CT colonography after incomplete colonoscopy in subjects with positive faecal occult blood test

Colon Capsule Endoscopy vs. CT Colonography Following Incomplete Colonoscopy: A Systematic Review with Meta-Analysis

Following incomplete colonoscopy (IC) patients often undergo computed tomography colonography (CTC), but colon capsule endoscopy (CCE) may be an alternative. We compared the completion rate, sensitivity and diagnostic yield for polyp detection from CCE and CTC following IC. A systematic literature search resulted in twenty-six studies. Extracted data included inter alia, complete/incomplete investigations and polyp findings. Pooled estimates of completion rates of CCE and CTC and complete colonic view rates (CCE reaching the most proximal point of IC) of CCE were calculated. Per patient diagnostic yields of CCE and CTC were calculated stratified by polyp sizes. CCE completion rate and complete colonic view rate were 76% (CI 95% 68-84%) and 90% (CI 95% 83-95%). CTC completion rate was 98% (CI 95% 96-100%). Diagnostic yields of CTC and CCE were 10% (CI 95% 7-15%) and 37% (CI 95% 30-43%) for any size, 13% (CI 95% 9-18%) and 21% (CI 95% 12-32%) for >5-mm and 4% (CI 95% 2-7%) and 9% (CI 95% 3-17%) for >9-mm polyps. No study performed a reference standard follow-up after CCE/CTC in individuals without findings, rendering sensitivity calculations unfeasible. The increased diagnostic yield of CCE could outweigh its slightly lower complete colonic view rate compared to the superior CTC completion rate. Hence, CCE following IC appears feasible for an introduction to clinical practice. Therefore, randomized studies investigating CCE and/or CTC following incomplete colonoscopy with a golden standard reference for the entire population enabling estimates for sensitivity and specificity are needed.

ACR Appropriateness Criteria® Colorectal Cancer Screening

This review summarizes the relevant literature regarding colorectal screening with imaging. For individuals at average or moderate risk for colorectal cancer, CT colonography is usually appropriate for colorectal cancer screening. After positive results on a fecal occult blood test or immunohistochemical test, CT colonography is usually appropriate for colorectal cancer detection. For individuals at high risk for colorectal cancer (eg, hereditary nonpolyposis colorectal cancer, ulcerative colitis, or Crohn colitis), optical colonoscopy is preferred because of its ability to obtain biopsies to detect dysplasia. After incomplete colonoscopy, CT colonography is usually appropriate for colorectal cancer screening for individuals at average, moderate, or high risk. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Development and validation of an algorithm to complete colonoscopy using standard endoscopes in patients with prior incomplete colonoscopy

BACKGROUND AND STUDY AIMS

 Incomplete colonoscopy may occur as a result of colon angulation (adhesions or diverticulosis), endoscope looping, or both. Specialty endoscopes/devices have been shown to successfully complete prior incomplete colonoscopies, but may not be widely available. Radiographic or other image-based evaluations have been shown to be effective but may miss small or flat lesions, and colonoscopy is often still indicated if a large lesion is identified. The purpose of this study was to develop and validate an algorithm to determine the optimum endoscope to ensure completion of the examination in patients with prior incomplete colonoscopy.

PATIENTS AND METHODS

 This was a prospective cohort study of 175 patients with prior incomplete colonoscopy who were referred to a single endoscopist at a single academic medical center over a 3-year period from 2012 through 2015. Colonoscopy outcomes from the initial 50 patients were used to develop an algorithm to determine the optimal standard endoscope and technique to achieve cecal intubation. The algorithm was validated on the subsequent 125 patients.

RESULTS

 The overall repeat colonoscopy success rate using a standard endoscope was 94 %. The initial standard endoscope specified by the algorithm was used and completed the colonoscopy in 90 % of patients.

CONCLUSIONS

 This study identifies an effective strategy for completing colonoscopy in patients with prior incomplete examination, using widely available standard endoscopes and an algorithm based on patient characteristics and reasons for prior incomplete colonoscopy.

CT colonography: role in FOBT-based screening programs for colorectal cancer

Computed tomographic colonography (CTC) is a minimally invasive imaging examination for the colon, and is safe, well tolerated and accurate for the detection of colorectal cancer (CRC) and advanced adenoma. While the role of CTC as a primary test for population screening of CRC is under investigation, the fecal occult blood test (FOBT) has been recommended for population screening of CRC in Europe. Subjects with positive FOBT are invited to undergo total colonoscopy, which has some critical issues, such as suboptimal compliance, contraindications and the possibility of an incomplete exploration of the colon. Based on available data, the integration of CTC in FOBT-based population screening programs for CRC may fall into three scenarios. First, CTC is recommended in FOBT-positive subjects when colonoscopy is refused, incomplete or contraindicated. For these indications CTC should replace double-contrast barium enema. Second, conversely, CTC is not currently recommended as a second-level examination prior to colonoscopy in all FOBT-positive subjects, as this strategy is most probably not cost-effective. Finally, CTC may be considered instead of colonoscopy for surveillance after adenoma removal, but specific studies are needed.

CT colonography for population screening of colorectal cancer: hints from European trials

CT colonography (CTC) is a minimally invasive radiological investigation of the colon. Robust evidence indicates that CTC is safe, well tolerated and highly accurate for the detection of colorectal cancer (CRC) and large polyps, which are the targets of screening. Randomized controlled trials were carried out in Europe to evaluate CTC as the primary test for population screening of CRC in comparison with faecal immunochemical test (FIT), sigmoidoscopy and colonoscopy. Main outcomes were participation rate and detection rate. Participation rate for screening CTC was in the range of 25-34%, whereas the detection rate of CTC for CRC and advanced adenoma was in the range of 5.1-6.1%. Participation for CTC screening was lower than that for FIT, similar to that for sigmoidoscopy and higher than that for colonoscopy. The detection rate of CTC was higher than that of one FIT round, similar to that of sigmoidoscopy and lower than that of colonoscopy. However, owing to the higher participation rate in CTC screening with respect to colonoscopy screening, the detection rates per invitee of CTC and colonoscopy would be comparable. These results justify consideration of CTC in organized screening programmes for CRC. However, assessment of other factors such as polyp size threshold for colonoscopy referral, management of extracolonic findings and, most importantly, the forthcoming results of cost-effectiveness analyses are crucial to define the role of CTC in primary screening.

CT Colonography: an update on current and future indications

Computed tomographic colonography (CTC) is a minimally invasive, patient-friendly, safe and robust colonic imaging modality. The technique is standardized and consolidated evidence from the literature shows that the diagnostic performances for the detection of colorectal cancer and large polyps are similar to colonoscopy (CS) and largely superior to alternative radiological exams, like barium enema. A clear understanding of the exact role of CTC will be beneficial to maximize the benefits and minimize the potential sources of frustration or disappointment for both referring clinicians and patients. Incomplete, failed, or unfeasible CS; investigation of elderly, and frail patients and assessment of diverticular disease are major indications supported by evidence-based data and agreed by the endoscopists. The use of CTC for symptomatic patients, colorectal cancer screening and colonic surveillance is still under debate and, thus, recommended only if CS is unfeasible or refused by patients.

Alternatives to Incomplete Colonoscopy

A thorough and complete colonoscopy is critically important in preventing colorectal cancer. Factors associated with difficult and incomplete colonoscopy include a poor bowel preparation, severe diverticulosis, redundant colon, looping, adhesions, young and female patients, patient discomfort, and the expertise of the endoscopist. For difficult colonoscopy, focusing on bowel preparation techniques, appropriate sedation and adjunct techniques such as water immersion, abdominal pressure techniques, and patient positioning can overcome many of these challenges. Occasionally, these fail and other alternatives to incomplete colonoscopy have to be considered. If patients have low risk of polyps, then noninvasive imaging options such as computed tomography (CT) or magnetic resonance (MR) colonography can be considered. Novel applications such as Colon Capsule™ and Check-Cap are also emerging. In patients in whom a clinically significant lesion is noted on a noninvasive imaging test or if they are at a higher risk of having polyps, balloon-assisted colonoscopy can be performed with either a single- or double-balloon enteroscope or colonoscope. The application of these techniques enables complete colonoscopic examination in the vast majority of patients.

Frequency and efficacy of additional investigations following incomplete colonoscopies: A population-based analysis

BACKGROUND

Limited data are available on the follow-up of patients with incomplete colonoscopy following positive faecal occult blood testing. Our study aimed to determine the proportion of and reasons for incomplete colonoscopies, the proportion of patients who completed colonic evaluations, the methods used and the subsequent findings.

METHODS

A total of 9483 colonoscopies performed after positive testing in a colorectal cancer screening programme setting were included. The study was prospective for index colonoscopy findings and partly retrospective for follow-up.

RESULTS

Overall 297 colonoscopies were incomplete (3.2%). A secondary colonic evaluation was deemed necessary in 245 patients, of which 126 underwent an additional examination (51.4%). Radiology was the primary method used for complete colonic evaluation, whereas a repeat colonoscopy was performed in only 6.4%; the examination was normal in 119 patients (94.4%). A mucosal high-grade neoplasia was removed in 1, and multiple (≥3) adenomas were removed in 2 patients.

CONCLUSIONS

The present screening programme with biennial faecal occult blood testing revealed a high colonoscopy completion rate, a low rate of secondary colonic evaluation, infrequent use of colonoscopy for completion, and a low detection rate of significant neoplasia.

Familial colorectal cancer screening: When and what to do?

Colorectal cancer (CRC) is the third leading cause of death worldwide and represents a clinical challenge. Family members of patients affected by CRC have an increased risk of CRC development. In these individuals, screening is strongly recommended and should be started earlier than in the population with average risk, in order to detect neoplastic precursors, such as adenoma, advanced adenoma, and nonpolypoid adenomatous lesions of the colon. Fecal occult blood test (FOBT) is a non invasive, widespread screening method that can reduce CRC-related mortality. Sigmoidoscopy, alone or in addition to FOBT, represents another screening strategy that reduces CRC mortality. Colonoscopy is the best choice for screening high-risk populations, as it allows simultaneous detection and removal of preneoplastic lesions. The choice of test depends on local health policy and varies among countries.

CT colonography with rectal iodine tagging: Feasibility and comparison with oral tagging in a colorectal cancer screening population

PURPOSE

To evaluate feasibility, diagnostic performance, patient acceptance, and overall examination time of CT colonography (CTC) performed through rectal administration of iodinated contrast material.

MATERIALS AND METHODS

Six-hundred asymptomatic subjects (male:female=270:330; mean 63 years) undergoing CTC for colorectal cancer screening on an individual basis were consecutively enrolled in the study. Out of them, 503 patients (group 1) underwent CTC with rectal tagging, of which 55 had a total of 77 colonic lesions. The remaining 97 patients (group 2) were randomly selected to receive CTC with oral tagging of which 15 had a total of 20 colonic lesions. CTC findings were compared with optical colonoscopy, and per-segment image quality was visually assessed using a semi-quantitative score (1=poor, 2=adequate, 3=excellent). In 70/600 patients (11.7%), CTC was performed twice with both types of tagging over a 5-year follow-up cancer screening program. In this subgroup, patient acceptance was rated via phone interview two weeks after CTC using a semi-quantitative scale (1=poor, 2=fair, 3=average, 4=good, 5=excellent).

RESULTS

Mean per-polyp sensitivity, specificity, positive and negative predictive values of CTC with rectal vs oral tagging were 96.1% (CI95% 85.4÷99.3%) vs 89.4% (CI95% 65.4÷98.1%), 95.3% (CI95% 90.7÷97.8%) vs 95.8% (CI95% 87.6÷98.9%), 86.0% (CI95% 73.6÷93.3) vs 85.0% (CI95% 61.1÷96.0%), and 98.8% (CI95% 95.3÷99.8%) vs 97.2% (CI95% 89.4÷99.5%), respectively (p>0.05). Polyp detection rates were not statistically different between groups 1 and 2 (p>0.05). Overall examination time was significantly shorter with rectal than with oral tagging (18.3±3.5 vs 215.6±10.3 minutes, respectively; p<0.0001).

CONCLUSIONS

Rectal iodine tagging can be an effective alternative to oral tagging for CTC with the advantages of greater patient acceptance and lower overall examination time.

Colorectal cancer screening: tests, strategies, and perspectives

Screening has a central role in colorectal cancer (CRC) control. Different screening tests are effective in reducing CRC-specific mortality. Influence on cancer incidence depends on test sensitivity for pre-malignant lesions, ranging from almost no influence for guaiac-based fecal occult blood testing (gFOBT) to an estimated reduction of 66–90% for colonoscopy. Screening tests detect lesions indirectly in the stool [gFOBT, fecal immunochemical testing (FIT), and fecal DNA] or directly by colonic inspection [flexible sigmoidoscopy, colonoscopy, CT colonography (CTC), and capsule endoscopy]. CRC screening is cost-effective compared to no screening but no screening strategy is clearly better than the others. Stool tests are the most widely used in worldwide screening interventions. FIT will soon replace gFOBT. The use of colonoscopy as a screening test is increasing and this strategy has superseded all alternatives in the US and Germany. Despite its undisputed importance, CRC screening is under-used and participation rarely reaches 70% of target population. Strategies to increase participation include ensuring recommendation by physicians, introducing organized screening and developing new, more acceptable tests. Available evidence for DNA fecal testing, CTC, and capsule endoscopy is reviewed.

ACR Appropriateness Criteria colorectal cancer screening

Colorectal cancer is the third leading cause of cancer deaths in the United States. Most colorectal cancers can be prevented by detecting and removing the precursor adenomatous polyp. Individual risk factors for the development of colorectal cancer will influence the particular choice of screening tool. CT colonography (CTC) is the primary imaging test for colorectal cancer screening in average-risk individuals, whereas the double-contrast barium enema (DCBE) is now considered to be a test that may be appropriate, particularly in settings where CTC is unavailable. Single-contrast barium enema has a lower performance profile and is indicated for screening only when CTC and DCBE are not available. CTC is also the preferred test for colon evaluation following an incomplete colonoscopy. Imaging tests including CTC and DCBE are not indicated for colorectal cancer screening in high-risk patients with polyposis syndromes or inflammatory bowel disease. This paper presents the updated colorectal cancer imaging test ratings and is the result of evidence-based consensus by the ACR Appropriateness Criteria Expert Panel on Gastrointestinal Imaging. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

CT-colonography after incomplete colonoscopy: what is the diagnostic yield?

BACKGROUND

Computed tomography-colonography is a diagnostic modality that can be used when the colon is not completely intubated during colonoscopy. It may have the additional advantage that information on extracolonic lesions can be obtained.

OBJECTIVE

The aim of this study was to investigate the yield of CT-colonography of relevant intra- and extracolonic findings in patients after incomplete colonoscopy.

DESIGN

This was an observational, retrospective study.

DATA SOURCES

Data were be obtained from standardized radiology and endoscopy reports and electronic medical records.

STUDY SELECTION

In total, 136 consecutive CT-colonographies performed after incomplete colonoscopy were evaluated.

MAIN OUTCOME MEASURES

All intra- and extracolonic findings on CT-colonography were recorded and interpreted for clinical relevance, and it was determined whether further diagnostic and/or therapeutic workup was indicated.

RESULTS

Major indications for colonoscopy included iron-deficiency anemia (25.7%), hematochezia (20.6%), change in bowel habits (18.4%), and colorectal cancer screening or surveillance (11.0%). Major reasons for incomplete colonoscopy were a fixed colon (34.6%) and strong angulation of the sigmoid colon (17.6%). Introduction of the colonoscope was limited to the left-sided colon in 53.7% of cases. Incomplete colonoscopy detected colorectal cancer in 12 (8.8%) patients and adenomatous polyps in 27 (19.9%) patients. CT-colonography after incomplete colonoscopy additionally revealed 19 polyps in 15 (11.0%) and a nonsynchronous colorectal cancer in 4 (2.9%) patients. CT-colonography also detected extracolonic findings with clinical consequences in 8 (5.9%) patients, including fistulizing diverticulitis (n = 3), gastric tumor (n = 2), liver abscess (n = 1), osteomyelitis (n = 1), and an infected embolus in both renal arteries (n = 1).

LIMITATIONS

This study was limited by the lack of confirmation of intraluminal CT-colonography findings in a subset of patients.

CONCLUSIONS

Computed tomography-colonography can be of added value in patients with incomplete colonoscopy, because it revealed 27 relevant additional (both intra- and extracolonic) lesions in 19.1% of patients. In cases where CT-colonography detected colorectal cancer after incomplete colonoscopy, it can also be used for staging purposes.

Synchronous triple carcinoma of the colon and rectum

Synchronous multiple colorectal cancers are defined as multiple malignant colorectal tumors that occur simultaneously. All tumors are distant from each other, and none are the result of metastasis from other tumors. Here, we present a case of a 79-year-old man who was admitted to our hospital because of a 3-month history of abdominal pain associated with anemia, loss of appetite, and body weight loss. The patient did not have a family history of cancer. Computed tomography revealed bowel wall thickness and mesentery inflammation at the hepatic flexure of the colon and cecum. Colonoscopy revealed a tumor located 10 cm from the anal verge. Colonoscopic examination of the large bowel was not possible because of bowel obstruction due to the rectal tumor. Synchronous triple adenocarcinoma of the colon and rectum was confirmed by pathologic examination. The tumor was surgically resected by two-segment resection of the colon, low anterior resection, and right hemicolectomy. We used intraoperative colonoscopy to confirm that there were no other lesions after the resection of the three tumors. To the best of our knowledge, this is the first case of synchronous triple carcinoma of the colon and rectum in Taiwan. We consider that comprehensive preoperative study, extensive intraoperative exploration, and radical resection can increase the survival rate of patients with synchronous multiple colorectal cancers.

Current status on performance of CT colonography and clinical indications

CT colonography (CTC) is a robust and reliable imaging test of the colon. Accuracy for the detection of colorectal cancer (CRC) is as high as conventional colonoscopy (CC). Identification of polyp is size dependent, with large lesions (≥10mm) accurately detected and small lesions (6-9mm) identified with moderate to good sensitivity. Recent studies show good sensitivity for the identification of nonpolypoid (flat) lesions as well. Current CTC indications include the evaluation of patients who had undergone a previous incomplete CC or those who are unfit for CC (elderly and frail individuals, patients with underlying severe clinical conditions, or with contraindication to sedation). CTC can also be efficiently used in the assessment of diverticular disease (excluding patients with acute diverticulitis, where the exam should be postponed), before laparoscopic surgery for CRC (to have an accurate localization of the lesion), in the evaluation of colonic involvement in the case of deep pelvic endometriosis (replacing barium enema). CTC is also a safe procedure in patients with colostomy. For CRC screening, CTC should be considered an opportunistic screening test (not available for population, or mass screening) to be offered to asymptomatic average-risk individuals, of both genders, starting at age 50. The use in individuals with positive family history should be discussed with the patient first. Absolute contraindication is to propose CTC for surveillance of genetic syndromes and chronic inflammatory bowel diseases (in particular, ulcerative colitis). The use of CTC in the follow-up after surgery for CRC is achieving interesting evidences despite the fact that literature data are still relatively weak in terms of numerosity of the studied populations. In patients who underwent previous polypectomy CTC cannot be recommended as first test because debate is still open. It is desirable that in the future CTC would be the first-line and only diagnostic test for colonic diseases, leaving to CC only a therapeutic role.

Patients' preferences about follow-up of medium size polyps detected at screening CT colonography

PURPOSE

To evaluate patients' preferences regarding follow-up of medium size polyps detected at screening CT colonography (CTC).

METHODS AND MATERIALS

193 C-RADS2 asymptomatic patients were asked to fill in a form explaining the indications, technique and potential complications of CTC, and were invited to choose their preferred examination technique (CTC or optical colonoscopy: OC) and their follow-up interval by repeated consultations at 3-month intervals. The follow-up interval for CTC and OC was recorded.

RESULTS

87/193 C-RADS2 patients (45.1%) accepted follow-up. Average time interval for follow-up was comparable between CTC and OC (9.00 ± 4.24 vs. 9.00 ± 4.39 months, respectively; P = 0.7188). No patients chose to undergo a 3-year follow-up with either CTC or OC. Most patients elected to have follow-up with either CTC or OC before 18 months rather than later (P = 0.0004).

CONCLUSIONS

A substantial fraction of C-RADS2 patients prefer to undergo immediate OC and polyp removal rather than follow-up, and the majority of those accepting follow-up are willing to wait for less than 18 months. Such findings may suggest a revision of the proposed C-RADS2 category.

Bowel Preparation Regimen for Computed Tomography Colonography

Purpose

This study was designed to determine whether a reduction in oral contrast dose and a change in timing of administration will result in less residual material in the colonic lumen.

Method

We retrospectively assessed, in a blinded fashion, the amount and nature of residual material in the colon in 40 patients who received computed tomography colonography. Half of the cohort received the standard bowel-preparation regimen, whereas a sex- and age-matched test arm received the modified regimen. A scoring system that consisted of metrics to quantify the nature and extent of residual fluid and solid material was defined. Image analysis was conducted with the investigators blinded to the group assignment of each patient. Three different trained observers independently reviewed and scored the 6 colonic segments in supine and prone positions for each patient in the cohort. In cases in which interobserver discrepancies existed, the observers reanalyzed the images together to come to an agreement on scores.

Results

The new bowel-preparation regimen resulted in significantly less “sticky coat” ( P < .005), a problematic phenomenon in which the colonic mucosa is covered in a thin coating of residual contrast and fecal material. There was no difference in the amount of residual fluid. Fewer masses of stool were noted with the new preparation, but this was not found to be statistically significant.

Conclusion

A new bowel-preparation regimen that consisted of lower quantities of contrast administered earlier in the day preceding computed tomography colonography resulted in a lower incidence of adherent contrast and fecal matter. The reduction of this “sticky coat” problem not only improved radiologic analysis of the colon but may permit same-day therapy via colonoscopy if indicated on imaging.

Should barium enema be the next step following an incomplete colonoscopy?

INTRODUCTION

Double contrast barium enema (DCBE) is used to screen and diagnose colorectal disease and is often recommended following an incomplete colonoscopy. The purpose of this study was to determine the value of DCBE following an incomplete colonoscopy.

MATERIALS AND METHODS

A retrospective review was conducted of all patients who had an incomplete colonoscopy at Kaiser Permanente, Los Angeles in a 6-year period. Patient data was extracted from the endoscopy and radiology databases. Variables collected included demographics, indication for colonoscopy, reason for incompletion, findings of DCBE, and findings of repeat colonoscopy if subsequently performed.

RESULTS

The incomplete colonoscopy rate was 1.6%. The mean age was 62 years with a predominance of females. The most common indication for colonoscopy was screening. The most frequent reason attributed to an incomplete colonoscopy was patient discomfort. Two hundred thirty three patients underwent DCBE and 42 patients underwent a repeat colonoscopy without DCBE; 13.3% of the DCBE were of poor quality and could not be interpreted. A repeat colonoscopy following DCBE was performed in 7% of patients. In 50% of these patients, the repeat colonoscopy revealed significant findings not noted on the DCBE or ruled out positive DCBE findings. In patients who had repeat colonoscopy without DCBE, completion rate was 95%.

CONCLUSION

The rate of incomplete colonoscopy in a high-volume modern endoscopy unit is extremely low. DCBE following incomplete colonoscopy has limited value. A repeat colonoscopy under deeper sedation and/or better bowel preparation may be the preferred next step.

Colorectal cancer screening: The role of CT colonography

Computed tomography colonography (CTC) in colorectal cancer (CRC) screening has two roles: one present and the other potential. The present role is, without any further discussion, the integration into established screening programs as a replacement for barium enema in the case of incomplete colonoscopy. The potential role is the use of CTC as a first-line screening method together with Fecal Occult Blood Test, sigmoidoscopy and colonoscopy. However, despite the fact that CTC has been officially endorsed for CRC screening of average-risk individuals by different scientific societies including the American Cancer Society, the American College of Radiology, and the US Multisociety Task Force on Colorectal Cancer, other entities, such as the US Preventive Services Task Force, have considered the evidence insufficient to justify its use as a mass screening method. Medicare has also recently denied reimbursement for CTC as a screening test. Nevertheless, multiple advantages exist for using CTC as a CRC screening test: high accuracy, full evaluation of the colon in virtually all patients, non-invasiveness, safety, patient comfort, detection of extracolonic findings and cost-effectiveness. The main potential drawback of a CTC screening is the exposure to ionizing radiation. However, this is not a major issue, since low-dose protocols are now routinely implemented, delivering a dose comparable or slightly superior to the annual radiation exposure of any individual. Indirect evidence exists that such a radiation exposure does not induce additional cancers.

CT colonography before colonoscopy in subjects with positive faecal occult blood test. Preliminary experience

PURPOSE

We report a preliminary evaluation of the performance of computed tomography colonography (CTC) systematically obtained before optical colonoscopy (OC) in subjects with positive faecal occult blood test (FOBT) within a population-based screening programme for colorectal cancer (CRC).

MATERIALS AND METHODS

Seventy-nine subjects with positive FOBT from a regional screening programme were invited to perform same day CTC and OC. CTC was performed with standard bowel preparation. OC with segmental unblinding was the reference standard. A per-patient per-adenoma analysis was performed.

RESULTS

Forty-nine of 79 subjects (62%) with positive FOBT adhered to the study and completed both examinations. Twenty-two (44.9%) of the 49 had a cancer or an adenoma ≥6 mm. Per-patient sensitivity, specificity, negative predictive value and positive predictive value for cancer or adenoma ≥6 mm were 95.5% (95%CI:77.2%-99.9%), 51.9% (95%CI:32.0%-71.3%), 93.3% (95%CI:68.1%-99.8%) and 61.8% (95%CI:43.6%-77.8%).

CONCLUSIONS

In the setting of a FOBT-based screening programme for CRC, CTC showed a high sensitivity, but relatively low specificity and positive predictive value, for cancer and adenoma ≥6 mm. Probably performing CTC without faecal tagging as second line test after a positive FOBT is not a cost-effective strategy.

Performance of CT colonography in clinical trials

The amount of data accumulated in trials of CT colonography (CTC) has greatly increased in the past decade. The information from these studies is shaping clinical practice and public health policy regarding screening for colorectal cancer (CRC). This article examines the performance of CTC in clinical trials for individuals at average risk and increased risk for CRC. It also addresses the efficacy of CTC after incomplete colonoscopy, when colon preparations are reduced or eliminated, and in academic versus nonacademic environments. The data suggest that CTC is effective especially for the detection of larger lesions and when more advanced imaging technology is used.

The Benefits of Computed Tomographic Colonography in Reducing a Long Colonoscopy Waiting List

Purpose

The Radiology Department, Royal Jubilee Hospital, Victoria, BC, with the support of gastroenterologists and surgeons, was awarded a BC Innovation fund to run a pilot project of computed tomographic colonography to reduce an unacceptably long 2-year colonoscopy waiting list. Funds were approved in April 2007 for a 1-year project, which was completed on March 31, 2008.

Methods

This article describes the challenges of delivering a high-volume computed tomographic colonography program at a busy community hospital, with discussion of the results for the 2,005 patients who were examined.

Results

Colonoscopy was avoided in 1,462 patients whose computed tomographic studies showed no significant lesions. In the remainder of patients, only lesions larger than 5 mm were reported, with a total of 508 lesions identified in 433 patients. There were 57 cancers of which 52 were reported as either definite or possible cancers, whereas 5 were not seen on initial scans. Some of the patients with cancer had been on the colonoscopy waiting list for 2 years. In addition, there were 461 patients with significant extracolonic findings, including 84 who required urgent or semi-urgent further management for previously unsuspected conditions, such as pneumonia, aneurysms larger than 5 cm, and a range of solid renal, hepatic, and pancreatic masses. There were no procedural complications from the computed tomographic colon studies.

Conclusions

We have shown that it is feasible to run a high volume CTC service in a general hospital given hospital support and funding. The benefits in this group of over 2000 patients included avoidance of colonoscopy in over 70% of patients, detection of significant polyps or cancer in approximately 20% of patients, and identification of clinically important conditions in 7%–18% depending on the definition used. The estimated costs including capital, operating, and professional fees were in the range of $400.