Two-Year Incidence of Colon Adenomas Developing after Tandem Colonoscopy

Objective: We attempted to determine an accurate frequency of new polyp growth in a cohort of veteran male patients who were initially cleared of polyps by tandem colonoscopy. Methods: Followup colonoscopy was performed 2 yr after tandem colonoscopy. A polyp was categorized as "new" if it was not located in a segment of the colon or rectum that had harbored a neoplastic polyp of the same histology at tandem colonoscopy, in contradistinction to lesions designated as "same-segment" polyps. Results: Fifty-eight of 90 patients who had tandem colonoscopy as a part of a previous study were available for follow-up colonoscopy for 2 yr. Ninety-one percent had a history of benign neoplastic polyps or cancer. Neoplastic polyps were documented in 52% (95% CI, 45–74%) of patients at followup, and 38% (95% CI, 26–52%) were found to have a total of 31 "new" lesions. All new lesions were tubular adenomas. The largest number of new polyps in an individual patient was four, and the largest new lesion was 20 mm in size with a flat, linear configuration. Most (25/31) new polyps were <5 mm, and the number of neoplastic polyps per patient at follow-up was less than at tandem colonoscopy. Conclusions: Approximately one-half of older, male patients with a history of neoplastic polyps will demonstrate neoplastic polyps at 2 yr. In at least one-third of patients, these appear to be new lesions. In some patients, de novo neoplastic polyps can grow to ≥1 cm within 2 yr.     

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.     

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.     

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.     

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.     

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

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

Flexible fiberoptic sigmoidoscopy and double-contrast barium-enema examination in the identification of adenomas and carcinoma of the colon

To assess the accuracy of the flexible fiberoptic sigmoidoscope, 227 consecutive patients (mean age 61.8±13 years) requiring investigation of colonic symptoms were evaluated using rigid and flexible sigmoidoscopy (PAF and KDV) and double-contrast barium enema (SSA). Patients with equivocal findings or adenomatous polyps underwent colonoscopy (TWB). Thirty-four patients had carcinoma and 50 patients had one or more adenomatous polyps (>5mm). The neoplastic yield from rigid sigmoidoscopy was 12 per cent, flexible fiberoptic sigmoidoscopy 90 per cent, and double-contrast barium enema only 76 per cent. Barium enema failed to identify eight carcinomas and 13 adenomatous polyps; seven of the eight carcinomas were polypoid Dukes' Stage A lesions, and associated diverticular disease was present in 62.5 per cent of cases. Flexible fiberoptic sigmoidoscopy failed to identify seven carcinomas and one adenomatous polyp. Five of the carcinomas were beyond range of the instrument; in one patient, a stricture was seen that was caused by the carcinoma; and in the seventh patient, the examination was terminated because of angulation spasm. Double-contrast barium enema is inaccurate in detecting lesions in the sigmoid colon, with flexible sigmoidoscopy being superior.     

The Sentinel Hyperplastic Polyp: A Marker for Synchronous Neoplasia in the Proximal Colon

We prospectively screened 129 asymptomatic subjects (mean age 64 yr) with flexible sigmoidoscopy. Colonoscopy was performed at a later date, regardless of the sigmoidoscopic result. Our intent was 1) to establish the prevalence of proximal neoplasms in patients with and without hyperplastic polyps within reach of the 60-cm sigmoidoscope and 2) to determine whether a distal (sentinel) hyperplastic polyp predicts the presence of synchronous neoplastic polyps higher up in the colon. Our results show that 15% of asymptomatic adult subjects without polyps on sigmoidoscopy have adenomas in proximal colonic segments that can be diagnosed only by colonoscopy. By comparison, proximal neoplasms were detected in 32% (p less than 0.05) and 37% (p less than 0.05) of patients when hyperplastic or adenomatous polyps, respectively, were present on the sigmoidoscopic examination. This finding suggests that a distal (sentinel) hyperplastic polyp by itself may be a marker for neoplastic polyps in proximal colonic segments. Also, the "index" adenoma and "sentinel" hyperplastic polyp may be equivalent for predicting the presence of proximal neoplasms. The observed detection rates for these polyps were both significantly higher than expected when compared to patients who did not have polyps in the distal colon or rectum. If these results can be confirmed by a larger prospective trial, then full colonoscopy for detection of proximal neoplasms may be indicated when either an index adenoma or sentinel hyperplastic polyp is detected by sigmoidoscopy.     

The natural history of isolated rectosigmoid adenomatous polyps

PURPOSE: Colonoscopic surveillance is recommended for patients with adenomatous polyps. Significant cost savings would result from identification of subgroups of patients in whom less costly surveillance would suffice. This study was performed to determine the natural history of patients undergoing removal of isolated rectosigmoid adenomas and to establish whether flexible sigmoidoscopy might be adequate for follow-up. METHODS: A retrospective review of a database of 7,677 colonoscopies, from 1990 to 1996, identified patients who had a minimal follow-up of two years after removal of adenomatous polyps isolated to the rectosigmoid. Polyps detected on surveillance colonoscopy were categorized as distal (60 cm from anal verge), proximal (>60 cm from anal verge), and diffuse (proximal plus distal). The risk of polyp formation was determined by actuarial analysis using the Kaplan-Meier method. RESULTS: Sixty-two patients undergoing surveillance for adenomas met inclusion criteria. At the index colonoscopy, 124 isolated rectosigmoid polyps were identified. The median polyp size was 1 cm and median frequency was one polyp. The median follow-up time for the entire cohort (N = 62) was 53 months. At follow-up surveillance colonoscopy, 105 additional adenomas were discovered and removed in 40 patients. No malignant polyps were detected. The pattern of polyps detected were proximal (n=19), rectosigmoid (n=16), and diffuse (n=5). CONCLUSIONS: The majority (65 percent) of patients with isolated rectosigmoid polyps have additional polyps on long-term surveillance, and 60 percent of patients will have these polyps located proximal to the reach of a sigmoidoscope. Therefore, flexible sigmoidoscopy is not a safe alternative for surveillance of patients with isolated rectosigmoid polyps.Read at The American Society of Colon and Rectal Surgeons' 100th Anniversary and Tripartite Meeting, Washington. D.C., May 1 to 6, 1999.     

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

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

Frequency of advanced neoplasia in the proximal colon without an index polyp in the rectosigmoid

PURPOSE: Screening endoscopy has the potential to reduce colorectal cancer mortality. However, the efficacy of screening flexible sigmoidoscopy compared with colonoscopy strongly depends on the frequency of advanced proximal neoplasms without an index polyp in the rectosigmoid. We have therefore determined this frequency in our endoscopy population. METHODS: Endoscopic and histologic data were analyzed from all patients on whom integral colonoscopy was performed between 1980 and 1995. Advanced neoplasia was defined as cancer or adenomas >10 mm in diameter, adenomas with a villous component, or severe dysplasia. Patients with polyposis syndrome or inflammatory bowel disease were excluded. RESULTS: Colonoscopy was performed on 11,760 patients. 2,272 (19.3 percent) had at least one colorectal neoplasm, of which 39 percent had the neoplasm above the rectosigmoid. Twenty-two percent of all patients with neoplasia had no index polyp in the rectosigmoid and 16 percent of these had no index polyp, but at least one advanced proximal neoplasm. CONCLUSIONS: Although 39 percent of patients had neoplasms above the rectosigmoid, only 16 percent had an advanced proximal neoplasm without an index polyp in the rectosigmoid. This gives a figure on which to base the evaluation of screening sigmoidoscopy programs against those of screening colonoscopy.     

Reducing the incidence and mortality of colon cancer: mass screening and colonoscopic polypectomy

Most colon cancers arise from conventional adenomatous polyps (conventional adenoma-to-carcinoma sequence), while some colon cancers appear to arise from the recently recognized serrated adenomatous polyp (serrated adenoma-to-carcinoma theory). Because conventional adenomas and serrated adenomas are usually asymptomatic, mass screening of asymptomatic patients has become the cornerstone for detecting and eliminating these precursor lesions to reduce the risk of colon cancer. Colonoscopy has become the primary screening test because of its high sensitivity and specificity, and the ability to perform polypectomy. Other screening tests include guaiac tests or fecal immunochemical tests (FIT) for fecal occult blood, and flexible sigmoidoscopy. A minimal colonoscopic withdrawal time of 6 minutes is important to maximize polyp detection at colonoscopy. Chromoendoscopy is an experimental technique used to highlight abnormal colonic areas to identify neoplastic tissue and to potentially determine the histology of colonic polyps at colonoscopy based on superficial pit anatomy.     

Colonic neoplasia in patients with nonspecific GI symptoms

BACKGROUND: The purpose of this study was to determine the prevalence rate of colonic polyps or masses 1 cm or greater in diameter in patients with nonspecific abdominal symptoms, from diverse practice settings, using a national endoscopic database. METHODS: Consecutive patients undergoing colonoscopy were included based on procedure indication. Endoscopic data were generated with a computer database at each practice site, transmitted to a central data bank and merged with data from multiple sites for analysis. Group 1 patients had nonspecific abdominal symptoms, which were defined as pain, constipation and diarrhea. Group 2 patients had a positive fecal occult blood test. Group 3 patients were asymptomatic, undergoing screening colonoscopy. Serious colon pathology was defined as a polyp or mass greater than 9 mm in size. RESULTS: Data were collected from 31 practice sites in 21 states during a period of 18 months. Of the 20,745 colonoscopy examinations, 9.2% were performed to evaluate patients with nonspecific abdominal symptoms, excluding other indications. Among patients with nonspecific symptoms 7.27% had polyp(s) 1 cm or greater in diameter compared with 17.05% of patients with positive fecal occult blood test (odds ratio 2.12: CI [1.73, 2.60]; p < 0.001). Patients with nonspecific symptoms had similar rates of large polyps as asymptomatic patients (7.27% vs. 6.45%, p = 0.32). Multivariate analysis identified several independent variables including increasing age, male gender and practice site at a Veterans Affairs Medical Center. CONCLUSIONS: In diverse, practice-based settings, patients with nonspecific abdominal symptoms who are referred for colonoscopy do not have a higher risk of serious colonic pathology than asymptomatic patients.     

Total Colonoscopy in Patients with Polyps in the Proctosigmoid Region

Abstract: We conducted a prospective study of the general population in Taiwan to determine how many patients with polyps in the proctosigmoid region would have synchronous polyps in the proximal colon. The pathology and the number of proctosigmoid polyps as well as the benefits of subsequent colonoscopy were taken into account. Proctosigmoid polyps were identified in 261 of 2746 asymptomatic patients by 60 cm sigmoidoscopy, yeilding a 9.5% (male: 11.0%; female: 5.0%) prevalence rate. Subsequent total colonoscopy combined with polypectomy was completed in 205 patients (152 males; 53 females) eligible for analysis. In all, 353 polyps were removed for pathological verification at colonoscopy. The mean size of adenomatous polyps was 6.2 mm and that of hyperplastic polyps 3.2mm (p<0.05). Five mucosal cancers as well as one submucosal cancer were identified, and one of the mucosal cancers was beyond the range of the prior 60 cm sigmoidoscopy. Of these 205 patients, 63 (31%) were found to have at least one proximal polyp. The prevalences of synchronous proximal colon polyps were 23%, 42% and 77% for the 1-polyp, 2-polyp and β2-polyp groups in the proctosigmoid region, respectively. When the pathology of the proctosigmoid polyps was taken into account, it was found that 42% of patients with adenomatous polyps in the proctosigmoid region had proximal polyps, compared with 10% of those with distal hyperplastic polyps and 8% of those with other findings (p<0.05). The present study suggests that all polyps, of all sizes, found at sigmoidoscopy merit pathological verification. Furthermore, colonoscopy should be reserved for patients proved to have adenomatous or multiple polyps in the proctosigmoid region.     

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.     

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.     

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.     

NARROW BAND IMAGING IN THE DETECTION OF COLORECTAL POLYP: KOREAN EXPERIENCE

Background: Although white light (WL) colonoscopy is a gold standard to detect colorectal polyps, substantial polyps are missed. Narrow band imaging (NBI) is a new technology that enables a more detailed visualization of the mucosal surface. The aim of the present study was to determine whether NBI can improve the detection of colorectal polyps. Methods: We prospectively enrolled 188 (M : F = 99:89, 21–80 years) subjects undergoing colonoscopy as a screening procedure in nine referral centers. After a careful WL examination of the whole colorectum, rectosigmoid colon (0–30 cm from the anal verge) was reobserved by NBI. Size, macroscopic morphology, and the histology of all the polyps detected during WL and NBI examination were analyzed. Results: WL examination detected 162 polyps in 188 subjects, of which 106 lesions were neoplastic, while NBI of rectosigmoid colon detected an additional 61 polyps of which eight lesions were neoplastic. Only 10 (6.2%) of 162 polyps discovered during WL examination were flat polyps compared to 10 (16.4%) of 61 newly detected polyps during NBI being flat type (P = 0.002). The mean polyp size detected by NBI was smaller than that found by WL colonoscopy (2.8 ± 1.0 mm vs 6.5 ± 4.5 mm, P < 0.001). Conclusion: Many additional colorectal polyps, especially flat type, could be detected by NBI examination for normal‐looking rectosigmoid mucosa. The role of NBI in colorectal neoplasm screening needs to be further investigated in future studies.     

Colonic Chicken Skin Mucosa Surrounding Colon Polyps Is an Endoscopic Predictive Marker for Colonic Neoplastic Polyps

Background/AimsNarrow band imaging provides an accurate diagnosis of colonic polyps. However, these diagnostic modalities are not used as standard endoscopic tools in most institutions. This study aims to investigate whether the chicken skin mucosa (CSM) surrounding the colon polyp yields additional information about colorectal polyps, including histological differentiation of neoplastic and non-neoplastic polyps, under conventional white light colonoscopy.MethodsThis study prospectively observed 173 patients who underwent endoscopic polypectomy and reviewed the clinical data and pathologic reports of 313 polyps from a university hospital. Two endoscopists each performed colonoscopy and polypectomy and assessed the CSM. The association between CSM surrounding colorectal polyps and histology was analyzed.ResultsThe majority (91.3%) of CSM-positive polyps were neoplastic (sensitivity, 37.90%; specificity, 86.15%; p<0.001). In logistic regression, the neoplastic polyps were associated with positive CSM (adjusted odds ratio [OR], 3.51; 95% confidence interval [CI], 1.45 to 9.25; p=0.007), protruded polyps (adjusted OR, 4.85; 95% CI, 1.65 to 17.23; p=0.008), and neoplastic histology–associated pit pattern (pit III, IV, and V) (adjusted OR, 10.14; 95% CI, 4.85 to 22.12; p=0.000). Furthermore, advanced adenomas were associated with positive CSM (adjusted OR, 5.64; 95% CI, 1.77 to 20.28; p=0.005), protruded polyps (adjusted OR, 3.30; 95% CI, 1.15 to 9.74; p= 0.026), and ≥10 cm polyp size (adjusted OR, 18.56; 95% CI, 3.89 to 147.01; p=0.001).ConclusionsNeoplastic and advanced polyps were associated with CSM-positive polyps. These findings suggest that CSM is a useful marker in differentiating neoplastic polyps and advanced polyps under conventional white 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.