The role of colonoscopy and flexible sigmoidoscopy in screening for Colorectal Carcinoma

Six hundred thirty-two patients were referred to the Colorectal Clinic from February 1983 to February 1986 for screening with the Pentax 65 cm flexible sigmoidoscope. Forty-nine of these patients (8 percent) had adenomatous polyps. There were 27 males and 22 females. The mean distance examined by the 65 cm flexible sigmoidoscope was 55 cm. Five patients were excluded from analysis, leaving 44 patients who underwent colonoscopy to the cecum. At the time of colonoscopy, 15 of the 44 patients (34 percent) had one or more adenomatous polyps beyond reach of the 65 cm flexible sigmoidoscope. The remaining 29 patients who underwent colonoscopy had no polyps beyond reach of the 65 cm flexible sigmoidoscope. Thirty adenomatous polyps, one invasive carcinoma of the ascending colon, and one hyperplastic polyp were found in these 15 patients. In summary, 34 percent of patients found to have adenomatous polyps within reach of the 65 cm flexible sigmoidoscope harbored one or more adenomatous polyps in the proximal colon at the time of colonoscopy. A positive 65 cm flexible sigmoidoscope examination requires colonoscopy to identify and remove proximal premalignant lesions, thereby aborting the polyp-cancer sequence.     

Fiberoptic sigmoidoscopy as the first screening procedure for colorectal neoplasms in an asymptomatic population

As the first screening for colorectal neoplasms, a total of 2243 examinations by fiberoptic sigmoidoscopy (FS) were performed on 1573 asymptomatic patients. One hundred seventy neoplasms were found in 134 patients (6 percent of total examinations), including nine adenocarcinomas (0.4 percent). A flat, intramucosal cancer and a small, 5-mm cancer detected by FS could not be demonstrated by barium enema examination. On further investigation, additional adenomas were identified in the proximal colon in 22 percent of patients in whom neoplasms had first been detected by FS and in only 4.4 percent of those in whom FS findings were negative but other criteria were positive. It is concluded that FS is the procedure of choice for the first screening of asymptomatic patients, not only because it enables detection of flat and small lesions within its observation range, but also because it could lead to detection of proximal neoplasms.     

Risk of proximal colorectal neoplasia among asymptomatic patients with distal hyperplastic polyps

PURPOSE: Many guidelines on colorectal cancer screening do not consider distal hyperplastic polyps to be a marker for proximal neoplasia. However, 11 of 17 published studies have shown an increased risk of proximal neoplasia in patients with distal hyperplastic polyps. Our goal is to assess the risk of proximal neoplasia in asymptomatic patients with distal hyperplastic polyps, compared to those with distal tubular adenomas or no distal polyps. METHODS: We assessed proximal (cecum, ascending, transverse colon and splenic flexure) and distal polyps in patients undergoing screening colonoscopy, classifying them into 3 groups: distal hyperplastic polyps only; distal adenomas with or without hyperplastic polyps; no distal polyps. The prevalence of proximal neoplasia and advanced neoplasia (polyps > or =1 cm, villous adenomas, or cancer) was compared among these groups. RESULTS: Of 2357 patients, 427 (18%) had neoplasia, including 103 (4%) with advanced neoplasia. Proximal neoplasia occurred in 175 (9%) of 1896 patients with no distal polyps, compared with 28 (12%) of 237 with distal hyperplastic polyps (P = 0.20) and 64 (29%) of 224 with distal adenomas (P <0.0001). Proximal advanced neoplasia occurred in 39 (2%) patients with no distal polyps, compared with 4 (2%) with distal hyperplastic polyps (P = 0.70) and 9 (4%) with distal adenomas (P = 0.13). CONCLUSIONS: Patients with distal hyperplastic polyps, unlike those with distal adenomas, do not exhibit an increased risk for proximal neoplasia or proximal advanced neoplasia compared to those with no distal polyps. The discovery of hyperplastic polyps on screening sigmoidoscopy should not prompt colonoscopy.     

Canadian Association of Gastroenterology position statement on screening individuals at average risk for developing colorectal cancer: 2010

The Canadian Association of Gastroenterology and the Canadian Digestive Health Foundation published guidelines on colon cancer screening in 2004. Subsequent to the publication of these guidelines, many advances have occurred, thereby necessitating a review of the existing guidelines in the context of new technologies and clinical knowledge. The assembled guideline panel recognized three recent American sets of guidelines and identified seven issues that required comment from a Canadian perspective. These issues included, among others, the role of program-based screening, flexible sigmoidoscopy, computed tomography colonography, barium enema and quality improvement. The panel also provided context for the selection of the fecal immunochemical test as the fecal occult blood test of choice, and the relative role of colonoscopy as a primary screening tool. Recommendations were also provided for an upper age limit for colon cancer screening, whether upper endoscopy should be performed following a negative colonoscopy for a positive fecal occult blood test and when colon cancer screening should resume following negative colonoscopy.     

Yield of advanced adenoma and cancer based on polyp size detected at screening flexible sigmoidoscopy

BACKGROUND & AIMS: Observational screening of the colon with subsequent referral for colonoscopy raises questions about the threshold of polyp size that necessitates referral. To examine the yield at colonoscopy when a given size lesion is observed, we assessed the yield of advanced adenoma and cancer at colonoscopy based on the size of the abnormality detected at flexible sigmoidoscopy (FSG). METHODS: We used data from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, a randomized, controlled, community-based study of FSG. RESULTS: Subsequent colonoscopy was performed on 10,850 subjects (60.4% male; mean age, 62.9 years) with a polyp visualized on screening FSG. For women with a polyp 0.5-0.9 cm on FSG (n = 1426), the yield in the distal colon on colonoscopy was 0.6% for cancer (number needed to screen [NNS] = 166) and 14.5% for advanced adenoma (NNS = 7). In men (n = 2183), the yield was 0.7% (NNS = 142) for cancer and 15.9% (NNS = 6) for advanced adenoma. Among persons with polyps 0.5-0.9 cm identified on FSG, 5.5% (198/3609) had distal advanced adenomas that measured <1.0 cm but had villous histology or high-grade dysplasia, and 9.9% (357/3609) had adenomas > or =1 cm. CONCLUSIONS: The yield for a distal advanced adenomatous lesion when a polyp 0.5-0.9 cm is observed at FSG is substantial and is due to the presence of advanced histology in polyps <1 cm and to detection of polyps that measure > or =1.0 cm on colonoscopy. Establishing thresholds for observation versus evaluation will require careful assessment of the overall yield.     

Screening for Colorectal Cancer in Personnel of an Academic Medical Center

The colorectal cancer (CRC) screening program in Israel offers the average-risk population fecal occult blood tests from the age of 50 years. Compliance, however, is very low, reaching only 6% of eligible persons in 2005. Our aim in this study was to describe the results of an improved CRC screening program directed at the in-house staff of Beilinson Hospital. All employees of Beilinson Hospital over age 50 years were sent a letter explaining the new CRC screening program and an accompanying questionnaire. Responders who reported a family history of CRC or related cancers or symptoms were offered colonoscopy; the remainder were offered sigmoidoscopy or, if they preferred, colonoscopy. Two hundred twenty of the 888 candidates (24.7%) completed the questionnaire, of whom 144 (16.2%) agreed to further investigation. These included 90 of 105 patients with a positive questionnaire and 20 of 115 with a negative questionnaire who underwent colonoscopy and 34 of 115 with a negative questionnaire who underwent sigmoidoscopy. The colonoscopy group included 26 of the 30 patients (86.6%) with a positive family history. Early-stage CRC was diagnosed in three patients (1.36%), all with a positive questionnaire. There were no pathologic findings on sigmoidoscopy. The sensitivity, specificity, and positive and negative predictive values of the questionnaire for identifying subjects with CRC or advanced adenoma were 100.00%, 18.86%, 2.27%, and 100.00%, respectively. In conclusion, using hospital facilities, we initiated a unique CRC screening program for employees. Our method may be applicable in other medical centers for the detection of adenomas and CRCs in the early, curative stages.     

大肠癌筛查方法研究新进展

大肠癌筛查能够有效降低大肠癌相关发病率及死亡率,现有多种基于人群的大肠癌筛查方法,本文对其筛查方法的研究进展进行概述,并展望未来发展趋势。     

大肠癌筛查开始年龄的研究

早期大肠癌筛查是有效降低大肠癌发病率和死亡率的重要方法。近来研究表明,不同种族、性别及吸烟、肥胖状况的无症状平均风险人群,大肠癌的发病风险各有不同,筛查开始年龄也有所差异。因此,本文就目前大肠癌筛查开始年龄的研究进行概述。     

Metabolic syndrome and colorectal neoplasms:An ominous association

AIM:To evaluate the association of metabolic syndrome(MS) and colorectal cancer and adenomas in a Western country,where the incidence of MS is over 27%.METHODS:This was a prospective study between March 2013 and March 2014.MS was diagnosed according to the National Cholesterol Education ProgramATP III.Demographic characteristics,anthropometric measurements,metabolic risk factors,and colonoscopic pathologic findings were assessed in patients with MS(group 1) who underwent routine colonoscopy at our department.This data was compared with consecutive patients without metabolic syndrome(group 2),with no differences regarding sex and age.Patients with incomplete colonoscopy,family history,or past history of colorectal neoplasm were excluded.Informed consent was obtained and the ethics committee approved this study.Statistical analysis was performed using Student's t-test and χ2 test,with a P value ≤ 0.05 being considered statistically significant.RESULTS:Of 258 patients,129 had MS;51% males;mean-age 67.1 years(50-87).Among the MS group,94% had high blood pressure,91% had increased waist circumference,60% had diabetes,55% had low high-density lipoprotein cholesterol level,50% had increased triglyceride level,and 54% were obese [body mass index(BMI) 30 kg/m2].51% presented 4 criteria of MS.MS was associated with increased prevalence of adenomas(43% vs 25%,P = 0.004) and colorectal cancer(13% vs 5%,P = 0.027),compared with patients without MS.MS was also positively associated with multiple(≥ 3) adenomas(35% vs 9%,P = 0.024) and sessile adenomas(69% vs 53%,P = 0.05).No difference existed between location(P = 0.086),grade of dysplasia(P = 0.196),or size(P= 0.841) of adenomas.In addition,no difference was found between BMI(P = 0.078),smoking(P = 0.146),alcohol consumption(P = 0.231),and the presence of adenomas.CONCLUSION:MS is positively associated with adenomas and colorectal cancer.However,there is not enough information in western European countries to justify screening in patients with MS.To our knowledge,no previous study has evaluated this association in Portuguese patients.     

大肠癌筛查方法的研究进展

定期大肠癌筛查是有效降低大肠癌发病率和死亡率的重要方法。近年来随着分子生物学、医学影像学等技术的发展,筛查方法不断获得改进和创新,为大肠癌的防治提供了更多技术选择。筛查方法因检测原理和目标的不同,效能不尽相同,本文就大肠癌常用筛查方法及研究进展进行综述。     

Heterogeneity of colorectal adenomas, the serrated adenoma, and implications for screening and surveillance

Current algorithms for screening and surveillance for colon cancer are valuable, but may be limited by the underlying nature of the targeted neoplastic lesions. Although part of the success of adenoma removal relates to interruption of so-called ＂adenoma-carcinoma sequence＂, an alternate serrated pathway to colon cancer may pose difficulties with the ultimate results achieved by traditional colonoscopic methods. The endpoint carcinoma in this unique pathway may be derived from a dysplastic serrated adenoma. These tend to be located primarily in the right colon, especially in females, and are frequently associated with co-existent colon cancer. Unfortunately, however, there are few, if any, other identifiable risk factors, including age or family history of colon polyps or colon cancer. Moreover, this alternate serrated pathway may itself also be quite biologically heterogeneous as reflected in sessile serrated adenomas （SSA） with virtually exclusive molecular signatures defined by the presence of either BRAF or KRAS mutations. Screening algorithms in the future may need to be modified and individualized, depending on new information that likely will emerge on the natural history of these biologically heterogeneous lesions that differs from traditional adenomatous polyps.     

Uptake, yield of neoplasia, and adverse effects of flexible sigmoidoscopy screening

Background—A multicentre randomised controlledtrial to evaluate screening by "once only" flexible sigmoidoscopy(FS) for prevention of bowel cancer is in progress.
Aims—To pilot the trial protocol examining ratesof attendance, yield of neoplasia, and adverse effects.
Subjects—A total of 3540 subjects aged 55-64years in Welwyn Garden City (WGC) and 19 706 in Leicester (LE).
Methods—Subjects responding positively to an"interest in screening" questionnaire were randomised to invitationfor screening or control arms. Small polyps were removed duringscreening. Colonoscopy was undertaken for high risk polyps (more thantwo adenomas, size at least 1 cm, villous histology, severe dysplasia,or malignancy). The remainder were discharged.
Results—In WGC and LE respectively, 59% and 61%indicated an interest in screening, of which 74% and 75% attended.Adenomas were detected in 10% and 9%, respectively, and cancers in 7 per 1000 (in both centres), 55% at Dukes's stage A. The colonoscopy referral rate was 6% in both centres. Mild, short lived bleeding occurred in 3%. One person died following surgery.
Conclusions—Compliance rates, yield of adenomas,and referral rate for colonoscopy were as expected, but cancerdetection rates were higher. Adverse effects following sigmoidoscopy or colonoscopy were mild and transient, but there was one postoperative death. A randomised trial is necessary to evaluate fully the risks andbenefits of this intervention.

Keywords:screening; colorectal cancer; adenomas; sigmoidoscopy; endoscopy; randomised trial

     

Favorable lifestyle before diagnosis associated with lower risk of screen-detected advanced colorectal neoplasia

AIM: To investigate the association between adherence to health recommendations and detection of advanced colorectal neoplasia(ACN) in colorectal cancer(CRC) screening.METHODS: A total of 14832 women and men were invited to CRC screening, 6959 in the fecal immunochemical test arm and 7873 in the flexible sigmoidoscopy arm. These were also sent a self-reported lifestyle questionnaire to be completed prior to their first CRC screening. A lifestyle score was created to reflect current adherence to healthy behaviors in regard to smoking, body mass index, physical activity, alcohol consumption and food consumption, and ranged from zero(poorest) to six(best). Odds ratios(ORs) and 95%CIs were calculated using multivariable logistic regression to evaluate the association between the single lifestyle variables and the lifestyle score and the probability of detecting ACN.RESULTS: In all 6315 women and men completed the lifestyle questionnaire, 3323(53%) in the FIT arm and 2992(47%) in the FS arm. This was 89% of those who participated in screening. ACN was diagnosed in 311(5%) participants of which 25(8%) were diagnosed with CRC. For individuals with a lifestyle score of two, three, four, and five-six, the ORs(95%CI) for the probability of ACN detection were 0.82(0.45-1.16), 0.43(0.28-0.73), 0.41(0.23-0.64), and 0.41(0.22-0.73), respectively compared to individuals with a lifestyle score of zero-one. Of the single lifestyle factors, adherence to non-smoking and moderate alcohol intake were associated with a decreased probability of ACN detection compared to being a smoker or having a high alcohol intake 0.53(0.42-0.68) and 0.63(0.43-0.93) respectively.CONCLUSION: Adopted healthy behaviors were inversely associated with the probability of ACN detection. Lifestyle assessment might be useful for risk stratification in CRC screening.     

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.     

A combination of clinical risk stratification and fecal immunochemical test is useful for identifying persons with high priority of early colonoscopy

BackgroundWe aimed to develop a combination screening strategy for advanced colorectal neoplasia based on the Asia-Pacific Colorectal Screening score and fecal immunochemical test results.MethodsWe reviewed the records of participants who had undergone a colonoscopy and fecal immunochemical test as part of a comprehensive health screening program. The prevalence of advanced colorectal neoplasia in participants 40–49 years old was analyzed according to Asia-Pacific Colorectal Screening scores and fecal immunochemical test results.ResultsWe analyzed the data of 9205 participants 40–49 years old and 3215 participants ≥50 years old. The prevalence of advanced colorectal neoplasia in participants 40–49 years old was 1.0%, 2.1%, 7.1%, and 13.4% in the “fecal immunochemical test (−) & Asia-Pacific Colorectal Screening < 2,” “fecal immunochemical test (−) & Asia-Pacific Colorectal Screening ≥ 2,” “fecal immunochemical test (+) & Asia-Pacific Colorectal Screening < 2,” and “fecal immunochemical test (+) & Asia-Pacific Colorectal Screening ≥ 2” subgroups, respectively. The prevalence of advanced colorectal neoplasia in “fecal immunochemical test (+) & Asia-Pacific Colorectal Screening ≥ 2” subgroup was higher than in participants ≥50 years old with Asia-Pacific Colorectal Screening ≥ 4 (13.4% vs. 5.8%, P < 0.001).ConclusionsFecal immunochemical test-positive individuals 40–49 years old with an Asia-Pacific Colorectal Screening ≥ 2 have a higher risk of advanced colorectal neoplasia than individuals ≥50 years old with an Asia-Pacific Colorectal Screening ≥ 4.     

Colorectal cancer screening

INTRODUCTION Colorectal cancer is a major public health burden. It is the fourth most common form of cancer worldwide and the most frequent in North America, Australia, New Zealand, Argentina, and parts of Europe[1]. When colorectal can- cer is detected a…     

Colorectal cancer screening in Europe

Colorectal cancer (CRC) is the second most freq uent malignant disease in Europe. Every year, 412 000 people are diagnosed with this condition, and 207 000 patients die of it. In 2003, recommendations for screening programs were issued by the Council of the European Union (EU), and these currently serve as the basis for the preparation of European guidelines for CRC screening. The manner in which CRC screening is carried out varies significantly from country to country within the EU, both in terms of organization and the screening test chosen. A screening program of one sort or another has been implemented in 19 of 27 EU countries. The most frequently applied method is test - ing stool for occult bleeding (fecal occult blood test, FOBT). In recent years, a screening colonoscopy has been introduced, either as the only method (Poland) or the method of choice (Germany, Czech Republic).     

Yield of screening colonoscopy in renal transplant candidates

BACKGROUND:

Cardiovascular disease is the most common cause of death among patients with end-stage renal disease undergoing maintenance dialysis. Renal transplantation offers a survival advantage to patients with end-stage renal disease; it is also associated with a three- to fivefold increase in the risk of developing a neoplasm.

OBJECTIVE:

To determine the yield of screening colonoscopy among patients with chronic kidney disease who were considered for renal transplantation.

METHODS:

Patients were included if they were ≥50 years of age, had chronic kidney disease and were being considered for renal transplantation. They underwent a screening colonoscopy that was performed as part of their pretransplant workup. Data from December 2008 to May 2014 were collected retrospectively for all eligible patients.

RESULTS:

During the study period, 433 patients were considered for renal transplantation. Of these, 170 underwent colonoscopies as part of their pretransplant workup. One was excluded because of previous history of colon cancer. Of the 169 procedures performed, ≥1 polyp(s) was diagnosed in 24%. The most common pathological diagnoses were hyperplastic polyp or normal colonic tissue. Fifteen (37%) patients had tubular adenomas and one patient had a sessile serrated adenoma. Advanced adenomas, defined as villous, tubulovillous or high-grade dysplasia, were found in four patients. Adenocarcinoma was diagnosed in one patient.

CONCLUSION:

In a population of asymptomatic potential kidney transplant recipients ≥50 years of age, the prevalence of colorectal adenomatous polyps was 24%. Colonoscopy appeared to be useful as a screening tool in potential transplant recipients.