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BACKGROUND In the National Polyp Study (NPS), colorectal cancer was prevented by colonoscopic removal of adenomatous polyps. We evaluated the long-term effect of colonoscopic polypectomy in a study on mortality from colorectal cancer. METHODS We included in this analysis all patients prospectively referred for initial colonoscopy (between 1980 and 1990) at NPS clinical centers who had polyps (adenomas and nonadenomas). The National Death Index was used to identify deaths and to determine the cause of death; follow-up time was as long as 23 years. Mortality from colorectal cancer among patients with adenomas removed was compared with the expected incidence-based mortality from colorectal cancer in the general population, as estimated from the Surveillance Epidemiology and End Results (SEER) Program, and with the observed mortality from colorectal cancer among patients with nonadenomatous polyps (internal control group). RESULTS Among 2602 patients who had adenomas removed during participation in the study, after a median of 15.8 years, 1246 patients had died from any cause and 12 had died from colorectal cancer. Given an estimated 25.4 expected deaths from colorectal cancer in the general population, the standardized incidence-based mortality ratio was 0.47 (95% confidence interval [CI], 0.26 to 0.80) with colonoscopic polypectomy, suggesting a 53% reduction in mortality. Mortality from colorectal cancer was similar among patients with adenomas and those with nonadenomatous polyps during the first 10 years after polypectomy (relative risk, 1.2; 95% CI, 0.1 to 10.6). CONCLUSIONS These findings support the hypothesis that colonoscopic removal of adenomatous polyps prevents death from colorectal cancer. (Funded by the National Cancer Institute and others.)

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 94 of the 242 colonoscopic examinations in which one or more adenomas were detected (rate of detection of adenomas, 39 percent; 95 percent confidence interval, 33 to 45 percent). The proportion of examinations in which ...

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 colore...

Background The current practice of removing adenomatous polyps of the colon and rectum is based on the belief that this will prevent colorectal cancer. To address the hypothesis that colonoscopic polypectomy reduces the incidence of colorectal cancer, we analyzed the results of the National Polyp Study with reference to other published results. Methods The study cohort consisted of 1418 patients who had a complete colonoscopy during which one or more adenomas of the colon or rectum were removed. The patients subsequently underwent periodic colonoscopy during an average follow-up of 5.9 years, and the incidence of colorectal cancer was ascertained. The incidence rate of colorectal cancer was compared with that in three reference groups, including two cohorts in which colonic polyps were not removed and one general-population registry, after adjustment for sex, age, and polyp size. Results Ninety-seven percent of the patients were followed clinically for a total of 8401 person-years, and 80 percent returned...

The National Polyp Study (NPS) is a multicenter prospective randomized trial designed to evaluate follow-up surveillance strategies in patients who have undergone polypectomy for the control of large bowel cancer. The study design was developed by a joint research committee from American Gastroenterological Association, the American Society for Gastrointestinal Endoscopy, and the American College of Gastroenterology. Subjects who met the eligibility criteria were randomized into two different treatment arms. Eligibility criteria included: removal of one or more adenomas; complete colonoscopy; no prior polypectomy, inflammatory bowel disease, or familial polyposis; and no history of colon cancer. The treatment arms consisted of a frequent follow-up (1 and 3 years after initial polypectomy) and a less frequent follow-up (3 years). Follow-up examinations included fecal occult blood tests, air-contrast barium enema, and colonoscopy. The latter was done on 9112 referred patients at the seven participating centers from November 1980 until February 1990 who had no history of polypectomy, colon cancer, familial polyposis, or inflammatory bowel disease. Of these patients, 4763 (52.3%) had no polyps; 549 (6.0%) had an invasive cancer; 776 (8.5%) had nonadenomatous polyps; 208 (2.3%) had incomplete examinations; 184 (2.0%) had other findings; and 2632 (28.9%) had one or more adenomas, of which 1418 (53.9%) were randomized to one of the two treatment arms. This article reports the background, rationale, objectives, methods, and organization of this study and includes patient characteristics on initial presentation. Future data provided by the NPS may help in the development of recommendations for surveillance guidelines for such patients. This study also provides a framework to address questions regarding the natural history of adenomas and their relationship with colorectal cancer.

The colonoscope was used on 210 patients. The examination was successful in 197. Technical problems in eight patients, unsatisfactory preparation of the colon in five prevented success. In 69 of these 210, a total of 91 polyps was removed. The only complication encountered was bleeding, which occurred in two patients and did not require laparotomy.

A zoom lens system has been adapted to fiberendoscopy. The authors have found this system to enhance the view of distant lesions in otherwise obscure situations, to facilitate biopsy, and to improve photography. Corollary editorial comment follows in this issue.

The Southern California Society for Gastrointestinal Endoscopy, by means of a questionnaire sent to its members, has reported on the complications encountered in a total of 3,850 colonoscopies and 901 polypectomies. The incidence of perforation and bleeding in this series is determined and compared to those available in the current literature. The morbidity and mortality of colonoscopic polypectomy is compared to polypectomy performed by surgery.

The major limiting factor in colonoscopy is the endoscopist. It depends on his training, experience, inherent ability, and honesty. I do not believe that the number of examinations performed by an aspiring endoscopist during training are really as important as some persons have stated. There are some trainees who will be able to perform colonoscopy after 10 procedures and some who will never learn it, no matter how many they perform. Experience is a great help to those people who have a natural knack for learning this technique. It does demand a hand-eye coordination that some people master very well, most people master fairly well, and some not at all. Honesty plays a role in this endeavor as it does in the practice of any type of medicine. However, I am beginning to see occurrences in gastrointestinal endoscopy that I do not like. It is too easy for the endoscopist to state that he has done a full colonoscopy when in reality he has reached only the splenic flexure, or to say that he has performed a left-sided colonoscopy with a flexible sigmoidoscope when he may have reached only the midsigmoid region. Although there is no practical way to monitor these misapprehensions, I do think it is important to continue to mention them. Perhaps they will decrease. The next limitation is the gastrointestinal assistant. Colonoscopy is extremely difficult without experienced help. Biopsy and polypectomy are much easier if you have someone helping you who knows what he is doing. The third limitation of colonoscopy is the organ itself. I have not gone into preparation of the colon because I think that was washed through thoroughly earlier in this symposium. The colon itself may present some anatomic problems. In addition to Dr. Haubrich's mention that an imperforate anus offers an impediment to colonoscopy, we do occasionally encounter patients with an anal stricture where the opening is less than 1 cm. Therefore, colonoscopes which have an outside diameter of approximately 1.3 cm cannot be introduced without difficulty. If the examination is essential, using general anesthesia, these patients can usually have the anus dilated and then successfully undergo colonoscopy. An extremely convoluted sigmoid colon is more difficult to intubate than a straight sigmoid colon. The greatest limitation that I have encountered is the presence of pelvic adhesions due to previous surgery or old diverticulitis, making it relatively unsafe to pursue a total colonoscopic examination. This occurs approximately 5% of the time with experienced examiners and perhaps as often as 30 to 40% of the time with inexpert colonoscopists. As a general rule, if you are having difficulty and the patient is experiencing discomfort, do nol proceed. The presence of diverticulosis is less of a limiting factor the more experience one gains. The examination is contraindicated in the presence of active diverticulitis. Sometimes the use of glucagon in the presence of marked sigmoid hypermuscularity and diverticulosis may be of help in facilitating examination. Other areas that may be difficult to examine are the splenic flexure, the deep pelvic transverse colon, a redundant hepatic flexure, and the ileocecal valve. Certain areas are more inaccessible than others, for example, the rectosigmoid junction, the sigmoid-descending colon junction, obstructing carcinomas, mesial inftiior aspects of the proximal splenic and hepatic flexures, and a mobile cecum. Certain techniques may help in these regions. The singlechannel endoscope gives a much better view of these areas because it can be turned back on itself owing to a greater degree of flexion. The double-channel endoscope, which may be preferable for polypectomy, does not lend itself as well to a sharp turning radius and is more likely to miss the lesions in these areas. If one is faced with a known lesion on barium enema in one of these difficult areas and the double-channel endoscope is in use and the lesion is not visible, switching to the more flexible, single-channel endoscope may be helpful in facilitating observation of the lesion. If the lesion still is not visible, then the barium enema should be repeated in order to see whether the radiologic or the colonoscopic examination is correct. The final limiting factor in colonoscopy is the instrument itself. I have already mentioned the inherent incapabilities of the 2 different types of instruments. Breakage of the instrument decreases as the colonoscopist's experience increases. There is more breakage in a teaching institution because residents, fellows, and other trainees are learning the procedure. The more the instrument is used by a variety of people, the higher the rate of breakage. Instruments, by and large, appear to be more sturdily made now than they have been in the past. Another problem is that the biopsy specimens we obtain are sometimes difficult to interpret because of their small size and the artifacts that result from crushing. Larger and safer biopsy forceps are being developed, and these should lessen the limitations of biopsy. Lastly, of course, the performance of colonoscopy is contingent on the patient's informed consent and cooperation. Major complications of colonoscopy are hemorrhage, perforation, bacteremia, mesenteric and serosal laceration

An instructive case of melanoma metastatic to the stomach is documented by gastroscopic photography and biopsy. Umbilicated lesions typical of metastatic melanoma are illustrated.