during the study period. Four had cancer on initial diagnosis and three patients developed cancer despite frequent colonoscopic surveillance. Five of seven colorectal cancers were located in the right colon.CONCLUSIONS Patients with hyperplastic polyposis are at high risk for colorectal cancer. Failure to identify this subset of patients could have dire consequences.Read at the meeting of The American Society of Colon and Rectal Surgeons, Dallas, Texas, May 8 to 13, 2004.Reprints are not available.     

Effects on Cell Proliferation,Activator Protein-1 and Genotoxicity by Fecal Water from Patients with Colorectal Adenomas

Background: The free water phase of feces (fecal water) may mediate the effects of diet on colon carcinogenesis. We examined the effects of fecal water from adenoma patients and controls on three parameters in colonocytes believed to be relevant to tumorigenesis, i.e. genotoxicity in intact cells and on isolated DNA, proliferative activity and activator protein-1 (AP-1) activity. Methods: Genotoxicity in intact colonic cells was assayed using the single-cell gel electrophoresis assay (`comet' assay) and on isolated DNA using double-stranded DNA from the X-174 RF plasmid. Cell proliferation was assessed using the commercially available `alamar blue' proliferation kit and AP-1 activity using cells transiently transfected with an AP-1-luciferase reporter construct. Results: The data showed that lipid extracts of fecal water samples from the adenoma patients had a significantly higher capacity to induce cell proliferation than those from controls, and that this effect could be explained to a large extent by the concentrations of deoxycholic and chenodeoxycholic acids in the fecal water using regression models. No difference between patients and controls was observed for induction of AP-1 activity or induction of DNA strand breaks in intact cells. However, induction of DNA strand breaks in isolated DNA was significantly higher for the fecal waters from patients than for those from controls, which could be explained in part in a regression model by concentrations of lithocholic acid in fecal water and fecapentaene-12 in feces. Conclusions: Our results support the hypothesis that the biochemistry of fecal waters from adenoma patients and controls differs.     

国内医务人员大肠癌筛查认识现状分析及建议

目的了解我国医务人员对大肠癌筛查的认识现状,分析影响筛查的因素并提出建议。方法随机对300名来自不同地方、不同等级医疗机构的医务人员进行问卷调查并分析结果。结果147名医务人员填写调查表,应答率49.00%;55%～80%的被调查者不了解普通人群大肠癌筛查方式、起始年龄及频率;大肠肿瘤筛查的了解程度与被调查医务人员的专业、学历、工作年限、医院等级无明显关系;76.87%的被调查者推荐高危人群定期行大肠癌筛查并能指出正确的筛查方法。结论我国医务人员对大肠癌筛查的相关知识不甚清楚且重视程度不够;对高危人群大肠癌筛查有一定认识但对普通人群筛查知识了解较少。     

Synchronous Colorectal Neoplasms in Patients With Colorectal Cancer: Predisposing Individual and Familial Factors

PURPOSE: Patients with colorectal cancer have an increased risk for developing synchronous and metachronous neoplasms. However, besides those cases with inherited disorders predisposing to tumor multicentricity, it is unknown which patients are prone to this condition. This study was designed to identify individual and familial characteristics associated with the development of synchronous colorectal neoplasms in patients with colorectal cancer.METHODS: During a one-year period, all patients with colorectal cancer attended in 25 Spanish hospitals were included. Exclusion criteria were colorectal cancer developed in the context of familial adenomatous polyposis or inflammatory bowel disease, refusal to participate in the study, incomplete family history, and inadequate examination of the colon and rectum. In addition to demographic, clinical, pathology, molecular (microsatellite instability status), and familial characteristics, presence of synchronous colorectal neoplasms (adenoma or carcinoma) were analyzed.RESULTS: A total of 1,522 patients were included in the study. Synchronous colorectal neoplasms were documented in 505 patients (33.2 percent): adenoma (n = 411), carcinoma (n = 27), or both (n = 67). Development of these lesions was associated with male gender (odds ratio, 1.94; 95 percent confidence interval, 1.43–2.65), personal history of colorectal adenoma (odds ratio, 3.39; 95 percent confidence interval, 1.58–7.31), proximal location of primary tumor (odds ratio, 1.40; 95 percent confidence interval, 1.02–1.94), tumor TNM Stage II (odds ratio, 1.31; 95 percent confidence interval, 1.15–4.66), mucinous carcinoma (odds ratio, 1.89; 95 percent confidence interval, 1.19–2.99), and family history of gastric cancer (odds ratio, 2.03; 95 percent confidence interval, 1.17–3.52).CONCLUSIONS: Based on individual and familial characteristics associated with synchronous colorectal neoplasms, it has been possible to identify a subgroup of patients with colorectal cancer prone to tumor multicentricity with potential implications on the delineation of preventive strategies.Supported by grants from the Fondo de Investigación Sanitaria (FIS 01/0104-01, 01/0104-02, and 01/0104-03), from the Instituto de Salud Carlos III (RC03/02 and RC03/10), and from Merck, Sharp and Dhome, Spain. Virgínia Piñol, M.D. received a research grant from the Institut dInvestigacions Biomèdiques August Pi i Sunyer (IDIBAPS).Presented at the meeting of the American Gastroenterological Association, Orlando, Florida, May 17 to 22, 2003.     

Tumor Pathology and Long-Term Survival in Emergency Colorectal Cancer

PURPOSE Patients who have an emergency operation for colorectal cancer have poorer long-term survival outcomes compared with elective patients. This study was designed to define the role of tumor pathology as a basis for the differences in survival outcomes. METHODS There were 1,537 elective and 286 emergency patients who had an operation for bowel cancer from 1997 to 2003. Tumor pathology and survival data collected prospectively for these patients were compared by modes of presentation. RESULTS Excluding 30-day mortality, emergency patients as a whole had a five-year all-cause survival rate of 39.2 percent compared with 64.7 percent for elective patients P < 0.0001 they also had more advanced Dukes C and D tumors (P < 0.0001). The rates of early T1 and T2 cancers were 4.7 percent for the emergency and 25 percent for the elective group. Emergency cases had more lymph node-positive patients and N2 patients (57.1 vs. 41.8 percent and 26.6 vs. 15.9 percent, respectively; P < 0.0001). Curatively resected emergency colon patients again had more advanced Dukes staged tumors (P < 0.0001) with a five-year survival rate of 51.6 percent compared with 75.6 percent for elective patients P < 0.0001. On stage-for-stage analysis, the survival rates for curatively resected Dukes B and C colon cancers remained worse for emergency patients (P = 0.003 and P = 0.0002, respectively). Both emergency Dukes B and C groups had more T4 cases (21.5 vs. 10.6 percent; P = 0.017 and 26.4 vs. 15 percent; P = 0.016, respectively). CONCLUSION Advanced tumor pathology is a basis for poor long-term survival in emergency colorectal cancers. Reprints are not available.     

Proximal Location of Colon Cancer Is a Risk Factor for Development of Metachronous Colorectal Cancer: A Population-Based Study

PURPOSE This study was undertaken to assess the incidence of 1) metachronous colorectal cancer and 2) subsequent extracolonic cancers, in relation to the location (proximal or distal to the splenic flexure) of the first primary colorectal tumor.METHODS In this population-based study, a cancer registry database was used to identify patients diagnosed with colorectal adenocarcinoma between 1970 and 1999. Patients with familial adenomatous polyposis and those with hereditary nonpolyposis colorectal cancer syndrome were excluded from the study, as were patients with nonepithelial tumors. Location of the first tumor was established according to International Classification of Diseases-Oncology-02 classification. The registry covers a population of 500,000 residents.RESULTS A total of 5,006 patients had sporadic adenocarcinoma of the colon or rectum during this period of time, with 1,703 first primary tumors (34 percent) being located proximal to the splenic flexure. One hundred twenty occurrences of second primary colorectal cancer were observed in this population (2.39 percent). The risk for developing a second incidence of primary colorectal cancer was higher in patients whose initial tumor was located in the proximal colon (3.4 percent vs. 1.8 percent; odds ratio, 1.92; 95 percent confidence interval, 1.33–2.77; P < 0.001). The risk for each segment of the large bowel was as follows: cecum, 3.4 percent; right colon, 3 percent; transverse colon, 3.8 percent; left colon, 2.8 percent; sigmoid colon, 1.7 percent; and rectum, 1.8 percent. By contrast, the risk for developing a second, extracolonic tumor did not differ between patients with proximal and distal tumors (13.7 percent vs. 13.4 percent, P = 0.73).CONCLUSION Patients with a first tumor located within the proximal colon are at twice the risk for developing metachronous colorectal cancer. From an epidemiologic standpoint, these data are in accordance with 1) the increasing incidence and 2) the better prognosis of proximal colon cancer in various populations. Our results confirm that proximal colon cancer is a distinct entity, which justifies the reporting of cases of colon cancer according to their location proximal or distal to the splenic flexure.© The American Society of Colon and Rectal SurgeonsPublished online: 28 January 2005.Presented at the meeting of the American Gastroenterological Association, Orlando, Florida, May 17 to 22, 2003..     

Insulin Therapy and Colorectal Adenoma Risk Among Patients with Type 2 Diabetes Mellitus: A Case-Control Study in Korea

Purpose Patients with Type 2 diabetes mellitus may be at increased colorectal adenoma and cancer risk. Moreover, chronic insulin therapy may increase the risk of colorectal cancer among patients with Type 2 diabetes mellitus. We investigated to determine whether insulin therapy might increase the risk of colorectal adenoma among clinically confirmed patients with Type 2 diabetes mellitus. Methods We conducted a retrospective study among patients with Type 2 diabetes mellitus who underwent total colonoscopy between January 2003 and July 2006 at Hallym University Sacred Heart Hospital. Among them (n = 325), patients with histologically confirmed colorectal adenomas (n = 100) and the same number of controls matched by age and sex were selected and analyzed. Results Adenoma cases showed significantly higher rate of chronic insulin therapy (more than 1 year) than controls (P = 0.018). In multivariate regression analysis, patients who received chronic insulin therapy had three times the risk of colorectal adenoma compared with patients who received no insulin (odds ratio, 3; 95 percent confidence interval, 1.1–8.9; P = 0.04). Conclusions Chronic insulin therapy was associated with increased colorectal adenoma risk among Type 2 diabetes mellitus patients. This result may provide a need for more intensive colorectal cancer screening program in patients with Type 2 diabetes mellitus, especially those who receive chronic insulin therapy.