Is there a role for sigmoidoscopy in symptomatic patients? Analysis of a study correlating distal and proximal colonic neoplasias detected by colonoscopy in a symptomatic population

BACKGROUND: Colonoscopy is the gold standard exam to investigate patients with colonic complaints. However, its availability is limited in developing countries. Sigmoidoscopy has been advocated as a first procedure in colorectal cancer screening strategies, in order to select those who need colonoscopy. AIM: To study the correlation between distal and proximal colonic neoplasias in symptomatic patients 50 years or older and patients 40 to 49 years old who underwent colonoscopy at a gastrointestinal endoscopy unit in 1999 and 2000 with the purpose to evaluate its role in a symptomatic population. METHODS: All colonoscopies performed in our Department in 1999-2000 were reviewed. The distal colon was defined as the colonic segment aboral to the splenic flexure. Advanced neoplasias were defined as adenomas larger than 10 millimeters and adenocarcinomas. RESULTS: Of the 2,701 colonoscopies retrieved, 1,125 were enrolled in this study. Prevalence rates for adenoma, advanced adenoma and carcinoma were 28.9%, 4.6% and 4% in the group of 830 patients 50 years or older (mean age 65 years, 491 women). The finding of one small (<10 mm) adenoma in the distal bowel doubled the likelihood of finding a proximal neoplasia (OR = 2.12, 95% CI, 1.27-3.54), and multiple (OR = 3.99, 95% CI, 1.72-9.28) or advanced (OR = 3.73, 95% CI, 1.81-7.7) adenomas increased this risk even further. Of the patients without adenoma or carcinoma in the distal colon, 1.93% had proximal advanced neoplasia. In the group of 40 to 49-year-old patients (n = 395; mean age 44.8 years, 208 women) the prevalence of adenomas (14.9%), advanced adenomas (3.4%), and carcinomas (1.7%) was lower. CONCLUSIONS: The likelihood of finding a proximal lesion is greater in patients with distal neoplasias. This likelihood is further increased when adenomas are multiple or larger than 10 mm. One out of 52 patients 50 years or older with an apparently normal distal colon has advanced proximal neoplasia. Sigmoidoscopy is not an adequate exam for symptomatic patients aged 50 years or older.     

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.     

Distribution of colon neoplasia in Chinese patients: implications for endoscopic screening strategies

OBJECTIVES: Our aim was to measure the prevalence and distribution of colonic neoplasia in Chinese adults, and to estimate the sensitivity of sigmoidoscopic screening strategies for detecting those with advanced neoplasia. METHODS: Asymptomatic, average-risk Chinese adults aged 50 years or older underwent screening colonoscopy. The prevalence and distribution of colonic neoplasia and advanced neoplasia (defined as an adenoma >or=10 mm or with villous, high-grade dysplastic, or malignant features) were reviewed retrospectively and the outcomes of various sigmoidoscopic screening strategies estimated. RESULTS: Of 1,382 individuals (833 men, 549 women; mean age 58.8 years) included, 243 (18%) had colorectal neoplasia and 72 (5.2%) had advanced neoplasia. Neoplasia prevalence was significantly higher in male and older patients. No significant differences were observed in neoplasia distribution between men and women. Overall, 24 patients had advanced neoplasia in the proximal colon, of whom four had synchronous distal neoplasia. The estimated sensitivity for detecting patients with advanced neoplasia was 72% if we assumed screening sigmoidoscopy was performed, with follow-up colonoscopy for those with distal neoplasia; 165 patients would need to undergo colonoscopy. If, instead, we assumed follow-up colonoscopy was done only for patients with distal advanced neoplasia, the estimated sensitivity would decrease slightly to 71%, but the number of colonoscopies would decrease substantially to 51. CONCLUSION: In average-risk Chinese adults, screening sigmoidoscopy is estimated to detect more than two-thirds of patients with advanced neoplasia. In Chinese societies with limited health-care resources, performing colonoscopy only on patients with distal advanced neoplasia is a screening approach that optimizes the return rate on colonoscopic capacity.     

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.     

Colonoscopic yield of colorectal neoplasia in daily clinical practice

AIM： To assess the prevalence and location of advanced neoplasia in patients undergoing colonoscopy, and to compare the yield per indication. METHODS： In a multicenter colonoscopy survey （n = 18 hospitals） in the Amsterdam area （Northern Holland）, data of all colonoscopies performed during a three month period in 2005 were analyzed. The location and the histological features of all colonic neoplasia were recorded. The prevalence and the distribution of advanced colorectal neoplasia and differences in yield between indication clusters were evaluated. Advanced neoplasm was defined as adenoma 〉 10 mm in size, with 〉 25% villous features or with high-grade dysplasia or cancer. RESULTS： A total of 4623 eligible patients underwent a total colonoscopy. The prevalence of advanced neoplasia was 13%, with 281 （6%） adenocarcinomas and 342 （7%） advanced adenomas. Sixty-seven percent and 33% of advanced neoplasia were located in the distal and proximal colon, respectively. Of all patients with right-sided advanced neoplasia （n = 228）, 51% had a normal distal colon, whereas 27% had a synchronous distal adenoma. Ten percent of all colonoscopies were performed in asymptomatic patients, 7% of whom had advanced neoplasia. In the respective procedure indication clusters, the prevalence of rightsided advanced neoplasia ranged from 11%-57%. CONCLUSION： One out of every 7-8 colonoscopies yielded an advanced colorectal neoplasm. Colonoscopy is warranted for the evaluation of both symptomatic and asymptomatic patients.     

Grading of distal colorectal adenomas as predictors for proximal colonic neoplasia and choice of endoscope in population screening: experience from the Norwegian Colorectal Cancer Prevention study (NORCCAP)

BACKGROUND AND AIMS: The purpose of this study was to evaluate the utility of easily measured clinical variables at flexible sigmoidoscopy (FS) screening that might predict a proximal advanced neoplasm (PAN). METHODS: We studied 1833 subjects with biopsy verified adenomas at FS who subsequently underwent full colonoscopy. RESULTS: A total of 387 (21%) subjects had proximal colonic neoplasms (PCN) and 85 (5%) had PAN. In univariate comparison, the risk of PAN increased more than threefold in the presence of a distal adenoma measuring either > or =10 mm in diameter or containing villous components. Multiplicity of distal adenomas, severe dysplasia, or age > or =60 years increased the risk of PAN more than twofold. In the multivariate model, the presence of a distal adenoma > or =10 mm, villousness, and multiplicity maintained their significance as predictive variables for increased risk of proximal neoplasms, whereas sex and severe dysplasia lost their significance. By recommending colonoscopy only to individuals with multiple (>1) adenomas or any high risk adenoma at FS, we would have reduced the number of colonoscopies by 1209 (66%) but would have missed 32 (38%) participants with PAN and 217 (56%) with PCN. By using a 60 cm endoscope instead of an ordinary colonoscope at FS, nine (2%) participants with advanced neoplasms, including three patients with cancer, would have been missed. CONCLUSION: The present study supports the concept of defining "any adenoma" as a positive FS, qualifying for colonoscopy. We recommend the use of an ordinary colonoscope instead of a 60 cm sigmoidoscope for FS screening examinations.     

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.     

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.     

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.     

Screening colonoscopy in asymptomatic average-risk African Americans

BACKGROUND: Recent data indicate that colorectal cancer incidence and mortality in white Americans have been declining since 1985 at a rate of 2% to 3% per year. In African Americans, however, mortality from colorectal cancer appears to be increasing. We sought to evaluate the prevalence of colonic neoplasia in asymptomatic African Americans. METHODS: We performed a cross-sectional colonoscopy screening study to determine the prevalence of colonic neoplasia in asymptomatic African Americans older than 50 years of age. RESULTS: One hundred sixty-six subjects were evaluated for the study of whom 121 (69 women) were deemed to be asymptomatic average-risk persons and completed colonoscopy. Forty-two individuals (35%) had a total of 72 adenomas (67 tubular and 5 tubulovillous); 47 (65.3%) of these were proximal to the splenic flexure. Three subjects had an adenoma 1 cm or greater in diameter and none had severe dysplasia. CONCLUSIONS: The overall prevalence of adenomas in asymptomatic average-risk African Americans was comparable to that of previously described populations. The predominance of right-sided adenomas in this study confirms previous findings and is an area requiring further study. Until this issue is resolved, we suggest the use of colonoscopy rather than sigmoidoscopy for screening for colorectal neoplasia in asymptomatic, average-risk African Americans.     

Adenoma incidence decreases under the effect of polypectomy

AIM:To investigate whether,under the influence of pol-ypectomy,the incidence of adenoma decreases with age.METHODS:Consecutive patients with colonic adenomas identified at index colonoscopy were retrospectively selected if they had undergone three or more complete colonoscopies,at least 24 mo apart.Patients who had any first-degree relative with colorectal cancer were excluded.Data regarding number of adenomas at each colonoscopy,their location,size and histological classification were recorded.The monthly incidence density of adenomas after the index examination was estimated for the study population,by using the person-years method.Baseline adenomas were excluded from incidence calculations but their characteristics were correlated with recurrence at follow-up,using the χ 2 test.RESULTS:One hundred and fifty-six patients were included(109 male,mean age at index colonoscopy 56.8 ± 10.3 years),with follow-up that ranged from 48 to 232 mo.No significant correlations were observed between the number,the presence of villous component,or the size of adenomas at index colonoscopy and the presence of adenomas at subsequent colonoscopies(P = 0.49,0.12 and 0.78,respectively).The incidence of colonic adenomas was observed to decay from 1.4% person-months at the beginning of the study to values close to 0%,at 12 years after index colonoscopy.CONCLUSION:Our results suggest the sporadic formation of adenomas occurs within a discrete period and that,when these adenomas are removed,all neoplasia-prone clones may be extinguished.     

Utilization of colonoscopy in the United States: results from a national consortium

BACKGROUND: To assess capacity for colonoscopy, we need to understand current utilization of colonoscopy in diverse clinical practice settings. The objective of this study was to determine the utilization of colonoscopy in diverse clinical practice settings. METHODS: The Clinical Outcomes Research Initiative (CORI) data repository, which receives endoscopy reports from 73 diverse adult practice sites in the United States was used. Colonoscopy reports from January 2000 to August 2002 were analyzed to determine the demographic characteristics of adult patients who received a colonoscopy and the procedure indication. The relationship of age, race, gender, and procedure indication was analyzed. RESULTS: Results of colonoscopies in 146,457 unique patients were analyzed. Of the reports, 68% came from nonacademic settings. Patients less than 50 years of age accounted for 20% of colonoscopies. The most common indications were rectal bleeding (33.6%), irritable bowel symptoms (23.8%), or screening because of a positive family history of colorectal cancer (22.4%) and screening with a primary colonoscopy or a fecal occult blood test (FOBT) (12.8%). In patients 50 years and older, asymptomatic screening (average-risk screening colonoscopy, positive family history, or FOBT positivity) accounted for 38.1% of all colonoscopies. Surveillance colonoscopy in patients with previous cancer or polyps accounted for 21.9% of colonoscopies performed in this age group. Differences in utilization were noted, based on gender and race. CONCLUSIONS: Colonoscopy utilization varies based on age, gender, and race. Colonoscopy often is performed in patients less than 50 years old for irritable bowel symptoms; rectal bleeding; or average-risk screening, for which benefits are uncertain. In patients older than 50 years, surveillance after polyp removal is a common indication and may be overused. Understanding utilization can lead to further study to determine outcomes, to optimize utilization, and to provide a basis for shifting limited resources.     

Patient age and duration of colonoscopy are predictors for adenoma detection in both proximal and distal colon

AIM: To investigate the relation of patient characteristics and procedural parameters to the endoscopic detection rate of colonic adenomas. Further to study,which factors may be capable to predict the localization of adenomatous lesions.METHODS: We used the data base of a prospective randomized colonoscopy study(The Colo Cap trial) to identify patients being diagnosed with colon adenoma. Logistic regression analysis was conducted to reveal predictors for adenoma detection in the entire colon and also with respect to the proximal and distal part. Covariates including age, gender, duration of colonoscopy and comorbidities were defined to determine association between predictors and adenoma detection.RESULTS: Equal numbers of adenomas were detected in the proximal and distal side of the splenic flexure [126(57%) vs 94(43%), P = 0.104]. Simultaneous occurrence of adenomas in both sides of the colon was rare. The appearance of both proximal and distal adenoma was associated with increasing age(P = 0.008 and P = 0.024) and increasing duration of colonoscopy(P < 0.001 and P = 0.001). Male gender was a predictor for adenoma detection in the proximal colon(P = 0.008) but statistical significance was slightly missed with respect to the distal colon(P = 0.089). Alcohol abuse was found to be a predictor for the detection of distal adenoma(P = 0.041). CONCLUSION: Increasing age and longer duration of colonoscopy are factors with a strong impact on adenoma detection both in the proximal and distal colon. Since proximal adenomas occurred in absence of distal adenomas, complete colonoscopy should be performed for screening.     

Significance of a normal surveillance colonoscopy in patients with a history of adenomatous polyps

PURPOSE: The aim of this study was to determine the appropriate surveillance for patients with a history of adenomatous polyps whose last colonoscopic examination was normal. METHODS: This was a retrospective review of a database of 7,677 colonoscopies (1990 to 1996). In patients under colonoscopic surveillance, we reviewed cases of patients who had received three colonoscopies (an index (initial) colonoscopy positive for adenomas and 2 follow-up colonoscopies (interim and final)). The risk of adenomas and cancers at final follow-up colonoscopy was compared between patients having a normal interim colonoscopy and those with a positive interim colonoscopy. The risk at final colonoscopy was also stratified by time interval and the size and number of adenomas at the initial index colonoscopy. RESULTS: Two hundred four patients undergoing surveillance for adenomas met inclusion criteria. At index colonoscopy the median polyp size was 1 cm and median frequency was three polyps. At all follow-up colonoscopies, we detected 493 adenomas and one cancer (median follow-up, 55 months). At 36 months patients with a normal interim colonoscopy (n = 91) had significantly fewer polyps than patients with a positive interim colonoscopy (n = 113; 15 vs. 40 percent; P = 0.0001). By 40 months, adenomas were detected in more than 40 percent of patients in both groups. The risk after a normal interim colonoscopy was not affected by time interval or number or size of polyps. Adenomas found subsequent to a normal interim colonoscopy were dispersed throughout the colon in 28 patients and isolated to the rectosigmoid in 6 patients. CONCLUSIONS: In patients with a history of adenomas, a normal follow-up colonoscopy is associated with a statistically but not clinically significant reduction in the risk of subsequent colonic neoplasms. These patients require follow-up surveillance colonoscopy at a four-year to five-year interval.     

Diagnostic value of distal colonic polyps for prediction of advanced proximal neoplasia in an average-risk population undergoing screening colonoscopy

BACKGROUND: For colorectal cancer screening, the predictive value of distal findings in the ascertainment of proximal lesions is not fully established. The aims of this study were to assess distal findings as predictors of advanced proximal neoplasia and to compare the predictive value of endoscopy alone vs. combined endoscopic and histopathologic data. METHODS: Primary colonoscopy screening was performed in 2210 consecutive, average-risk adults. Age, gender, endoscopic (size, number of polyps), and histopathologic distal findings were used as potential predictors of advanced proximal neoplasms (i.e., any adenoma > or =1 cm in size, and/or with villous histology, and/or with severe dysplasia or invasive cancer). Polyps were defined as distal if located in the descending colon, the sigmoid colon, or the rectum. Those in other locations were designated proximal. RESULTS: Neoplastic lesions, including 11 invasive cancers, were found in 617 (27.9%) patients. Advanced proximal neoplasms without any distal adenoma were present in 1.3% of patients. Of the advanced proximal lesions, 39% were not associated with any distal polyp. Older age, male gender, and distal adenoma were independent predictors of advanced proximal neoplasms. The predictive ability of a model with endoscopic data alone did not improve after inclusion of histopathologic data. In multivariate logistic regression analysis, the predictive ability of models that use age, gender, and any combination of distal findings was relatively low. The proportion of advanced proximal neoplasms identified if any distal polyp was an indication for colonoscopy was only 62%. CONCLUSIONS: A strategy in which colonoscopy is performed solely in patients with distal colonic findings is not effective screening for the detection of advanced proximal neoplasms in an average-risk population.     

Predictors of advanced proximal neoplasia in persons with abnormal screening flexible sigmoidoscopy.

BACKGROUND & AIMS: The relationship between distal and proximal colonic findings is uncertain. Thus, there is no consensus on which findings on screening flexible sigmoidoscopy should trigger colonoscopy. METHODS: We analyzed data from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial to assess the relationship between distal and proximal colonic findings. RESULTS: A total of 8802 subjects had an abnormal baseline sigmoidoscopy and colonoscopy follow-up. Subjects with <10-mm single or multiple tubular adenomas had similar risks for advanced proximal neoplasia as subjects with hyperplastic polyps or other benign lesions (3%-5%). Subjects with large (>or=10 mm), villous, or severely dysplastic distal adenomas had similarly elevated risks for advanced proximal neoplasia (11%-12%). Multivariate logistic modeling showed a significantly increased risk for advanced proximal neoplasia associated with the presence of a large tubular (odds ratio [OR], 2.6; 95% confidence interval [CI], 2.0-3.4) or villous distal adenoma (OR, 2.7; 95% CI, 2.1-3.5) but not with the presence of one (OR, 1.05; 95% CI, 0.8-1.3) or multiple (OR, 0.8; 95% CI, 0.5-1.2) <10-mm tubular distal adenomas. CONCLUSIONS: Among subjects with a polypoid lesion on screening flexible sigmoidoscopy, those with small tubular distal adenomas are at similar risk for advanced proximal neoplasia as those without distal adenomas. Subjects with a large, villous, or dysplastic distal adenoma are at increased risk. A strategy that encourages individuals with small tubular adenomas on sigmoidoscopy to undergo follow-up colonoscopy and excludes those with nonadenomatous lesions is of questionable validity, because both groups are at similar risk for advanced proximal neoplasia.     

Screening colonoscopy in asymptomatic average-risk persons with negative fecal occult blood tests.

Colonoscopy was performed on 210 asymptomatic average-risk persons, aged 50-75 years, who had negative fecal occult blood test results. Colonoscopy was complete to the cecum in 209 subjects. Fifty-three subjects (25%) had adenomas and two had cancer. All of the adenomas greater than or equal to 1 cm in size and both cancers occurred in subjects aged greater than or equal to 60 years. Fifty-one percent of subjects with adenomas and one with cancer had no neoplasms distal to the sigmoid-descending colon junction. One subject had a major postpolypectomy hemorrhage that stopped spontaneously. Screening colonoscopy, therefore, has a high yield for detection of neoplasms in asymptomatic average-risk persons aged greater than or equal to 60 years with negative fecal occult blood test results. The yield is low in persons aged 50-54 years and intermediate in persons aged 55-59 years.     

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.     

Age and distal colonic findings determine the yield of advanced proximal neoplasia in Chinese patients with rectal bleeding

BACKGROUND AND AIMS: Few data were available on the optimal diagnostic strategy for Chinese patients with hematochezia. We aimed to evaluate the impact of age and distal colonic findings on the yield of diagnostic strategies in young Chinese patients with hematochezia. METHODS: Consecutive outpatients aged less than 50 years were analyzed using a hypothesized mixed diagnostic strategy to determine the optimal cut-off age for the use of sigmoidoscopy and colonoscopy. The efficacy and cost of the diagnostic strategy and the number of colonoscopies needed to detect one advanced proximal neoplasm (APN) using different cut-off ages were assessed. RESULTS: In the hypothesized mixed diagnostic strategy for young patients, the sensitivities for the detection of APN were 100%, 92% and 75% if the cut-off ages were 30, 35 and 40 years, respectively. The cost needed to detect one APN would be $US 3155, $US 3179 and $US 3497 if the cut-off ages were 30, 35 and 40 years, respectively. Colonoscopy would be performed in 84%, 69% and 51% of patients if the cut-off ages were 30, 35 and 40 years, respectively. CONCLUSION: Colonoscopy should be considered for Chinese patients with rectal bleeding who are aged > or =35 years or those aged <35 years who have adenoma in the distal colon.