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.     

Colorectal neoplasm in asymptomatic Asians: a prospective multinational multicenter colonoscopy survey

BACKGROUND: Colorectal neoplasm is rapidly increasing in Asia, but a guideline for screening is not available. OBJECTIVE: To evaluate the characteristics of colorectal neoplasm in asymptomatic Asian subjects. DESIGN: Prospective cohort study. SETTING: Multinational multicenters, including both primary and referral centers in Asia. PATIENTS: A total of 860 consecutive asymptomatic adults undergoing screening colonoscopy in 11 Asian cities from July 2004 to December 2004. Patients under 16 years old; those patients with a colorectal resection history, colonoscopies, or barium enema within 5 years; symptoms suggestive of colorectal diseases; and those who had undergone surveillance colonoscopy were excluded. MAIN OUTCOME MEASUREMENTS: The incidence and distribution of colorectal neoplasm and advanced neoplasm. RESULTS: The mean age (+/-SD) was 54.4+/-11.6 years; 471 were men (54.8%). The prevalence of colorectal neoplasm and advanced neoplasm was 18.5% and 4.5%, respectively. Male sex, advancing age, and a family history of colorectal cancer were risk factors for advanced neoplasm. Of the 168 patients with colorectal neoplasm, 76 had distal neoplasm only (45.2%), 66 had proximal neoplasm only (39.3%), and 26 had both proximal and distal neoplasms (15.5%). Although the presence of distal advanced neoplasm was a significant risk factor for proximal advanced neoplasm, 14 of the 758 subjects without distal neoplasm had proximal advanced neoplasm (1.8%). LIMITATIONS: The small number of enrolled subjects, especially from certain ethnic groups. CONCLUSIONS: The overall prevalence of advanced colorectal neoplasm in asymptomatic Asians is comparable with the West. Male sex, advancing age, and a family history of colorectal cancer were associated with a higher risk of advanced neoplasm.     

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.     

Prevalence of clinically important histology in small adenomas.

BACKGROUND & AIMS: The prevalence of advanced histology in small polyps has become a crucial issue in optimizing colorectal cancer screening strategies, especially in view of the advent of computed tomography colonography. We evaluated the prevalence of advanced histology in small and diminutive adenomas to clarify their clinical importance in terms of malignant potential. METHODS: Data were reviewed retrospectively from 3291 colonoscopies performed on asymptomatic patients found to have an adenoma on screening with flexible sigmoidoscopy a few weeks before the colonoscopy or who had a family history of colorectal cancer. All polyps were excised endoscopically and sent for pathology testing. Specimens with advanced histology were confirmed by a second reading. RESULTS: Of the 3291 colonoscopies performed, 1235 colonoscopies yielded a total of 1933 small or diminutive adenomatous polyps. Advanced histology including carcinoma was found in 10.1% of small (5-10 mm) adenomas and in 1.7% of diminutive adenomas (< or = 4 mm). Carcinoma was found in .9% of small adenomas, and 0% of diminutive adenomas. Of the 107 patients found to have polyps 2-10 mm with advanced histology, 100 (93%) were referred for colonoscopy because of an adenoma found on a recent screening with flexible sigmoidoscopy. Seven patients underwent colonoscopy for a positive family history of colon cancer; all 7 had a single affected first-degree relative older than age 50. CONCLUSIONS: Adenomas 5-10 mm in size harbor pathologically significant histology, and the need for removal of these lesions must be addressed to optimize colorectal cancer prevention.     

Colorectal neoplasia in Asia: a multicenter colonoscopy survey in symptomatic patients

BACKGROUND: The incidence of colorectal cancer is rising rapidly in some Asian countries. OBJECTIVE: To determine the prevalence and the distribution of colorectal neoplasm in Asian populations. DESIGN: A multicenter colonoscopy survey. PATIENTS: Between July 2004 and April 2005, consecutive symptomatic patients undergoing colonoscopic examinations in 10 different Asian countries. SETTING: The location and the histologic features of all colonic neoplasms were recorded. Advanced neoplasm was defined as adenoma larger than 10 mm in size, with >25% villous features or with high-grade dysplasia or invasive carcinoma. MAIN OUTCOME MEASUREMENTS: The prevalence and the distribution of colorectal neoplasm and advanced neoplasm. RESULTS: A total of 5464 eligible patients underwent colonoscopy. Advanced neoplasm was found in 512 patients (9.4%). Factors associated with the presence of advanced neoplasm in this symptomatic Asian population included male sex (relative risk [RR] 1.52, 95% confidence interval [CI] 1.26-1.84), older age (RR 1.05, 95% CI 1.04-1.06), and ethnicity (P = .001). Advanced proximal neoplasm was detected in 136 patients (2.5%); 83 (61.0%) of the patients had normal distal colon. The RR of proximal advanced neoplasm was 2.5, 95% CI 1.7-3.7 in those with any adenoma in the distal colon compared with those with normal distal colon. LIMITATIONS: Possible underrepresentation of some ethnic groups because of uneven ethnic group distribution and the lack of population-based registry. CONCLUSIONS: This was the first multicenter colonoscopy survey that examined the characteristics of colorectal neoplasm in Asia. The results will have important implications on the planning for future colorectal cancer screening in this region.     

Detection of proximal adenomatous polyps with screening sigmoidoscopy: a systematic review and meta-analysis of screening colonoscopy

BACKGROUND: The relative effectiveness of flexible sigmoidoscopy compared with colonoscopy to screen for colorectal cancer depends on the magnitude of the association between findings in the proximal and distal colon and the false-negative rate of screening sigmoidoscopy for proximal neoplasia. To address this, we performed a systematic review and meta-analysis of screening colonoscopy studies. METHODS: Published studies through July 31, 2000, of asymptomatic patients undergoing screening colonoscopy were identified from the MEDLINE database. We generated pooled estimates of the odds ratio for the association between findings in the distal and proximal colon and the prevalence of isolated proximal adenomatous neoplasia. RESULTS: Using the sigmoid-descending colon junction to identify the beginning of the distal colon, the pooled odds ratio for the association between distal adenomatous polyps and any proximal neoplasia was 2.40 (95% confidence interval [CI], 1.42-4.05). Diminutive distal adenomatous polyps were also associated with proximal neoplasia (odds ratio, 2.36; 95% CI, 1.30-4.29). Distal hyperplastic polyps were not associated with proximal neoplasia (odds ratio, 1.44; 95% CI, 0.79-2.62). The prevalence of isolated advanced proximal neoplasia in the 3 studies was 2%, 3%, and 5%. Using the sigmoid-descending colon junction to identify the beginning of the distal colon yields a pooled estimate of isolated proximal neoplasia of 16.3% (95% CI, 13.6%-19.1%). CONCLUSIONS: Distal adenomatous polyps, including diminutive distal adenomatous polyps, are associated with an increased prevalence of synchronous proximal neoplasia. Two percent to 5% of patients undergoing screening colonoscopy may have isolated advanced proximal neoplasia. Even more patients may have isolated nonadvanced proximal neoplasia.     

Significance of small distal adenoma for detection of proximal neoplasms in the colorectum

BACKGROUND: The significance of the small distal tubular adenoma detected by sigmoidoscopy as a predictor of proximal neoplasm remains controversial. The aim of this study was to examine the prevalence of proximal neoplasms in patients with and without distal neoplasms. METHODS: This is a retrospective study of 3131 asymptomatic middle-aged men who underwent total colonoscopy. For 812 men with colorectal neoplasms characteristics of the identified neoplasms were determined. RESULTS: The prevalence of proximal neoplasms in patients with small distal tubular adenoma was 20% (92 of 461), whereas the prevalence of proximal neoplasms in patients without distal neoplasms was 11.5% (301 of 2620). The prevalence of advanced proximal neoplasms in patients with small distal tubular adenoma and without distal neoplasm was 1.3% and 0.8%, respectively. In the 29 patients with advanced proximal neoplasms, only 6 (21%) had a small distal tubular adenoma. CONCLUSIONS: The presence of small distal tubular adenomas may provide a clue to the presence of small proximal tubular adenomas. However, the majority of advanced proximal neoplasms (79%) do not have a synchronous small distal tubular adenoma. (Gastrointest Endosc 2000;52:358-61).     

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.     

Risk of Advanced Proximal Adenoma and Cancer According to Rectosigmoid Findings in the Korean Population

Colorectal cancer is one of the leading causes of cancer death in the United States and Europe. Recently, the incidence of colorectal cancer has been increasing remarkably in Korea. To reduce the high incidence, screening of colorectal cancer in asymptomatic individuals has been advocated. Sigmoidoscopy is simpler, faster, and better tolerable than total colonoscopy, but the scope cannot reach the proximal colon segment and, therefore, may miss proximal colon cancer. In the present study, we intended to investigate the prevalence of proximal adenoma and cancer according to the findings in rectosigmoid colon and to find their risk factors. Data were collected retrospectively from 1541 consecutive patients who underwent total colonoscopy at the Department of Gastroenterology, Hanyang University, between October 2003 and December 2004. Neoplasms were classified as diminutive adenoma (≤5 mm), small adenoma (6–9 mm), advanced adenoma (≥10 mm, with villous component or high-grade dysplasia), and cancer. The sites of neoplasms were defined as rectosigmoid (rectum and sigmoid colon) and proximal (from cecum to descending colon) colon. The prevalence of advanced proximal adenoma was associated with severe rectosigmoid findings. On the other hand, the prevalence of proximal colon cancer did not show such a tendency. Among the 131 patients with proximal advanced adenoma, 66% had no neoplasm in the rectosigmoid colon. Moreover, among the 27 patients with proximal cancer, 52% had no neoplasm in the rectosigmoid colon. Multivariate logistic regression analysis revealed that age, gender, and advanced rectosigmoid adenoma were the risk factors of advanced proximal adenoma, but nothing was associated with the risk for proximal colon cancer. Advanced rectosigmoid adenoma may be the predictor of advanced proximal adenoma, especially in old males. However, nothing is related to the risk for proximal colon cancer. Therefore, colonoscopy may be more adequate for colorectal cancer screening than sigmoidoscopy in the Korean population.     

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.     

What does sigmoidoscopy really miss?

The relative effectiveness of flexible sigmoidoscopy compared with colonoscopy to screen for colorectal cancer depends on the magnitude of the association between findings in the proximal and distal colon and the false-negative rate of screening sigmoidoscopy for proximal neoplasia. Lewis et al. performed a systematic review and meta-analysis of screening colonoscopy studies. Published studies through July 31, 2000 of asymptomatic patients undergoing screening colonoscopy were identified from the MEDLINE database. The authors generated pooled estimates of the odds ratio for the association between findings in the distal and proximal colon and the prevalence of isolated proximal adenomatous neoplasia. With the sigmoid–descending colon junction used to identify the beginning of the distal colon, the pooled odds ratio for the association between distal adenomatous polyps and any proximal neoplasia was 2.40 (95% confidence interval [Cl] = 1.42–4.05). Diminutive distal adenomatous polyps were also associated with proximal neoplasia (odds ratio = 2.36; 95% CI = 1.30–4.29). Distal hyperplastic polyps were not associated with proximal neoplasia (odds ratio = 1.44; 95% CI = 0.79–6.62). The prevalence of isolated advanced proximal neoplasia in the three studies was 2%, 3%, and 5%, respectively. When the sigmoid–descending colon junction is used to identify the beginning of the distal colon, this yields a pooled estimate of isolated proximal neoplasia of 16.3% (95% CI = 13.6%–19.1%). Distal adenomatous polyps, including diminutive distal adenomatous polyps, are associated with an increasing prevalence of synchronous proximal neoplasia. From 2% to 5% of patients undergoing screening colonoscopy might have isolated advanced proximal neoplasia.     

Predictive value of morphologic characteristics in rectosigmoid adenomatous polyps for the probability of synchronous polyps or cancer in the proximal colon.

BACKGROUND/AIMS: Sigmoidoscopy is performed more frequently than colonoscopy, especially for screening purposes and searching for colorectal neoplasm. The necessity of colonoscopy in patients with an adenoma ofor=11 mm) polyps. These groups were compared regarding the presence of proximal adenoma and advanced proximal neoplasia (>10 mm adenoma and/or villous histology and/or high grade dysplasia or cancer). Polyps found in the rectum and sigmoid colon were considered as distal polyps and polyps other than these were considered as proximal polyps. RESULTS: In this study, of 1124 consecutive patients who underwent colonoscopy between April 1997 and January 2002, 184 (16%) had 258 adenomatous polyps in the rectosigmoid area. The polyps were diminutive (or=11 mm) in 33 patients. Forty-one of the patients (39%) with diminutive polyps, 20 of the patients (43%) with small polyps and 19 of the patients (57%) with large polyps had neoplasm in the proximal bowel. In these patients, advanced proximal neoplasm was found in 8 (8%), in 6 (13%) and in 11 (33%), respectively. There was no difference regarding the presence of neoplasm in the proximal colon between these groups. The rate of advanced proximal neoplasm was found to be significantly higher in the group with large polyps in the rectosigmoid area than in the groups with small and diminutive polyps (p<0.05). In 104 patients (57%) with polyp(s) in rectum and sigmoid colon, no associated polyp or cancer was encountered in the proximal colon. CONCLUSION: Colonoscopy is indicated when adenomatous polyp, regardless of size, is found on rectosigmoidoscopy performed because of symptoms.     

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.     

Rectosigmoid findings are not associated with proximal colon cancer： Analysis of 6 196 consecutive cases undergoing total colonoscopy

AIM: To review the risk of proximal colon cancer in patients undergoing colonoscopy. METHODS: We estimated the risk of advanced proximal adenomas and cancers in 6 196 consecutive patients that underwent colonoscopy (mean age 60 years, 65% males, without prior history of colorectal examination). Neoplasms were classified as diminutive adenoma (5 mm or less), small adenoma (6-9 mm), advanced adenoma (10 mm or more, with villous component or high-grade dysplasia) and cancer (invasive adenocarcinoma). The sites of neoplasms were defined as rectosigmoid (rectum and sigmoid colon) and proximal colon (from cecum to descending colon). RESULTS: The trend of the prevalence of advanced proximal adenoma was to increase with severe rectosigmoid findings, while the prevalence of proximal colon cancer did not increase with severe rectosigmoid findings. Among the 157 patients with proximal colon cancer, 74% had no neoplasm in the rectosigmoid colon. Multivariate logistic-regression analysis revealed that age was the main predictor of proximal colon cancer and existence of rectosigmoid adenoma was not a predictor of proximal colon cancer. CONCLUSION: Sigmoidoscopy is inadequate for colorectal cancer screening, especially in older populations.     

Five-year colon surveillance after screening colonoscopy

BACKGROUND & AIMS: Outcomes of colon surveillance after colorectal cancer screening with colonoscopy are uncertain. We conducted a prospective study to measure incidence of advanced neoplasia in patients within 5.5 years of screening colonoscopy. METHODS: Three thousand one hundred twenty-one asymptomatic subjects, age 50 to 75 years, had screening colonoscopy between 1994 and 1997 in the Department of Veterans Affairs. One thousand one hundred seventy-one subjects with neoplasia and 501 neoplasia-free controls were assigned to colonoscopic surveillance over 5 years. Cohorts were defined by baseline findings. Relative risks for advanced neoplasia within 5.5 years were calculated. Advanced neoplasia was defined as tubular adenoma greater than > or =10 mm, adenoma with villous histology, adenoma with high-grade dysplasia, or invasive cancer. RESULTS: Eight hundred ninety-five (76.4%) patients with neoplasia and 298 subjects (59.5%) without neoplasia at baseline had colonoscopy within 5.5 years; 2.4% of patients with no neoplasia had interval advanced neoplasia. The relative risk in patients with baseline neoplasia was 1.92 (95% CI: 0.83-4.42) with 1 or 2 tubular adenomas <10 mm, 5.01 (95% CI: 2.10-11.96) with 3 or more tubular adenomas <10 mm, 6.40 (95% CI: 2.74-14.94) with tubular adenoma > or =10 mm, 6.05 (95% CI: 2.48-14.71) for villous adenoma, and 6.87 (95% CI: 2.61-18.07) for adenoma with high-grade dysplasia. CONCLUSIONS: There is a strong association between results of baseline screening colonoscopy and rate of serious incident lesions during 5.5 years of surveillance. Patients with 1 or 2 tubular adenomas less than 10 mm represent a low-risk group compared with other patients with colon neoplasia.     

The yield of lower endoscopy in patients with constipation: survey of a university hospital,a public county hospital,and a Veterans Administration medical center

BACKGROUND: The role of endoscopy in the evaluation of constipation is controversial. The aim of this study was to clarify the yield of lower endoscopy in patients with constipation. METHODS: Endoscopic databases from 3 diverse hospitals were searched for procedures with constipation as an indication. Detection of neoplasia was the main outcome of interest. RESULTS: Among 19,764 sigmoidoscopies or colonoscopies, constipation was a procedure indication for 563 patients (mean age 61 [16] years, 52% women); 58% had procedure indications in addition to constipation. Colorectal cancer was diagnosed in 8 (1.4%), adenomas in 82 (14.6%), and advanced lesions (cancer or adenoma with malignancy, high-grade dysplasia, villous features, or size > or = 10 mm) in 24 (4.3%). In the 358 patients who underwent colonoscopy, cancer was detected in 1.7%, adenomas in 19.6%, and advanced lesions in 5.9%. Two patients with cancer were less than 50 years of age. In as many as 6 patients with cancer, the tumor may have caused partial obstruction. CONCLUSIONS: The range of neoplasia in patients with constipation evaluated with lower endoscopy was comparable with what would be expected in asymptomatic subjects undergoing colorectal cancer screening. Although chronic constipation alone may not be an appropriate indication for lower endoscopy, age-appropriate colorectal cancer screening should be pursued when patients with constipation seek medical care.     

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.     

A comparison of the immunochemical fecal occult blood test and total colonoscopy in the asymptomatic population

BACKGROUND & AIMS: The fecal occult blood test (FOBT) is recommended as a screening test for colorectal cancer, but there are few reliable studies on the accuracy of immunochemical FOBT. The aim of this study was to analyze the sensitivity of immunochemical FOBT and to compare the results with the findings from complete colonoscopy. METHODS: Asymptomatic adults underwent 1-time immunochemical FOBT and total colonoscopy simultaneously. The prevalence and location of colorectal neoplasia were determined by colonoscopy. The results of immunochemical FOBT and the colonoscopic findings were compared. RESULTS: Of 21,805 patients, immunochemical FOBT was positive in 1231 cases (5.6%). The sensitivity of 1-time immunochemical FOBT for detecting advanced neoplasia and invasive cancer was 27.1% and 65.8%, respectively. In addition, the sensitivity for invasive cancer according to Dukes' stage showed 50.0% for Dukes' stage A, 70.0% for Dukes' stage B, and 78.3% for Dukes' stages C or D. The sensitivity for detecting advanced neoplasia at the proximal colon was significantly lower than that detected in the distal colon (16.3% vs 30.7%, P = .00007). CONCLUSIONS: Although the screening of asymptomatic patients with immunochemical FOBT can identify patients with colorectal neoplasia to a certain extent, the sensitivity is relatively low and different according to the tumor location. Therefore, programmatic and repeated screening by immunochemical FOBT may be necessary to increase sensitivity for colorectal cancer detection.     

Five-year risk of colorectal neoplasia after normal baseline colonoscopy in asymptomatic Chinese Mongolian over 50?years of age

Background

After normal colonoscopy, the 5-year risk of colorectal neoplasia is sufficiently low for asymptomatic people over 50?years of age. In China, the incidence of colorectal carcinoma of Mongolian people is higher than that of Han people. The aim of this study was to assess the 5-year risk of colorectal neoplasia after normal colonoscopy in asymptomatic Chinese Mongolian population.

Patients and methods

A cohort of asymptomatic Chinese Mongolian people (??50?years old) were recruited and followed up with colonoscopy 5?years after colonoscopy. Baseline colonoscopy and follow-up colonoscopy findings were categorized based on the most advanced lesions: no adenoma, nonadvanced adenoma, and advanced adenoma. Five-year risk of colorectal neoplasia in these people was assessed according to the rates of no baseline adenoma and advanced adenoma at the end of 5?years.

Results

A total of 480 of the 538 recruited people underwent follow-up colonoscopy at the end of 5?years. In people with no baseline adenoma, 27.3?% (82/301) was found to have any adenoma, and 1.7?% had advanced adenoma at follow-up colonoscopy. The risk of an advanced adenoma did not differ significantly between people with no adenoma at baseline and those with nonadvanced adenoma (relative risk (RR), 1.06; 95?% confidence interval (CI), 0.19?C6.07). Advanced adenoma at baseline colonoscopy was the independent risk factor for advanced adenoma recurrence, compared with no adenoma at baseline (RR, 8.25; 95?% CI, 1.90?C35.77).

Conclusion

The risk of advanced adenoma is low 5?years after the normal baseline colonoscopy, even in asymptomatic Chinese Mongolian population over 50?years of age.     

Is diverticulosis associated with colorectal neoplasia? A cross-sectional colonoscopic study

OBJECTIVE: To determine the relationship between distal diverticulosis and risk for colorectal neoplasia. METHODS: Patients undergoing first-time colonoscopy for any indication were eligible if they had no prior polypectomy, colonic resection, or inflammatory bowel disease. Patients completed a survey about risk factors for colorectal cancer (CRC) prior to colonoscopy. Endoscopists, blinded to study objective and survey results, recorded the size, extent (none, few, or many), and location of diverticuli and polyps. RESULTS: The 502 participants were 67% male with a mean age of 58.6 yr. Twenty-three percent had extensive distal diverticulosis (EDD), 36% had > or =1 adenoma, and 14% had advanced neoplasia. Overall comparison of those with EDD versus few or no diverticuli revealed no differences in the risks of any neoplasia or advanced neoplasia, either distally (26.7%vs 25.4%; 12.9%vs 8.8%, respectively) or proximally (25%vs 18.4%; 6.0%vs 4.9%). Compared to women with few or no distal diverticuli, however, women with EDD were more likely to have any neoplasia and advanced neoplasia, both distally (34.6%vs 16.3%; p= 0.03, and 23.1%vs 5.7%; p= 0.003) and proximally (30.8%vs 14.9%; p= 0.049, and 11.5%vs 4.3%, p= 0.13). Adjustment for age did not affect results for advanced distal neoplasia (OR = 3.92; CI: 1.18-13); however, adjustment for the presence of a distal neoplasm eliminated the increased risk of proximal neoplasia associated with EDD (OR = 1.31; CI: 0.43-4.02). CONCLUSION: In this study, women with EDD were more likely to have advanced distal neoplasia. The presence of distal neoplasia in women with EDD accounted for their increased risk of proximal neoplasia. Distal diverticulosis was not independently associated with proximal neoplasia in men or women.