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.     

Spatial clustering of multiple hyperplastic,adenomatous, and malignant colonic polyps in individual patients

Analysis of relative polyp locations in 426 consecutive patients with multiple colonic polyps found on colonoscopy showed novel findings. First, synchronous and metachronous neoplastic polyps showed spatial clustering in individual patients. For example, patients with their largest neoplasm in the cecum or proximal ascending colon, had 34.3 percent±4.6 percent (standard error) of their other colonic neoplasms in the same location. Second, hyperplastic polyps showed spatial clustering in individuals that was statistically significantly greater than expected from the increased hyperplastic polyp concentration in the rectum and sigmoid. Third, hyperplastic polyps showed spatial clustering with neoplastic polyps; this clustering was similar in magnitude to clustering for exclusively hyperplastic or neoplastic polyps. In contrast, lipomas were not spatially clustered with hyperplastic and neoplastic polyps. The magnitude of clustering between hyperplas and neoplasia showed a closer association between these histologic types than previously appreciated. Because of clustering, regions with prior polyps appear to merit closer surveillance. These findings suggest clinical study, using a randomized controlled clinical trial, of whether a patient who had only rectal and sigmoid adenomas on initial and follow-up colonoscopy should have surveillance with flexible sigmoidoscopy alternating annually with colonoscopy. A patient with a prior cecal adenoma should have surveillance only with a complete colonoscopy or adequate cecal views on barium enema.     

Flexible sigmoidoscopy may be ineffective for secondary prevention of colorectal cancer in asymptomatic,average-risk men

Asymptomatic men (N=114) 50 years of age or older had screening for colorectal neoplasia with flexible sigmoidoscopy followed by colonoscopy regardless of the sigmoidoscopic result. Our study objective was to determine the prevalence of patients having isolated adenomatous polyps in a proximal colonic segment in the absence of a distal index neoplasm within reach of the sigmoidoscope. Through the combined use of sigmoidoscopy and colonoscopy, adenomatous polyps were detected in 47 of 114 individuals (41%). A total of 88 adenomas was found. Seventeen patients had isolated neoplasms in proximal colonic segments in the absence of distal adenomas. These patients represented 15% of screened subjects (17 of 114) and 20% of individuals who lacked adenomas on sigmoidoscopy (17 of 84). The majority of proximal neoplasms were small (<1.0 cm), tubular adenomas. Flexible sigmoidoscopy may be ineffective for screening asymptomatic men for neoplasia. However, it remains to be determined if a 20% miss rate (for those with a normal sigmoidoscopic examination) is significant and whether small proximal adenomas are worth finding.     

Colon pathology detected after a positive screening flexible sigmoidoscopy: a prospective study in an ethnically diverse cohort

OBJECTIVES: Although the association between distal neoplasia on sigmoidoscopy and proximal colonic pathology on follow-up colonoscopy has been well-described, it is not known if these findings are consistent across ethnic groups. The aim of this study was to evaluate ethnic variations in the prevalence of proximal neoplasia on follow-up colonoscopy after a neoplastic lesion is found on sigmoidoscopy. METHODS: Consecutive asymptomatic patients at average-risk for colorectal cancer who were referred for screening flexible sigmoidoscopy were prospectively enrolled. Colonoscopy was recommended for all patients with a polyp on flexible sigmoidoscopy, regardless of size. Advanced neoplasms were defined as adenomas > or = 10 mm in diameter or any adenoma, regardless of size, with villous histology, high-grade dysplasia, or cancer. RESULTS: Among the 2,207 patients who had sigmoidoscopy, 970 were Caucasian, 765 were African American, 395 were Hispanic, and 77 were Asian. The prevalence of neoplasia in the distal colon was 12.6% in Caucasians, 11.2% in African Americans, 15.9% in Hispanics, and 24.7% in Asians (p = 0.002). Of the 290 patients with neoplastic lesions on sigmoidoscopy, follow-up colonoscopy identified neoplasms in the proximal colon in 63.9% of Caucasians, 59.3% of African Americans, 66.7% of Hispanics, and 26.3% of Asians (p = 0.01). Advanced neoplasms in the proximal colon were highest in African Americans (34.9%) and lowest in Asians (10.5%). CONCLUSIONS: In our study population, Asians demonstrated a higher prevalence of distal colonic neoplasia and a lower prevalence of proximal colonic neoplasia compared to non-Asians. Future studies should explore ethnic variation in colonic neoplasia prevalence and location since ethnic variation could lead to tailored colorectal cancer screening strategies.     

Hyperplastic Colonic Polyps as a Marker for Adenomatous Colonic Polyps

Hyperplastic colonic polyps are generally regarded as being of little or no clinical consequence. Recently, however, hyperplastic polyps have been found to share numerous functional similarities with colorectal carcinoma. To determine whether the presence of an isolated left-sided colonic hyperplastic (metaplastic) polyp could serve as a marker for more proximal synchronous adenomatous colonic polyps, we retrospectively analyzed all consecutive colonoscopic polypectomies performed over an 18-month period at two medical centers. It is the policy at both institutions to remove or biopsy all polyps, regardless of size. Indications for colonoscopy included known or previous colonic polyps or carcinoma, hemoccult positive stool, lower gastrointestinal bleeding, iron deficiency anemia, abnormal barium enema, inflammatory bowel disease, abdominal pain, and family history of colon cancer. The location of adenomatous polyps and hyperplastic polyps was recorded and compared. One hundred sixty-three of 845 consecutive patients (19.3%) had at least one colonic polyp. The prevalence of adenomatous polyps alone was 10.3%, hyperplastic polyps 9%, and both types 1.9%. The prevalence rate for an adenomatous polyp in patients without a hyperplastic polyp was 15%. In contrast, among patients with a hyperplastic polyp, 49% had a synchronous adenomatous polyp. Only 3.4% of patients had an adenomatous polyp proximal to the splenic flexure when no polyps were present in the left colon. Conversely, among the 29 patients in whom an isolated hyperplastic polyp was found in the left colon, there was a 32.5% prevalence of adenomatous polyps in the proximal colon (p less than 0.01). The results of this study suggest that left-sided hyperplastic colonic polyps (generally within the reach of a screening sigmoidoscopy) serve as a marker for neoplastic polyps.     

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.     

Screening for Colorectal Cancer in Average-Risk Chinese Population Using a Mixed Strategy with Sigmoidoscopy and Colonoscopy

Purpose The Chinese population has been shown to have more distal colonic neoplasm and a higher sensitivity of sigmoidoscopic screening strategy for detecting advanced neoplasm compared with Western populations. This study was designed to evaluate the efficacy of the mixed screening strategy with sigmoidoscopy and colonoscopy in the average-risk Chinese population. Methods Consecutive average-risk adults aged ≥50 years who underwent colonoscopy as part of a health checkup were enrolled. Data were analyzed in a hypothetical graded screening strategy using colonoscopy on patients older than a certain cutoff age or those with distal sentinel polyps. The sensitivity in detecting advanced colonic neoplasm and advanced proximal neoplasm as well as the number of colonoscopies reduced were assessed. Results Of the 2,106 persons eligible for analysis, 1,193 (56.6 percent) were males and 913 (43.4 percent) were females. If the cutoff ages were 55, 60, and 65 years, and adenoma detected in the distal colon was the indication for subsequent colonoscopy, the detection rate for 1) advanced colonic neoplasm in the entire colon would be 94, 93.1, and 83.6 percent, respectively, and 2) advanced proximal neoplasm would be 84.8, 82.6, and 58.7 percent, respectively. The number of colonoscopic procedures could be reduced by 28, 48, and 65 percent if the cutoff ages were 55, 60, and 65 years, respectively. Conclusions The mixed screening strategy using a cutoff age at 60 years and distal adenoma as the sentinel lesion is an effective screening program in the average-risk Chinese population.     

Diminutive colonic polyps: An indication for colonoscopy

A prospective study investigated the significance of solitary diminutive colonic polyps discovered during screening flexible sigmoidoscopy. Eighty-two patients with a solitary diminutive polyp (5 mm) underwent colonoscopy after cold biopsy of the index polyp. Of the patients with adenomatous index polyps, 42.5 percent had proximal neoplastic polyps. Of the patients with hyperplastic index polyps, proximal neoplastic polyps were found in 38.9 percent. These data suggest that diminutive polyps identified during flexible sigmoidoscopy, whether adenomatous or hyperplastic, place the patient in the intermediate risk group for colorectal neoplasia. We recommend that any patient with polyps seen during screening sigmoidoscopy, regardless of histopathology, should undergo colonoscopy.Read at the meeting of The American Society of Colon and Rectal Surgeons, St. Louis, Missouri, April 29 to May 4, 1990.     

Small rectosigmoid polyps as markers of proximal neoplasms

PURPOSE: The aim of this study was to determine the spatial distribution and histotype of small colorectal polyps and to determine the validity of distal-small colorectal polyps as markers of proximal neoplasms. METHODS: In 366 patients who underwent total colonoscopy and removal of all polyps, the presence and features of polyps were recorded. The relationship between proximal neoplasms and distal polyps was investigated in 216 of 366 subjects who had no personal or familial history of colorectal neoplasia. RESULTS: Of 366 patients, 96 were free from polyps. A total of 733 small colorectal neoplasms was removed from the remainder: 79.9 percent neoplastic and 20.1 percent hyperplastic, inflammatory, or hamartomatous. High-grade dysplasia was noted in 2.7 percent of the neoplastic polyps. One adenoma containing invasive carcinoma was observed. In the subset of 216 patients, proximal neoplasms were found in 11.4 percent of those with no distal polyps, 338 percent of those with distal-small colorectal polyps only (P <0.01), and 58.8 percent of those with at least one polyp >5 mm in diameter (P =0.001). The proximal neoplasm percentage was the same in patients with at least one adenomatous-small polyp and those with only hyperplastic-small polyps. CONCLUSIONS: A distal-small colorectal polyp, whether adenomatous or hyperplastic, may be a proximal neoplasm marker. Total colonoscopy is thus justified in all patients with distal polyps, regardless of their size and histotype     

Screening for Colon Malignancy with Colonoscopy

Screening of asymptomatic individuals for colon malignancy has been advocated for the past 20 yr in the hopes of reducing colon cancer mortality. Although sigmoidoscopy is an important element of current screening recommendations, the sensitivity of this test in asymptomatic subjects has never been studied. The purpose of this study was to determine the prevalence and location of polyps and cancers in an asymptomatic population by performing full colonoscopy. We wished to assess the sensitivity of screening flexible sigmoidoscopy to 60 cm by determining how many patients with adenomas or cancer had "index" adenomatous polyps in the distal 60 cm. One hundred five healthy male outpatients, over 50 yr old, with negative examinations for occult blood in stools and no prior history of colon pathology, had full colonoscopy. Careful examination of the distal 60 cm was performed, followed by a full colon examination to the cecum. Forty-three patients (41%) had adenomatous polyps, and only 19 of these patients had an index adenomatous polyp in the distal 60 cm. Therefore, the sensitivity of sigmoidoscopy was 44%. The prevalence of adenomas increased with age. Patients were assigned to one of three groups based on the findings in the distal 60 cm. Group 1 (n = 65) had no polyps in the distal 60 cm, but 18 of these patients (28%) had adenomatous polyps in the proximal colon. Among 21 patients with only hyperplastic polyps in the distal 60 cm (group 2), six patients (29%) had proximal adenomas. In group 3, eight of 19 patients (42%) with adenomas in the distal 60 cm also had proximal adenomatous polyps. We conclude that adenomatous polyps are common in asymptomatic men who have negative tests for fecal occult blood. Sigmoidoscopy to 60 cm had a sensitivity of only 44% in this patient population, suggesting that this is an insensitive test for the detection of patients with adenomatous polyps.     

Distal colonic hyperplastic polyps do not predict proximal adenomas in asymptomatic average-risk subjects.

The significance of distal colonic hyperplastic polyps was investigated in 482 asymptomatic average-risk subjects, aged 50-75 years, in whom fecal occult blood test results were negative and who underwent screening colonoscopy. The incidence of adenomas in the colon proximal to the sigmoid-descending colon junction in subjects with hyperplastic polyps distal to that point was 18% and was similar to the incidence of proximal colonic adenomas in subjects with no distal colonic polyps (15%). The incidence of proximal colonic adenomas in subjects with no distal colonic adenomas was 38% and was significantly greater than the incidence found in individuals with no distal colonic polyps or only hyperplastic polyps. Our data do not support distal colonic hyperplastic polyps as markers for proximal colonic adenomas in asymptomatic average-risk subjects.     

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.     

Distal colonic neoplasms predict proximal neoplasia in average-risk, asymptomatic subjects

Flexible sigmoidoscopy has been recommended as a screening method to reduce the incidence of colorectal cancer in asymptomatic, average-risk subjects through the early detection and removal of polyps. However, the association between distal and proximal colonic neoplasia and, hence, the requirement for colonoscopic follow up of screen-detected distal neoplasms is unclear. Our aims were: (i) to evaluate the risk of having proximal neoplasms in those with distal colonic neoplasms; and (ii) to determine whether the risk was dependent on the number, size, histology or morphology of the distal lesions. We prospectively evaluated asymptomatic subjects in a flexible sigmoidoscopy based screening programme. Those with rectosigmoid neoplasia underwent colonoscopy. The number, size, histology and morphology of the polyps were recorded. Advanced lesions were defined as adenomas > 1 cm or with a villous component or severe dysplasia, carcinoma in situ or cancer. Adenomatous polyps were found in 17% (135) of screening flexible sigmoidoscopies. At colonoscopy, up to 30% of subjects with distal colonic neoplasms had synchronous proximal lesions at colonoscopy and up to 20% had advanced proximal lesions. The risk of proximal colonic neoplasia was increased in those with distal sessile colonic neoplasms but appeared independent of distal lesion size, number or morphology. In conclusion, distal colonic neoplasia predicts proximal neoplasia in up to 30% of subjects and these were advanced lesions in up to 20%. We recommend that all subjects with biopsy proven distal colonic neoplasia undergo colonoscopy.     

Prevalence of advanced colonic polyps in asymptomatic Chinese

AIM: To investigate the prevalence of advanced polyps in asymptomatic Chinese and to determine the risk of proximal advanced colonic polyps in subjects with and without polyps in the distal colon.METHODS: Data were collected prospectively during colonoscopic examinations performed in 5 973 subjects as part of health evaluation at our unit from December 1997 to December 2003. Polyps were considered advanced, if they were larger than 10 mm or were tubovillous, villous or malignant. Proximal colon was defined as the splenic flexure and more proximal portions of the colon.RESULTS: Colon polyps were detected in 971 (16.3%)subjects (613 males and 358 females) with their mean age being 56.6±10.7 years. Advanced polyps were noted in 199 (3.3%) individuals. Subjects were sub-classified according to the location of polyps into three groups: distal (569, 58.6%), proximal (284, 29.2%), and combined proximal and distal (118, 12.2%) groups. Subjects with advanced polyps in these three groups were 95 (9.8%),56 (5.8%), and 48 (4.9%) respectively. In the 48 subjects with advanced combined polyps, 13 advanced polyps were distributed at the distal colon, 17 at the proximal colon,and 18 at both. Eighteen colon cancers including 12 at sigmoid and 6 at ascending colon were confirmed by final pathology. The relative risk for advanced proximal polyp according to distal findings was 3.1 (95%CI: 1.3-7.4) for hyperplastic polyp, 2.7 (95%CI: 1.4-5.3) for tubular polyp and 13.5 (95%CI: 5.1-35.4) for advanced polyp as compared to that for no polyp. However, 56 (28.2%) of 199 subjects with advanced polyps had no index polyps at the distal colon and might go undetected under sigmoidoscopic screening.CONCLUSION: Although distal lesions can predict the risk of advanced proximal polyps, a substantial portion of Chinese with advanced proximal polyps is not associated with any distal sentinel lesions. These data have implications for screening policy of colon cancers in Taiwanese Chinese.     

Prevalence of advanced colonic polyps in asymptomatic Chinese

AIM: To investigate the prevalence of advanced polyps in asymptomatic Chinese and to determine the risk of proximal advanced colonic polyps in subjects with and without polyps in the distal colon. METHODS: Data were collected prospectively during colonoscopic examinations performed in 5 973 subjects as part of health evaluation at our unit from December 1997 to December 2003. Polyps were considered advanced, if they were larger than 10 mm or were tubovillous, villous or malignant. Proximal colon was defined as the splenic flexure and more proximal portions of the colon. RESULTS: Colon polyps were detected in 971 (16.3%) subjects (613 males and 358 females) with their mean age being 56.6±10.7 years. Advanced polyps were noted in 199 (3.3%) individuals. Subjects were sub-classified according to the location of polyps into three groups: distal (569, 58.6%), proximal (284, 29.2%), and combined proximal and distal (118, 12.2%) groups. Subjects with advanced polyps in these three groups were 95 (9.8%), 56 (5.8%), and 48 (4.9%) respectively. In the 48 subjects with advanced combined polyps, 13 advanced polyps were distributed at the distal colon, 17 at the proximal colon, and 18 at both. Eighteen colon cancers including 12 at sigmoid and 6 at ascending colon were confirmed by final pathology. The relative risk for advanced proximal polyp according to distal findings was 3.1 (95%CI: 1.3-7.4) for hyperplastic polyp, 2.7 (95%CI: 1.4-5.3) for tubular polyp and 13.5 (95%CI: 5.1-35.4) for advanced polyp as compared to that for no polyp. However, 56 (28.2%) of 199 subjects with advanced polyps had no index polyps at the distal colon and might go undetected under sigmoidoscopic screening. CONCLUSION: Although distal lesions can predict the risk of advanced proximal polyps, a substantial portion of Chinese with advanced proximal polyps is not associated with any distal sentinel lesions. These data have implications for screening policy of colon cancers in Taiwanese Chinese.     

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.     

Synchronous Proximal Polyps and Cancer in Patients with Polyps Detected at Sigmoidoscopy: Results of a Single, Rural-Based Sigmoidoscopy Clinic

The prevalence of polyps and cancer in the proximal colon among patients who have polyps detected on sigmoidoscopy was determined in a large rural referral hospital in north central Pennsylvania. Eleven thousand one hundred sixty patients underwent sigmoidoscopy between 1991 and 1997. Polyps were detected in 709 patients. Five hundred twenty-three patients who had a polyp at sigmoidoscopy and full colonoscopy completed within one year were included in this study. 120 patients (23%) had a proximal polyp detected at colonoscopy. The prevalence of proximal polyps and histologically advanced polyps was related to the size, number, and histology of the distal index polyp found at sigmoidoscopy. However, the absolute difference in prevalence of proximal polyps stratified by dings at sigmoidoscopy was small. A total of 5 adenocarcinomas were detected in the proximal colon. All proximal cancers detected at colonoscopy occurred in patients with a distal polyp less than 10 mm. Our data emphasize the importance of colonoscopy in all patients with a polyp detected at sigmoidoscopy independent of its size and histology.     

Is the distal hyperplastic polyp a marker for proximal neoplasia?

CONTEXT: The current literature is unclear about the association between distal hyperplastic polyps and synchronous neoplasia (adenomatous polyps and cancer) in the proximal colon. OBJECTIVE: To estimate the prevalence of proximal neoplasia associated with distal hyperplastic polyps. DATA SOURCES: Database searches (medline and embase from 1966 to 2001) and manual search of the bibliographies of included and excluded studies, case reports, editorials, review articles, and textbooks of Gastroenterology. STUDY SELECTION: Studies describing the prevalence of proximal neoplasia in persons with distal hyperplastic polyps. DATA EXTRACTION: Demographics, clinical variables, study design, and prevalence of proximal neoplasia associated with various distal colorectal findings. DATA SYNTHESIS: Of 18 included studies, 12 involved asymptomatic individuals in which the pooled absolute risk of any proximal neoplasia associated with distal hyperplastic polyps was 25% (95% confidence interval [95% CI], 21% to 29%). In 4 studies where colonoscopy was performed irrespective of distal findings, the absolute risk was 21% (95% CI, 14% to 28%). The relative risk of finding any proximal neoplasia in persons with distal hyperplastic polyps was 1.3 (95% CI, 0.9 to 1.8) compared to those with no distal polyps. Among 6 studies of patients with symptoms or risk factors for neoplasia, the absolute risk of proximal neoplasia was 35% (95% CI, 32% to 39%) in persons with distal hyperplastic polyps. In 2 studies of screening colonoscopy, advanced proximal neoplasia (cancer, or a polyp with villous histology or severe dysplasia, or a tubular adenoma >/=1 cm) was present in 4% to 5% of persons with distal hyperplastic polyps, which was 1.5 to 2.6 times greater than in those with no distal polyps. CONCLUSIONS: In asymptomatic persons, a distal hyperplastic polyp is associated with a 21% to 25% risk for any proximal neoplasia and a 4% to 5% risk of advanced proximal neoplasia, and may justify examination of the proximal colon. Further study is needed to determine the risk of advanced proximal neoplasia associated with size and number of distal hyperplastic polyps.     

Risk for colon adenomas in patients with rectosigmoid hyperplastic polyps

OBJECTIVE: To determine whether hyperplastic polyps found in the rectosigmoid area of the colon are associated with proximal adenomas, and to judge whether patients with distal hyperplastic polyps found during sigmoidoscopy might benefit from full colonoscopy. DESIGN: Data on patients having colonoscopy collected prospectively according to a set protocol. The size and location of all polyps were noted, and all polyps were biopsied. SETTING: Two university hospitals. PATIENTS: One thousand eight hundred and thirty-six consecutive patients referred for colonoscopy between 31 December 1987 and 31 August 1989. RESULTS: Of the 970 patients who met eligibility requirements, 274 (28.3%) had adenomas and 108 (11.1%) had hyperplastic polyps. The proportion of patients with distal hyperplastic polyps and proximal adenomas (31.9%) was similar to the proportion of those without distal hyperplastic polyps (23.0%) (crude odds ratio, 1.57; 95% CI, 0.77 to 3.06). After adjusting for age and sex, the results were unchanged (adjusted odds ratio, 1.53; CI, 0.82 to 2.88). Patients with distal adenomas, on the other hand, were three times more likely to have proximal adenomas than those without distal adenomas (adjusted odds ratio, 3.42; CI, 1.99 to 5.88). CONCLUSIONS: Distal hyperplastic polyps are not strong predictors of risk for proximal adenomas. Based on the magnitude of the risk difference, we do not believe that finding a hyperplastic polyp during sigmoidoscopy justifies doing a full colonoscopy to search for proximal adenomas. Because rectosigmoid adenomas are associated with proximal adenomas, however, small polyps seen during sigmoidoscopy should be biopsied to determine their type. Colonoscopy should be reserved for patients who are proved to have adenomas.     

Frequency of isolated proximal colonic polyps among patients referred for colonoscopy

The American Cancer Society now advocates screening asymptomatic populations over the age of 40 to 50 years for colonic malignancy. It is possible, however, that fecal occult blood testing and sigmoidoscopy to 60 cm would fail to identify patients with adenomatous polyps located only in the proximal colon. The purpose of this study was to determine how many patients without polyps in the distal 60 cm of the colon would have more proximal lesions. Ninety-eight consecutive patients with positive fecal blood test results or suspicious barium enema results were studied, using the assumption that if they had been seen six months earlier, when asymptomatic, they would have been candidates for screening examination. Forty-one (42%) of 98 patients had adenomatous polyps or cancer, and 15 (37%) of these patients had isolated proximal lesions. The polyp detection rate from 0 to 60 cm was significantly less than the detection rate for a full colonoscopy (27% vs 42%). We conclude that isolated proximal colonic polyps may be common.