Inter‐endoscopist variation in polyp and neoplasia pick‐up rates in flexible sigmoidoscopy screening for colorectal cancer

Background: The Norwegian Colorectal Cancer Prevention study is an ongoing flexible sigmoidoscopy (FS) screening trial for colorectal cancer. Twenty‐one thousand average‐risk individuals, aged 50–64 years, living in two separate areas in Norway were randomly drawn from the Population Registry and invited to once‐only screening flexible sigmoidoscopy. Examinations were performed over 3 years, at 2 centres, by 8 different endoscopists, using the same type of equipment. The aim of the present study was to investigate possible differences between endoscopists in detecting individuals with polyps, adenomas and advanced lesions (adenomas with severe dysplasia and/or villous components and/or size larger than 9?mm and carcinoma) in flexible sigmoidoscopy screening. Methods: The present trial comprises data from 8822 individuals, aged 55–64 years, who have undergone a flexible sigmoidoscopy. In the study period, all lesions detected by the different endoscopists were registered. Tissue samples were taken from all lesions detected. Results: Detection rates varied significantly between endoscopists, ranging from 36.4% to 65.5% for individuals with any polyp, from 12.7% to 21.2% for any adenoma and from 2.9% to 5.0% for advanced lesions. In a multiple logistic regression model, the performing endoscopist was a strong independent predictor for detection of individuals with polyps (P?P?P?=?0.01). Conclusion: Detection rates for colorectal lesions vary significantly between endoscopists in colorectal cancer screening. Establishing systems for monitoring performance in screening programmes is important. Supervised training and re‐certification for endoscopists with poor performance should be considered.     

Flat adenomas exist in asymptomatic people: important implications for colorectal cancer screening programmes

BACKGROUND: Flat adenomas are non-exophytic with a flat top or central depression and histologically the depth of dysplastic tissue is never more than twice the mucosal thickness. Flat adenomas frequently contain severely dysplastic tissue, and may progress rapidly through the adenoma-carcinoma sequence. Flat lesions have never been described in a British asymptomatic population. AIMS: To determine whether flat adenomas exist in an asymptomatic population participating in a large randomised controlled trial of flexible sigmoidoscopy screening. PATIENTS: A total of 3000 subjects (aged 55-64 years) underwent screening by flexible sigmoidoscopy. METHODS: All polyps were removed and sent for histology. The number of polyps with endoscopic and histological features of flat adenomas was recorded. RESULTS: Three subjects had a total of four flat lesions--that is, one per 1000 people screened. Three contained severely dysplastic tissue, one a focus of adenocarcinoma. Three of the four lesions were less than 5 mm in size and the fourth was 15 mm in diameter. CONCLUSIONS: Flat lesions with severe dysplasia exist in the asymptomatic population. This has major implications for gastroenterologists who should be trained to identify them. Their existence is of importance to molecular biologists and epidemiologists investigating the aetiology of colorectal cancer.     

Accuracy of polyp detection by gastroenterologists and nurse endoscopists during flexible sigmoidoscopy: a randomized trial.

BACKGROUND & AIMS: The use of nurse endoscopists to perform flexible sigmoidoscopy is expanding, increasing the availability of colorectal cancer screening. However, the effectiveness of this practice has not been studied in randomized trials. The aim of this trial was to examine the miss rate of polyps, the depth of sigmoidoscope insertion, and the incidence of complications during flexible sigmoidoscopy performed by nurse endoscopists and by gastroenterologists. METHODS: Three hundred twenty-eight patients were randomized to undergo screening flexible sigmoidoscopy performed by a nurse endoscopist or by a gastroenterologist. Frequency of missed polyps was determined by repeat sigmoidoscopy, performed by a gastroenterologist blinded to the identity of the first endoscopist. Multiple logistic regression analysis identified characteristics associated with missed polyps. RESULTS: Gastroenterologists and nurse endoscopists had equivalent miss rates for adenomatous polyps (20% vs. 21%, respectively; P = 0.91). No complications occurred in any patient. Gastroenterologists inserted the sigmoidoscope further than nurse endoscopists (61 vs. 55 cm, respectively; P < 0.00001). Polyp location in the descending colon (odds ratio, 4.1; 95% confidence interval, 1.7-10.3) was highly associated with missed polyps. CONCLUSIONS: No differences in detection of adenomatous polyps or frequency of complications were found. These data suggest that experienced nurse endoscopists may perform screening flexible sigmoidoscopy as safely and as effectively as gastroenterologists.     

The role of colonoscopy in screening persons with family history of colorectal cancer

Abstract First-degree relatives of colorectal cancer patients are at increased risk for developing colorectal neoplasms. In order to assess the potentiality of colonoscopy screening in this high-risk population, 213 asymptomatic family members (age range 30-69 years, mean 42.8 years) of those patients with colorectal cancer received colonoscopic examination at Chang-Gung Memorial Hospital from April 1992 to May 1994. Twenty-eight persons with 42 lesions (polyps or cancer) were identified, including 28 adenomas, nine hyperplastic polyps and five adenocarcinomas. The positive detection rate was 9.9% for adenoma and 2.3% for cancer. Colorectal neoplasms afflicted males more frequently than females (16.7 vs 5.7%, P < 0.05) and occurred less frequently in those < 40 years of age (5.5 vs 17.2%, P < 0.05). Forty-two per cent of the detected neoplastic lesions were beyond the reach of 60 cm flexible sigmoidoscopy and 36% of adenomas were < 0.5 cm in size and would be missed if patients were screened by air contrast barium enema. Cost analysis revealed that the charges of both screening colonoscopy and screening flexible sigmoidoscopy/air contrast barium enema were approximate. Colonoscopy also has a high acceptability and safety. It appears appropriate to use colonoscopy, rather than flexible sigmoidoscopy or air contrast barium enema, as an initial screening procedure for persons with a family history of colorectal cancer, especially those > 40 years of age.     

History of negative colorectal endoscopy and risk of rectosigmoid neoplasms at screening flexible sigmoidoscopy

Background and aims Screening sigmoidoscopy can reduce incidence of colorectal cancer and mortality. The optimal re-screening interval has not yet been defined. This study is aimed at estimating the risk of distal advanced adenomas (diameter 10 mm, villous component >20%, high-grade dysplasia) and cancer at screening flexible sigmoidoscopy in subjects aged 55–64 years who reported pre-screening negative colorectal endoscopy.Patients Eight thousands two hundred two subjects aged 55–64 years who underwent screening flexible sigmoidoscopy within the SCORE trial in Italy and who were able to report their previous history of colorectal endoscopy.Results Eight hundred eighty three of 8,202 subjects (10.8%) reported at least one prescreening negative endoscopy: among them, after 3–5 years, 6–10 years and >10 years intervals between last reported examination and screening endoscopy, the Absolute Risk of advanced adenomas was 1.5%, 0.9% and 0.9%; one cancer was detected (0.1%). Among the 7,319 subjects who did not report prescreening endoscopy the risks of advanced adenoma and cancer were 3.2% and 0.4%, respectively. Subjects with a previous colorectal examination had a 65% decreased risk of advanced adenomas (OR=0.35, 95%CI 0.18–0.66) and a 71% decreased risk of cancer (OR=0.29, 95%CI 0.04–1.12) as compared to those who did not. For subjects without family history of colorectal cancer the statistically significant decrease of the risk persisted up to ten years. The observed benefit seems not to apply to subjects with family history of colorectal cancer.Conclusions Our results are consistent with the hypothesis that the interval between screening sigmoidoscopies could be safely expanded beyond 5 years for subjects without specific risk factors for colorectal cancer.Members of the SCORE Working Group are provided in Appendix A     

Use of flexible sigmoidoscopy to screen for colorectal cancer in HIV-infected patients 50 years of age and older

BACKGROUND: Although many patients with human immunodeficiency virus (HIV) infection are now living well beyond 50 years of age, there are no data available on colorectal cancer screening in this population. The aim of this study was to determine the utility of screening flexible sigmoidoscopy in patients with HIV. METHODS: Consecutive patients at average risk for colorectal cancer who were referred for screening flexible sigmoidoscopy were prospectively identified. A detailed medical history was obtained from all patients before flexible sigmoidoscopy, and colonoscopy was recommended for all subjects with positive sigmoidoscopic findings. RESULTS: A total of 2382 patients were enrolled in the study; 165 were HIV positive. The prevalence of neoplastic lesions (adenomas or adenocarcinomas) in the distal colon was significantly higher in HIV-infected patients than in control subjects (25.5% vs 13.1%, P<.001), and the odds of HIV-infected patients having a neoplastic lesion was significantly higher even after adjustment for potential confounding variables (odds ratio, 2.34; 95% confidence interval, 1.60-3.44). The prevalence of adenomas of any size (25.5% vs 12.9%, P<.001) and advanced neoplasia (7.3% vs 3.8%, P = .03) in the distal colon was significantly higher in HIV-infected patients. Among individuals with positive results on flexible sigmoidoscopy, proximal colonic neoplastic lesions on follow-up colonoscopy were more common in HIV-infected patients after adjustment for age, sex, and race/ethnicity (odds ratio, 1.88; 95% confidence interval, 1.02-3.46). CONCLUSIONS: Patients infected with HIV are more likely to have colonic neoplasms on screening flexible sigmoidoscopy than those without HIV, and these individuals should be offered colorectal cancer screening.     

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.     

Circulating insulin-like growth factor II and colorectal adenomas

Circulating insulin-like growth factor I (IGF-I) and IGF-binding protein-3 (IGFBP-3) may be risk factors for the development of colorectal cancer. On the other hand, IGF-II and IGFBP-2 are overexpressed in colorectal carcinomas. These contrasting backgrounds led us to investigate the relationship between serum IGF-I, IGF-II, IGFBP-2, and IGFBP-3 and the presence of colorectal adenomas, known precursors of colorectal carcinoma, in 345 volunteers attending a screening flexible sigmoidoscopy trial (entry criteria: healthy, aged 55-64 yr). The most striking finding was an elevated mean serum IGF-II in individuals with adenomas (n = 52) compared with controls (mean difference, 139 ng/mL; 95% confidence intervals, 82, 196; P < 0.0001). Logistic regression adjusting for confounding factors confirmed the significant association between IGF-II and adenoma occurrence (P < 0.0001) and revealed an additional positive association with serum IGFBP-2 (P < 0.0001). However, there was no association found between either serum IGF-I and/or IGFBP-3 and the presence of adenomas. Additionally, in 31 individuals with adenomas in whom levels were determined pre- and postpolypectomy, there was a significant fall in mean IGF-II (P < 0.001) and IGFBP-2 (P < 0.001) after adenoma removal, but no difference in IGF-II and IGFBP-2 concentrations between repeated samples in 20 individuals without adenomas. Immunohistochemical studies demonstrated IGF-II expression in 83% of all adenomas, which contrasted with absent expression in normal colonic expression and hyperplastic polyps. This study has shown for the first time that serum IGF-II may be a tumor marker in individuals with colorectal adenomas. Further studies are needed to validate these relationships in larger populations, including individuals undergoing colonoscopy.     

Screening for colorectal cancer with flexible sigmoidoscopy by nonphysician endoscopists.

PURPOSE: Screening with sigmoidoscopy reduces the risk of death from colorectal cancer. Only 30% of eligible patients have undergone sigmoidoscopy, in part because of a limited supply of endoscopists. We evaluated the performance and safety of screening sigmoidoscopic examinations by trained nonphysician endoscopists in comparison with board-certified gastroenterologists. SUBJECTS AND METHODS: Asymptomatic patients 50 years or older without evidence of fecal occult blood and no personal history or family history of a first-degree relative with colorectal cancer under age 55 years were offered sigmoidoscopy. All examinations were performed either by a gastroenterologist or a trained nonphysician endoscopist at a staff model health maintenance organization. Outcomes included the depth of examination, number and histology of polyps, and complications. RESULTS: Nonphysicians performed 2,323 sigmoidoscopic examinations, and physicians performed 1,378 examinations. The mean (+/-SD) depth of sigmoidoscopy examinations performed by nonphysicians was 52 +/- 10 cm compared with 55 +/- 9 cm (P <0.001) in physicians. Nonphysicians detected neoplastic polyps in a greater proportion of patients (7.8%) than physicians (5.8%), but this difference was not significant after adjusting for differences in the age, sex, and family history of the patients (P = 0.35). No major complications occurred. The cost per examination, including the nonphysician training cost, was lower for nonphysicians ($186 per examination) than for physicians ($283 per examination). CONCLUSIONS: Appropriately trained nonphysicians may be capable of performing safe and effective screening for colorectal cancer with flexible sigmoidoscopy. An increased use of nonphysicians to perform sigmoidoscopy may increase the availability and reduce the cost of the procedure.     

Fecal occult blood and flexible sigmoidoscopy screening for colorectal cancer: modeling the impact on colonoscopy requirements and cancer detection rates

AiM: The aim of this study was to estimate the colonoscopy requirements and the likely impact of fecal occult blood and flexible sigmoidoscopy screening on the detection of colorectal cancer by using previously published data. METHODS: Fecal occult blood and flexible sigmoidoscopy screening programs were applied to the 2.04 million subjects aged 50-65 years, at a participation rate of 40%. The following strategies were evaluated: Fecal occult blood testing with colonoscopy follow up of all positive tests; flexible sigmoidoscopy with colonoscopy follow up of all adenomatous polyps; and flexible sigmoidoscopy with colonoscopy follow up of all adenomatous polyps > 10 mm in size. RESULTS: The fecal occult blood program detected 5.6% of all colorectal cancer cases at a rate of 2,914 colonoscopies/percentage of detection of colorectal cancer. The flexible sigmoidoscopy program detected 14% of all colorectal cancer cases at a rate of 8,160 colonoscopies/percentage of detection of colorectal cancer. The flexible sigmoidoscopy program with follow up of adenomatous polyps > 10 mm in size detected 13% of all colorectal cancer cases at a rate of 1,230 colonoscopies/percentage of detection of colorectal cancer. CONCLUSIONS: Flexible sigmoidoscopy screening followed by colonoscopic follow up of adenomatous polyps > 10 mm in size is the most efficient screening strategy in terms of colonoscopies generated and cases of colorectal cancer detected.     

Flexible sigmoidoscopy may be ineffective for secondary prevention of colorectal cancer in asymptomatic,average-risk men

Asymptomatic men (N=114) 50 years of age or older had screening for colorectal neoplasia with flexible sigmoidoscopy followed by colonoscopy regardless of the sigmoidoscopic result. Our study objective was to determine the prevalence of patients having isolated adenomatous polyps in a proximal colonic segment in the absence of a distal index neoplasm within reach of the sigmoidoscope. Through the combined use of sigmoidoscopy and colonoscopy, adenomatous polyps were detected in 47 of 114 individuals (41%). A total of 88 adenomas was found. Seventeen patients had isolated neoplasms in proximal colonic segments in the absence of distal adenomas. These patients represented 15% of screened subjects (17 of 114) and 20% of individuals who lacked adenomas on sigmoidoscopy (17 of 84). The majority of proximal neoplasms were small (<1.0 cm), tubular adenomas. Flexible sigmoidoscopy may be ineffective for screening asymptomatic men for neoplasia. However, it remains to be determined if a 20% miss rate (for those with a normal sigmoidoscopic examination) is significant and whether small proximal adenomas are worth finding.     

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

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

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.     

Efficacy of screening flexible sigmoidoscopy for colorectal neoplasia in asymptomatic subjects

PURPOSE: Although flexible sigmoidoscopy is recommended in patients over age 40 to complement fecal occult blood screening for colorectal neoplasia, the yield of this procedure in asymptomatic, average-risk subjects has varied between studies. In addition, the efficacy of flexible sigmoidoscopy in detecting early curable carcinoma has been the subject of debate. We therefore undertook this study to assess the efficacy, safety, and cost of the procedure for early detection of colorectal neoplasia in asymptomatic subjects. PATIENTS AND METHODS: Flexible sigmoidoscopy with a 60-cm scope was performed in 412 asymptomatic veterans (mean age, 63.2 years). Subjects with positive fecal occult blood and those at increased risk for colorectal neoplasia were excluded. Costs were estimated on the basis of Medicare payments. RESULTS: A mean length of 56.1 cm of sigmoid and descending colon was examined. A total of 132 polyps were detected in 93 subjects (22.6%). Thirty-five percent of the polyps were located at a distance of greater than 30 cm from the anal verge. Of 122 polyps removed, 26% were 1 cm in size or larger. A total of 77 polyps (63%) were adenomas, and six polyps (5%) were carcinomas. Of the six carcinomas detected (two carcinoma in situ, one Astler Coller stage A, two stage B1, and one stage C1), five were in a localized stage and thus potentially curable. The cost of detecting each potentially curable carcinoma was $47,174. No complications from flexible sigmoidoscopy were noted. CONCLUSION: In conclusion, 60-cm flexible sigmoidoscopy is a safe, high-yield procedure for the initial screening of colorectal neoplasia in asymptomatic, average-risk subjects over the age of 50. Because the carcinomas detected were still in an early stage, such screening may improve survival.     

Effect of hysterectomy status on polyp detection rates at screening flexible sigmoidoscopy

BACKGROUND: Flexible sigmoidoscopy with polypectomy reduces the incidence of colorectal cancer by removal of premalignant lesions. Factors that reduce the area examined by flexible sigmoidoscopy may reduce its benefit. The aim of this study was to determine whether hysterectomy affects completion and polyp detection rates at flexible sigmoidoscopy. METHODS: Within the setting of a multicenter, prospective, controlled trial of screening flexible sigmoidoscopy, patient and examination variables were compared by appropriate statistical methods for women between the ages of 55 and 64 years with and without a history of a hysterectomy. RESULTS: One quarter of women participants had undergone a hysterectomy. These women were more likely to have incomplete examinations (risk ratio [RR] of incomplete examination, 1.53; 95% CI [1.4, 1.6]). Flexible sigmoidoscopy was more difficult (p < 0.001), more painful (p < 0.001), and less extensive (46 cm vs. 48 cm insertion on average; p < 0.0001) in women who had undergone a hysterectomy. There was a significant trend toward lower relative detection rates of polyps and adenomas at more proximal sites (rectum, sigmoid colon, and proximal to sigmoid; respectively, p = 0.008, p = 0.009) in this group. CONCLUSIONS: Women who have undergone a hysterectomy have less extensive flexible sigmoidoscopy examinations, which are more difficult and more painful, than women without a hysterectomy. Hysterectomy is associated with a reduction in polyp detection rate in the sigmoid colon. This modality of screening may be less effective in women who have undergone a hysterectomy.     

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.     

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.     

Cost-effectiveness of colorectal cancer screening: comparison of community-based flexible sigmoidoscopy with fecal occult blood testing and colonoscopy

BACKGROUND AND AIMS: To determine the cost-effectiveness of screening for colorectal cancer using flexible sigmoidoscopy once every 10 years, compared with annual and biennial rehydrated Hemoccult fecal occult blood testing and colonoscopy once every 10 years, or no screening. METHODS: A Markov model was developed in order to simulate the progression of a cohort of asymptomatic, average-risk individuals aged 55-64 years who were moving through a defined series of states towards death. The main outcome measures were: cases of colorectal cancer averted, colorectal cancer deaths averted, and cost per life-year saved. RESULTS: Colonoscopy averted the greatest number of cases of colorectal cancer (35%), followed by flexible sigmoidoscopy (25%), and annual (24%) and biennial (14%) fecal occult blood testing. Colonoscopy averted the greatest number of deaths from colorectal cancer (31%), followed by annual fecal occult blood testing (29%), flexible sigmoidoscopy (21%) and biennial fecal occult blood testing (19%). Flexible sigmoidoscopy was the most efficient in terms of cost per life-year saved (16,801 Australian dollars), followed by colonoscopy (19,285 Australian dollars), biennial (41,183 Australian dollars), and annual (46,900 Australian dollars) fecal occult blood testing. CONCLUSIONS: Flexible sigmoidoscopy and colonoscopy are cost-effective strategies for reducing the disease burden of colorectal cancer.     

Impact of a Family History of Colorectal Cancer on the Prevalence of Advanced Adenomas of the Rectosigmoid Colon at Flexible Sigmoidoscopy in 3147 Asymptomatic Patients

Flexible sigmoidoscopy is advised as a screening test for colorectal cancer for persons with a family history of late-onset colorectal cancer. The expected outcome for this approach is not well established. We designed a large, prospective study of an unselected population to assess the impact of a family history of one first-degree relative with colorectal cancer on the prevalence of advanced adenomas at screening flexible sigmoidoscopy. We evaluated 8121 patients referred for flexible sigmoidoscopy between 1997 and 1999 and 3147 patients met the inclusion criteria. The 3147 patients were divided into 210 with a family history of colorectal cancer and 2937 without a family history and analyzed for differences in the prevalence of advanced adenomas. Of the 210 with a family history, 3 had an advanced adenoma of the rectosigmoid colon (1.4%) Of the 2937 without a family history, 52 had an advanced adenoma of the rectosigmoid colon (1.8%), including 2 cancers. These differences were not significant. In conclusion, a family history of colorectal cancer had no impact on the prevalence of advanced adenomas in asymptomatic patients at screening flexible sigmoidoscopy. The prevalence rates for advanced adenomas and carcinomas of the rectosigmoid colon were low.