[Colonoscopic screening in first-degree relatives of patients with sporadic colorectal cancer]. / Screening colonscopico nei parenti di primo grado di pazienti operati per carcinoma colorettale sporadico.

UNLABELLED: Colonoscopic screening has been recommended in asymptomatic first-degree relatives of patients with colorectal cancer. In fact this population is believed to have an increased risk in developing colorectal neoplasia. The purpose of this study is to report the impact of colonoscopy in a series of completely asymptomatic first-degree relatives of patients operated on for colorectal cancer at our institution. A total of 480 individuals was requested to participate in a screening program based on faecal occult blood testing (FOBT) and colonoscopy in those with positive FOBT. Colonoscopy was also suggested to persons with negative FOBT. After the first 195 examined relatives, FOBT was abandoned because of continuously increasing acceptance of colonoscopy. RESULTS: Two hundred fifty four subjects (52.4%) accepted to participate at the screening program. After the first 195 examined relatives, FOBT was abandoned because of continuously increasing acceptance of colonoscopy. A total of 142 colonoscopies was performed. Colonoscopy was completed in 112 relatives (78.9%). Thirty-three subjects (23.2%) had a positive colonoscopy: one had invasive adenocarcinoma, one had large villous adenoma and 31 had 54 polyps. Twenty-three lesions (40.3%) were located proximal to the splenic flexure. Of the 54 polyps, 45 (83.3%) were less than 1 cm in size. These findings confirm the utility of colonoscopic screening in asymptomatic first-degree relatives of patients with colorectal cancer. However, its feasibility with the current endoscopic facilities remains an unsolved question.

Screening for colorectal cancer.

Second only to lung cancer in mortality, colon cancer is amenable to cure if detected early. Because fecal occult blood testing and flexible sigmoidoscopy are effective individually but have limitations, both are now recommended for screening. However, after successful polyp removal, surveillance colonoscopy does not need to be performed as often as previously thought.

Inhibitory effects of dietary curcumin on forestomach, duodenal, and colon carcinogenesis in mice.

Curcumin (diferuloylmethane), a yellow pigment that is obtained from the rhizomes of Curcuma longa Linn., is a major component of turmeric and is commonly used as a spice and food-coloring agent. The inhibitory effects of feeding commercial grade curcumin (77% curcumin, 17% demethoxycurcumin, and 3% bisdemethoxycurcumin) in AIN 76A diet on carcinogen-induced tumorigenesis in the forestomach, duodenum, and colon of mice were evaluated. Administration p.o. of commercial grade curcumin in the diet inhibited benzo(a)pyrene-induced forestomach tumorigenesis in A/J mice, N-ethyl-N'-nitro-N-nitrosoguanidine-induced duodenal tumorigenesis in C57BL/6 mice, and azoxymethane (AOM)-induced colon tumorigenesis in CF-1 mice. Dietary commercial grade curcumin was given to mice at: (a) 2 weeks before, during, and for 1 week after carcinogen administration (during the initiation period); (b) 1 week after carcinogen treatment until the end of the experiment (during the postinitiation period); or (c) during both the initiation and postinitiation periods. Feeding 0.5-2.0% commercial grade curcumin in the diet decreased the number of benzo(a)pyrene-induced forestomach tumors per mouse by 51-53% when administered during the initiation period and 47-67% when administered during the postinitiation period. Feeding 0.5-2.0% commercial grade curcumin in the diet decreased the number of N-ethyl-N'-nitro-N-nitrosoguanidine-induced duodenal tumors per mouse by 47-77% when administered during the postinitiation period. Administration of 0.5-4.0% commercial grade curcumin in the diet both during the initiation and postinitation periods decreased the number of AOM-induced colon tumors per mouse by 51-62%. Administration of 2% commercial grade curcumin in the diet inhibited the number of AOM-induced colon tumors per mouse by 66% when fed during the initiation period and 25% when fed during the postinitiation period. The ability of commercial grade curcumin to inhibit AOM-induced colon tumorigenesis is comparable to that of pure curcumin (purity greater than 98%). Administration of pure or commercial grade curcumin in the diet to AOM-treated mice resulted in development of colon tumors which were generally smaller in number and size as compared to the control group of AOM-treated mice. These results indicate that not only did curcumin inhibit the number of tumors per mouse and the percentage of mice with tumors but it also reduced tumor size. Histopathological examination of the tumors showed that dietary curcumin inhibited the number of papillomas and squamous cell carcinomas of the forestomach as well as the number of adenomas and adenocarcinomas of the duodenum and colon.

Screening/early detection model for colorectal cancer. Why screen?

Colon cancer is a leading cause of cancer death in the United States, causing approximately 60,000 deaths each year. Ideal screening would identify high risk patients and screen them with sensitive tests. Most cancers evolve from adenomatous polyps. There is now evidence that detection and removal of adenomas can prevent cancer. Unfortunately, our ability to identify high risk patients is limited. Screening of asymptomatic, average-risk individuals has been advocated, with the goal of reducing colon cancer mortality by detecting cancers at an early, curable stage or preventing cancer by detecting and removing adenomatous polyps. Recent data have suggested that screening populations older than age 50 with sigmoidoscopy and fecal occult blood tests can reduce colon cancer mortality. These reports are encouraging but also highlight significant limitations of this form of screening. Screening itself is designed merely to identify something that, once identified, needs further evaluation. Therefore, any discussion of colon screening must include consideration of how physicians will approach positive test results. The strategies for dealing with positive test results are costly and invariably lead to further surveillance. Current data suggest that patients with large polyps (> 1 cm) or villous adenomas have a high risk of colon cancer and are likely to benefit from full colonoscopy and subsequent surveillance. The benefits are far less clear for patients with small polyps. The subject of colon screening becomes even more complicated as consideration is given to when to start and stop screening, and how often to perform screening exams. There is clearly a need to improve upon the ability to identify patients most likely to develop colon cancer and design strategies to prevent cancer in this group. In the future, it may be possible to identify the high risk patient with some precision using genetic or biologic markers.