Adverse events during CT colonography for screening, diagnosis and preoperative staging of colorectal cancer: a Japanese national survey

Acceptance and Preference of Computed Tomographic Colonography and Colonoscopy: Results of a Nationwide Multicenter Comparative Questionnaire Survey in Japan

Objectives

To investigate patient acceptance and preference for computed tomographic colonography (CTC) over colonoscopy.

Methods

Participants were recruited from a nationwide multicenter trial in Japan to assess the accuracy of CTC detection. They were scheduled to undergo colonoscopy after CTC with common bowel preparation on the same day. Some were administered sedative drugs during colonoscopy, depending on the referring clinician and participant's preferences. The participants were requested to complete a questionnaire to evaluate the acceptability of bowel preparation, examinations, and preference for future examinations.

Results

Of the 1,257 enrolled participants, 1,180 (mean age: 60.6 years; women: 43.3%) completed the questionnaire. Sedative drugs were not administered in 687 participants (unsedated colonoscopy group) and were administered intravenously during colonoscopy in 493 participants (sedated colonoscopy group). Before propensity score matching, the mean participants' age, percentages of asymptomatic participants, insufflation of gas during colonoscopy, and number of participants with a history of abdominal/pelvic operation significantly differed between the groups. After propensity score matching, 912 participants from each group were included in the analysis. In the unsedated colonoscopy group, CTC was answered as significantly easier than colonoscopy (p<0.001). Conversely, CTC was significantly more difficult than colonoscopy in the sedated colonoscopy group (p<0.001). In the unsedated colonoscopy group, 48% preferred CTC and 22% preferred colonoscopy for future examinations, whereas in the sedated colonoscopy group, 26% preferred CTC and 38% preferred colonoscopy (p<0.001).

Conclusions

CTC has superior participant acceptability compared with unsedated colonoscopy. However, our study did not observe the advantages of CTC acceptance over sedative colonoscopy.

Canadian Association of Radiologists Practice Guidelines for Computed Tomography Colonography

Colon cancer is the third most common malignancy in Canada. Computed tomography colonography (CTC) provides a creditable and validated option for colon screening and assessment of known pathology in patients for whom conventional colonoscopy is contraindicated or where patients self-select to use imaging as their primary modality for initial colonic assessment. This updated guideline aims to provide a toolkit for both experienced imagers (and technologists) and for those considering launching this examination in their practice. There is guidance for reporting, optimal exam preparation, tips for problem solving to attain high quality examinations in challenging scenarios as well as suggestions for ongoing maintenance of competence. We also provide insight into the role of artificial intelligence and the utility of CTC in tumour staging of colorectal cancer. The appendices provide more detailed guidance into bowel preparation and reporting templates as well as useful information on polyp stratification and management strategies. Reading this guideline should equip the reader with the knowledge base to perform colonography but also provide an unbiased overview of its role in colon screening compared with other screening options.

Virtual monoenergetic dual-layer dual-energy CT images in colorectal cancer: CT diagnosis could be improved?

PURPOSE

To compare conventional CT images and virtual monoenergetic images (VMI) at dual-layer dual-energy CT (dlDECT) in patients with colorectal cancer (CRC) through quantitative analysis and to investigate the added value of VMI.

MATERIAL AND METHODS

Sixty-six consecutive patients with histologically documented CRC and available VMI reconstructions were retrospectively investigated. Subsequently, forty-two patients, without any colonic disease at colonoscopy, were selected as control group. Conventional CT images and VMI reconstructions at energy levels ranging from 40 (VMI₄₀) to 100 keV (VMI₁₀₀) in 10 keV increments, were obtained from the late arterial phase. First, signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were obtained to select the best VMI reconstruction. Finally, the diagnostic accuracy of conventional CT and VMI₄₀ in late arterial phase was evaluated.

RESULTS

On quantitative analysis, SNR and CNR were higher for VMI₄₀ (19.5 ± 7.7 and 11.8 ± 6.2, respectively) with statistically significant differences compared to conventional CT (P < 0.05) and all the other VMI reconstructions (P < 0.05), except for VMI₅₀ (P > 0.05). The addition of VMI₄₀ to conventional CT images significantly improved the area under the curve (AUC) for the diagnosis of CRC, increasing it from 0.875 to 0.943 for reader 1 (P < 0.05) and from 0.916 to 0.954 for reader 2 (P < 0.05). The improvement was greater in the less experienced radiologist (0.068) compared to the more experienced one (0.037).

CONCLUSION

VMI₄₀ has showed the highest quantitative image parameters. Furthermore, the use of VMI₄₀ can lead to a significant improvement in the diagnostic performance for detecting CRC.

Pan-Asian adapted ESMO Clinical Practice Guidelines for the diagnosis treatment and follow-up of patients with localised colon cancer

The most recent version of the European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, treatment and follow-up of localised colon cancer was published in 2020. It was decided by both the ESMO and the Japanese Society of Medical Oncology (JSMO) to convene a special virtual guidelines meeting in March 2021 to adapt the ESMO 2020 guidelines to take into account the ethnic differences associated with the treatment of localised colon cancer in Asian patients. These guidelines represent the consensus opinions reached by experts in the treatment of patients with localised colon cancer representing the oncological societies of Japan (JSMO), China (CSCO), India (ISMPO), Korea (KSMO), Malaysia (MOS), Singapore (SSO) and Taiwan (TOS). The voting was based on scientific evidence and was independent of the current treatment practices and drug availability and reimbursement situations in the different Asian countries.

Recent trends in the prevalence and distribution of colonic diverticula in Japan evaluated using computed tomography colonography

BACKGROUND

Computed tomography colonography (CTC) may be superior to colonoscopy and barium enema for detecting diverticula. However, few studies have used CTC to diagnose diverticula.

AIM

To evaluate the current prevalence and distribution of colonic diverticula in Japan using CTC.

METHODS

This study was conducted as part of the Japanese National Computed Tomographic Colonography Trial, which included 1181 participants from 14 hospitals in Japan. We analyzed the prevalence and distribution of colonic diverticula and their relationships with age and sex. The relationship between the diverticula and the length of the large intestine was also analyzed.

RESULTS

Diverticulosis was present in 48.1% of the participants. The prevalence of diverticulosis was higher in the older participants (P < 0.001 for trend). The diverticula seen in younger participants were predominantly located in the right-sided colon. Older participants had a higher frequency of bilateral type (located in the right- and left-sided colon) diverticulosis (P < 0.001 for trend). The length of the large intestine with multiple diverticula in the sigmoid colon was significantly shorter in those without diverticula (P < 0.001).

CONCLUSION

The prevalence of colonic diverticulosis in Japan is higher than that previously reported. The prevalence was higher, and the distribution tended to be bilateral in older participants.

What is the impact of CT colonography interpretation by advanced practitioner radiographers on delivery of the 28 day colorectal cancer target?

INTRODUCTION

CT Colonography (CTC) is an indicated test to assess the colon and rectum for evidence of polyps and neoplasms. The advanced practitioner radiographer (APR) is increasingly involved with the entirety of the radiology pathway including procedural modification, preliminary clinical evaluation (PCE) and multi-disciplinary team (MDT) meeting notification of high risk colonic pathologies.

METHODS

A retrospective audit of the Radiology Information System (RIS) was undertaken at a large secondary care centre, 12 months of data of 119 consecutive patients who had undergone CTC with summary coded reports of high risk pathology were included for analysis. Analysis of accuracy of procedural modification, PCE and impact of hypothesised earlier full radiological staging data being available for MDT discussions were measured and evaluated.

RESULTS

For high risk C4b studies, just 16.67% of colonic pathology was observed during the CTC study, rising to 79% during radiographer PCE. For likely colonic neoplasm C5a studies 86% of colonic pathology was observed during the CTC study, rising to 93% during radiographer PCE. Where subsequent CT chest staging was deemed necessary following CTC by the referring team, patients had a median wait of 34 days for completion CT chest scan staging.

CONCLUSION

This study supports the integration of the advanced practitioner radiographer into the entire radiological processes of a CTC, with time advantages apparent for both diagnostics, but also the decision to treat.

IMPLICATIONS FOR PRACTICE

Appropriately trained radiographers are able to support CTC services to ensure delivery of an effective two-week wait diagnostic service with direct MDT liaison.

Preoperative Staging Diagnosis of Colorectal Cancer Based on Multi-Row Spiral CT

Colorectal cancer is a common malignant tumor of digestive tract, and its incidence has increased significantly in recent years. The 5-year survival rate of patients with early local colorectal cancer is more than 90%, with local invasion of about 68%, and distant metastasis of less than 10%. Therefore, early diagnosis and early treatment is an effective means for the prevention and treatment of colorectal cancer. At present, X-ray air-barium double contrast radiography and fiberoptic endoscope are most commonly used in the examination of colorectal tumors in the world. These two methods have the advantages of simple operation, intuition and low cost. However, it is limited to judge the depth of tumor invasion, whether to break through the serosa, lymphatic metastasis, and distant metastasis. In this work, it can be confirmed that the measurement of preoperative tumor vascular volume reconstruction density is feasible in the preoperative evaluation of colorectal cancer, it will provide clinicians with more valuable information about preoperative tumor staging. Besides, multi-slice spiral CT has the advantages of less trauma, high speed, and clear image. It can not only judge the location of the tumor, the depth, and extent of tumor invasion, and show distant organ metastasis, but also has good application value in tumor staging. In this paper, the clinical data and MSCT imaging data of patients with colorectal cancer were analyzed retrospectively, and the value of MSCT in the diagnosis of colorectal cancer was discussed.

Imaging alternatives to colonoscopy: CT colonography and colon capsule. European Society of Gastrointestinal Endoscopy (ESGE) and European Society of Gastrointestinal and Abdominal Radiology (ESGAR) Guideline - Update 2020

1: ESGE/ESGAR recommend computed tomographic colonography (CTC) as the radiological examination of choice for the diagnosis of colorectal neoplasia.Strong recommendation, high quality evidence.ESGE/ESGAR do not recommend barium enema in this setting.Strong recommendation, high quality evidence. 2: ESGE/ESGAR recommend CTC, preferably the same or next day, if colonoscopy is incomplete. The timing depends on an interdisciplinary decision including endoscopic and radiological factors.Strong recommendation, low quality evidence.ESGE/ESGAR suggests that, in centers with expertise in and availability of colon capsule endoscopy (CCE), CCE preferably the same or the next day may be considered if colonoscopy is incomplete.Weak recommendation, low quality evidence. 3: When colonoscopy is contraindicated or not possible, ESGE/ESGAR recommend CTC as an acceptable and equally sensitive alternative for patients with alarm symptoms.Strong recommendation, high quality evidence.Because of lack of direct evidence, ESGE/ESGAR do not recommend CCE in this situation.Very low quality evidence.ESGE/ESGAR recommend CTC as an acceptable alternative to colonoscopy for patients with non-alarm symptoms.Strong recommendation, high quality evidence.In centers with availability, ESGE/ESGAR suggests that CCE may be considered in patients with non-alarm symptoms.Weak recommendation, low quality evidence. 4: Where there is no organized fecal immunochemical test (FIT)-based population colorectal screening program, ESGE/ESGAR recommend CTC as an option for colorectal cancer screening, providing the screenee is adequately informed about test characteristics, benefits, and risks, and depending on local service- and patient-related factors.Strong recommendation, high quality evidence.ESGE/ESGAR do not suggest CCE as a first-line screening test for colorectal cancer.Weak recommendation, low quality evidence. 5: ESGE/ESGAR recommend CTC in the case of a positive fecal occult blood test (FOBT) or FIT with incomplete or unfeasible colonoscopy, within organized population screening programs.Strong recommendation, moderate quality evidence.ESGE/ESGAR also suggest the use of CCE in this setting based on availability.Weak recommendation, moderate quality evidence. 6: ESGE/ESGAR suggest CTC with intravenous contrast medium injection for surveillance after curative-intent resection of colorectal cancer only in patients in whom colonoscopy is contraindicated or unfeasibleWeak recommendation, low quality evidence.There is insufficient evidence to recommend CCE in this setting.Very low quality evidence. 7: ESGE/ESGAR suggest CTC in patients with high risk polyps undergoing surveillance after polypectomy only when colonoscopy is unfeasible.Weak recommendation, low quality evidence.There is insufficient evidence to recommend CCE in post-polypectomy surveillance.Very low quality evidence. 8: ESGE/ESGAR recommend against CTC in patients with acute colonic inflammation and in those who have recently undergone colorectal surgery, pending a multidisciplinary evaluation.Strong recommendation, low quality evidence. 9: ESGE/ESGAR recommend referral for endoscopic polypectomy in patients with at least one polyp ≥ 6 mm detected at CTC or CCE.Follow-up CTC may be clinically considered for 6 - 9-mm CTC-detected lesions if patients do not undergo polypectomy because of patient choice, comorbidity, and/or low risk profile for advanced neoplasia.Strong recommendation, moderate quality evidence.

Improved Sensitivity and Reader Confidence in CT Colonography Using Dual-Layer Spectral CT: A Phantom Study

Background Limited cathartic preparations for CT colonography with fecal tagging can improve patient comfort but may result in nondiagnostic examinations from poorly tagged stool. Dual-energy CT may overcome this limitation by improving the conspicuity of the contrast agent, but more data are needed. Purpose To investigate whether dual-energy CT improves polyp detection in CT colonography compared with conventional CT at different fecal tagging levels in vitro. Materials and Methods In this HIPAA-compliant study, between December 2017 and August 2019, a colon phantom 30 cm in diameter containing 60 polyps of different shapes (spherical, ellipsoid, flat) and size groups (5-9 mm, 11-15 mm) was constructed and serially filled with simulated feces tagged with four different iodine concentrations (1.26, 2.45, 4.88, and 21.00 mg of iodine per milliliter), then it was scanned with dual-energy CT with and without an outer fat ring to simulate large body size (total diameter, 42 cm). Two readers independently reviewed conventional 120-kVp CT and 40-keV monoenergetic dual-energy CT images to record the presence of polyps and confidence (three-point scale.) Generalized estimating equations were used for sensitivity comparisons between conventional CT and dual-energy CT, and a Wilcoxon signed-rank test was used for reader confidence. Results Dual-energy CT had higher overall sensitivity for polyp detection than conventional CT (58.8%; 95% confidence interval [CI]: 49.7%, 67.3%; 564 of 960 polyps vs 42.1%; 95% CI: 32.1%, 52.8%; 404 of 960 polyps; P < .001), including with the fat ring (48% and 31%, P < .001). Reader confidence improved with dual-energy CT compared with conventional images on all tagging levels (P < .001). Interrater agreement was substantial (κ = 0.74; 95% CI: 0.70, 0.77). Conclusion Compared with conventional 120-kVp CT, dual-energy CT improved polyp detection and reader confidence in a dedicated dual-energy CT colonography phantom, especially with suboptimal fecal tagging. © RSNA, 2020.

Assessment of the Clinical Usefulness of Preoperative Computed Tomography in Colorectal Cancer Patients Who Received Unplanned Reoperation

Background

In the unplanned reoperation of colorectal cancer patients, computed tomography (CT) is increasingly utilized to locate postoperative complications and previously unlocalized lesions. The purpose of this study is to explore the application of CT in the mortality and complications of the reoperation of colorectal cancer. Patients and Methods. We performed a retrospective review of collected data from the colorectal surgeries of 90 identified colorectal cancer patients who received an unplanned reoperation from 2010 to 2018. Patients were stratified according to those with preoperative CT imaging (CT group, n = 36) and those without preoperative CT imaging (NCT group, n = 54). Twenty-four statistical indicators of each patient were studied, including their preoperative risk, surgical characteristics, and postoperative outcomes, and satisfaction was evaluated. All data were statistically analysed for predicting postoperative complications by univariate and multivariate logistic regression analyses.

Results

Ninety patients received an unplanned reoperation in the study, and 40% (36/90) of these patients underwent preoperative CT examination. Patients' risk factors were similar between CT and NCT groups. Preoperative imaging was more commonly performed for reoperative new anastomosis + ileostomy but less common for reoperative Dixon's procedure. The operative duration of the NCT group was longer (139 vs. 104 min, respectively, P = 0.01). Preoperative NCT examination (OR 1.24; 95% CI = 1.09-1.42; P = 0.01) was an independent predictor of postoperative complications. Importantly, three patients died after an unplanned reoperation for colorectal cancer, which occurred only in the NCT group (5.6% vs. 0.0%, P = 0.01).

Conclusion

The use of conventional preoperative CT optimizes the choice of the surgical site and the strategy of laparotomy, so as to reduce the length of operation. Preoperative imaging evaluation should be performed for patients undergoing repeat abdominal surgery.

Circulating Tumour Cells, Circulating Tumour DNA and Circulating Tumour miRNA in Blood Assays in the Different Steps of Colorectal Cancer Management, a Review of the Evidence in 2019

Despite many advances in the diagnosis and treatment of colorectal cancer (CRC), its incidence and mortality rates continue to make an impact worldwide and in some countries rates are mounting. Over the past decade, liquid biopsies have been the object of fundamental and clinical research with regard to the different steps of CRC patient care such as screening, diagnosis, prognosis, follow-up, and therapeutic response. They are attractive because they are considered to encompass both the cellular and molecular heterogeneity of tumours. They are easily accessible and can be applied to large-scale settings despite the cost. However, liquid biopsies face drawbacks in detection regardless of whether we are testing for circulating tumour cells (CTCs), circulating tumour DNA (ctDNA), or miRNA. This review highlights the different advantages and disadvantages of each type of blood-based biopsy and underlines which specific one may be the most useful and informative for each step of CRC patient care.

[Colorectal cancer: role of imaging in screening]

CLINICAL PROBLEM

Colorectal cancer (CRC) is a major cause of cancer-related morbidity and mortality. Most colorectal cancers derive from benign precursor lesions, so-called adenomatous polyps, over a long period of time. Colorectal cancer screening is based on the detection of precancerous polyps and early stage CRC in asymptomatic individuals to reduce CRC incidence and mortality. The protective effect of screening programs can be improved by increasing the screening rates.

PRACTICAL RECOMMENDATIONS

Apart from the established examinations, CT colonography (CTC) has been proposed as an optional test for colorectal cancer screening. The detection rates of CTC for large polyps and cancer are similar to the ones of colonoscopy and superior to stool-based tests. CTC is therefore the radiological test of choice for the detection of colorectal neoplasia. It has replaced double contrast barium enema for almost all indications. As a minimally invasive procedure, CTC has a high safety profile and good patient acceptance. The evaluation of extracolonic organs in addition to the colon can increase examination efficacy. The option to choose CTC as a CRC screening test has the potential to increase the overall screening rates.

A novel volume-reduced CT colonography regimen using hypertonic laxative (polyethylene glycol with ascorbic acid): randomized controlled trial

OBJECTIVES

The aim of this study is to investigate the feasibility of bowel preparation using a hypertonic laxative (polyethylene glycol with ascorbic acid, PEG + Asc) for CT colonography (CTC) and to examine the volume limit of laxative.

METHODS

In one institution, patients who met the indications for CTC were enrolled and randomly assigned to CTC with regimen A (800 ml PEG + Asc), B (600 ml PEG + Asc), or C (400 ml PEG + Asc). Sodium diatrizoate was given orally for fecal tagging. On the previous day, patients ate low-residue meals and took the assigned lavage solution after dinner. A reader blinded to the preparation graded residual stool/fluid and fecal tagging quality in six segments of the colorectum. The primary outcome was a proportion of colon segments without stool. One hundred twenty segments in 20 patients with each regimen were needed to show a non-inferiority margin of 15%, assuming 85% of no stool.

RESULTS

A total of 360 segments in 60 patients were analyzed. There were 83% of segments with no stool in regimen A, 89% in regimen B, and 88% in regimen C. Using the delta method, the 95% confidence interval of the risk difference (6.7%) between regimens A and B was - 2.2% to 15.6%, and the risk difference (5.0%) between regimens A and C was - 4.1% to 14%, both within the non-inferiority margin. Residual fluid and fecal tagging quality were also within the non-inferiority margin. No adverse events occurred.

CONCLUSIONS

A novel CTC regimen using hypertonic laxative demonstrated optimal colon cleansing effectiveness even with the lowest volume of laxative (UMIN000022851).

KEY POINTS

• A novel CTC regimen using a hypertonic laxative is feasible. • The lowest volume of laxative provides excellent colon imaging. • However, the lowest volume of laxative did not improve patient acceptance.

CT colonography: implementation, indications, and technical performance - a follow-up national survey

BACKGROUND

Computed tomography colonography (CTC) is an accepted complement or alternative to optical colonoscopy (OC) but its implementation is incompletely analyzed, and technical performance varies between centers.

PURPOSE

To evaluate implementation, indications, and technical performance of CTC in Sweden and to evaluate compliance to international guidelines.

MATERIAL AND METHODS

A structured, self-assessed questionnaire regarding implementation and technical performance of CTC was sent to all eligible radiology departments in Sweden. Eighty-six out of 89 departments replied. Comparisons were made with similar national surveys from 2004 and 2009.

RESULTS

The number of centers performing CTC gradually increased from 23 in 2004 to 77 in 2016. In parallel, centers performing barium enema (BE) examinations have decreased from 89 in 2004 to 13 in 2016. Main reasons stated for still performing BE were lack of resources regarding CTC/OC. Main reasons for not performing CTC were lack of suitable software, lack of machine/reading time, and lack of experience. The majority of centers follow international CTC guidelines. An important exception is fecal tagging, which was implemented in only 63% of the centers. Incomplete OC remains a major indication for CTC, while preoperative CTC in colorectal cancer and follow-up after diverticulitis have emerged as new indications.

CONCLUSION

CTC today is well implemented in routine healthcare but still lacking in capacity. Indications have expanded over time, and most departments perform "state of the art" CTC, although fecal tagging is incompletely implemented.

Colonic distention and patient acceptance of CT colonography: supine/prone vs left/right lateral scanning

OBJECTIVE

To prospectively evaluate and complete the colonic distention and patient acceptance of CT colonography (CTC) in the supine/prone and left/right lateral positions.

METHODS

A total of 220 consecutive patients were alternately allocated to the supine/prone positioning or left/right lateral positioning group. Two readers scored the degree of colonic distention by segment using a 4-point Likert scale (4 = optimal, 3 = adequate, 2 = inadequate, 1 = collapsed). In addition, patients were asked to rate the discomfort due to positioning during each scan using a 3-point animated face scale (3 = difficult, 2 = somewhat unacceptable, 1 = easy).

RESULTS

The overall mean colonic distention scores for supine, prone, left lateral, and right lateral positions were 3.16, 3.29, 3.22, and 3.42, respectively. Of all, the right lateral position provided the best colonic distention (p < 0.01). Combined left lateral and right lateral positions provided more adequately distended segments compared with combined supine and prone positions (95.6% vs 90.7 %, respectively, p < 0.01). Patient acceptance was significantly lower in the prone position compared to other positions; however there was no difference in patient acceptance between the supine and left/right lateral positions.

CONCLUSION

Right lateral positioning provided the best colonic distention and good patient acceptance.

ADVANCES IN KNOWLEDGE

The left/right lateral position should be considered for routine CTC positioning protocols.