A comparison of colonoscopy and double-contrast barium enema for surveillance after polypectomy. National Polyp Study Work Group.

BACKGROUND: After patients have undergone colonoscopic polypectomy, it is uncertain whether colonoscopic examination or a barium enema is the better method of surveillance. METHODS: As part of the National Polyp Study, we offered colonoscopic examination and double-contrast barium enema for surveillance to patients with newly diagnosed adenomatous polyps. Although barium enema was performed first, the endoscopist did not know the results. RESULTS: A total of 973 patients underwent one or more colonoscopic examinations for surveillance. In the case of 580 of these patients, we performed 862 paired colonoscopic examinations and barium-enema examinations that met the requirements of the protocol. The findings on barium enema were positive in 222 (26 percent) of the paired examinations, including 139 of the 392 colonoscopic examinations in which one or more polyps were detected (rate of detection, 35 percent; 95 percent confidence interval, 31 to 40 percent). The proportion of examinations in which adenomatous polyps were detected by barium enema colonoscopy was significantly related to the size of the adenomas (P=0.009); the rate was 32 percent for colonoscopic examinations in which the largest adenomas detected were 0.5 cm or less, 53 percent for those in which the largest adenomas detected were 0.6 to 1.0 cm, and 48 percent for those in which the largest adenomas detected exceeded 1.0 cm. Among the 139 paired examinations with positive results on barium enema and negative results on colonoscopic examination in the same location, 19 additional polyps, 12 of which were adenomas, were detected on colonoscopic reexamination. CONCLUSIONS: In patients who have undergone colonoscopic polypectomy, colonoscopic examination is a more effective method of surveillance than double-contrast barium enema.

Screening and surveillance for colorectal cancer.

Colorectal cancer is the second most common cause of cancer death among American men and woman. Currently available screening and surveillance techniques are effective in detecting early-stage colorectal cancer and its premalignant precursor lesion, the adenomatous polyp (adenoma). Removal of adenomas by colonoscopic polypectomy significantly reduces the incidence of colorectal cancer. Appropriate screening and surveillance recommendations should be based on the individual's colorectal cancer risk stratification. High-risk groups, such as patients with hereditary nonpolyposis colorectal cancer (HNPCC) and familial adenomatous polyposis (FAP), should be offered genetic counseling and specialized screening recommendations for colorectal and associated extracolonic malignancies.

Natural history of colorectal cancer.

Colorectal cancer arises from a precursor lesion, the adenomatous polyp, which forms in a field of epithelial cell hyperproliferation and crypt dysplasia. Progression from this precursor lesion to colorectal cancer is a multistep process, accompanied by alterations in several suppressor genes that result in abnormalities of cell regulation, and has a natural history of 10-15 years. Environmental factors and inherited susceptibility play major roles in this sequence of events. As a result of familial and genetic studies, we now have a better understanding of various high-risk groups and the application of screening methods to these individuals and to people at average risk. In the future, further identification of genetically predisposed individuals and colonoscopic screening of the general population may provide new opportunities for control of colorectal cancer through secondary prevention, and a better understanding of lifestyle factors and their modification will lead to improved strategies for primary prevention.

Screening and surveillance for colorectal carcinoma.

Screening and surveillance examinations are effective in lowering colorectal cancer risk. Screening tests have been demonstrated to reduce colorectal cancer mortality. Colonoscopic removal of adenomatous polyps has been determined to reduce colorectal cancer incidence. High-risk individuals and their family members should be identified and offered more aggressive recommendations for appropriate screening and surveillance guidelines. Colorectal cancer screening strategies are in an acceptable range of cost effectiveness.

Initial management and follow-up surveillance of patients with colorectal adenomas.

The clinical management of patients with adenomas is interesting because of the adenomas' malignant potential, the availability of effective intervention by colonoscopy, and the increasing number of patients having adenomas detected and removed. The current literature on follow-up surveillance is reviewed, and surveillance intervals are suggested based on data from the National Polyp Study. Patients newly diagnosed with three or more adenomas, an adenoma of more than 0.5 cm, or with a family history of colorectal cancer should have surveillance colonoscopy at 3 years following the polypectomy. Surveillance of patients with single, small tubular adenomas can be extended to 5 or more years. Patients with large sessile or malignant adenomas need to have follow-up earlier. Identification and removal of adenomatous polyps have been shown to reduce colorectal cancer incidence.

Risk of colorectal cancer in the families of patients with adenomatous polyps. National Polyp Study Workgroup.

BACKGROUND: The adenoma-adenocarcinoma sequence in colorectal cancer suggests an increased risk of colorectal cancer in the families of patients with adenomatous polyps. METHODS: A random sample of participants in the National Polyp Study who had newly diagnosed adenomatous polyps were interviewed for information on the history of colorectal cancer in their parents and siblings. The risk of colorectal cancer in family members was analyzed according to the characteristics of the patients with adenomas and in comparison with a sample of patients' spouses, who served as controls. RESULTS: Among the patients with adenomas, 1199 provided information on whether they had a family history of colorectal cancer. After the exclusion of families for which information was incomplete and of 48 patients who had been referred for colonoscopy solely because they had a family history of colorectal cancer, there were 1031 patients with adenomas, 1865 parents, 2381 siblings, and 1411 spouse controls. The relative risk of colorectal cancer, adjusted for the year of birth and sex, was 1.78 for the parents and siblings of the patients with adenomas as compared with the spouse controls (95 percent confidence interval, 1.18 to 2.67). The relative risk for siblings of patients in whom adenomas were diagnosed before 60 years of age was 2.59 (95 percent confidence interval, 1.46 to 4.58) as compared with the siblings of patients who were 60 or older at the time of diagnosis and after adjustment for the sibling's year of birth and sex and a parental history of colorectal cancer. The risk increased with decreasing age at the time of the diagnosis of adenoma (P for trend < 0.001). The relative risk for the siblings of patients who had a parent with colorectal cancer, as compared with those who had no parent with cancer, was 3.25 (95 percent confidence interval, 1.92 to 5.52), after adjustment for the sibling's year of birth and sex and the patient's age at diagnosis. CONCLUSIONS: Siblings and parents of patients with adenomatous polyps are at increased risk for colorectal cancer, particularly when the adenoma is diagnosed before the age of 60 or--in the case of siblings--when a parent has had colorectal cancer.

Recurrent deletions involving chromosomes 1, 5, 17, and 18 in colorectal carcinoma: possible role in biological and clinical behavior of tumors.

We have employed cytogenetic and restriction fragment length polymorphism (RFLP) analysis to identify a full spectrum of cytogenetic and molecular alterations associated with initiation and progression of "sporadic" colorectal cancer and also to correlate the alterations with biological and clinical behavior of the tumors. The study series included 63 colorectal cancers, 47 primary and 16 metastatic recurrences. Cytogenetic analysis was successful in 48 tumors (76%) of which 44 (91%) were abnormal. Of these 44 tumors, clonal abnormalities were identified in 43, whereas chromosomes from one tumor were unsuitable for complete analysis. Each of these abnormal tumors displayed heterogeneity with regard to extent and complexity of recurrent chromosomal abnormalities. Numerical losses of chromosomes 17 and 18 (20-34%) and gains of chromosome 7 (28%) were significantly higher. The four most frequent structural rearrangements on the other hand, involved specific regions of chromosomes 1p, 5q, 17p, and 18q. The shortest regions of overlap of these rearrangements or losses were located at 1p36, 5q21-22, 17p13 and 18q21- > ter. RFLP analysis directed at 1p, 5q, 17p and 18q identified allelic deletions of these regions in 39 tumors (64%) which included 17 normal and 11 cytogenetic failures. Of all the informative tumors, 32%, 37%, 31%, and 63% showed allelic losses at chromosomes 1p, 5q, 17p and 18q respectively. The two methods of analysis (cytogenetics and RFLP) employed to identify genetic alterations were complementary; probes for chromosome 1 and 18 showed the greatest degree of concordance, whereas probes for chromosomes 5 and 17 provided relatively higher rate of discordance with cytogenetic results. These differences could be attributed mainly to three reasons: 1) a limited number of probes used for RFLP analysis; 2) contamination of tumor cells with normal cells, and 3) either mutational inactivation or deletion of specific alleles not closely linked to the probes used. Regardless of these limitations, however, the combined use of cytogenetic and RFLP identified genetic alterations in a large number of tumors and help elucidate the role of hyperdiploidy and/or relative deficiency of a given chromosomal segment in expression of recessive mutations. In addition, alterations of either chromosomes 1 or 17 predicted poorer survival for the patients with primary colorectal cancer (p = 0.03).

Prevention of colorectal cancer: guidelines based on new data. WHO Collaborating Center for the Prevention of Colorectal Cancer.

Recently published good quality data are the basis for this update. The newly reported studies include randomized trials, non-randomized cohort studies, and case-control studies; some of the data had mortality reduction as the endpoint. These guidelines, which were developed by the WHO Collaborating Center for the Prevention of Colorectal Cancer at Memorial Sloan-Kettering Cancer Center in conjunction with an International Advisory Committee, include primary prevention, screening of average-risk individuals, screening of individuals with heritable factors for colorectal cancer, surveillance of patients with colorectal polyps, and surveillance of patients with chronic ulcerative colitis. A list of papers reviewed for this update are cited, including recently published trials evaluating faecal occult-blood testing, case-control studies of sigmoidoscopy, the National Polyp study, and familial colon cancer studies. These guidelines will help inform patients and guide physicians in their approach to the prevention of colorectal cancer.