Complications of screening flexible sigmoidoscopy

BACKGROUND & AIMS: Flexible sigmoidoscopy (FS) is recommended for mass screening for colorectal cancer (CRC), yet little is known about the risk of adverse events when FS is used in general clinical practice. We aimed to determine the incidence of gastrointestinal complications and acute myocardial infarction (MI) after screening FS. METHODS: Northern California Kaiser Permanente Medical Care Program members of average risk for CRC (n = 107,704) who underwent screening FS during 1994 to 1996 (109,534 FS), as part of the Colorectal Cancer Prevention (CoCaP) program. The main outcome measure was hospitalization for gastrointestinal complications or acute MI within 4 weeks of FS. RESULTS: The mean age of subjects was 61 years, and 48.8% were female. Nongastroenterologist physicians, nurses, or physician assistants performed 72% of FS. Overall, 24 persons were hospitalized for a gastrointestinal complication. Of these, 7 were serious (2 perforations, 2 episodes of diverticulitis requiring surgery, 2 cases of bleeding requiring transfusion, and 1 episode of unexplained colitis). In multivariate models, complications were significantly more common in men than in women (odds ratio, 3.34; 95% confidence interval [CI], 1.34-10.13). MI occurred in 33 persons within 4 weeks of FS, but the incidence for this period was similar to that in the subsequent 48 weeks (rate ratio, 0.8; 95% CI, 0.6-1.2). CONCLUSIONS: The risk of serious complications after screening FS in this setting appears to be modest. Although MI occurs after FS, the risk during the 4 weeks after the procedure appears to be similar to expectations for persons of screening age.     

Patient satisfaction with screening flexible sigmoidoscopy

BACKGROUND: Screening flexible sigmoidoscopy is an underused cancer prevention procedure. Physicians often cite patient discomfort as a reason for not requesting sigmoidoscopy, but patient experiences and attitudes toward sigmoidoscopy have not been well studied. OBJECTIVE: To measure patient satisfaction and the determinants of satisfaction with screening sigmoidoscopy. METHODS: An instrument to assess satisfaction with screening sigmoidoscopy was developed. Responses were evaluated with a factor analysis, tested for reproducibility and internal consistency, and validated against an external standard. RESULTS: A total of 1221 patients (666 men and 555 women; mean age, 61.8 years) were surveyed after sigmoidoscopy. Examinations were performed by a nurse practitioner (n = 668), internist (n = 344), or gastrointestinal specialist (n= 184). More than 93% of the participants strongly agreed or agreed they would be willing to undergo another examination, and 74.9% would strongly recommend the procedure to their friends. Regarding pain and discomfort, 76.2% strongly agreed or agreed that the examination did not cause a lot of pain, 78.1% stated that it did not cause a lot of discomfort, and 68.5% thought that it was more comfortable than they expected. Fifteen percent to 25% of the patients indicated they had a lot of pain, great discomfort, or more discomfort than expected. Women were more likely to have significant pain or discomfort than men (adjusted odds ratio, 2.9; 95% confidence interval, 1.9-4.3; P<.001). CONCLUSIONS: Approximately 70% of individuals who undergo screening sigmoidoscopy are satisfied and find the procedure more comfortable than expected, whereas only 15% to 25% find the procedure unpleasant. Physicians should not project discomfort onto patients as a reason for not requesting screening sigmoidoscopy.     

The use of the 130-cm colonoscope for screening flexible sigmoidoscopy

The 130-cm colonoscope was utilized to determine whether a deeper insertion could be accomplished after the usual enema preparation for routine flexible sigmoidoscopy and, if so, to what extent that would enhance the yield of neoplastic findings. Sixty-four patients were examined, and intubation was accomplished to the level of 69 cm compared with 48.1 cm for a matched control group that had flexible sigmoidoscopy with the 60-cm endoscope. Another 24 patients who had a barium enema prep had a significantly greater depth of insertion (81.4 cm). Only two polyps were found proximal to 60 cm. The 130-cm colonoscope does not offer any substantial advantage over the standard 60-cm sigmoidoscope unless a bowel preparation more thorough than enemas is given and then it would probably only be worthwhile using the colonoscope in patients who are above average risk for colorectal neoplasia.     

The incidence of colorectal cancer following a negative screening sigmoidoscopy: implications for screening interval

BACKGROUND & AIMS: Current guidelines recommend a 5-year interval for colorectal cancer (CRC) screening by sigmoidoscopy. However, the optimal screening interval is uncertain. We estimated the annual incidence of distal and proximal CRC in the first 5 years following a negative sigmoidoscopy examination to gauge the potential benefit of rescreening in <5 years. METHODS: A cohort of 72,483 participants in the Colon Cancer Prevention program of Kaiser Permanente of Northern California (KP) was defined using computerized databases. Men and women aged 50 years and older who had a negative screening flexible sigmoidoscopy examination between 1994 and 1996 and were considered not to be at high risk for developing CRC were included. Subjects were censored at the time of diagnosis (for cases), death, termination of KP membership, or subsequent colon examination. RESULTS: Thirty cases of distal and 80 cases of proximal CRC occurred. Age-adjusted incidence rates of distal CRC ranged from a low of 2.8 per 100,000 person-years in the first year of follow-up to a high of 13.0 per 100,000 in the fourth year (rate difference, 10.2; 95% confidence interval, 1.1-19.3). However, for the entire follow-up period, incidence of distal CRC remained much lower than age-adjusted rates of 70.6 in the general population (Surveillance, Epidemiology, and End Results registry). The incidence of proximal CRC was also decreased modestly over population rates of disease. CONCLUSIONS: Screening by sigmoidoscopy more frequently than every 5 years would likely lead, at best, to only modest improvements as compared with a 5-year screening interval.     

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.     

Achieving quality in flexible sigmoidoscopy screening for colorectal cancer.

BACKGROUND: Sigmoidoscopy screening, which can dramatically reduce colorectal cancer mortality, is supported increasingly by physicians and payers, and is likely to be performed more frequently in the future. As more physicians and nonphysician medical personnel learn how to perform this procedure, and with attention to quality standards, the overall impact of sigmoidoscopy screening may improve. This review describes elements that characterize high-quality examinations and identifies resources for in-depth information on performing flexible sigmoidoscopy. METHODS: The domains of quality were identified from textbooks, articles, and the professional opinions of gastroenterologists and primary care physicians. Information was obtained from MEDLINE, bibliographies in recent articles, medical professional organizations, equipment manufacturers' representatives, and focus groups of primary care physicians. RESULTS: Nine domains of quality are identified and discussed: training, logistical start-up, patient interaction, bowel preparation, examination technique, lesion recognition, complications, reporting, and processing (equipment cleaning and disinfection). CONCLUSIONS: Persons learning how to perform and to implement flexible sigmoidoscopy may use this information to help ensure the quality of screening examinations.     

Wide variation in adenoma detection rates at screening flexible sigmoidoscopy

BACKGROUND & AIMS: Wide between-center variation in adenoma detection rates (ADRs) was observed in the U.K. Flexible Sigmoidoscopy Screening Trial (overall, 12.1%; range, 8.6%-15.9%; P < 0.0001). The aim of this study was to determine whether the observed differences could be attributed to varying performance by endoscopists, to examine the effect of experience on performance, and to identify an attainable, standard ADR to which endoscopists could aspire. METHODS: Thirteen medical endoscopists, one per trial center, each performed about 3000 examinations (200 per month) using the same equipment and protocol. Overall and monthly ADRs were compared using multivariable logistic regression. RESULTS: Differences in ADRs were not explained by patient characteristics, incidence of colorectal cancer in the local population, or the endoscopists' medical specialty or previous experience. Average ADRs increased significantly with screening experience (up to 400 examinations). Endoscopists were classified as higher, intermediate, or lower adenoma detectors, and performance levels were maintained over time. Higher detectors had ADRs of 15% overall (men, 20%; women, 10%) and also detected more adenomas per case (higher/lower detectors, 21.7/10.4 adenomas per 100 examinations). CONCLUSIONS: The differences in ADRs were due to variation in performance of the endoscopists. Long-term follow-up will determine whether this variation is clinically important. We suggest that the standards in higher detecting centers should be achievable by all endoscopists screening unscreened populations aged older than 55 years. Endoscopists should aim to stay above the lower 95% confidence interval band for 200 examinations (10% overall; 5% in women, 15% in men).     

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.     

Audio and visual stimulation reduces patient discomfort during screening flexible sigmoidoscopy

Objective: Despite current recommendations calling for regular screening flexible sigmoidoscopies over the age of 50, only a small percentage of the population have regular examinations. Improving patient tolerance of flexible sigmoidoscopies could therefore increase patient compliance with these recommended guidelines. The aim of this study was to determine whether audio and visual stimulation reduces discomfort during flexible sigmoidoscopy and whether the effects of the stimulation are secondary to distraction.
Methods: A total of 37 patients undergoing routine screening flexible sigmoidoscopy were randomized to receive no intervention, audio stimulation alone, or audio and visual stimulation. Patient discomfort ratings and affect states were measured prior to and immediately following flexible sigmoidoscopy using a visual analogue scale and the Stress Symptom Ratings (SSR) ratings.
Results: Patients receiving audio and visual intervention had lower abdominal discomfort ratings (7.1 ± 1.4) than patients receiving audio stimulation (9.5 ± 1.3) or no intervention (10.8 ± 1.6) (   p < 0.05  ). Patients receiving audio and visual intervention also had higher arousal (7.3 ± 0.4) and attention (9.2 ± 0.2) ratings than patients receiving no intervention (6.1 ± 0.4 and 6.2 ± 0.7, respectively) (   p < 0.05  ). Anxiety and anger ratings, on the other hand, were significantly lower in patients receiving audio and visual intervention (2.5 ± 0.4, 1.4 ± 0.3, respectively) than patients receiving no intervention (4.4 ± 0.6, 3.6 ± 0.7).
Conclusion: Audio and visual stimulation reduces abdominal discomfort associated with flexible sigmoidoscopy. This effect appears to be due to distraction.     

Performing screening flexible sigmoidoscopy using colonoscopes: experience in 500 subjects

There is still controversy regarding the optimal length of flexible sigmoidoscopes. We performed screening distal colon examinations using 168-cm colonoscopes in 500 asymptomatic subjects who were unsedated and had sigmoidoscopy cleansing preparation. The mean depth of penetration was 66 cm and was similar in persons in whom the examination was discontinued because of poor preparation versus those with discomfort. Polyps were detected in 87 patients, but only 5 subjects had polyps detected above 60 cm. We conclude that in a group of unsedated subjects scheduled for flexible sigmoidoscopy after a sigmoidoscopy prep, the use of instruments longer than 60 cm gives very little additional yield.     

Surveillance interval of endoscopic examinations for colorectal cancer screening

Background: There have been a few evidence‐based studies concerning the relationship between the length of the surveillance interval of colonoscopic examinations and the risk of colorectal cancer (CRC). The aim of the present study was to assess the appropriate interval between endoscopic examinations for CRC screening in a retrospective cohort study. Methods: The cohort included subjects in whom cancer was not detected at the initial endoscopic examination and in whom endoscopic examination(s) was subsequently performed one or more times. The results of the endoscopic examinations performed in the mass screening for CRC between November 1983 and March 1999 were analyzed. The study end point was the detection of CRC and the detection rates of cancer were assessed among those who underwent examinations at various intervals between successive endoscopic examinations. Results: Among the 117 636 cohort subjects, 63 invasive cancer cases and 112 mucosal cancer cases were found. The odds ratio (OR) for invasive cancer was not significantly elevated even when the interval between successive examinations was over 5 years. The OR for mucosal or invasive cancer was significantly elevated among the subjects in whom the interval between successive examinations was over 5 years (OR, 1.71; 95% confidence interval (CI), 1.07–2.73), than among those in whom the interval was 1 year. Conclusions: Since prolongation of the interval between endoscopic examinations of up to 5 years did not result in any change in the cancer risk among persons who are at average risk for CRC, 5 years may be an adequate interval between endoscopic examinations in the mass screening for CRC.     

The benefits of systematic fiberoptic flexible sigmoidoscopy

We used the flexible fiberoptic sigmoidoscope (FFS) on 656 subjects who were receiving their yearly physical examinations. Neoplastic disease was disclosed by the FFS in 138 subjects (21%), including 26 adenocarcinomas, 19 of which were out of reach of a rigid sigmoidoscope. Nineteen of the subjects whose adenocarcinomas were found by the FFS had barium enemas, which detected the carcinomas in only 11. Routine FFS in asymptomatic persons is helpful in detecting both premalignant and malignant lesions, it should be seriously considered as a part of regular preventive physical examinations.     

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.     

Variability in flexible sigmoidoscopy performance among examiners in a screening trial.

BACKGROUND & AIMS: The efficacy of flexible sigmoidoscopy (FSG) in reducing colorectal cancer mortality is being evaluated in randomized trials. In 2 European trials, wide variability across examiners in FSG performance was noted. We report on the performance of examiners in the US randomized trial: the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. METHODS: Screening was performed at 10 geographically dispersed clinical centers. Patients with screens positive for a lesion or mass were referred to their private health care providers for endoscopic follow-up evaluation; lesions were not removed and a biopsy examination was not performed at screening. FSG performance among 64 examiners at these centers, each performing 100 or more baseline FSG examinations, with an aggregate of almost 50,000 examinations, was analyzed. RESULTS: Screen-positivity results among examiners ranged from 9%-58%, with a coefficient of variation (CV) of 36%. CVs were 29% for distal polyp detection and 21% for distal adenoma detection. Inadequate rates ranged from 1%-27% (CV, 52%). Examiners with higher screen-positivity rates had higher false-positive rates, defined as a positive screen with no distal lesion found on endoscopic follow-up evaluation. CONCLUSIONS: Considerable variability exists in the rates of positive screens and in polyp and adenoma detection rates among FSG examiners performing the procedures using a common protocol.     

Prospective, randomized, single-blind comparison of two preparations for screening flexible sigmoidoscopy

BACKGROUND: The best and most cost-effective bowel cleansing regimen for patients undergoing flexible sigmoidoscopy is not known. The aim of this study was to compare patient tolerance, quality of preparation, and cost of 2 bowel cleansing regimens for flexible sigmoidoscopy. METHODS: Two hundred fifty consecutive patients referred for screening flexible sigmoidoscopy were randomized to receive an oral preparation (45 mL oral sodium phosphate and 10 mg bisacodyl) or an enema preparation (2 Fleet enemas and 10 mg bisacodyl). Tolerance of the preparation was graded as easy, tolerable, slightly difficult, extremely difficult, or intolerable. The endoscopist was blinded to which preparation the patient received and graded the quality of the preparation as poor, fair, good, or excellent. Cost was calculated by adding the cost of the medications and the cost for the nursing time required to prepare the patient for endoscopy. RESULTS: Patients in the oral preparation group were more likely to grade the preparation as easy or tolerable when compared with the enema group (96.8% vs. 56.4%, p < 0.001). The endoscopist graded the quality of the preparation as good or excellent in 86.5% of the patients in the oral preparation group compared with 57.3% in the enema group (p < 0.001). In the oral preparation group, the mean nursing time (34.6 vs. 65.3 minutes, p < 0.001) and cost ($16.39 vs. $31.13, p < 0.001) were significantly less than in the enema group. CONCLUSIONS: An oral sodium phosphate preparation results in a superior quality endoscopic examination that is better tolerated and more cost-effective than enemas in patients undergoing screening flexible sigmoidoscopy.     

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.     

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