Screening for colon cancer--can we afford colonoscopy?

Population-based screening for colorectal cancer in Wuhan, China

Fecal DNA test has emerged as a non-invasive alternative for colorectal cancer (CRC) screening in average-risk population. However, there is currently insufficient evidence in China to demonstrate the effectiveness of population-based CRC screening using fecal DNA based test. Here, a large-scale real-world study for CRC screening was implemented in Wuhan, Hubei province, China. A total of 98,683 subjects aged between 45 and 60 years were screened by a fecal DNA test (ColoTect®) which detected methylation status of SDC2, ADHFE1, and PPP2R5C. Participants who tested positive were advised to receive diagnostic colonoscopy. 4449 (4.5%) subjects tested positive for fecal DNA test, and 3200 (71.9%) underwent colonoscopy. Among these, 2347 (73.3%) had abnormal colonoscopy findings, of which 1330 (56.7%) subjects received pathological diagnosis. Detection rates for CRC and advanced precancerous lesions were 1.3% and 2.3%, respectively. Detection rates for nonadvanced adenomas and polyps were 14.0% and 21.6%, respectively. 28.0% of all colonoscopies showed colorectal neoplasm but lack pathological diagnosis. 6.1% showed other abnormalities such as enteritis. In conclusion, preliminary real-world evidence suggested that fecal DNA tests had promising diagnostic yield in population-based CRC screening.

Clinical trial registration

https://www.chictr.org.cn/showproj.html?proj=192838, identifier ChiCTR2300070520.

I-scan optical enhancement for the in vivo prediction of diminutive colorectal polyp histology: Results from a prospective three-phased multicentre trial

Background and aims

Dye-less chromoendoscopy is an emerging technology for colorectal polyp characterization. Herein, we investigated whether the newly introduced I-scan optical enhancement (OE) can accurately predict polyp histology in vivo in real-time.

Methods

In this prospective three-phased study, 84 patients with 230 diminutive colorectal polyps were included. During the first two study phases, five endoscopists assessed whether analysis of polyp colour, surface and vascular pattern under i-scan OE can differentiate in vivo between adenomatous and hyperplastic polyps. Finally, junior and experienced endoscopists (JE, EE, each n = 4) not involved in the prior study phases made a post hoc diagnosis of polyp histology using a static i-scan OE image database. Histopathology was used as a gold-standard in all study phases.

Results

The overall accuracy of i-scan OE for histology prediction was 90% with a sensitivity, specificity, positive (PPV) and negative prediction value (NPV) of 91%, 90%, 86% and 94%, respectively. In high confidence predictions, the diagnostic accuracy increased to 93% with sensitivity, specificity, PPV and NPV of 94%, 91%, 89% and 96%. Colonoscopy surveillance intervals were predicted correctly in ≥ 90% of patients. In the post hoc analysis EE predicted polyp histology under i-scan OE with an overall accuracy of 91%. After a single training session, JE achieved a comparable diagnostic performance for predicting polyp histology with i-scan OE.

Conclusion

The histology of diminutive colorectal polyps can be accurately predicted with i-scan OE in vivo in real-time. Furthermore, polyp differentiation with i-scan OE appears to require only a short learning curve.

Colonoscopy with magnetic control system to navigate the forepart of colonoscope shortens the cecal intubation time

BACKGROUND

Colonoscopy is considered the most effective method for diagnosing colorectal diseases, but its application is sometimes limited due to invasiveness, patient intolerance, and the need for sedation.

OBJECTIVE

The aim of this study was to improve the problem of loop formation and shorten the cecal intubation time of colonoscopy by using a magnetic control system (MCS).

METHODS

Two experienced gastroenterologists, three trainees, and a novice repeated colonoscopy without or with MCS on three colonoscopy training model simulator cases. These cases were divided into introductory (case 2) and challenging levels (cases 4 and 5). The cecal intubation times were recorded.

RESULTS

For all cases, the average cecal intubation times for the experienced gastroenterologists with MCS were significantly shorter than without MCS (case 2: 52.45 vs. 27.65 s, p < 0.001; case 4: 166.7 vs. 120.55 s, p < 0.01; case 5: 130.35 vs. 100.2 s, p < 0.05). Those of the trainees also revealed significantly shorter times with MCS (case 2: 67.27 vs. 51 s, p < 0.01; case 4: 253.27 vs. 170.97 s, p < 0.001; case 5: 144.1 vs. 85.57 s, p < 0.001).

CONCLUSION

Conducting colonoscopy with MCS is safe and smooth, and shortens the cecal intubation time by navigating the forepart of the colonoscope. In addition, all diagnostic and therapeutic benefits of conventional colonoscopy are retained.

Design of near-infrared fluorescent bioactive conjugated functional iron oxide nanoparticles for optical detection of colon cancer

Background

Colon cancer is one of the major causes of death in the Western world. Early detection significantly improves long-term survival for patients with the disease. Near- infrared (NIR) fluorescent nanoparticles hold great promise as contrast agents for tumor detection. NIR offers several advantages for bioimaging compared with fluorescence in the visible spectrum, ie, lower autofluorescence of biological tissues, lower absorbance, and consequently deeper penetration into biomatrices.

Methods and results

NIR fluorescent iron oxide nanoparticles with a narrow size distribution were prepared by nucleation, followed by controlled growth of thin iron oxide films onto cyanine NIR dye conjugated gelatin-iron oxide nuclei. For functionalization, and in order to increase the NIR fluorescence intensity, the NIR fluorescent iron oxide nanoparticles obtained were coated with human serum albumin containing cyanine NIR dye. Leakage of the NIR dye from these nanoparticles into phosphate-buffered saline solution containing 4% albumin was not detected. The work presented here is a feasibility study to test the suitability of iron oxide-human serum albumin NIR fluorescent nanoparticles for optical detection of colon cancer. It demonstrates that encapsulation of NIR fluorescent dye within these nanoparticles significantly reduces photobleaching of the dye. Tumor-targeting ligands, peanut agglutinin and anticarcinoembryonic antigen antibodies (αCEA), were covalently conjugated with the NIR fluorescent iron oxide-human serum albumin nanoparticles via a poly(ethylene glycol) spacer. Specific colon tumor detection was demonstrated in chicken embryo and mouse models for both nonconjugated and the peanut agglutinin-conjugated or αCEA-conjugated NIR fluorescent iron oxide-human serum albumin nanoparticles.

Conclusion

Conjugation of peanut agglutinin or αCEA to the nanoparticles significantly increased the fluorescence intensity of the tagged colon tumor tissues relative to the nonconjugated nanoparticles.

Performance of a colorectal cancer screening protocol in an economically and medically underserved population

The performance of combining fecal immunochemical tests (FITs) and a high-risk factor questionnaire (HRFQ) in colorectal cancer (CRC) screening in economically and medically underserved populations is uncertain. This study investigated the performance of a CRC screening protocol of combining FITs and an HRFQ as primary screening methods in a rural Chinese population. A CRC mass screening was conducted using FITs and an HRFQ as the first and colonoscopy as the second stage of screening in Jiashan, 2007-2009. The target population was 31,963 residents in three communities. The compliance was 84.7% for HRFQ, 76.4% for FITs, and 78.7% for colonoscopy. The detected rates of cancer, adenoma, nonadenomatous polyps, and advanced neoplasm were 2.7%, 14.8%, 5.9%, and 8.9% by FITs, which were higher than those by HRFQ (0.5%, 9.2%, 4.8%, and 3.8%, respectively). There was no significant difference in detected rate for nonadenomatous polyps between FITs and HRFQ. A total of 41.2% adenomas, 53.2% nonadenomatous polyps, and 29.8% advanced neoplasms were detected by HRFQ but missed by FITs. Positive predictive value of the screening protocol of combining FITs and HRFQ for advanced neoplasm was 5.7%, which was higher than FITs alone. Men had a higher prevalence of advanced neoplasm than women. Results indicate that combining FITs and HRFQ as primary screening methods is an efficient CRC screening strategy in economically and medically underserved populations.

Push enteroscopy has a 96% cecal intubation rate in colonoscopies that failed because of redundant colons

BACKGROUND

Performing a complete colonoscopy to the cecum is important for ruling out malignancy and other lesions, but failure rates are significant with a standard colonoscope. A previous study using a push enteroscope for failed colonoscopies had a completion rate of 68.7%.

OBJECTIVE

To improve the cecal intubation rate by using a newer version of a push enteroscope.

DESIGN

Retrospective study at first, then a prospective study.

SETTING

Single-center veterans health care system.

PATIENTS

A total of 47 patients in whom the cecum was not reached with a regular adult colonoscope between January 2007 and December 2010 were included. Those with poor bowel preparation were excluded.

INTERVENTIONS

Repeat colonoscopy using a new version of a push enteroscope.

MAIN OUTCOME MEASUREMENTS

The rate of cecal intubation and additional pathological findings.

RESULTS

The cecum or terminal ileum was reached in 45 patients (96%). Additional significant pathological findings in the previously unexamined colon were seen in 18 patients (38%).

LIMITATIONS

Small sample size, lack of comparison with other endoscopes.

CONCLUSIONS

Colonoscopy with a push enteroscope could be advanced to either the terminal ileum or cecum in 96% of patients, which is one of the highest known completion rates in patients in whom colonoscopy failed. Clinical management changed in all patients with additional findings.

CT colonography for postoperative surveillance after curative gastrectomy in patients with gastric cancer

AIM

The purpose was to evaluate the diagnostic role of contrast-enhanced CT colonography (CTC) for follow-up of colorectal cancer screening after curative gastrectomy in patients with gastric adenocarcinomas.

MATERIALS AND METHODS

Contrast-enhanced CTC was performed as a substitute for routine follow-up CT for the detection of recurrent lesions in 700 consecutive patients who underwent curative surgery for gastric adenocarcinomas. Prospectively, patients with polyps measuring 6 mm or larger on CTC were referred for optical colonoscopy. Clinical and radiologic follow-up with respect to detection of polyp and recurrent lesion was retrospectively assessed.

RESULTS

Colorectal polyps measuring 6 mm or larger were identified by CTC in 104 (14.9%) of the 700 patients. Optical colonoscopy was recommended to these patients and was performed in 72 cases. True positive lesions were identified in 62 of the 72 patients (per-patient positive predictive value: 86.1%). The diagnostic yield for primary colonic malignancies was 1.6% (11/700). Recurrent lesions of gastric cancer were also detected in eight patients (1.1%).

CONCLUSION

In patients who undergo gastrectomy due to gastric adenocarcinoma, contrast-enhanced CTC may offer a unique advantage by allowing simultaneous colorectal cancer screening in addition to its routine role of detecting recurrent lesions during follow-up.

Colon cancer screening update and management of the malignant polyp

Colorectal carcinoma is common, but screening for this cancer has found less acceptance with the public than screening for breast, prostate, and cervical cancer. Available methods include fecal occult blood tests (FOBTs), flexible sigmoidoscopy (FOS), double-contrast barium enema, colonoscopy, computed tomographic colography, and fecal DNA. Evaluation of these options demonstrates that colonoscopy at ages 55 and 65 offers the best combination of reduction in colorectal cancer at the lowest cost. However, when compliance with screening recommendations is very high, costs are high, and the proportion of cancers arising from adenomas is low, the combination of FOS and FOBT is most cost effective. Malignant polyps look friable and irregular and feel hard. Sessile malignant polyps need to be treated by formal resection. Patients with pedunculated polyps with favorable histology (clear margin, well or moderately differentiated, no lymphovascular invasion) can be observed, and those whose polyps show unfavorable histology should have the polyp-bearing segment of colon resected along with its draining lymph nodes.

Computed tomography colonography: advantages and main points

AIM: To evaluate the advantages of computed tomography (CT) colonography and to summarize the main points for CT colonography.

METHODS: Multislice CT colonography was performed in 46 patients with suspected colonic diseases, of which some patients underwent CT colonography in both the supine and prone positions. Different post-processing techniques such as multiplanar reformation (MPR), CT virtual colonoscopy, shaded surface display, Raysum and virtual pathology were employed to evaluate the mucosal and peripheral appearance of the colon.

RESULTS: Eleven patients showed negative results. Eleven patients were diagnosed as colon polyps, of which one had familial colonic polyposis. Sixteen patients were diagnosed as malignant lesions, of which 2 showed local thickening of the colon wall and 14 showed mass lesions. Five patients were diagnosed as inflammatory diseases.

CONCLUSION: The location, size, density and adjacent invasion of colon lesions can be evaluated objectively by CT colonography. The main points for CT colonography include sufficient cleansing of the colon lumen, adequate air injection, and combination of multiple post-processing techniques.

Performance value of high risk factors in colorectal cancer screening in China

AIM: To analyze the performance value of high risk factors in population-based colorectal cancer (CRC) screening in China.

METHODS: We compared the performance value of the immunochemical fecal occult blood test (iFOBT) and other high risk factors questionnaire in a population sample of 13 214 community residents who completed both the iFOBT and questionnaire investigation. Patients with either a positive iFOBT and/or questionnaire were regarded as a high risk population and those eligible were asked to undergo colonoscopy.

RESULTS: The iFOBT had the highest positive predictive value and negative predictive value in screening for advanced neoplasia. The iFOBT had the highest sensitivity, lowest number of extra false positive results associated with the detection of one extra abnormality for screening advanced neoplasias and adenomas. A history of chronic cholecystitis or cholecystectomy, chronic appendicitis or appendectomy, and chronic diarrhea also had a higher sensitivity than a history of adenomatous polyps in screening for advanced neoplasias and adenomas. The sensitivity of a history of chronic cholecystitis or cholecystectomy was highest among the 10 high risk factors in screening for non-adenomatous polyps. A history of chronic appendicitis or appendectomy, chronic constipation, chronic diarrhea, mucous and bloody stool, CRC in first degree relatives, malignant tumor and a positive iFOBT also had higher sensitivities than a history of adenomas polyps in screening for non-adenomatous polyps. Except for a history of malignant tumor in screening for non-adenomatous polyps, the gain in sensitivity was associated with an increase in extra false positive results associated with the detection of one extra abnormality.

CONCLUSION: The iFOBT may be the best marker for screening for advanced neoplasias and adenomas. Some unique high risk factors may play an important role in CRC screening in China.

A prospective evaluation of the feasibility of primary screening with unsedated colonoscopy

BACKGROUND

Colonoscopy is the most effective screening tool for colorectal cancer. In Taiwan, colonoscopy is used much less than sigmoidoscopy for screening because sedation significantly increases the cost and is not readily available, and unsedated colonoscopy is considered to be poorly tolerated. However, unsedated colonoscopy has been shown to be well accepted and may improve the cost-effectiveness and access to colonoscopic screening.

OBJECTIVES

To compare the feasibility of unsedated colonoscopy and sigmoidoscopy for primary screening and to analyze factors associated with acceptance of the procedures and need for sedation.

DESIGN

Single center, prospective.

SETTING

National Taiwan University Medical Center. POPULATION AND INTERVENTIONS: A consecutive series of 261 subjects without history of colonoscopy or sigmoidoscopy who underwent unsedated colonoscopy (n = 176) or sigmoidoscopy (n = 85) for primary screening.

MAIN OUTCOME MEASUREMENTS

Pain scores, acceptance, and need for sedation.

RESULTS

No significant differences in pain, acceptance, and need for sedation were found between the colonoscopy and sigmoidoscopy groups. Only 9.6% in the colonoscopy group and 10.1% in the sigmoidoscopy group considered sedation necessary. Multivariate analyses revealed that the examinee's sex and the endoscopist, but not the type of endoscopic examination, were associated with the severity of pain and need for sedation.

LIMITATIONS

Nonrandomized study design.

CONCLUSIONS

Unsedated colonoscopy for primary screening is well accepted in nine tenths of examinees who accept this option and is similar to sigmoidoscopy in pain, acceptance, and need for sedation. Primary screening with unsedated colonoscopy is feasible, as with sigmoidoscopy.

Fecal DNA screening in colorectal cancer

Colorectal cancer (CRC) is the third most common type of cancer diagnosed in Canada, and is the leading cause of cancer-related deaths in nonsmokers. Although CRC is considered to be 90% curable if detected early, the majority of patients present with advanced stage III or IV disease. An effective screening test may significantly decrease disease burden. The present paper examines the rationale and potential of fecal DNA testing as an alternative and adjunct to other CRC screening tests. The most efficacious fecal DNA test developed to date has a sensitivity and specificity of 87.5% and 82%, respectively. The approach has a higher positive predictive value than the currently used fecal occult blood test and offers a noninvasive option to patients. It is not reliant on the presence of bleeding, which may be intermittent or altogether absent. The test is now commercially available and is supported by a number of American insurers. Current challenges include cost reduction and demonstration of mortality benefit in a rigorous clinical trial. Despite current challenges, fecal DNA testing is worth pursuing. Both the American Gastroenterological Society and the American Cancer Society maintain that molecular testing is in its infancy but is promising. Fecal DNA testing has the potential to be an exciting addition to the current armament of CRC screening options.

Q&A on diagnosis, screening and follow-up of colorectal neoplasia

The impressive and brisk evolution of medical science prevents many physicians from a thorough update on all the research fields. Colorectal cancer diagnosis, screening and follow-up is well known to require a multi-disciplinary approach, as it is faced by several specialties such as primary care physicians, gastroenterologists, non-gastroenterologist internists, radiologists and surgeons. To address this issue in a mutual perspective, we focused on the main points of the epidemiology, diagnosis, screening and follow-up of colorectal neoplasia by using a simple "Question & Answers" structure.

Value of a negative colonoscopy in patients with non-specific gastrointestinal symptoms

BACKGROUND

The yield of colonoscopy for neoplasia among patients aged <50 years with non-specific gastrointestinal symptoms is very low. However, a negative colonoscopy may benefit these patients by decreasing anxiety and thereby reducing subsequent health resource utilization. This study sought to characterize the effect of a negative colonoscopy in terms of: (i) reassurance value; and (ii) decreasing health resource utilization, in patients under 50 years of age with non-specific gastrointestinal symptoms (abdominal pain, diarrhea, constipation).

METHODS

Consecutive patients, aged 18-49 years, undergoing their first colonoscopy for evaluation of non-specific gastrointestinal symptoms (abdominal pain, diarrhea, constipation) were prospectively enrolled. Health-related anxiety was evaluated before and immediately after disclosure of the negative result of colonoscopy using a validated questionnaire and at 1-, 2- and 6-month intervals postcolonoscopy by telephone follow-up. Symptom scores and health resource utilization were assessed prior to colonoscopy and at 2 and 6 months postcolonoscopy.

RESULTS

Fifty-nine patients were prospectively enrolled. Mean health anxiety score declined immediately after colonoscopy from 20.6 to 17.8. Sustained improvement was seen in anxiety scores at 1, 2 and 6 months. Symptom scores also decreased at 6 months for abdominal pain (2.3 to 1.5), diarrhea (2.3 to 1.6) and constipation (1.9 to 1.6). There was a significant decrease in all four measures of health resource utilization at 6 months postcolonoscopy.

CONCLUSIONS

Despite minimal diagnostic yield, colonoscopy for non-specific gastrointestinal symptoms in patients <50 years of age is associated with a decline in health-related anxiety and symptom scores. These effects appear to translate into reductions in health resource utilization.

Screening for colorectal cancer in average-risk Chinese population using a mixed strategy with sigmoidoscopy and colonoscopy

PURPOSE

The Chinese population has been shown to have more distal colonic neoplasm and a higher sensitivity of sigmoidoscopic screening strategy for detecting advanced neoplasm compared with Western populations. This study was designed to evaluate the efficacy of the mixed screening strategy with sigmoidoscopy and colonoscopy in the average-risk Chinese population.

METHODS

Consecutive average-risk adults aged >/=50 years who underwent colonoscopy as part of a health checkup were enrolled. Data were analyzed in a hypothetical graded screening strategy using colonoscopy on patients older than a certain cutoff age or those with distal sentinel polyps. The sensitivity in detecting advanced colonic neoplasm and advanced proximal neoplasm as well as the number of colonoscopies reduced were assessed.

RESULTS

Of the 2,106 persons eligible for analysis, 1,193 (56.6 percent) were males and 913 (43.4 percent) were females. If the cutoff ages were 55, 60, and 65 years, and adenoma detected in the distal colon was the indication for subsequent colonoscopy, the detection rate for 1) advanced colonic neoplasm in the entire colon would be 94, 93.1, and 83.6 percent, respectively, and 2) advanced proximal neoplasm would be 84.8, 82.6, and 58.7 percent, respectively. The number of colonoscopic procedures could be reduced by 28, 48, and 65 percent if the cutoff ages were 55, 60, and 65 years, respectively.

CONCLUSIONS

The mixed screening strategy using a cutoff age at 60 years and distal adenoma as the sentinel lesion is an effective screening program in the average-risk Chinese population.

Comparison of a brush-sampling fecal immunochemical test for hemoglobin with a sensitive guaiac-based fecal occult blood test in detection of colorectal neoplasia

BACKGROUND

Fecal immunochemical tests (FIT) are an advanced fecal occult blood test (FOBT) technology that reduces barriers to population screening by simplifying the logistics of stool-sampling. The current study was conducted to undertake a paired comparison of a sensitive guaiac FOBT (GFOBT; Hemoccult II Sensa, Beckman Coulter, Fullerton, CA) with a brush-sampling FIT (InSure; Enterix, North Ryde, NSW, Australia), to determine whether this FIT improves detection of significant neoplasia.

METHODS

Individuals sampled consecutive stools, at home, with both FIT and GFOBT sampling devices while following dietary restrictions appropriate for GFOBT. Study populations included a screening cohort (n = 2351) and a symptomatic diagnostic group (n = 161). Paired comparison of positivity rates was undertaken in those found to have cancer and/or significant adenoma (high-grade dysplasia, villous change, > or =10 mm, serrated histology or > or =3 polyps), benign pathology, or no pathology.

RESULTS

Combined results for both cohorts showed that the FIT returned a true-positive result significantly more often in cancer (n = 24; 87.5% vs. 54.2%) and in significant adenomas (n = 61; 42.6% vs. 23.0%). Of all UICC Stage I cancers, the FIT was positive in 12 of 13 compared with 4 of 13 with the GFOBT (P = .002). In analyses of just the screening cohort, the FIT remained significantly better at detecting cancers and significant adenomas; the false-positive rate for any neoplasia was marginally higher with the FIT than the GFOBT (3.4% vs. 2.5%; 95% CI of difference, 0-1.8%), whereas positive predictive values were 41.9% and 40.4%, respectively.

CONCLUSIONS

This brush-sampling FIT is more sensitive for cancers and significant adenomas than a sensitive GFOBT. As such, it should deliver greater reductions in colorectal cancer mortality and incidence than the GFOBT.

Screening tests for colorectal cancer: A menu of options remains relevant

Until the early 1990s, no evidence was available to show that screening for colorectal cancer (CRC) by any means actually saved lives. Subsequently, sufficient evidence for the efficacy of fecal occult blood testing (FOBT) and flexible sigmoidoscopy allowed the US Preventive Services Task Force to publish guidelines for CRC screening. Since that time the major organizations in the United States concerned with screening guidelines have recommended a menu of screening test options including FOBT, flexible sigmoidoscopy, flexible sigmoidoscopy plus FOBT, barium enema, and colonoscopy. No organization, except for the American College of Gastroenterology, has designated any one of these options as "preferred." Nevertheless, the lay press and many gastroenterology opinion leaders have encouraged Americans to have only one test--colonoscopy. In this review we discuss the rationale for caution in designating one screening test as "the best" and present information on how new stool and serum tests can be used effectively to screen for CRC.

Risk stratification for colon neoplasia: screening strategies using colonoscopy and computerized tomographic colonography

BACKGROUND & AIMS

We developed a risk index to identify low-risk patients who may be screened for colorectal cancer with computerized tomographic colonography (CTC) instead of colonoscopy.

METHODS

Asymptomatic persons aged 50 years or older who had undergone screening colonoscopy were randomized retrospectively to derivation (n = 1512) and validation (n = 1493) subgroups. We developed a risk index (based on age, sex, and family history) from the derivation group. The expected results of 3 screening strategies--universal colonoscopy, universal CTC, and a stratified strategy of colonoscopy for high-risk and CTC for low-risk patients--were then compared. Outcomes for the 3 strategies were extrapolated from the known colonic findings in each patient, using sensitivity/specificity values for CTC from the medical literature. Results were validated in the validation subgroup.

RESULTS

In the derivation subgroup, universal colonoscopy detected 94% of advanced neoplasia and universal CTC detected only 70% and resulted in the largest total number of procedures and number of patients undergoing both procedures. The stratified strategy detected 92% of advanced neoplasia, requiring colonoscopy in 68% and CTC in 36% of patients, with only 4% having to undergo both procedures. In the validation subgroup, universal colonoscopy detected 94% and universal CTC detected 71% of advanced neoplasia, whereas the stratified strategy detected 89%, requiring colonoscopy in 64% and CTC in 40%. Unlike universal CTC, the stratified strategy was independent of assumptions for CTC sensitivity, specificity, and threshold for colonoscopy.

CONCLUSIONS

The stratified strategy based on our risk index may optimize the yield of colonoscopic resources and reduce the number of patients undergoing colonoscopy.

Incident rates of colonic neoplasia in older patients: when should we stop screening?

INTRODUCTION

Current guidelines endorse colon cancer screening every 5-10 years in patients over 50 years of age. However, there is no consensus regarding what age is appropriate to stop screening. The aim of this study was to characterize neoplasia occurrence/recurrence in a large cohort of patients > or =70 years of age undergoing colonoscopy.

METHODS

The Mayo Rochester endoscopic database was reviewed to determine the incidence of colonic neoplasia in patients > or =70 years undergoing two colonoscopies at least 12 months apart between January 1996 and December 2000. Patients were classified based on (i) age: 70-74, 75-79, > or =80 years; and (ii) polyp detection on initial examination, that is, subsequent examination for screening or surveillance.

RESULTS

Overall, 1353 patients underwent two colonoscopies at least 12 months apart (median interval 140 weeks) with removal of polyp on initial examination in 726 (53.7%) patients (surveillance cohort). On subsequent endoscopy, polyps > or =10 mm were detected in 54 (4.0%) and cancer in 13 (1.0%) patients. All age groups were well matched with respect to detection of neoplasia on index examination (P = 0.9) and polyp size on initial colonoscopy among the surveillance group (P = 0.9). Using a Cox proportional hazards model, adjusted hazard ratios (95% confidence interval [CI]) for neoplasia (polyps > or =10 mm) were: 2.0 (1.50-2.73, P < 0.0001) (surveillance vs screening), 1.33 (0.96-1.79, P = 0.08) (> or =80 vs 70-74), and 1.05 (0.78-1.38, P = 0.75) (75-79 vs 70-74). Adjusted hazard ratios for development of cancer were: 1.87 (1.03-3.97, P = 0.04) (surveillance vs screening), 1.73 (0.84-3.56, P = 0.13) (> or =80 vs 70-74), and 1.38 (0.71-2.77, P = 0.34) (75-79 vs 70-74).

CONCLUSIONS

Prior history of neoplasia remains a strong risk factor for colorectal neoplasia development in elderly patients and should be considered when deciding the need for continuing screening/surveillance. Incident neoplasia rates in a previously screened elderly population rise slowly with advancing age although cancer rates rise more sharply. Therefore, screening still retains a role in elderly patients; however, clinical judgment is still required to individualize screening practice. As the risk of competing comorbid illnesses continues to increase over time, the threshold to perform colon screening should increase accordingly.

Surgeon-initiated screening colonoscopy program based on SAGES and ASCRS recommendations in a general surgery practice

BACKGROUND

This study aimed to determine the utility of a screening colonoscopy program initiated by general surgeons in an academic center.

METHODS

New patients presenting to three general surgeons who met screening colonoscopy indications were asked whether they had undergone colorectal cancer (CRC) screening. The patients who had not undergone CRC screening were offered screening colonoscopies or referred to their gastroenterologists.

RESULTS

In the first 9-month period of the program, 200 patients who met the Society of American Gastrointestinal and Endoscopic Surgeons/American Society of Colon and Rectal Surgeons indications for CRC screening were asked whether they had undergone screenings. Only 46% (n = 92) reported any prior appropriate screenings. Of the patients who elected CRC screening by the surgeons, 55 underwent full colonoscopies (2 concurrently with hemorrhoidectomies), and 2 had flexible sigmoidoscopies. As a result of screening, 10 patients (18%) required treatment: 7 had polypectomies, 2 had partial colectomies, and 1 with an indication for surgery deferred treatment.

CONCLUSIONS

Most of the patients presenting to the general surgeon likely have not had CRC screening, and diligence in making appropriate recommendations should be routine. Colonoscopic findings requiring intervention are not insignificant.

CT colonography: where have we been and where are we going?

Over the past decade, computed tomographic (CT) colonography (also known as virtual colonoscopy) has been used to investigate the colon for colorectal neoplasia. Numerous clinical and technical advances have allowed CT colonography to advance slowly from a research tool to a viable option for colorectal cancer screening. However, substantial controversy remains among radiologists, gastroenterologists, and other clinicians with regard to the current role of CT colonography in clinical practice. On the one hand, all agree there is much excitement about a noninvasive imaging examination that can reliably depict clinically important colorectal lesions. However, this is tempered by results from several recent studies that show the sensitivity of CT colonography may not be as great when performed and the images interpreted by radiologists without expertise and training. The potential to miss important lesions exists; moreover, if polyps cannot be differentiated from folds and residual fecal matter, unnecessary colonoscopy will be performed. In this review, current issues will be discussed regarding colon cancer and the established and reimbursed strategies to screen for it and the past, current, and potential future role of CT colonography.

Incident rates of colonic neoplasia according to age and gender: implications for surveillance colonoscopy intervals

INTRODUCTION

Current guidelines endorse surveillance colonoscopy at 3 to 5 years following initial detection of neoplasia. However, individual patients' risks may vary according to age and gender. This study aimed to characterize neoplasia recurrence in a large patient cohort undergoing surveillance colonoscopy.

METHODS

All patients undergoing two colonoscopies at least 12 months apart between 1996 and 2000, with detection and removal of a polyp on the index colonoscopy, were identified using our endoscopic database to determine the incidence of colonic neoplasia. Patients were classified according to age (<50, 50-64, 65-74, > or =75 years) and gender.

RESULTS

Overall, 1803 patients underwent two colonoscopies at least 12 months apart (median interval, 140 weeks) with removal of a polyp on initial examination. Polyps > or =5 mm were detected in 334 (19%) patients and polyps > or =10 mm in 105 (6%) on subsequent endoscopy. All age and gender groups were well matched with respect to size of polyp detected on initial colonoscopy (P = 0.2). Kaplan-Meier curves and a Cox proportional hazards model demonstrated similar rates of neoplasia recurrence for all patients irrespective of age and gender.

CONCLUSIONS

Similar rates of neoplasia recurrence were observed among patients of different gender and age groups on surveillance colonoscopy. From a health resource utilization perspective, these findings support current recommendations for similar surveillance intervals for patients regardless of age and gender.

Market for colorectal cancer screening by endoscopy in the United States

In the United States, colorectal cancer (CRC) ranks third among all cancer sites in incidence, and second in cancer-related mortality. Although screening reduces CRC incidence and mortality, current screening rates among the average-risk population are low. The traditional way of promoting CRC screening has been to educate healthcare providers and the public on its benefits, available screening procedures, and current guidelines. In this paper, we focus on economics and provide an overview of some key factors that affect the demand for and the supply of CRC screening by endoscopy. Factors affecting the demand for endoscopic CRC screening include the number of people for whom screening is recommended, consumers' income and health insurance status, time and travel costs, prices of non-endoscopic CRC screening tests, and personal preferences and perceived quality of care. Factors influencing the supply of endoscopic screening include the availability of endoscopic providers, increased efficiency, procedure costs, current reimbursement rates for endoscopic procedures, and technical progress. The volume of screening tests in the market is determined jointly by the collective demand and supply decisions of consumers and providers. The discussion includes policy implications for the current effort to promote widespread use of CRC screening in the United States.

From Colonic Polyps to Colon Cancer: Pathophysiology, Clinical Presentation, and Diagnosis

Epidemiologists, basic researchers, clinicians, and public health administrators unite! Develop and implement a simple, safe, and effective preventive and screening test for colon cancer. The public will willingly and enthusiastically accept such a test. Many thousands of lives are at stake every year.

The pathophysiology, clinical presentation, and diagnosis of colon cancer and adenomatous polyps

A review of the pathophysiology, clinical presentation, and diagnosis of colon cancer and colonic polyps is important and timely. This field is rapidly changing because of breakthroughs in the molecular basis of carcinogenesis and in the technology for colon cancer detection and treatment. This article reviews colon cancer and colonic polyps, with a focus on recent dramatic advances, to help the pri-mary care physician and internist appropriately refer patients for screening colonoscopy and intelligently evaluate colonoscopic findings to reduce the mortality from this cancer.

Value of Fentanyl in Flexible Sigmoidoscopy

Studies have recorded significant patient discomfort during flexible sigmoidoscopy when it is performed without sedation/analgesia. This study observed whether a single dose of 50 mcg intravenous fentanyl reduces pain, improving compliance, acceptability, and completion rates. In a prospective study, 109 consecutive patients were offered the option of 50 mcg intravenous fentanyl or no analgesia. Patient's pre-procedure expectations, objective pain scores, and willingness to undergo a subsequent procedure using the same technique were recorded. Endoscopist recorded the success, complications, and objective pain scores for each patient. Of the 46 patients (42%) choosing fentanyl, 9 (20%) experienced moderate/severe pain as against 26 (41%) of the 63 patients (58%) opting for no analgesia (p < 0.05). Further, 52% receiving fentanyl had a significantly better experience compared to their pre-procedure expectations as against 33% who received no analgesia (p < 0.05). No patient receiving fentanyl expressed unwillingness to undergo the procedure again using the same technique, whereas 16 (25%) of those receiving no analgesia indicated they would not (p < 0.01). Endoscopists recorded moderate/severe pain in 13 patients (12%), whereas 35 patients (32%) recorded moderate/severe pain (p < 0.001). Analgesia for endoscopy should involve patient choice. However, a single dose of 50 mcg fentanyl reduced patient discomfort and improved satisfaction. It appeared safe and likely to improve patient compliance and acceptability for flexible sigmoidoscopy.

Community-based screening by colonoscopy or computed tomographic colonography in asymptomatic average-risk subjects

OBJECTIVES

Visualizing the entire colorectum in screening is an advantage of colonoscopy, and also computed tomographic (CT) colonography, another potentially suitable screening test. Our objective was to compare screening CT colonography and colonoscopy in an asymptomatic average-risk population, and to determine whether providing a choice of tests increased participation.

METHODS

One thousand and four hundred subjects from the general community, randomly selected from the parliamentary electoral roll, were allocated one of three screening groups: colonoscopy, CT colonography, or a choice of these tests, and were sent an institutional letter of invitation. Those with symptoms, colorectal cancer in first-degree relatives, or colonoscopy within 5 yr were ineligible. Outcome measures were participation, acceptability of screening, and yield for advanced colorectal neoplasia in participants.

RESULTS

Of the subjects, 24.9% were ineligible; the overall participation rate was 18.2% (184/1,009). Participation in each screening group was not different. Both tests were accompanied by the same high levels of acceptability; most participants found colonoscopy (87%) and CT colonography (67%, p < 0.001) less unpleasant than expected. About 29% (26/89) CT colonography subjects had a positive screening test. The yield of advanced colorectal neoplasia was 8.7% (95% CI 5-14%), with no difference in yield between tests.

CONCLUSION

Colorectal neoplasia screening by colonoscopy or CT colonography was associated with modest participation, high levels of acceptability, and similar yield for advanced colorectal neoplasia. Providing a choice of test did not increase participation.

Cancer control in women. Update 2003

The global cancer burden in women appeared to be increasing quickly at the end of the twentieth century with notable increases in the absolute numbers of cases of breast, cervix, lung and colorectal cancer of concern. However, prospects for cancer control in women appear to be good within our current knowledge and deserve close attention. Rates of lung cancer in women are increasing substantially in many countries and seem set to overtake breast cancer as the commonest form of cancer death in women in many parts of the world. These changes are due to the effects of cigarette smoking, a habit which women widely embraced during the second half of the last century. The high levels of smoking current in young women, which have yet to have their full inpact on death rates, constitute an important hazard not only for future cancer risks but for several other important causes of death. Although the breast is the commonest form of cancer in women in most western countries, the etiology of this disease remains elusive and preventable causes remain to be identified. Endogenous hormones also appear to have a role in cancer risk in women: oral contraceptives seem to increase slightly the risk of breast cancer in users in the use, and in the immediate post-use, period, but ten years after cessation the risk returns to that of never users. Oral contraceptive usage also appears to be protective against ovarian and endometrial cancer. The use of Hormonal Replacement Therapy (HRT) appears to increase the risk of endometrial cancer and a positive association with breast cancer risk appears to exist. Within the current knowledge of the epidemiology of cancer in women, the most important Cancer Control strategy is the prevention of cigarette smoking and the increase in the prevalence of adult women quitting smoking. Screening has also shown to be effective in reducing incidence and mortality of cervix cancer and mortality from breast and colorectal cancer. Although more work is needed, it is becoming clear that there could be an important role of HPV testing to further enhance cervix cancer screening.

Colorectal polyps and cancers in asymptomatic average-risk patients: evaluation with CT colonography

PURPOSE

To compare thin-section multi-detector row computed tomographic (CT) colonography with conventional colonoscopy in the evaluation of colorectal polyps and cancer in asymptomatic average-risk patients.

MATERIALS AND METHODS

Sixty-eight asymptomatic men (age > 50 years) scheduled to undergo screening colonoscopy were enrolled in this study. CT colonography was followed by conventional colonoscopy, performed on the same day. Supine and prone CT colonography were performed after colonic insufflation with room air. A gastroenterologist measured all polyps, which were categorized as 1-5, 6-9, or over 10 mm. Biopsy and histologic evaluation were performed of all polyps. CT colonography and colonoscopy results were compared for location, size, and morphology of detected lesions. Point estimates and 95% CIs were provided for specificity and sensitivity of CT by using results at conventional colonoscopy as the reference standard.

RESULTS

At colonoscopy, 98 polyps were identified in 39 patients; 21 (21.4%) of 98 were detected at CT colonography. Sensitivity was 11.5% (nine of 78) for polyps 1-5 mm, 52.9% (nine of 17) for polyps 6-9 mm, and 100% (three of three) for polyps over 10 mm. Results at colonoscopy were normal in 29 (42.6%) of 68 patients; at CT colonography, results were correctly identified as normal in 26 of these 29 patients. In one of these patients, a lesion larger than 10 mm was detected at CT colonography. The per-patient specificity of CT was 89.7% (26 of 29; 95% CI: 72.7%, 97.8%). The mean time for CT image interpretation was 9 minutes.

CONCLUSION

In patients at average risk for colorectal cancer, CT colonography is a sensitive and specific screening test for detecting polyps 10 mm or larger; the sensitivity for detecting smaller polyps is decreased. Examination findings can be interpreted in a clinically feasible amount of time.

[Distribution of polyps in the inside region of Vizcaya (Spain): implications for diagnostic tests and colorectal cancer screening]

INTRODUCTION

The importance of colonic polyp is increasing because colorectal cancer (CRC) screening is based on their identification. However, consensus is lacking on which technique should be used in CRC screening, whether colonoscopy or other methods such as sigmoidoscopy, which shows good sensitivity only in distal segments of the colon. We studied the characteristics and localization of polyps in our environment to verify their tendency to change localization and determine the implications of this in screening.

MATERIAL AND METHODS

We reviewed the prevalence and characteristics of colonic polyps in 3604 patients who underwent colonoscopy for various causes in our service, as well as their distribution in 837 patients with a diagnosis of polyps who underwent complete colonoscopy. Localization proximal or distal to the splenic flexure and polyp size (less than or more than 1 cm) were analyzed.

RESULTS

Polyps were found in 28.3% of 3604 patients (11.7% showed polyps > or = 1 cm). Of the 837 patients who underwent complete colonoscopy, proximal polyps were found in 44.9% (14.6% showed polyps > or = 1 cm), while distal polyps were found in 79.9% (30.3% showed polyps > or = 1 cm). Both proximal and distal polyps were found in 24.8%. The probability of finding both proximal and distal lesions was 31%. Proximal lesions without distal lesions were found in 20% of the patients (5.6% presented polyps > or = 1 cm), and consequently sigmoidoscopy would miss 15.6% of polyps > or = 1 cm.

CONCLUSIONS

A relatively high percentage of patients with proximal polyps > or = 1 cm would remain undiagnosed if complete colonoscopy were only performed in patients with distal polyps. Because of the well-known increase in the frequency of proximal polyps and because a considerable number of these present without distal sentinel lesions, there are increasing arguments for considering colonoscopy as the basic technique for CRC screening.

Screening for colorectal cancer on the front line

OBJECTIVE

The aim of this study was to assess knowledge, beliefs, and practices of primary care clinicians regarding colorectal cancer screening.

METHODS

We surveyed 77 primary care providers in six clinics in central Massachusetts to evaluate several factors related to colorectal cancer screening.

RESULTS

Most agreed with guidelines for fecal occult blood test (97%) and sigmoidoscopy (87%), which were reported commonly as usual practice. Although the majority (86%) recommended colonoscopy as a colorectal cancer screening test, it was infrequently reported as usual practice. Also, 36% considered barium enema a colorectal cancer screening option, and it was rarely reported as usual practice. Despite lack of evidence supporting effectiveness, digital rectal examinations and in-office fecal occult blood test were commonly reported as usual practice. However, these were usually reported in combination with a guideline-endorsed testing option. Although only 10% reported that fecal occult blood test/home was frequently refused, 60% reported sigmoidoscopy was. Frequently cited patient barriers to sigmoidoscopy compliance included fear the procedure would hurt and that patients assume symptoms occur if there is a problem. Perceptions of health systems barriers to sigmoidoscopy were less strong.

CONCLUSIONS

Most providers recommended guideline-endorsed colorectal cancer screening. However, patient refusal for sigmoidoscopy was common. Results indicate that multiple levels of intervention, including patient and provider education and systems strategies, may help increase prevalence.

Colorectal cancer screening: clinical applications

Screening for colorectal cancer reduces mortality in individuals aged 50 years or older. A number of screening tests, including fecal occult blood tests, sigmoidoscopy, double-contrast barium enema, and colonoscopy, are recommended by professional organizations for colorectal cancer screening, yet the rates of colorectal cancer screening remain low. Questions regarding the quality of evidence for each screening test, whether screening for individuals at higher risk should be modified, the availability of the tests, and cost-effectiveness are addressed. Many potential barriers to colorectal cancer screening exist for the patient and the physician. Strategies to increase compliance for colorectal cancer screening are proposed.

Risk of perforation after colonoscopy and sigmoidoscopy: a population-based study

BACKGROUND

Although the risk of bowel perforation is often cited as a major factor in the choice between colonoscopy and sigmoidoscopy for colorectal screening, good estimates of the absolute and relative risks of perforation are lacking.

METHODS

We used a large population-based cohort that consisted of a random sample of 5% of Medicare beneficiaries living in regions of the United States covered by the Surveillance, Epidemiology, and End Results (SEER) Program registries to determine rates of perforation in people aged 65 years and older. We identified individuals who were cancer-free and had undergone colonoscopy or sigmoidoscopy between 1991 and 1998, calculated both the incidence and risk of perforation within 7 days of the procedure, and explored the impact on incidence and risk of perforation of age, race/ethnicity, sex, comorbidities, and indication for the procedure. We also estimated the risk of death after perforation. Risks were calculated with odds ratios (ORs) and 95% confidence intervals (CIs). All statistical tests were two-sided.

RESULTS

There were 77 perforations after 39 286 colonoscopies (incidence = 1.96/1000 procedures) and 31 perforations after 35 298 sigmoidoscopies (incidence = 0.88/1000 procedures). After adjustment, the OR for perforation from colonoscopy relative to perforation from sigmoidoscopy was 1.8 (95% CI = 1.2 to 2.8). Risk of perforation from either procedure increased in association with increasing age (P(trend)<.001 for both procedures) and the presence of two or more comorbidities (P(trend)<.001 for colonoscopy and P(trend) =.03 for sigmoidoscopy). Compared with those who were endoscopied and did not have a perforation, the risk of death was statistically significantly increased for those who had a perforation after either colonoscopy (OR = 9.0, 95% CI = 3.0 to 27.3) or sigmoidoscopy (OR = 8.8, 95% CI = 1.6 to 48.5). The risk of perforation after colonoscopy, especially for screening procedures, declined during the 8-year study period.

CONCLUSIONS

The risk of perforation after colonoscopy is approximately double that after sigmoidoscopy, but this difference appears to be decreasing. These observations should be useful to clinicians making screening and diagnostic decisions for individual patients and to policy officials setting guidelines for colorectal cancer screening programs.

Volume and yield of screening colonoscopy at a tertiary medical center after change in medicare reimbursement

OBJECTIVE

Starting July 1, 2001, Medicare began to reimburse for screening colonoscopy in asymptomatic adults older than 50 yr with no risk factors for colorectal cancer. We sought to determine the short-term impact of the change in Medicare reimbursement on the demand for and yield of screening colonoscopy at our tertiary institution.

METHODS

Asymptomatic patients older than 50 referred for first screening colonoscopy after the change in Medicare reimbursement from July 1, 2001 to December 31, 2001 were compared with a similar cohort screened before Medicare coverage for a family history of cancer or polyps during the same months the previous year (July 1, 2000 to December 31, 2000). Patient demographics, number, size, location, and histology of polyps/cancers for these screening colonoscopies were collected.

RESULTS

A total of 1282 colonoscopies were performed in our institution from July 1, 2001 to December 31, 2001, 257 (20%) for screening. During the same months in the previous year, 121 of 938 colonoscopies (12.9%) were for screening (p < 0.01). This was a 55% increase in the percentage of colonoscopies performed for screening, and a 112% increase in the number of screening colonoscopies. Patients screened after the change in Medicare reimbursement were on average 5 yr older compared with patients of the previous year (62 +/- 10 [mean +/- SD] vs 56 +/- 9 yr; p < 0.01). A total of 61 screening colonoscopies (24%) performed after the change in Medicare reimbursement had adenomatous lesions, compared with 25 (21%) screened for family history (p = ns). The number of adenomas 10 mm or larger or cancers did not differ significantly between the two groups (17 in 2001 vs 12 in 2000; p = ns). Age of 65 or older was associated with detection of adenomatous lesions (OR = 1.7; 95% CI = 1.01-2.9013).

CONCLUSIONS

Since the change in Medicare reimbursement, there has been a significant increase in the number and proportion of colonoscopies performed for screening at our institution. Patients screened since this change are older, and the detection rate of neoplastic lesions is similar to those previously screened for a family history of colorectal cancer or polyps.

Colon cancer: prevention, diagnosis, treatment

Colorectal cancer is the second leading cause of death from cancer in the United States. It is third leading cause of cancer death in men behind lung and prostate respectively, and behind lung and breast in cancer deaths among women. More than 130,000 cases are diagnosed each year with over 56,000 of those patients dying. Six percent of the United States population will develop colorectal cancer in their lifetime.

The yield of colonoscopy in average-risk patients with non-specific colonic symptoms

OBJECTIVES

The need for full colonoscopies in average-risk patients with non-specific colonic symptoms is controversial. We aimed to evaluate: (1) the yield of full colonoscopy; (2) the prevalence of proximal neoplasia in these patients; (3) the yield if any of doing full colonoscopies to diagnose proximal lesions in patients in whom the distal colon was clear; (4) the significance of this yield with respect to age.

DESIGN

This is a retrospective analysis to assess the value of open access colonoscopy.

PATIENTS AND METHODS

All patients who underwent a colonoscopy in our Endoscopy Unit during January 1996 to December 1999 were assessed (n = 3357).

RESULTS

We analysed 945 patients with average risk and non-specific colonic symptoms (significant risk factors excluded). The overall yield of adenomas was 5.8%. The yield of distal adenomas in patients > or= 50 years of age was 8.2% (37 out of 450) versus 0.2% in the 50 years group (one out of 495; = 0.0001). The proximal adenoma yield in > or= 50 year olds was 3.8% (17 out of 495) versus 0.2% in < 50 year olds (one out of 495) (P = 0.0001).

CONCLUSIONS

In a cohort of average-risk patients with non-specific colonic symptoms attending an "open access" colonoscopy clinic, the yield for proximal adenomas is small in the < 50 years group. In patients aged < 50 years, distal colonic examination is all that is required, whereas a full colonoscopy may be justified in patients > or = 50 years old.

Colon cancer screening strategies

Screening has been shown to reduce morbidity and mortality related to colorectal cancer. However, the optimal strategy for population screening for colorectal cancer has been a topic of heated debate. Recent studies have challenged the efficacy and cost-effectiveness of current population screening practices. Novel approaches to improve the assessment of an individual's colorectal cancer risk and advances in technology are changing our approach to colorectal screening. This review covers current guidelines for screening for colorectal cancer, recent advances in cancer risk assessment, and the role of endoscopy, virtual colonoscopy, and fecal DNA testing in colorectal cancer screening.