Difficult or incomplete flexible sigmoidoscopy: implications for a screening programme

Colon cancer screening in women

Colorectal cancer is the third leading cause of cancer-related deaths in women. Colorectal cancer is a preventable disease with accepted screening modalities that have been proven to save lives. As women are more likely than men to develop right-sided colon cancers, colonoscopy is the preferred screening test in women. Currently, women are less likely to undergo colorectal cancer screening than men. Frank discussions addressing the fear or embarrassment of endoscopic screening are important in helping women overcome these barriers. Enhanced education of both practitioners and patients targeted to improve colorectal cancer screening adherence will improve early diagnosis and patient survival.

Targeting risk groups for screening

Currently colorectal cancer (CRC) screening guidelines are based on age and to some extent on family history of screenees only. Potentially CRC screening could be also customised according to gender, race, ethnicity, smoking habits, presence of obesity, diabetes and metabolic syndrome. The factors that could be individually modified are: choice of screening test, age of initiation of screening and screening intervals. Gender is probably the easiest factor to be included. One of the professional societies has already included the race into guidelines in order to lower the age of starting screening in African-Americans. Targeting persons at higher than average-risk aims at optimising the use of available resources. However, an important drawback of such approach exists; it is the risk of making guidelines too complex and incomprehensible for both eligible screenees and physicians.

Quality assurance in flexible sigmoidoscopy: medical and nonmedical endoscopists

PURPOSE

The clinical assessment of position in colon and hence completion during flexible sigmoidoscopy (FS) is believed to be inaccurate. The technique of applying endomucosal clips with follow-up X-ray has previously been used for establishing completion in colonoscopy. Furthermore, we have now trained non-healthcare professionals (non-medical endoscopists, NME) to perform FS, but there is no data on assessment of their performance of FS. We performed this study with the aims of determining accuracy of endoscopists' clinical impression regarding actual position of endoscope in colon during FS, comparing medical (ME) and NME in terms of clinical accuracy, and to determine role of endomucosal clips with follow-up X-rays in documenting completion and hence quality assurance.

METHODS

All patients undergoing elective FS, except those with surgical resection, were included, after ethics approval. During FS, endoscopist applied an endomucosal clip at most proximal bowel reached and endoscopists recorded their independent opinion about position of clip. Post procedure, all patients underwent an abdominal X-ray, reported by consultant radiologist, blinded to outcome of FS. X-ray results were compared with endoscopist findings. Complete FS was defined as one where descending colon was reached.

RESULTS

Fifty-one patients, with median age of 55 years, participated in study. The endoscopists were accurate in their assessment of position in colon in 38 patients (75%). The attending nurse was accurate in only 31% of cases. The crude and corrected completion rates were 73% and 84%, respectively. There was no correlation between length of endoscope and its position in colon. There were no differences between NME and ME in terms of clinical accuracy.

CONCLUSION

This study has shown that clinical impression of endoscopist during FS regarding position is not very accurate, implying need for regular quality assurance. The technique of applying endomucosal clips with follow-on abdominal X-ray is an excellent objective measure of quality assurance in FS. NME can perform FS with comparable completion rates and accuracy.

Incomplete screening flexible sigmoidoscopy associated with female sex, age, and increased risk of colorectal cancer

BACKGROUND

Several previous studies have found that females and older individuals are at greater risk of having incomplete flexible sigmoidoscopy. However, no prior study has reported the subsequent risk of colorectal cancer (CRC) following incomplete sigmoidoscopy.

METHODS

Using data from 55 791 individuals screened as part of the Colon Cancer Prevention (CoCaP) programme of Kaiser Permanente of Northern California, we evaluated the likelihood of having an inadequate (<40 cm) examination by age and sex, and estimated the risk of distal CRC according to depth of sigmoidoscope insertion at the baseline screening examination. Multivariate estimation of risks was performed using Poisson regression.

RESULTS

Older individuals were at a much greater risk of having an inadequate examination (relative risk (RR) for age 80+ years compared with 50-59 years 2.6 (95% confidence interval (CI) 2.3-3.0)), as were females (RR 2.3 (95% CI 2.2-2.5)); these associations were attenuated but remained strong if Poisson models were further adjusted for examination limitations (pain, stool, and angulation). There was an approximate threefold increase in the risk of distal CRC if the baseline sigmoidoscopy did not reach a depth of at least 40 cm; a smaller increase in risk was observed for examinations that reached 40-59 cm.

CONCLUSIONS

Older individuals and women are at an increased risk of having inadequate sigmoidoscopy. Because inadequate sigmoidoscopy results in an increased risk of subsequent CRC, physicians should consider steps to maximise the depth of insertion of the sigmoidoscope or, failing this, should consider an alternative screening test.

Selecting patients for flexible sigmoidoscopy. Determinants of incomplete depth of insertion

BACKGROUND

Flexible sigmoidoscopy (FS) is an effective method to prevent and reduce mortality from colorectal carcinoma (CRC). Incomplete depth of insertion (IDI) during FS may result in missed polyps and carcinomas. To determine whether it is possible to predict IDI, the authors analyzed factors that affected the depth of insertion in FS.

METHODS

For the current study, FS results were recorded prospectively over a 5-year period. A questionnaire was administered to the patient by the investigator prior to FS to collect data, including age, gender, weight, comorbid illnesses, history of prior abdominal and pelvic surgeries, family history of colon carcinoma or polyps, and prior FS or colonoscopies. The depth of insertion of the flexible sigmoidoscope from the anal verge, which was defined as the reading on the outside of the instrument at its maximal insertion, was measured in centimeters. IDI was defined as a depth of insertion < 50 cm. Classification and regression tree analysis was used to develop a model that included variables predictive of IDI.

RESULTS

The best classification tree included gender, age < 69 years (in women), and a history of hysterectomy. Men had a < 5% risk of an IDI and women age < 69 years without a hysterectomy fared as well (6.6%). Older women and younger women who underwent hysterectomy had higher rates of IDI (29.2% and 22.3%, respectively.)

CONCLUSIONS

The authors developed a model based on age, gender, and hysterectomy status that, after further validation, may be useful for predicting which patients likely will have an incomplete examination. In those patients who have a high probability of IDI, the choice can be made to offer colonoscopy or perform FS under sedation, with analgesia, or with the help of distraction techniques.

The evaluation of rectal bleeding in adults. A cost-effectiveness analysis comparing four diagnostic strategies

BACKGROUND

Though primary care patients commonly present with rectal bleeding, the optimal evaluation strategy remains unknown.

OBJECTIVE

To compare the cost-effectiveness of four diagnostic strategies in the evaluation of rectal bleeding.

DESIGN

Cost-effectiveness analysis using a Markov decision model.

DATA SOURCES

Systematic review of the literature, Medicare reimbursement data, Surveillance, Epidemiology, and End Results (SEER) Cancer Registry.

TARGET POPULATION

Patients over age 40 with otherwise asymptomatic rectal bleeding.

TIME HORIZON

The patient's lifetime.

PERSPECTIVE

Modified societal perspective.

INTERVENTIONS

Watchful waiting, flexible sigmoidoscopy, flexible sigmoidoscopy followed by air contrast barium enema (FS+ACBE), and colonoscopy.

OUTCOME MEASURES

Incremental cost-effectiveness ratio.

RESULTS OF BASE-CASE ANALYSIS

The incremental cost-effectiveness ratio for colonoscopy compared with flexible sigmoidoscopy was 5,480 dollars per quality-adjusted year of life saved (QALY). Watchful waiting and FS+ACBE were more expensive and less effective than colonoscopy.

RESULTS OF SENSITIVITY ANALYSES

The cost of colonoscopy was reduced to 1,686 dollars per QALY when age at entry was changed to 45. Watchful waiting became the least expensive strategy when community procedure charges replaced Medicare costs, when age at entry was maximized to 80, or when the prevalence of polyps was lowered to 7%, but the remaining strategies provided greater life expectancy at relatively low cost. The strategy of FS+ACBE remained more expensive and less effective in all analyses. In the remaining sensitivity analyses, the incremental cost-effectiveness of colonoscopy compared with flexible sigmoidoscopy never rose above 34,000 dollars.

CONCLUSIONS

Colonoscopy is a cost-effective method to evaluate otherwise asymptomatic rectal bleeding, with a low cost per QALY compared to other strategies.

Screening flexible sigmoidoscopy using an upper endoscope is better tolerated by women

BACKGROUND

Flexible sigmoidoscopy (FS) is a commonly used method for colorectal cancer screening. Women are more likely than men to have a FS with a limited depth of insertion, in part due to differences of anatomy and perception of pain.

AIM

The objective of this prospective single-blinded randomized clinical study is to assess satisfaction in women undergoing screening FS using an upper endoscope (E, diameter 9.8 mm) versus a standard sigmoidoscope (S, diameter 13.3 mm) as measured by pain and discomfort and overall satisfaction using a validated survey instrument. Secondary endpoints of FS efficacy included the depth of insertion of the instrument, frequency of polyp detection, and complication rate.

RESULTS

A total of 160 asymptomatic women undergoing screening FS were entered over a 4-month period (July through November 2002). All procedures were performed by two experienced physician assistants. The two groups were of similar age (E = 57.5, S = 58.2, p= 0.579) and had a similar rate of previous abdominal surgery (E = 51.2%, S = 45.0%, p= 0.428) or hysterectomy (E = 34.2%, S = 26.3%, p= 0.274). Depth of insertion of the scope was 54.5 cm (+/-9.2 cm) with the E and 51.6 cm (+/- 10.3 cm) with the S (p= 0.058). Polyps were found more frequently in the study group (18.3%) compared with the control group (p= 10.2%) though this did not reach statistical significance (p= 0.131). Overall satisfaction with FS was similar in both groups (p= 0.694) but pain and discomfort were less in the patients undergoing FS using the E (p= 0.006). Controlling for age and previous surgery the differences in pain scores remained significant (p= 0.035). Endoscopist assessment of procedure difficulty (p= 0.726) and complication rates (p= 0.614) was equivalent. Controlling for the presence of polyps, the total duration for the procedure was 7.2 min in the E group and 5.7 min in the S group (p= 0.008). There were no significant differences between women with and without hysterectomy on either overall satisfaction or pain and discomfort.

CONCLUSION

Screening FS in women using an upper endoscope is a feasible approach to colorectal cancer screening. Patients screened with an upper endoscope reported less pain and discomfort compared to standard sigmoidoscope while overall satisfaction did not differ. The trend toward increased polyp detection in patients undergoing FS with an upper endoscope may be related to a more thorough examination due to less patient discomfort and/or an increased depth of insertion of the upper endoscope. Thinner, more flexible endoscopes should be considered when performing screening FS in women.

Evaluation of flexible sigmoidoscopy as an investigation for "left sided" colorectal symptoms

BACKGROUND

Colonoscopy is the best way of imaging the colon with concurrent biopsy and treatment. However it is expensive, requires full bowel preparation, and carries a risk of complications. Flexible sigmoidoscopy is an alternative way to investigate symptoms that raise the suspicion of a lesion of the rectum or left colon.

AIM OF THE STUDY

To evaluate flexible sigmoidoscopy as the main investigation for "left sided" colorectal symptoms.

METHODS

The clinical records of 317 patients who were assessed at a colorectal specialist clinic and were thought to have a suspicion of a lesion of the rectum or left colon were retrospectively reviewed. All patients had flexible sigmoidoscopy as the primary investigation. Primary outcome was the diagnostic yield of flexible sigmoidoscopy and secondary outcomes were any additional colonic investigations required, failure rates, and complication rates.

RESULTS

Three hundred and sixteen patients who had flexible sigmoidoscopy with the above criteria were retrospectively analysed. Twenty four procedures (7.6%) had to be abandoned because of poor bowel preparation. The examination was considered complete when it reached the splenic flexure, which was the case in 205 cases (65%). In 137 flexible sigmoidoscopies (43.3%) there were no abnormal findings. Of the remaining 179 a carcinoma of the rectum or colon was found in 28 cases (8.8%) and one or more polyps was found in 57 (18%) cases. On the basis of the findings it was calculated that 31% of the patients would require an additional investigation for further imaging of the right colon.

DISCUSSION

Although flexible sigmoidoscopy has a high yield of pathologies when carried out by a specialist colorectal clinic, the presence of those pathologies makes the full imaging of the whole colon with an additional investigation necessary. Therefore the cost efficiency of flexible sigmoidoscopy is questionable. Although flexible sigmoidoscopy is indicated for certain patients, it cannot replace colonoscopy as the main investigation used by a specialist colorectal clinic.

Colorectal cancer screening with flexible sigmoidoscopy—participants' experiences and technical feasibility

AIM

To evaluate tolerability and technical feasibility of colorectal cancer screening with flexible sigmoidoscopy.

METHODS

One thousand men and women aged 59-61 years, randomly selected from the population register of Uppsala, Sweden, were invited by mail. After random allocation, half of them were called up by a nurse (group 1), while the other half were asked to call themselves (group 2) to book a sigmoidoscopy. After the examination, the participants anonymously answered a questionnaire about their subjective experiences. Endoscopists and their assisting nurse filled out structured forms documenting various technical aspects including an estimation of the subjects' discomfort.

RESULTS

Four hundred and sixty-nine subjects participated. Mean intubation depth was 59 cm (range 28-60) and mean duration 5.8 min (range 2-23). On average, participants reported low degrees of discomfort and feeling of exposure, but 19 and 27% rated pain and distension, respectively, on the upper half of a visual analogue scale (VAS). Most subjects found the duration acceptable. Patient discomfort, as appraised by the endoscopists, was lower in men than in women, positively linked to duration of the procedure, but inversely associated with intubation distance. However, the overall differences between strata of participants were small. Among self-reported variables, group 1 and 2 differed significantly only with regard to 'other discomfort'. All but six subjects would accept a repeat examination. Failures, resulting in incomplete examinations, occurred in 14 subjects.

CONCLUSIONS

Flexible sigmoidoscopy is generally well tolerated and technically feasible in screening for colorectal cancer. A more personalised invitation did not have any important effects on the subjective experience.

Association of older age and female sex with inadequate reach of screening flexible sigmoidoscopy

PURPOSE

Estimates of the sensitivity of screening sigmoidoscopy assume an adequate depth of insertion is reached. However, in clinical practice, the frequency that sigmoidoscopy reaches various lengths of the colon is not known. We assessed the frequency of inadequate reach (depth of <50 cm of the colon) in a large U.S. cohort, according to age and sex.

METHODS

We performed a cross-sectional study of 15,406 asymptomatic persons aged 50 years or older who underwent screening flexible sigmoidoscopy between April 1997 and October 2001 at sites participating in the Clinical Outcomes Research Initiative, which examines outcomes of endoscopy in "real life" settings. The maximum depth of insertion of the sigmoidoscope was measured in centimeters from the anus and classified as adequate (> or =50 cm) or inadequate (< 50 cm). Patient characteristics as well as procedure-related variables were also recorded.

RESULTS

Eighteen percent (n = 2801) of subjects had an inadequate examination. In men, the percentage of inadequate examinations increased progressively with age, from 10% (343/3338) in those aged 50 to 59 years to 22% (53/248) in those aged 80 years or older (P <0.001). Inadequate examinations were more common in women at all ages, ranging from 19% (733/3798) in those aged 50 to 59 years to 32% (86/267) in those aged 80 years or older (P <0.001). These associations were confirmed in a multivariable analysis.

CONCLUSION

Our finding that advancing age and female sex were independently associated with the risk of inadequate reach of screening sigmoidoscopy suggests that the sensitivity of sigmoidoscopy may be lower in these populations. Estimates of the benefits of sigmoidoscopy may need to be tailored to the age and sex of the patient.

Female gender and other factors predictive of a limited screening flexible sigmoidoscopy examination for colorectal cancer

OBJECTIVE

Flexible sigmoidoscopy (FS) screening for colorectal cancer (CRC) is associated with reduced mortality from CRC. It is unknown whether FS is equally effective in men and women, but differences in anatomy and perception of pain may increase the difficulty of performing FS in women. The aim of this study was to determine factors associated with a shorter or limited screening FS.

METHODS

Patients referred by their primary care provider were eligible for screening sigmoidoscopy if they were 50 yr or older with negative fecal occult blood tests and no first-degree relative with colorectal cancer at age 55 yr or younger. A detailed questionnaire regarding demographic characteristics and risk factors for CRC, aspirin and multivitamin use, and previous abdominal surgery was completed by the patient on a standardized form before their procedure. The histologic type (hyperplastic, adenoma, normal mucosa, or carcinoma) of each polyp was recorded. Depth of examination (in cm) was recorded based on the standardized markings on the shaft of the sigmoidoscope when it was thought to be in a straight position. Limitations to the examination (angulation, pain, and poor preparation), other mucosal findings, and complications were also noted.

RESULTS

A total of 3980 patients (52% female) were prospectively enrolled in a screening program over a 22-month period. Women were more likely than men to report previous pelvic or abdominal surgery (OR = 2.64, 95% CI = 2.29-3.05) and were less likely to have had a previous sigmoidoscopy (OR = 0.71, 95% CI = 0.61-0.83). Females were almost twice as likely as males to have a procedure limited in some way (angulation, spasm, or pain) (OR = 1.86, 95% CI = 1.63-2.13). When defined by depth of examination, females were significantly more likely than males to have a procedure of <50 cm (OR = 1.93, 95% CI = 1.63, 2.29) and were less likely to have an adenomatous polyp or cancer detected (OR = 0.55, 95% CI = 0.42-0.71). The average endoscopy distance for women was 52.3 cm, compared with 55.2 cm in men (p < 0.0001), and the average number of polyps detected in women was 1.4, compared with 1.56 in men (p = 0.003) among patients with at least one polyp. Using multivariable analysis, females were more likely to have an examination of <50 cm compared with men, controlling for age, spasm or pain on examination, previous surgery, angulation of the colon, and type of endoscopist-MD or nonphysician endoscopist (OR = 1.67, 95% CI = 1.41-1.99).

CONCLUSIONS

Women are more likely than men to have a shorter and more limited FS. This is partly owing to increased colonic angulation and pain during the examination. Methods aimed at reducing pain and improving maneuverability in an angulated colon during FS may improve the effectiveness of CRC screening in women.

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.

Rationale for colonoscopy screening and estimated effectiveness in clinical practice

Colonoscopy screening has the highest anticipated level of effectiveness of the available colorectal cancer screening techniques. Its long-term cost-effectiveness is also comparable with or superior to other modalities. Evidence for the expected reduction in colorectal cancer incidence and mortality varies with colonoscopy screening from 50% to 90%, for reasons that are not fully understood. Maintaining a high standard of performance is critical with regard to achieving the highest level of effectiveness possible.

Flexible sigmoidoscopy: an important screening option for average-risk individuals

Colorectal cancer screening techniques should be effective, acceptable to patients, affordable, widely available, and safe. For average-risk adults aged more than 50 years who do not have significant colorectal symptoms, significant family history, or significant predisposing conditions, flexible sigmoidoscopy is an important option for reducing the risk for colorectal cancer, meeting all criteria for an effective and feasible screening modality. This article discusses evidence supporting flexible sigmoidoscopy, practical issues in implementation, and current controversies.

Training general practitioners in flexible sigmoidoscopy to screen for colorectal cancer

BACKGROUND

A screening programme to detect polyps or early carcinoma would significantly reduce the mortality and morbidity of colorectal cancer (CRC). The aims of the present study were to evaluate: (i) the feasibility of training general practitioners in flexible sigmoidoscopy (FS) for CRC screening; (ii) the acceptability of screening by faecal occult blood testing (FOBT) and FS in asymptomatic standard risk Australians aged over 50 years; and (iii) the yield of such screening.

METHODS

Subjects were recruited by general practitioner (GP) referral, newspaper advertisement or by a direct approach to retirement villages. Participants were mailed a FOBT kit and a prescreening questionnaire. Flexible sigmoidoscopy was performed by a GP supervised by an experienced endoscopist. Subjects then completed a second questionnaire. General practitioners were assessed after 50 unassisted procedures.

RESULTS

A total of 264 individuals contacted the study coordinator; 169 were screened. Screening was accepted well by the participants. Fifteen per cent of subjects had polyps and 4% had a positive FOBT. Training in FS was adversely affected by the availability of resources. Three GPs completed 50 unassisted procedures over a 15-month period, but none were able to reliably assess the distal bowel.

CONCLUSIONS

Although the three trainees and their supervisors did not consider that the GPs were adequately trained after 50 unassisted procedures, training was adversely affected by limited resources within the Victorian public hospital system. Screening by FOBT and FS was considered to be acceptable by the patients undergoing these procedures. Existing facilities are not adequate if GPs are to be trained in FS as part of a national CRC screening program.