Barium enema versus colonoscopy for patients with polyps found during flexible sigmoidoscopy

This prospective study compares the accuracy of barium enema examination performed by experienced radiologists to colonoscopy performed by experienced gastroenterologists blinded to the radiographic findings to detect proximal, synchronous lesions in patients with polyps detected during fiberoptic sigmoidoscopy. Three thousand six patients were examined, of whom 147 (5%) had polyps larger than 0.5 cm in diameter. Of 114 patients who completed the protocol, 46 patients (40%) had synchronous, proximal colonic lesions. There were no radiographic false positives, but the single-contrast barium enema missed polyps in 13 while detecting polyps in 2 patients (sensitivity = 13%). The double-contrast barium enema missed proximal polyps in 23 patients while detecting them in 8 (sensitivity = 26%). We conclude that patients with neoplastic polyps found during fiberoptic sigmoidoscopy should have colonoscopy without barium enema. If the entire colon cannot be examined at colonoscopy, we advise double-contrast barium enema.     

Small early tubular adenomas and mixed colonic polyps found on screening flexible sigmoidoscopy do not predict proximal neoplasia in males.

BACKGROUND & AIMS: Distal colonic adenomas found on flexible sigmoidoscopy are associated with proximal neoplasias, thus requiring a complete colonoscopic examination, but data regarding the association of distal mixed polyps with proximal neoplasia are lacking. We conducted this study to elucidate the significance of distal mixed colonic polyps in predicting proximal neoplasia. METHODS: We retrospectively analyzed data from patients who underwent a flexible sigmoidoscopic examination for colorectal cancer screening and a follow-up colonoscopic examination because of distal colonic polyps. Distal index polyps were classified by a pathologist as early tubular adenoma (ETA), serrated, or true mixed categories. Index polyps also were immunostained with a monoclonal antibody, Adnab-9, a marker for the colorectal adenoma carcinoma sequence. RESULTS: In 636 patients with distal index polyps, 6% were malignant, 55% were adenomas, 13% were ETAs, 6% were serrated, 4% were true mixed, and 17% were hyperplastic. Compared with distal hyperplastic index polyps, distal malignant polyps (P = 0.0006) and adenomas (P = 0.001) were associated with a significantly increased number of synchronous proximal neoplasia, but the small distal mixed, serrated, or ETA did not predict the increased incidence of proximal neoplasia. Large distal polyps of each category were significantly associated with an increased number of synchronous proximal neoplasias. In support of these findings, immunostaining of distal polyps with Adnab-9 showed predictability for proximal neoplasia only in the adenoma category (P < 0.05). CONCLUSIONS: Small ETAs, serrated, or mixed polyps found on flexible sigmoidoscopic examination do not increase the probability of synchronous proximal neoplasia.     

Small polyps found during fiberoptic sigmoidoscopy in asymptomatic patients

STUDY OBJECTIVE: To determine the prevalence of small polyps in the rectosigmoid in an asymptomatic group and the likelihood of finding synchronous neoplastic polyps proximally at colonoscopy. DESIGN: Asymptomatic patients with polyps 9 mm or less found at screening fiberoptic sigmoidoscopy were referred for colonoscopy, at which time all polyps were removed. SETTING: Screening fiberoptic sigmoidoscopy unit. PATIENTS: Referral from Executive Health Wellness Clinic and large multispeciality clinic. RESULTS: From 3923 sigmoidoscopic examinations, 258 asymptomatic subjects (7%) were identified who had polyps 9 mm or smaller. One hundred and eighty-nine patients (73%) had colonoscopy. In 179 patients, the target lesion noted at sigmoidoscopy was identified at colonoscopy. Based on histology of the target lesion, patients were divided into three groups: Group 1 (72 patients) had only hyperplastic polyps; Group 2 (69 patients) had at least one neoplastic polyp; and Group 3 (31 patients) had polyps with normal histology. Seven patients were not classified. Neoplastic polyps were found proximally in 21 patients in Group 1 (29%; 95% CI, 19 to 39), 23 patients in Group 2 (33%; 95% CI, 22 to 44), and 4 patients in Group 3 (13%; 95% CI, 4 to 30). There was no difference in mean age between groups. The results were similar when only polyps 5 mm or smaller were analyzed. CONCLUSION: Because small polyps of any histologic type in the rectosigmoid indicate a high risk for having neoplastic polyps proximally, the guidelines of both the American College of Physicians and the American Society of Gastrointestinal Endoscopy may need to be revised. Colonoscopy seems justified in any patient in whom a small polyp is discovered at sigmoidoscopy.     

Follow-up of hot biopsy forceps treatment of diminutive colonic polyps.

Although the hot biopsy technique is widely used to treat diminutive colon polyps, there is concern over its efficacy and safety. Our study involved 39 patients undergoing routine colonoscopy in whom 62 diminutive polyps were found in the rectosigmoid. These lesions were treated with hot biopsy forceps in the standard manner. Flexible sigmoidoscopy was repeated 1 and 2 weeks later with the original treatment sites being identified. Eleven of the 62 sites (17%) revealed persistent viable polyp remnants, indicating incomplete treatment. In terms of safety, there were no clinical complications in this small study and most post-biopsy ulcers were healed by 2 weeks. This study shows that the hot biopsy technique may be unreliable in eradicating diminutive colon polyps.     

Combustible colonic gas levels during flexible sigmoidoscopy and colonoscopy.

To what extent the standard preparation for sigmoidoscopy (phosphosoda enemas) makes the bowel safe for electrocautery is unknown. Sixty patients were prospectively evaluated to compare the presence of the combustible gases hydrogen and methane during colonoscopy and flexible sigmoidoscopy. Thirty patients underwent flexible sigmoidoscopy after phosphosoda enema preparation, and 30 patients underwent colonoscopy after a polyethylene glycol solution preparation. During colonoscopy, the concentrations of hydrogen and methane remained below combustible levels in all patients. Even segments of colon with significant fecal matter present did not have combustible levels of these two gases. However, at flexible sigmoidoscopy, combustible levels of hydrogen and methane were measured in 3 of 30 (10%) patients. Due to the risk of explosion, electrocautery should not be performed during routine flexible sigmoidoscopy after the standard phosphosoda enema preparation.     

Clinical significance of diminutive polyps of the rectum and sigmoid colon

A retrospective review of 637 consecutive colonoscopies with polypectomy in 526 patients was performed to determine the association of small polyps of the rectum and sigmoid colon with more proximal colonic neoplasms. All colonic polyps were proximal to the sigmoid colon in 117 procedures. Proximal neoplasms were found in 32 percent of patients with a single polyp in the rectum or sigmoid colon. The incidence increased to 83 percent for those with three or more polyps. The occurrence of proximal colonic neoplasms was not affected by the size or histologic type of the rectosigmoid polyps. These findings would suggest that total colonic evaluation be considered in all patients with a polyp in the rectum or sigmoid colon regardless of the size or histologic type of the polyp.     

Are tiny polyps important when found on sigmoidoscopy in asymptomatic people?

To determine the occurrence of synchronous large bowel polyps located proximal to the sigmoid, in persons undergoing screening flexible sigmoidoscopy, we examined those who had diminutive polyps (less than or equal to 0.5 cm) as the only finding in the distal colon by further colonoscopy. One hundred one asymptomatic persons (mean age 61 +/- 13 years) had 143 diminutive polyps; a single polyp was found in 76%, and 64% of all polyps were located in the rectum. Thirty (21%) were hyperplastic and 86 (60%) were neoplastic, including 14 with moderate and one with severe dysplasia. The others were inflammatory (five) or unclassified (hot biopsy changes or normal mucosa, 14 polyps), and eight were lost before processing. Colonoscopy revealed that 16 (16%) of the 101 patients had 21 additional polyps proximally, mostly less than 1 cm in diameter. These included one hyperplastic and 18 neoplastic polyps, and two specimens showed hot biopsy changes. Age, histological type, number or location of the index diminutive polyps, were not associated with proximal lesions. We question whether immediate colonoscopy is justified in asymptomatic patients with only diminutive polyps at flexible sigmoidoscopy.     

Significance of distal polyps detected with flexible sigmoidoscopy in asymptomatic patients.

BACKGROUND--Colorectal cancer is a frequent cause of death from cancer. To reduce the mortality associated with this disease, regular flexible sigmoidoscopy is recommended. However, the significance of diminutive polyps (adenomatous or hyperplastic) detected during flexible sigmoidoscopy remains controversial, as does the appropriate endoscope length (35 vs 60 cm) for colorectal cancer screening. METHODS--One hundred one consecutive patients with no history of colonic disease, gastrointestinal tract symptoms, or positive results of fecal occult blood testing underwent flexible sigmoidoscopy as part of a colorectal cancer screening program. All patients with distal polyps detected during flexible sigmoidoscopy underwent colonoscopy. RESULTS--More than 25% of these asymptomatic, predominantly male subjects had colonic neoplasms or polyps detected. Fifty percent more lesions could be detected with a 60-cm sigmoidoscope than with a 35-cm sigmoidoscope, and detection of any distal polyp, whether adenomatous or hyperplastic, was associated with at least one proximal colon adenoma in 20% of patients. "Extended flexible sigmoidoscopy" for colorectal cancer screening was well tolerated by patients, as evidenced by insertion to the hepatic flexure in 25% of patients, and provided significantly more information than could be obtained with a 35-cm sigmoidoscope. CONCLUSIONS--Colorectal cancer screening should be performed with a 60-cm flexible sigmoidoscope, and distal colonic polyps or neoplasms will be detected in 25% of asymptomatic patients.     

Management of small and diminutive polyps

Cold forceps are an appropriate tool for resection of 1-3-mm polyps that can be engulfed in a single bite. Jumbo and large-capacity forceps are more likely to engulf a tiny polyp in a single bite and are more effective and efficient than standard-size forceps. Cold snaring (transection of a polyp by guillotining without the use of electrocautery current) is more effective than either cold or hot forceps for resection of small polyps and can be used for polyps 1-9 mm in size. The size at which hot snaring (the use of snare and cautery in the traditional manner for polypectomy) should be used is unknown, but the author often uses hot snaring for pedunculated polyps, bulky sessile polyps, and proximal colon serrated polyps that are 6-9 mm in size. The cold snaring technique involves grasping a rim of normal tissue around the polyp and does not require tenting, and is therefore fundamentally different than hot snaring. Hot forceps should only be used for polyps ≤5 mm in size, it can leave residual polyp and create a thermal injury that risks delayed hemorrhage and rarely perforation. The author never uses hot forceps. The current paradigm of diminutive polyp (polyps ≤5 mm in size) management is to resect and send for pathologic evaluation. The pathology (adenoma vs hyperplastic) following removal is used to guide the postpolypectomy surveillance interval. Polyps in this size range very rarely have cancer, and infrequently have either villous elements or high-grade dysplasia. This observation has generated interest in developing endoscopic imaging technologies that could serve as alternatives to the pathologist's examination of diminutive polyps and would be less expensive than the histologic evaluation. The American Society for Gastrointestinal Endoscopy has recommended minimum performance thresholds for imaging technologies with regard to 2 clinically relevant end points: (1) a policy of “resect and discard” for high-confidence interpretations of diminutive polyps anywhere in the colon and (2) leaving distal colon hyperplastic polyps in place without resection. Several technologies appear promising with regard to reaching the recommended performance thresholds, and additional study of how well they function when used by community endoscopists is awaited.     

The benefits of systematic fiberoptic flexible sigmoidoscopy

We used the flexible fiberoptic sigmoidoscope (FFS) on 656 subjects who were receiving their yearly physical examinations. Neoplastic disease was disclosed by the FFS in 138 subjects (21%), including 26 adenocarcinomas, 19 of which were out of reach of a rigid sigmoidoscope. Nineteen of the subjects whose adenocarcinomas were found by the FFS had barium enemas, which detected the carcinomas in only 11. Routine FFS in asymptomatic persons is helpful in detecting both premalignant and malignant lesions, it should be seriously considered as a part of regular preventive physical examinations.     

Complications of screening flexible sigmoidoscopy

BACKGROUND & AIMS: Flexible sigmoidoscopy (FS) is recommended for mass screening for colorectal cancer (CRC), yet little is known about the risk of adverse events when FS is used in general clinical practice. We aimed to determine the incidence of gastrointestinal complications and acute myocardial infarction (MI) after screening FS. METHODS: Northern California Kaiser Permanente Medical Care Program members of average risk for CRC (n = 107,704) who underwent screening FS during 1994 to 1996 (109,534 FS), as part of the Colorectal Cancer Prevention (CoCaP) program. The main outcome measure was hospitalization for gastrointestinal complications or acute MI within 4 weeks of FS. RESULTS: The mean age of subjects was 61 years, and 48.8% were female. Nongastroenterologist physicians, nurses, or physician assistants performed 72% of FS. Overall, 24 persons were hospitalized for a gastrointestinal complication. Of these, 7 were serious (2 perforations, 2 episodes of diverticulitis requiring surgery, 2 cases of bleeding requiring transfusion, and 1 episode of unexplained colitis). In multivariate models, complications were significantly more common in men than in women (odds ratio, 3.34; 95% confidence interval [CI], 1.34-10.13). MI occurred in 33 persons within 4 weeks of FS, but the incidence for this period was similar to that in the subsequent 48 weeks (rate ratio, 0.8; 95% CI, 0.6-1.2). CONCLUSIONS: The risk of serious complications after screening FS in this setting appears to be modest. Although MI occurs after FS, the risk during the 4 weeks after the procedure appears to be similar to expectations for persons of screening age.     

Advances in the removal of diminutive colorectal polyps

Diminutive polyps (<5 mm in diameter) represent the majority of polyps found during colonoscopy; about a half of them are adenomatous, with low risk of advanced neoplasia. Recent studies have demonstrated that cold polypectomy should be considered the recommended approach for resecting diminutive polyps and that cold snaring may be superior to cold forceps biopsy, at least for polyps of 4–5 mm. Recently, electronic chromoendoscopy has been applied to characterization of diminutive polyps to discriminate adenomatous from nonadenomatous lesions. Optical diagnosis of polyp histology could potentially exert huge cost savings by the ‘resect and discard’ strategy for diminutive polyps and ‘leaving-in’ for diminutive hyperplastic polyps in the recto-sigmoid colon. These policies represent the mainstay for adopting endoscopy-directed post-polypectomy surveillance strategies, endorsed by both American and European Endoscopy Societies. Accuracy of both histology and surveillance intervals predictions from academic centers have been encouraging, although the same performance has not been replicated in community practices.     

Hyperplastic polyps seen at sigmoidoscopy are markers for additional adenomas seen at colonoscopy

Asymptomatic individuals undergoing screening flexible sigmoidoscopy were prospectively studied. Polyps were found in 185 subjects. The endoscopist recorded an opinion on the polyps' histology based on endoscopic appearance. No polyps were removed at sigmoidoscopy. All subjects with rectosigmoid polyps then underwent colonoscopy and polypectomy. Of them, 99 subjects (54%) had at least one rectosigmoid adenoma, 69 (37%) had only hyperplastic polyps, and 17 (9%) had other findings. The endoscopists' opinion of the histopathology of polyps at sigmoidoscopy was correct for 61% of the lesions. Of subjects with adenomatous rectosigmoid polyps, 29% had additional adenomas at more proximal sites. Proximal adenomas were found in 28% of patients with hyperplastic rectosigmoid polyps. Patients with rectosigmoid hyperplastic polyps had the same risk for additional proximal adenomas as patients with rectosigmoid adenomatous polyps.     

Wide variation in adenoma detection rates at screening flexible sigmoidoscopy

BACKGROUND & AIMS: Wide between-center variation in adenoma detection rates (ADRs) was observed in the U.K. Flexible Sigmoidoscopy Screening Trial (overall, 12.1%; range, 8.6%-15.9%; P < 0.0001). The aim of this study was to determine whether the observed differences could be attributed to varying performance by endoscopists, to examine the effect of experience on performance, and to identify an attainable, standard ADR to which endoscopists could aspire. METHODS: Thirteen medical endoscopists, one per trial center, each performed about 3000 examinations (200 per month) using the same equipment and protocol. Overall and monthly ADRs were compared using multivariable logistic regression. RESULTS: Differences in ADRs were not explained by patient characteristics, incidence of colorectal cancer in the local population, or the endoscopists' medical specialty or previous experience. Average ADRs increased significantly with screening experience (up to 400 examinations). Endoscopists were classified as higher, intermediate, or lower adenoma detectors, and performance levels were maintained over time. Higher detectors had ADRs of 15% overall (men, 20%; women, 10%) and also detected more adenomas per case (higher/lower detectors, 21.7/10.4 adenomas per 100 examinations). CONCLUSIONS: The differences in ADRs were due to variation in performance of the endoscopists. Long-term follow-up will determine whether this variation is clinically important. We suggest that the standards in higher detecting centers should be achievable by all endoscopists screening unscreened populations aged older than 55 years. Endoscopists should aim to stay above the lower 95% confidence interval band for 200 examinations (10% overall; 5% in women, 15% in men).     

Risk of cancer in small and diminutive colorectal polyps

The prevalence of cancer in small and diminutive polyps is relevant to “resect and discard” and CT colonography reporting recommendations.We evaluated a prospectively collected colonoscopy polyp database to identify polyps <10 mm and those with cancer or advanced histology (high-grade dysplasia or villous elements).Of 32,790 colonoscopies, 15,558 colonoscopies detected 42,630 polyps <10 mm in size. A total of 4790 lesions were excluded as they were not conventional adenomas or serrated class lesions.There were 23,524 conventional adenomas <10 mm of which 22,952 were tubular adenomas. There were 14,316 serrated class lesions of which 13,589 were hyperplastic polyps and the remainder were sessile serrated polyps. Of all conventional adenomas, 96 had high-grade dysplasia including 0.3% of adenomas ≤5 mm in size and 0.8% of adenomas 6–9 mm in size. Of all conventional adenomas, 2.1% of those ≤5 mm in size and 5.6% of those 6–9 mm in size were advanced. Among 36,107 polyps ≤5 mm in size and 6523 polyps 6–9 mm in size, there were no cancers.These results support the safety of resect and discard as well as current CT colonography reporting recommendations for small and diminutive polyps.     

Histology of colonic polyps

The authors present the modern classification of colorectal polyps. They discuss the dysplastic and preneoplastic changes in the light of new data on predisposing factors. Although new techniques are developing such as immunocytochemistry, DNA cytophotometry, DNA recombination, it is clear that presently, the basic morphological data, microscopical as well as histological, retain an irreplaceable diagnostic value. From a practical point of view, the authors recall the importance of an adequate orientation of the polyps before their histological examination in order to obtain all the necessary informations permitting an accurate diagnosis: type of the polyp, possible areas of cancer formation and their depth of penetration, histology of the surrounding mucosa and tissues.