腺瘤性息肉的癌变及治疗

为探讨已癌变的结肠腺瘤性息肉的最佳治疗选择，回顾性总结了内镜诊断和治疗的３１４例腺瘤性息肉中３７例癌变息肉的结果。３７例中为管状腺瘤癌变者２５例（占８．９％），绒毛状腺瘤癌变者１１例（占３６．３％），混合性腺瘤癌变１例。１８例仅行内镜下电切，电切后又追加手术８例，手术切除１１例。分期为原位癌１２例，早期浸润癌１３例，浸润癌１２例。１９例手术及术后病理证实的淋巴结转移者３例（１５．７％），包括１例绒毛状腺瘤恶变的早期浸润癌和２例浸润癌。认为除原位癌外，对电切后病理证实的早期浸润癌或浸润性癌，只要无手术禁忌，应追加外科手术治疗为妥。     

Endoscopic Removal of Large Colorectal Polyps

PURPOSE: Because of the potential risk of malignancy and technical difficulties in achieving complete removal, large colorectal polyps represent a special problem for the endoscopist. The aim of this study was to evaluate the capabilities and risks of endoscopy in complete removal of large colorectal polyps. METHODS: Endoscopic polypectomy of 186 colorectal polyps larger than 3 cm in diameter (range, 3-13 cm) was performed; 141 were sessile and 45 pedunculated. Most of the polyps were located in the rectum (n = 88), sigmoid (n = 63), and cecum (n = 9). The remaining adenomas were situated in other parts of the colon. Sessile polyps were removed using the piecemeal technique. RESULTS: Histology results showed an adenoma in 167 cases, and invasive carcinoma was present in the adenoma in 19 patients. Of the adenomas, 29 were tubulous, 118 tubulovillous, and 20 villous; adenoma with severe dysplasia was found in 49 cases. Complete endoscopic removal was achieved in all sessile and pedunculated polyps. None of the patients with invasive carcinoma who underwent surgical resection (n = 10) had any evidence of tumor in the resected specimen. Bleeding occurred in 4 patients after polypectomy (2 percent). Perforation occurred in 1 patient (0.5 percent), who had an invasive carcinoma of the cecum. There was no procedure-related mortality. During a mean follow-up period of 40 (range, 3-87) months, 6 patients presented with recurrence of a benign adenoma (3 percent), which was treated endoscopically, and 1 patient presented with a recurrent invasive carcinoma, which was treated surgically. CONCLUSIONS: Endoscopic polypectomy is a safe and effective method of treating large colorectal polyps.     

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.     

结直肠腺瘤切除术后息肉复发及内镜监测的临床分析

目的研究结直肠腺瘤(colorectal adenoma,CRA)切除术后息肉复发的情况,以确定合理的内镜监测间隔时间。方法收录2005年5月-2012年5月于北京朝阳医院消化内科完成结肠镜下息肉切除术、病理组织学确诊为CRA、术后再次入院行肠镜复查的患者共143例,男89例,女54例。统计分析复发息肉的累计复发率,确定影响复发息肉的重要危险因素和中位复发时间。结果息肉总体复发率为72%,患者性别、年龄、息肉大小、息肉数目、息肉发生部位、病理类型等因素中,仅CRA的大小和病理类型对复发有重要影响。初检CRA直径1 cm的患者较CRA直径≤1 cm的患者复发风险高(P=0.02)。CRA病理中含有绒毛成分的患者较仅为管状腺瘤的患者复发风险高(P=0.08)。结论建议含绒毛成分或直径1 cm的CRA患者术后6~12个月复查肠镜,而直径≤1 cm的管状腺瘤患者可在术后2年左右复查肠镜。     

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.     

Evolution of hereditary non-polyposis colorectal cancer.

The prevalence of colorectal adenoma in 23 affected patients with hereditary non-polyposis colorectal cancer (HNPCC) was compared with that in an age matched forensic autopsy population. The mean ages at diagnosis of colorectal cancer in men (13) and women (10) were 39 and 37 years respectively. In HNPCC patients who presented below the age of 50 years, at least one adenoma was found in 3 of 10 (30%) men and in 4 of 9 (44%) women. In the age matched autopsy specimens of large bowel, a solitary adenoma was found in 2/42 (5%) men (p = 0.015) and 1/21 (5%) women (p = 0.0075). Of the 11 adenomas from HNPCC patients, nine were greater than 1 cm and six showed a pure villous architecture. Contiguous adenocarcinoma was observed with six adenomas. Adenomas do not occur in large numbers in HNPCC, but develop at a young age, attain a large size, often show a villous configuration, and are more prone to malignant conversion than sporadic adenomas.     

The effect of attending a flexible sigmoidoscopic screening program on the prevalence of colorectal adenomas at 13-year follow-up

OBJECTIVES: Understanding the epidemiology of colorectal adenomas is a prerequisite for designing follow-up programs after polypectomy. The aim of the study was to investigate the effect of polypectomy on the long-term prevalence of adenomas. METHODS: In 1983, a total of 799 men and women aged 50-59 yr were drawn from the general population register. Of these, 400 comprised a screening group and 399 a matched control group. The screenees were invited to undergo a once-only flexible sigmoidoscopy. Persons with polyps had a baseline colonoscopy with follow-ups in 1985 and 1989. In 1996, both the screenees and the controls were invited to a colonoscopic examination. RESULTS: In 1996, a total of 451 (71%) individuals attended. Adenomas were found in 78 (37%) individuals in the screening group and 103 (43%) in the control group, relative risk (95% confidence interval): 0.9 (0.7-1.1), p = 0.3, and high-risk adenomas (severe dysplasia, adenomas > or = 10 mm, villous components) were found in 16 (8%) and 32 (13%), respectively; relative risk (95% confidence interval): 0.6 (0.3-1.0), p = 0.07. CONCLUSIONS: There was no significant difference in adenoma prevalence between the group after the screening program and the controls after the usual care. There was a trend toward more high-risk adenomas in the control group. This suggests a very limited effect of one-time screening sigmoidoscopy with surveillance colonoscopy on the prevalence of adenomas, but a preventive effect on the development of high-risk adenomas consistent with the reported effect on cancer prevention.     

Korean guidelines for post-polypectomy colonoscopic surveillance

Post-polypectomy surveillance has become a major indication for colonoscopy as a result of increased use of screening colonoscopy in Korea. However, because the medical resource is limited, and the first screening colonoscopy produces the greatest effect on reducing the incidence and mortality of colorectal cancer, there is a need to increase the efficiency of postpolypectomy surveillance. In the present report, a careful analytic approach was used to address all available evidences to delineate the predictors for advanced neoplasia at surveillance colonoscopy. Based on the results of review of the evidences, we elucidated the high risk findings of the index colonoscopy as follows: 1) 3 or more adenomas, 2) any adenoma larger than 10 mm, 3) any tubulovillous or villous adenoma, 4) any adenoma with high-grade dysplasia, and 5) any serrated polyps larger than 10 mm. In patients without any high-risk findings at the index colonoscopy, surveillance colonoscopy should be performed five years after index colonoscopy. In patients with one or more high risk findings, surveillance colonoscopy should be performed three years after polypectomy. However, the surveillance interval can be shortened considering the quality of the index colonoscopy, the completeness of polyp removal, the patient's general condition, and family and medical history. This practical guideline cannot totally take the place of clinical judgments made by practitioners and should be revised and supplemented in the future as new evidence becomes available.     

Duodenal Adenoma Removed by Endoscopic Polypectomy

Abstract: We report two duodenal adenoma cases treated by endoscopic polypectomy. Case 1, a 59-year-old male, visited our hospital for further examination of a duodenal polyp found elsewhere. X-ray examination revealed a semi-pedunculated polyp with an irregular surface in the second portion of the posterior wall of the duodenum. Case 2, a 68-year-old male, was admitted to our hospital for endoscopic polypectomy of a duodenal polyp. Upper GI series demonstrated a semi-pedunculated round polyp with a shallow central depression. Endoscopic polypectomy was performed for both lesions and the polyps were successfully removed. The resected polyps were 11 × 10 mm and 13 × 12 mm in size, respectively. The polyps were histologically diagnosed as tubulovillous and tubular adenomas, respectively, with no evidence of malignancy. Endoscopic polypectomy provides histological confirmation of adenoma of the gastrointestinal tract, and it is frequently applicable to the duodenum.     

Accuracy of pathologic interpretation of colorectal polyps by general pathologists in community practice.

BACKGROUND: The histologic features of colorectal polyps often guide colonoscopic surveillance and the need for surgical intervention. Our objective was to evaluate the pathologic interpretation of colorectal polyps by general pathologists in community practice. METHODS: Twenty histologic slides of colorectal polyps were reviewed by 20 randomly selected general pathologists in community practice. There were 5 malignant polyps, 9 adenomas, and 6 miscellaneous polyps. RESULTS: Cancer was correctly identified in 91% of readings and adenoma in 94%. The grade of differentiation of cancer was provided in 55% of readings, and comment regarding whether the resection margin was free of cancer was made by 50% of pathologists. Tubular adenoma was called tubulovillous or villous in 35% of readings, but tubulovillous or villous adenoma was seldom (2%) called tubular. High-grade dysplasia was correctly identified in 47% of 60 readings, was called invasive cancer in 22%, and was missed in 31%. Among miscellaneous polyps, hyperplastic polyp was correctly recognized in 75% of cases, and inflammatory polyp and juvenile polyp each were recognized by 16 of 20 pathologists (80%). Peutz-Jeghers hamartoma was identified by 4 of 20 pathologists (20%), and the polypoid phase of solitary rectal ulcer syndrome was recognized by 2 pathologists (10%). CONCLUSION: Areas of strength with regard to interpretation of colon polyps by general pathologists in community practice included identification of cancer, adenoma, and certain non-neoplastic polyps (e.g., inflammatory and juvenile polyps). Areas of weakness included lack of comment on cancer differentiation and proximity to the resection line, erroneous identification of high-grade dysplasia, and identification of rare lesions. The results of this study suggest areas on which to focus continuing education and continuous quality improvement efforts with regard to polyp interpretation.     

Immunohistochemical Study of Colorectal Polyps with Antibodies against CEA,CA19-9, CA125, CA15-3 (DF3), PCNA and p53

Abstract: We analyzed the expression of CEA, CA19-9, CA125, CA15-3 (DF3), PCNA and p53 immunohistochemically in 14 tissue specimens of mucosal cancers in adenoma, seven tubulovillous adenoma specimens, and 16 tubular adenoma specimens. The rates of positive staining for mucosal cancer in adenoma, tubulovillous adenoma and tubular adenoma specimens, respectively, were: for CEA: 100%, 85.7% and 75%; for CA19-9: 71.4%, 71.4% and 56.2%; for CA125:0%, 0% and 0%;for CA15-3 (DF3): 64.3 %, 0% and 0 %; for PCNA: 100%, 88.9% and 56.2%; and for p53: 35.7%, 0% and 0% . The results suggest that the expressions of CEA, CA19-9, CA15-3 (DF3), PCNA and p53 are related to colorectal tumorigenesis. None of the specimens studied showed staining for CA125, suggesting that CA125 is not involved in the early stages of colorectal carcinogenesis. There was no significant difference in the rates of positive staining for CEA and CA19-9 among mucosal cancer in adenoma, tubular adenoma and tubulovillous adenoma specimens. However, the rates of positive staining for PCNA and p53 were significantly higher in mucosal cancer in adenoma specimens than for tubular adenoma specimens (p<0.05), and the rate of CA15-3 (DF3) positive staining was significantly higher for mucosal cancer in adenoma than for tubulovillous adenoma (p<0.01) and tubular adenoma (p< 0.001) specimens. Therefore, the CA15-3 (DF3) antigen is an immunohistochemical marker for colorectal carcinomas. The present results suggest that CA15-3 (DF3), PCNA and p53 play important roles in the genesis of colorectal adenomas.     

Prevalence and Malignant Potential of Colorectal Polyps in Asymptomatic, Average-Risk Men

Screening colonoscopy was performed on 119 asymptomatic elderly men with no other risk factors for colonic neoplasms. Ninety adenomas were detected in 49 (41%) subjects. Mean adenoma size was 6.5 mm, with 83 (92%) less than or equal to 10 mm. Forty-nine (54%) adenomas were located proximal to the splenic flexure, and 17 (19%) were classified as tubulovillous or villous. Moderate- to high-grade dysplasia was found in 29 (32%) adenomas and was associated with larger size (p less than 0.0001) and villous architecture (p = 0.0038). Two subjects harbored adenomas with invasive cancer. Seventy-one hyperplastic polyps were found in 40 (34%) subjects. The mean size of hyperplastic polyps was 3.4 mm, and 64 (90%) were located in the left colon. We conclude that, in this population, adenomas are common lesions that are frequently small. However, substantial proportions of these adenomas may be at risk for malignant degeneration due to the presence of villous architecture and higher grades of dysplasia. Because adenomas and hyperplastic polyps are endoscopically indistinguishable, all polyps found at endoscopy should be removed or ablated.     

放大内镜下大肠黏膜腺管开口分型对早期大肠癌检出的意义

目的 评价腺管开口分型对早期大肠癌及癌前病变检出的临床价值.方法 回顾2004年11月至2007年8月结肠镜检查,采用内镜下黏膜染色技术,结合放大内镜及实体镜观察腺管开口分型并与病理诊断对照,腺管开口分型采用工藤进英分型标准.结果 结肠镜检杳大肠病变共1496个,非肿瘤性病变占30.6%(458/1496),各类型腺瘤占43.9%(657/1496),大肠癌占25.5%(381/1496).早期大肠癌61个;大肠侧向发育型肿瘤36个,直径10～62 mm,其中Ⅱ型3个,Ⅲ1.型14个,Ⅳ型17个,Ⅴ型2个.管状腺瘤中以低级别上皮内瘤变居多,占87.5%(363/415);管状绒毛状腺瘤高级别上皮内瘤变占40.7%(61/150);绒毛状腺瘤腺管开口以Ⅳ型为主,高级别上皮内瘤变达85.7%(42/49).结论 大肠腺管开口分型对于判断肿瘤性、非肿瘤性病变以及早期大肠癌的检出有重要意义,对及时进行内镜治疗或手术切除具有一定的临床指导意义.     

Case-control study supports extension of surveillance interval after colonoscopic polypectomy to at least 5 yr

OBJECTIVE: Colonoscopy with removal of polyps may strongly reduce colorectal cancer (CRC) incidence and mortality. Recommended time intervals to surveillance colonoscopy differ between countries and have recently been extended to 5 yr or longer for the majority of cases in the United States. Whereas previous evidence is mainly based on observations of adenoma recurrence, we aimed to assess risk of CRC occurrence according to time since polypectomy. METHODS: In a population-based case-control study conducted in Germany, detailed history and results of previous large bowel endoscopies were obtained by interview and from medical records. Risk of CRC among subjects with history of endoscopic polypectomy compared to subjects without previous large bowel endoscopy was assessed according to time since polypectomy among 454 cases with CRC and 391 matched controls. RESULTS: Odds ratios (95% confidence intervals) of CRC up to 2 yr, 3-5 yr, and 6-10 yr after polypectomy (using subjects without previous endoscopy as reference group) were 0.16 (0.09-0.69), 0.27 (0.08-0.87), and 1.90 (0.67-5.43), respectively. Risk was significantly reduced (odds ratio 0.27, 95% confidence interval 0.10-0.77) within 5 yr even after detection and removal of high-risk polyps (3+ polyps, at least 1 polyp > or =1 cm, at least 1 polyp with villous components). Odds ratios (95% confidence intervals) for the entire 10-yr time interval following polypectomy were 0.50 (0.23-1.12) and 0.36 (0.18-0.76) for patients with recorded high-risk adenomas and other patients, respectively. CONCLUSIONS: Our study provides empirical support for extension of the surveillance interval after colonoscopic polypectomy to at least 5 yr.     

Incidence of Advanced Adenomas of the Rectosigmoid Colon Three Years and Five Years After Negative Flexible Sigmoidoscopy in 4010 Patients

Flexible sigmoidoscopy is recommended for persons at average risk for colorectal cancer. A follow-up is advised in 3 to 5 years, although the outcomes are not well established. We designed a large, prospective study of an unselected population to measure the incidence of advanced adenomas at flexible sigmoidoscopy 3 and 5 years after an initial negative examination. Adenomas were considered advanced if they were villous, tubulovillous, high-grade dysplasia, adenocarcinoma, or > or = 10 mm in size. We evaluated 8121 patients referred for flexible sigmoidoscopy and 4010 met the inclusion criteria. Group 1 had flexible sigmoidoscopy between 3 and 4 years and Group 2 between 5 and 6 years after a negative examination. Group 1 included 1300 patients with an incidence rate for advanced adenomas of 0.9% (12/1300) and Group 2 included 2710 patients with an incidence rate for advanced adenomas of 1.1% (30/2710). When the two group were subdivided by the presence or absence of a family history of a first-degree relative with sporadic colorectal cancer, the incidence rates for advanced adenomas between the populations were not different. Our data indicate incidence rates of 0.9 and 1.1% for advanced adenomas at flexible sigmoidoscopy 3 and 5 years, respectively, after a negative flexible sigmoidoscopy, with no impact from a family history.     

Colonoscopic screening of persons with suspected risk factors for colon cancer. I. Family history

A family history of colorectal cancer is believed to place persons at increased risk for development of the disease. It is unclear, however, how "strong" a family history must be to increase this risk or to make colonoscopic screening appropriate. We performed initial colonoscopy in 154 asymptomatic subjects whose only suspected risk factor was one or two first-degree relatives with colorectal cancer; 48 of these subjects also had affected second- and third-degree relatives. We found 45 adenomas in 28 subjects (18%). One subject had a 3-cm villous adenoma. In 6 subjects, the most advanced findings were tubular adenomas 5-9 mm in diameter; in 21 subjects, we found only tubular adenomas that were 2-4 mm in diameter. The prevalence of adenomas increased significantly with age of subjects (p less than 0.01). Although the overall prevalence of colorectal neoplasms in our group was no greater than might be expected in the general population, subjects with two first-degree relatives tended to have more diminutive adenomas than those with one such relative. Our findings suggest that colonoscopy is not an appropriate first step in screening persons with one affected first-degree relative. For those with more complex family histories, more data are needed--particularly on the prevalence of advanced neoplasms--to determine whether a screening technique that is less costly and less invasive than colonoscopy may be adequate.     

Colonic Neoplasia in Asymptomatic Persons with Negative Fecal Occult Blood Tests: Influence of Age, Gender, and Family History

Six hundred twenty-one asymptomatic persons with negative fecal occult blood tests (ages 50–75 yr), including 496 with no known risk factors for colorectal cancer and 125 with a single first-degree relative with a history of colonic neoplasia developed after age 40, underwent screening colonoscopy. Three Dukes A cancers were detected in average-risk persons. The overall prevalence of adenomatous polyps was 27%. Multiple logistic regression analysis revealed that increasing age and male gender were both strong predictors of colonic neoplasia ( p < 0.001). A positive family history of a single first-degree relative with colorectal cancer was not associated with an increased prevalence of colonic neoplasia ( p = 0.29), although an effect may be present if the relative was <60 yr at diagnosis. Overall 16% of males and 7% of women > 60 yr had at least one adenoma that was large (>1 cm in size), villous or tubulovillous, or had grade 3 dysplasia. We conclude that the prevalence of colonic neoplasia in asymptomatic persons with negative fecal occult blood tests is substantial, particularly in elderly males. A family history of a single first-degree relative diagnosed at age >60 yr with colorectal cancer is not associated with an increased prevalence of colonic adenomas.     

Excessive alcohol consumption favours high risk polyp or colorectal cancer occurrence among patients with adenomas: a case control study.

BACKGROUND AND AIMS: Excessive alcohol consumption is a risk factor for developing colorectal adenomas. This study aimed to investigate the influence of excessive alcohol consumption on the occurrence of high risk polyps (adenoma > or = 10 mm, villous component, high grade dysplasia) or colorectal cancer among patients with at least one colonic adenoma. PATIENTS AND METHODS: Three groups of patients with at least one colorectal adenoma were included in a case control study: 401 heavy drinkers (group HD, mean daily alcohol intake 117 (SD 4) g/day for a mean duration of 22 (SD 0.6) years), aged 57 (0.5) years (78% men); 152 patients suffering from irritable bowel syndrome (IBS), aged 61 (0.9) years (57% male); and 108 patients with a family history (FH) of colorectal adenoma or cancer, aged 55 (1) years (64% male). Exclusion criteria were: anaemia, haematochezia, personal history of colorectal adenoma or cancer, and for groups HD and IBS a family history of colorectal adenoma and/or cancer. Relative risks were estimated by the odds ratio (OR) using a logistic regression model and were expressed with 95% confidence interval (CI). RESULTS: After age and sex adjustment, the likelihood of having an adenoma > or = 10 mm was higher in group HD than in the IBS group (OR 1.8, 95% CI (1.2-2.7)) and the likelihood of having high risk adenomas or cancer was higher in group HD compared with the IBS group (OR 1.6, 95% CI (1.2-2.1)) and the FH group although this was not significant (OR 1.6, 95% CI (0.97-2.6) (p=0.081); 90% CI (1.03-2.4)). After age and sex adjustment, the likelihood of having an adenoma with high grade dysplasia or cancer was higher in group HD than in the IBS group (OR 1.7, 95% CI (1.02-2.8)) or group FH, although this was not significant (OR 3.7, 95% CI (0.98-15) (p=0.076); 90% CI (1.10-12.47)). CONCLUSION: In patients with at least one colorectal adenoma, excessive alcohol consumption increases the likelihood of developing high risk adenomas or colorectal cancer.     

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.     

High-grade dysplasia and invasive carcinoma in colorectal adenomas: a multivariate analysis of the impact of adenoma and patient characteristics

BACKGROUND AND AIMS: Most colorectal carcinomas develop from preformed adenomas, but only a minority of adenomas undergo malignant transformation. The clinical significance of polyps of size < 0.5 cm is controversial. The primary goal of this study was to assess the independent risk factors of adenoma and patient characteristics associated with advanced pathological features (APF; i.e. high-grade dysplasia or invasive carcinoma) in colorectal adenomas. A secondary goal was to assess the malignant potential of adenomas with a diameter of < 0.5 cm. PATIENTS AND METHODS: Patients who underwent total colonoscopy at our Medical Department between 1978 and 1996 and had at least one colorectal adenoma were considered for this study. Patients with a history of colorectal cancer, prior polypectomy or colorectal surgery were excluded. A total of 7590 adenomas removed from 4216 patients were included in this analysis. Logistic regression analysis was used to study the impact of different adenoma and patient characteristics on the risk of APF. RESULTS: Size proved to be the most important risk factor for APF. The percentage of adenomas with APF was 3.4%, 13.5% and 38.5% for adenomas of diameter < 0.5 cm, 0.5-1 cm and > 1 cm, respectively. Villous or tubulovillous histology, left-sided location and age >or= 60 years were also associated with APF, whereas sex and number of adenomas had no significant impact. Logistic regression analysis revealed that the risk of an adenoma containing APF was best described by a model incorporating the factors size, location, age, and the age by histology interaction. In the class of adenomas with diameter < 0.5 cm, no invasive carcinoma was found, but 3.4% of adenomas had high-grade dysplasia. CONCLUSIONS: The risk of a colorectal adenoma containing APF can be estimated only by a complex model taking into account several adenoma and patient characteristics. Size, histological type, location and age are independent risk factors for APF in colorectal adenomas. As a considerable percentage of adenomas with diameter < 0.5 cm contain high-grade dysplasia, the clinical conclusion from our study is that all adenomas, including those with diameter < 0.5 cm, should be removed whenever possible.