大肠癌病人胃泌纱和生长抑素的检测及其临床意义

目的：研究胃泌素和生长抑素含量的变化及其对大肠癌的临床意义。方法：用放射免疫分析法测定了４３例大肠癌病人的空腹血清胃泌素（ＳＧ）和生长抑素（ＳＳ）,并对不同临床分期、不同病理类型、手术前后ＳＧ和ＳＳ水平进行了比较。结果：发现空腹血清胃泌素Ｄｕｋｅｓ ＣＤ期显著高于Ｄｕｋｅｓ ＡＢ期,即随着病程的进展逐渐升高;相反生长抑素降低。并提示它们升高或降低的程度同癌肿浸润和扩散的程度有关。而不同病理组织学型     

甘氨酸延伸型胃泌素受体在结肠和结直肠肿瘤中的研究

目的建立甘氨酸延伸型胃泌素胞浆膜受体结合试验,并应用该方法检测甘氨酸延伸型胃泌素受体的部分特性及其在正常结肠和人结直肠肿瘤中的表达.方法用人结直肠肿瘤细胞株DLD-1建立胞浆膜制备方法,125I标记的甘氨酸延伸型胃泌素进行受体结合试验.结果胞浆膜受体结合试验的条件为5～10mg胞浆膜(离心25000r/min45min制备),37℃温育60min.正常Sprague-Dawley大鼠结肠粘膜和从结肠粘膜制备的胞浆膜有特异结合,而从完整结肠制备的胞浆膜无特异结合.胞浆膜甘氨酸延伸型胃泌素受体抑制50%结合的非标记配体浓度(IC50)为3.64μmol/L±1.93μmol/L;特异性胆囊收缩素(CCK)-A受体拮抗剂L364和特异性CCK-B受体拮抗剂L365不能拮抗该受体;非特异性受体拮抗剂氯苯酰色氨酸则能拮抗.结论甘氨酸延伸型胃泌素受体位于正常大鼠结肠粘膜、结肠粘膜和结直肠肿瘤细胞膜上,属单结合位点、低亲和力受体,不能被特异性CCK-A或CCK-B受体拮抗剂拮抗,是一种新受体.     

Depressed-Type Submucosal Colon Cancer

PURPOSE: The article presents one of very few Korean reports on the detection of depressed early colorectal cancers, which have been cited by some Japanese doctors as another pathway for the development of colon cancers. Depressed-type early colorectal cancers have mainly been reported in Japan, and recently a few have also been reported in Western countries. Depressed early colorectal cancers are still rarely detected in Korea, where most colorectal surgeons, endoscopists, and radiologists refer to Western guidelines. METHODS: Recently, the authors experienced a typical 12-mm depressed-type early colon cancer in the ascending colon of a 55-year-old Korean male patient. It was detected by a colonoscopic examination. RESULTS: The lesion was flexible on insufflation and deflation with air and was considered an early colon cancer. Because of the large size, a surgical resection was performed. The final pathologic result was a minimally invasive submucosal cancer without lymph node metastasis. CONCLUSION: This Korean case is one of very few reported abroad, so we think that it might make an important contribution to research on depressed-type early colorectal cancer.     

Obesity Potentiates AOM-Induced Colon Cancer

Obesity and diet affect the incidence and severity of various types of cancer, including colon cancer. It is not known whether obesity, independent of diet, is a risk factor for colon adenocarcinoma. We used azoxymethane (AOM) to induce colon cancer in mature genetically obese male Zucker rats (fa/fa) on low-fat crude diet (LFC, 10% fat) and their lean counterparts (Fa/fa and Fa/fa) on high-fat crude diet (HFC, 40% fat) for three months. At death visible tumors, histopathology, and colonic aberrant crypt (AC) formation were studied by blinded investigators. At death the obese animals were heavier (719 ± 19 g; mean ± sem) than lean animals regardless of diet or genotype (Fa/fa-LFC:451 ± 6 g; Fa/fa-HFC:441 ± 10 g; Fa/Fa-HFC:412 ± 9 g; P < 0.001 vs fa/fa by ANOVA). All AOM-treated rats developed AC, compared to none of the saline-injected controls. Macroscopic adenocarcinoma developed in 8/9 obese rats on LFC (P < 0.001), compared to none in lean rats regardless of diet. Obese rats had significantly more AC (876 ± 116) than any of the lean rats (Fa/fa-LFC:550 ± 99; Fa/fa-HFC:325 ± 37; Fa/Fa-HFC:360 ± 36; P < 0.05 vs fa/fa). We conclude that obesity more than exposure to high-fat diet was associated with colon carcinogenesis in these rats.     

Adjuvant therapy for Colon Cancer

In patients with colon cancer who undergo resection for potential cure, 40% to 60% have advanced locoregional disease and are classified as either stage II or stage III. The role of adjuvant therapy in stage III colon cancer is well defined. The results from the MOSAIC trial (Multicenter International Study of Oxaliplatin/5-Fluorouracil/Leucovorin in the Adjuvant Treatment of Colon Cancer) and the National Surgical Adjuvant Breast and Bowel Project C-07 trial confirm a definite disease-free survival (DFS) benefit with the addition of oxaliplatin to either infusional or bolus 5-fluorouracil/leucovorin (5-FU/LV). The Xeloda in Adjuvant Colon Cancer Therapy (X-ACT) trial showed capecitabine to be of equivalent clinical benefit to bolus 5-FU/LV. However, adjuvant trials with irinotecan, including Cancer and Leukemia Group B (CALGB 89803), the Pan-European Trial in Adjuvant Colorectal Cancer 3 (PETACC-3), and the French ACCORD trial, have not shown a significant DFS advantage. In contrast, in patients with stage II disease, a small survival benefit of 1% to 5% exists with chemotherapy. Perhaps the analysis of molecular markers in combination with high-risk histopathologic features will help increase patient specificity and identify subsets of patients with stage II colon cancer who will derive a survival benefit with adjuvant therapy. The current Intergroup study stratifying stage II patients based on presence of microsatellite instability and loss of heterozygosity 18q allele will help us better understand the risk versus benefit observed.     

Cost-Effectiveness of Colon Cancer Screening

The cost-effectiveness of two colon cancer-screening strategies was compared. The first strategy mirrors the recommendations of the American Cancer Society and includes sigmoidoscopy starting at age 50, and yearly fecal occult blood testing. The second strategy is screening with colonoscopy. The analysis revealed that the 10-yr cost of screening with sigmoidoscopy is nearly $1,700, compared with nearly $2,500 for colonoscopy, using prevailing procedure costs. This difference can be reduced by lowering the cost of normal colonoscopies. The cost of identifying one patient with an adenomatous polyp is $8,766 with sigmoidoscopy, compared to $5,988 with colonoscopy because of the higher detection rate with colonoscopy. The calculated cost of preventing one death from colon cancer is $444,133 with sigmoidoscopy versus $347,214 with colonoscopy. In conclusion, colon cancer prevention with current screening methods is very costly. Screening with sigmoidoscopy and fecal occult blood testing may not be cost-effective, compared to screening with colonoscopy.