Detection of flat colorectal polyps at screening CT colonography in comparison with conventional polypoid lesions

Best Approach for Incomplete Colonoscopy: Colon Capsule Endoscopy or Repeat Conventional Colonoscopy?

Background: The most appropriate strategy for completing a previous incomplete colonoscopy (IC) is not standardized. We aimed to compare the efficacy and safety of two strategies for completing a previous IC: colon capsule endoscopy (CCE) versus repeat conventional colonoscopy. Methods: A retrospective cohort study that included consecutive adult patients referred to our center after IC under sedation due to irreducible loop formation or colonic fixed angulation was performed. Patients underwent CCE (PillCam COLON2 Medtronic®) or repetition of conventional colonoscopy under sedation. In this setting, an appropriate CCE progression was defined as the capsule reaching the segment achieved during the previous IC. Repeated conventional colonoscopy was considered complete when cecal intubation was accomplished. We compared the rate of appropriate CCE colon progression with the cecal intubation rate from repeated conventional colonoscopy. Quality of colon preparation, diagnostic yield, and rate of adverse events for CCE and colonoscopy was also analyzed. Results: A total of 192 CCE and 181 colonoscopies were performed for IC, primarily due to fixed angulation of the left colon (69.2%, n = 258). There were no significant differences between the two groups (CCE vs. colonoscopy) concerning age, sex, overweight/obesity status, previous abdominal surgery, and reasons for IC. The rate of appropriate colon progression with CCE was not significantly different from the cecal intubation rate of repeated colonoscopy (95.3% vs. 90.1%, p = 0.073, respectively), even after adjusting for the quality of colon preparation (p = 0.122), which differed significantly between the groups (76.0% vs. 92.8%, p < 0.001, respectively). There were no significant differences in overall colorectal findings identified between the CCE and colonoscopy groups (55.2% vs. 62.4%, p = 0.172, respectively), and no adverse events were reported in either group. Conclusions: Our findings suggest that both CCE and repeat conventional colonoscopy are effective and safe options for completing a previous IC.

Current Status and Emerging Trends in Colorectal Cancer Screening and Diagnostics

Colorectal cancer (CRC) is a prevalent and potentially fatal disease categorized based on its high incidences and mortality rates, which raised the need for effective diagnostic strategies for the early detection and management of CRC. While there are several conventional cancer diagnostics available, they have certain limitations that hinder their effectiveness. Significant research efforts are currently being dedicated to elucidating novel methodologies that aim at comprehending the intricate molecular mechanism that underlies CRC. Recently, microfluidic diagnostics have emerged as a pivotal solution, offering non-invasive approaches to real-time monitoring of disease progression and treatment response. Microfluidic devices enable the integration of multiple sample preparation steps into a single platform, which speeds up processing and improves sensitivity. Such advancements in diagnostic technologies hold immense promise for revolutionizing the field of CRC diagnosis and enabling efficient detection and monitoring strategies. This article elucidates several of the latest developments in microfluidic technology for CRC diagnostics. In addition to the advancements in microfluidic technology for CRC diagnostics, the integration of artificial intelligence (AI) holds great promise for further enhancing diagnostic capabilities. Advancements in microfluidic systems and AI-driven approaches can revolutionize colorectal cancer diagnostics, offering accurate, efficient, and personalized strategies to improve patient outcomes and transform cancer management.

Current and future colorectal cancer screening strategies

Despite strong evidence of effectiveness, colorectal cancer (CRC) screening remains underused. Currently, there are several options for CRC screening, each with its own performance characteristics and considerations for practice. This Review aims to cover current CRC screening guidelines and highlight future blood-based and imaging-based options for screening. In current practice, the leading non-invasive option is the faecal immunochemical test (FIT) based on its high specificity, good sensitivity, low cost and ease of use in mailed outreach programmes. There are currently five blood-based CRC screening tests in varying stages of evaluation, including one that is currently sold in the USA as a laboratory-developed test. There are ongoing studies on the diagnostic accuracy and longitudinal performance of blood tests and they have the potential to disrupt the CRC screening landscape. Imaging-based options, including the colon capsule, MR colonography and the CT capsule, are also being tested in active studies. As the world attempts to recover from the COVID-19 pandemic and adapts to the start of CRC screening among people at average risk starting at age 45 years, non-invasive options will become increasingly important.

Colorectal carcinoma screening: Established methods and emerging technology

Colorectal carcinoma screening programs have shown success in lowering both the incidence and mortality rate of colorectal carcinoma at a population level, in part because this carcinoma is relatively slow growing and has an identifiable premalignant lesion. Still, many patients do not undergo the recommended screening for colorectal carcinoma, and of those who do, a subset may be over- or under-diagnosed by the currently available testing methods. The primary purpose of this article is to review the data regarding currently available colorectal cancer screening modalities, which include fecal occult blood testing, direct colonic visualization, and noninvasive imaging techniques. In addition, readers will be introduced to a variety of biomarkers that may serve as stand-alone or adjunct tests in the future. Finally, there is a brief discussion of the current epidemiologic considerations that public health officials must address as they create population screening guidelines. The data we provide as laboratory physicians and scientists are critical to the construction of appropriate recommendations that ultimately decrease the burden of disease from colorectal carcinoma.

Newly-developed colonoscope (PCF-PQ260L) is useful for patients with difficult colons

BACKGROUND/AIMS

Preforming total colonoscopy (TCS) is sometimes difficult due to adhesions or long colons. The PCF-PQ260L (PQL) was developed to overcome TCS-related difficulties. The aim of this study was to investigate the performance and usefulness of PQL for difficult colon cases.

MATERIALS AND METHODS

This was a retrospective single center observational cohort study investigating differences in patient characteristics and examination performance between patients examined with PQL, versus standard (SD), scopes. Secondly, we directly compared PQL and SD scopes in patients treated with both types of scope.

RESULTS

The PQL was used with 105 patients and SD scopes were used with 1119 patients. Patients in the PQL group were significantly shorter (157cm vs 163cm, p< 0.01) and lighter, compared to the SD group (52 kg vs 58 kg, p< 0.01). There were no significant statistical differences with regard to cecal intubation rate, cecal intubation time, and adenoma detection. Direct comparison of use of PQL and SD scopes on the same patients revealed shorter average cecal intubation time (7 min vs 10 min, p< 0.01), and significantly increased numbers of patients reporting no pain (66 % vs 20 %, p< 0.01) and needing no sedative drugs (48% vs 25 %, p< 0.01) associated with PQL use.

CONCLUSION

The examination performance of the PQL scope was similar to the SD scope. The PQL may be a good option for patients who with difficult colons.

Current state and future direction of screening tool for colorectal cancer

As the second-most-common cause of cancer death, colorectal cancer (CRC) has been recognized as one of the biggest health concerns in advanced countries. The 5-year survival rate for patients with early-stage CRC is significantly better than that for patients with CRC detected at a late stage. The primary target for CRC screening and prevention is advanced neoplasia, which includes both CRC itself, as well as benign but histologically advanced adenomas that are at increased risk for progression to malignancy. Prevention of CRC through detection of advanced adenomas is important. It is, therefore, necessary to develop more efficient detection methods to enable earlier detection and therefore better prognosis. Although a number of CRC diagnostic methods are currently used for early detection, including stool-based tests, traditional colonoscopy, etc., they have not shown optimal results due to several limitations. Hence, development of more reliable screening methods is required in order to detect the disease at an early stage. New screening tools also need to be able to accurately diagnose CRC and advanced adenoma, help guide treatment, and predict the prognosis along with being relatively simple and non-invasive. As part of such efforts, many proposals for the early detection of colorectal neoplasms have been introduced. For example, metabolomics, referring to the scientific study of the metabolism of living organisms, has been shown to be a possible approach for discovering CRC-related biomarkers. In addition, a growing number of high-performance screening methodologies could facilitate biomarker identification. In the present, evidence-based review, the authors summarize the current state as recognized by the recent guideline recommendation from the American Cancer Society, US Preventive Services Task Force and the United States Multi-Society Task Force and discuss future direction of screening tools for colorectal cancer. Further, we highlight the most interesting publications on new screening tools, like molecular biomarkers and metabolomics, and discuss these in detail.

Recent Advance in Colon Capsule Endoscopy: What's New?

Colon capsule endoscopy (CCE) is a relatively new diagnostic procedure for patients with suspected colonic diseases. This convenient,noninvasive method enables the physician to explore the entire colon without significant discomfort to the patient. However, while CCEcan be performed painlessly without bowel air insufflation, the need for vigorous bowel preparation and other technical limitationsexist. Due to such limitations, CCE has not replaced conventional colonoscopy. In this review, we discuss historical and recentadvances in CCE including technical issues, ideal bowel preparation, indications and contraindications and highlight further technicaladvancements and clinical studies which are needed to develop CCE as a potential diagnostic tool.

Colorectal Cancer Screening: Recommendations for Physicians and Patients From the U.S. Multi-Society Task Force on Colorectal Cancer

This document updates the colorectal cancer (CRC) screening recommendations of the U.S. Multi-Society Task Force of Colorectal Cancer (MSTF), which represents the American College of Gastroenterology, the American Gastroenterological Association, and The American Society for Gastrointestinal Endoscopy. CRC screening tests are ranked in 3 tiers based on performance features, costs, and practical considerations. The first-tier tests are colonoscopy every 10 years and annual fecal immunochemical test (FIT). Colonoscopy and FIT are recommended as the cornerstones of screening regardless of how screening is offered. Thus, in a sequential approach based on colonoscopy offered first, FIT should be offered to patients who decline colonoscopy. Colonoscopy and FIT are recommended as tests of choice when multiple options are presented as alternatives. A risk-stratified approach is also appropriate, with FIT screening in populations with an estimated low prevalence of advanced neoplasia and colonoscopy screening in high prevalence populations. The second-tier tests include CT colonography every 5 years, the FIT-fecal DNA test every 3 years, and flexible sigmoidoscopy every 5 to 10 years. These tests are appropriate screening tests, but each has disadvantages relative to the tier 1 tests. Because of limited evidence and current obstacles to use, capsule colonoscopy every 5 years is a third-tier test. We suggest that the Septin9 serum assay (Epigenomics, Seattle, Wash) not be used for screening. Screening should begin at age 50 years in average-risk persons, except in African Americans in whom limited evidence supports screening at 45 years. CRC incidence is rising in persons under age 50, and thorough diagnostic evaluation of young persons with suspected colorectal bleeding is recommended. Discontinuation of screening should be considered when persons up to date with screening, who have prior negative screening (particularly colonoscopy), reach age 75 or have <10 years of life expectancy. Persons without prior screening should be considered for screening up to age 85, depending on age and comorbidities. Persons with a family history of CRC or a documented advanced adenoma in a first-degree relative age <60 years or 2 first-degree relatives with these findings at any age are recommended to undergo screening by colonoscopy every 5 years, beginning 10 years before the age at diagnosis of the youngest affected relative or age 40, whichever is earlier. Persons with a single first-degree relative diagnosed at ≥60 years with CRC or an advanced adenoma can be offered average-risk screening options beginning at age 40 years.

Colorectal Cancer Screening: Recommendations for Physicians and Patients from the U.S. Multi-Society Task Force on Colorectal Cancer

This document updates the colorectal cancer (CRC) screening recommendations of the U.S. Multi-Society Task Force of Colorectal Cancer (MSTF), which represents the American College of Gastroenterology, the American Gastroenterological Association, and The American Society for Gastrointestinal Endoscopy. CRC screening tests are ranked in 3 tiers based on performance features, costs, and practical considerations. The first-tier tests are colonoscopy every 10 years and annual fecal immunochemical test (FIT). Colonoscopy and FIT are recommended as the cornerstones of screening regardless of how screening is offered. Thus, in a sequential approach based on colonoscopy offered first, FIT should be offered to patients who decline colonoscopy. Colonoscopy and FIT are recommended as tests of choice when multiple options are presented as alternatives. A risk-stratified approach is also appropriate, with FIT screening in populations with an estimated low prevalence of advanced neoplasia and colonoscopy screening in high prevalence populations. The second-tier tests include CT colonography every 5 years, the FIT-fecal DNA test every 3 years, and flexible sigmoidoscopy every 5 to 10 years. These tests are appropriate screening tests, but each has disadvantages relative to the tier 1 tests. Because of limited evidence and current obstacles to use, capsule colonoscopy every 5 years is a third-tier test. We suggest that the Septin9 serum assay (Epigenomics, Seattle, Wash) not be used for screening. Screening should begin at age 50 years in average-risk persons, except in African Americans in whom limited evidence supports screening at 45 years. CRC incidence is rising in persons under age 50, and thorough diagnostic evaluation of young persons with suspected colorectal bleeding is recommended. Discontinuation of screening should be considered when persons up to date with screening, who have prior negative screening (particularly colonoscopy), reach age 75 or have <10 years of life expectancy. Persons without prior screening should be considered for screening up to age 85, depending on age and comorbidities. Persons with a family history of CRC or a documented advanced adenoma in a first-degree relative age <60 years or 2 first-degree relatives with these findings at any age are recommended to undergo screening by colonoscopy every 5 years, beginning 10 years before the age at diagnosis of the youngest affected relative or age 40, whichever is earlier. Persons with a single first-degree relative diagnosed at ≥60 years with CRC or an advanced adenoma can be offered average-risk screening options beginning at age 40 years.

Comparison of pathological diagnosis between tissue biopsy and endoscopic resection of colon polyps

AIM: To evaluate the discrepancy of pathological diagnosis between tissue biopsy and resection of colon polyps, and explore the main influencing factors to improve the accuracy of biopsy methods.

METHODS: This study retrospectively analyzed 161 colon polyps from 142 patients who underwent polyp resection at our hospital (patients with polyps of at least 1.0 cm in diameter). The discrepancy in the pathological diagnosis between endoscopic biopsy and resected tissues of colon polyps was evaluated. Factors that contributed to such discrepancy were analyzed.

RESULTS: The concordance rate of pathological diagnosis between endoscopic biopsy and resection was 51% (82/161), and the discrepancy rate was 49% (79/161). The lesion size was the main factor that undermined the diagnostic accuracy of biopsy (1.0-1.9 cm, the discrepancy rate was 42%; ≥2.0 cm, the discrepancy rate was 65%; P < 0.05).

CONCLUSION: The pathological diagnosis by endoscopic biopsy of colon polyps is of limited accuracy, especially in larger diameter polyps.

Colonic distention at screening CT colonography: role of spasmolytic agents and body habitus

Sufficient colonic dilation is important when using CT colonography (CTC) for colorectal cancer screening. We investigated the effect of antispasmodic agents and the patient body habitus on the degree of colonic dilation in screening CTC.We assessed the effect of clinical characteristics [age, gender, body mass index (BMI), and the presence of diverticula] and the use of antispasmodics on colonic distention in 140 patients who underwent CTC for colorectal cancer screening. The CTC was performed in both the supine- and prone positions. Seventy patients received antispasmodics prior to CT examination and the other 70 did not. Colonic distention was scored using a 5-point scale: 1=collapsed, 2=poorly visualized, 3=visualized but underdistended, 4=acceptable, and 5=excellent. Images scored as 4 or 5 were considered to be of diagnostic quality. The mean visual evaluation score was significantly higher in the supine- than the prone position (4.2±0.5 vs. 4.0±0.5, p<0.01). For the supine position, only the use of antispasmodic was statistically associated with sufficient colonic dilation by univariate logistic analysis (odds ratio=2.365, p=0.03). For the prone position, age, BMI, and the use of antispasmodic were statistically associated with sufficient colonic dilation by multivariate analysis. The odds ratio of these parameters was 0.955 (p=0.02), 0.874 (p=0.03), and 2.391 (p=0.02), respectively.We obtained sufficient colonic dilation with an antispasmodic for CTC in both positions. Younger age and a lower BMI were also associated with better colonic dilation in the prone position.

[Experience of low volume split-dose bowel preparation for computed tomography colonography]

We propose a new preparation method for the computed tomography colonography (CTC). This method consists of giving a small volume (400 ml) of cleansing solution on the day before the examination and the same volume of solution on the day of the examination [low volume split-dose (LVSD) method]. Using this method, we compared the volume of residual fluid in the colon, the CT value of the residual fluid, and the quality of stool tagging with those for patients undergoing the conventional bowel preparation method. Polyp detectability of the CTC using this method and the acceptability of the preparation were also investigated. The volume of residual fluid in the colon with this method was smaller than that with the conventional method. The CT value of the residual fluid with this method was higher than that with the conventional method. Visual assessment of the quality of stool tagging with this method gave similar results to those obtained using the conventional method. The sensitivities were 95% for 5-10 mm polyps and 100% for polyps larger than 10 mm. The PPVs were 91% for 5-10 mm polyps and 100% for polyps larger than 10 mm. These results appear to be as good as in previous reports. In the questionnaires, about 80% of the answers were favorable regarding the volume and the taste of laxative. We conclude that LVSD bowel preparation method for CTC maintains polyp detectability and is better tolerated.

High success rate of repeat colonoscopy with standard endoscopes in patients referred for prior incomplete colonoscopy

BACKGROUND

In patients with incomplete colonoscopy, cecal intubation is sometimes unsuccessful due to a redundant or tortuous colon. Repeat colonoscopy may be successful with the use of alternate endoscopes or careful attention to technique but limited outcomes data is available. The aim of this study was to describe the technique, success rate and outcomes of consecutive patients referred for previous incomplete colonoscopy.

METHODS

We conducted a retrospective chart review of incomplete colonoscopy procedures in patients age 18-90 at an academic teaching hospital referred to an endoscopist specializing in difficult colonoscopy.

RESULTS

Cecal intubation was successful in 96 of 100 repeat colonoscopies and 83 procedures were completed with a standard endoscope (adult, pediatric, or gastroscope). The adenoma detection rate was 28% for successful repeat colonoscopies; a majority of these patients had no adenomas identified on incomplete exam. In 69.4% of cases, an endoscope was used to successfully complete colonoscopy that was not used in the incomplete colonoscopy. The median insertion time was significantly less for the complete colonoscopy (10.6 min) compared to the incomplete colonoscopy (18.8 min, P = 0.004).

CONCLUSIONS

Repeat colonoscopy has a high success rate and identified a significant number of new adenomas. Use of all available endoscopes should be considered prior to procedure termination in patients with a tortuous colon. Repeat colonoscopy can often be accomplished using a standard endoscope and is not attributed to increased endoscope insertion time.

Contrast coating for the surface of flat polyps at CT colonography: a marker for detection

OBJECTIVES

To assess the frequency of oral contrast coating of flat polyps, which may promote detection, and influencing factors within a screening CT colonography (CTC) population.

METHODS

This was a retrospective, observational study performed at one institution. From 7,426 individuals, 123 patients with 160 flat polyps were extracted. Flat polyps were defined as plaque-like, raised at most 3 mm in height and reviewed for contrast coating. Factors including demographic variables such as age and sex, and polyp variables such as polyp size, location and histology were analysed for effect on coating.

RESULTS

Of 160 flat polyps (mean size 9.4 mm ± 3.6), 78.8 % demonstrated coating. Mean coat thickness was 1.5 mm ± 0.6; 23.8 % (n = 30) demonstrated a thin film of contrast. Large size (≥10 mm) and proximal colonic location (relative to splenic flexure) were predictive variables by univariate logistic regression [OR (odds ratio) 3.4 (CI 1.3-8.9; p = 0.011), 2.0 (CI 1.2-3.5; p = 0.011), respectively]. Adenomas (OR 0.37, CI 0.14-1.02; p = 0.054) and mucosal polyps or venous blebs (OR 0.07, CI 0.02-0.25; p < 0.001) were less likely to coat than serrated/hyperplastic lesions. Age and sex were not predictive for coating (p = 0.417, p = 0.499, respectively).

CONCLUSIONS

Surface contrast coating is common for flat polyps at CTC, promoted by large size, proximal location and serrated/hyperplastic histology. Given the difficulty in detection, recognition may aid in flat polyp identification.

KEY POINTS

• Oral contrast coats the surface of most flat colorectal polyps at CT colonography. • Large size, proximal colonic location and serrated/hyperplastic histology increase polyp coating. • Contrast coating increases diagnostic confidence for flat polyps. • Contrast coating may help in flat polyp detection at CTC.

Carpet lesions detected at CT colonography: clinical, imaging, and pathologic features

PURPOSE

To describe carpet lesions (laterally spreading tumors ≥ 3 cm) detected at computed tomographic (CT) colonography, including their clinical, imaging, and pathologic features.

MATERIALS AND METHODS

The imaging reports for 9152 consecutive adults undergoing initial CT colonography at a tertiary center were reviewed in this HIPAA-compliant, institutional review board-approved retrospective study to identify all potential carpet lesions detected at CT colonography. Carpet lesions were defined as morphologically flat, laterally spreading tumors 3 cm or larger. For those patients with neoplastic carpet lesions, CT colonography studies were analyzed to determine maximal lesion width and height, oral contrast material coating, segmental location, and computer-aided detection (CAD) findings. Demographic data and details of clinical treatment in these patients were reviewed.

RESULTS

Eighteen carpet lesions in 18 patients (0.2%; mean age, 67.1 years; eight men, 10 women) were identified and were subsequently confirmed at colonoscopy and pathologic examination among 20 potential flat masses (≥3 cm) prospectively identified at CT colonography (there were two nonneoplastic rectal false-positive findings). No additional neoplastic carpet lesions were found in the cohort undergoing colonoscopy after CT colonography and/or surgery (there were no false-negatives). Mean lesion width was 46.5 mm (range, 30-80 mm); mean lesion height was 7.9 mm (range, 4-14 mm). Surface retention of oral contrast material was noted in all 18 cases. All but two lesions were located in the distal rectosigmoid or proximal right colon. At CAD, 17 (94.4%) lesions were detected (mean, 6.2 CAD marks per lesion). Sixteen lesions (88.9%) demonstrated advanced histologic features, including a villous component (n = 11), high-grade dysplasia (n = 4), and invasive cancer (n = 5). Sixteen patients (88.9%) required surgical treatment for complete excision.

CONCLUSION

CT colonography can effectively depict carpet lesions. Common features in this series included older patient age, rectal or cecal location, surface coating with oral contrast material, multiple CAD hits, advanced yet typically benign histologic features, and surgical treatment.

Endoscopic and pathological features of colorectal polyps and risk factors for their malignant transformation

AIM: To summarize the endoscopic and pathological characteristics of colorectal polyps and to analyze risk factors for their malignant transformation.

METHODS: A total of 406 patients with colorectal polyps treated at our hospital were included in this study. The endoscopic and pathological characteristics of colorectal polyps (including age, size, shape, location, and pathological type) were explored and risk factors for their malignant transformation were analyzed.

RESULTS: The elderly group was associated with the highest incidence of colorectal polyps, followed by the middle-aged group and young group. Colorectal polyps were most commonly seen in the sigmoid colon and rectum, and ileocecal polyps were relatively rarely seen. Polyps with a diameter ≤ 1 cm were most commonly seen, and most of them were hyperplastic polyps. Polyps with a diameter of 1-2 cm were mostly adenomas. Polyps with a diameter > 2 cm were mostly juvenile polyps. Non-lobulated colorectal polyps were more commonly seen. Lobulated polyps were mostly adenomatous, while non-lobulated ones were mostly proliferative. The rate of malignant transformation was significantly higher in the elderly group than in the young and middle-aged groups (χ² = 10.317, P < 0.05). Malignant transformation was more commonly seen in the ileocecal junction, rectum, sigmoid colon than in other locations (χ² = 5.787, P < 0.05). With the increase in polyp diameter, the probability of malignant transformation increased. The probability of malignant transformation was more commonly seen in adenomas than in other pathologic types (χ² = 67.183, P < 0.05), and in lobulated adenomas than in non-lobulated ones.

CONCLUSION: Patients with colorectal polyps should undergo endoscopy to examine the whole colon to carefully observe the shape, size, site of polyps and conduct a biopsy. If possible, polyps should be removed to avoid the occurrence of malignant transformation.

The new view of colon cancer screening: forwards and backwards

Many different techniques for colon cancer screening are available. The fecal immunochemical test is best for fecal-based screening, although the DNA investigation may be more specific when further developed. Computed tomographic colonography is as good as colonoscopy for detecting colon cancer and is almost as good as colonoscopy for detecting advanced adenomas, but has limitations. The flexible sigmoidoscopic examination markedly decreases the incidence of cancer in the visualized segments, but colonoscopy is currently the best procedure for evaluating the large bowel. Techniques for retroflexion or backward view of the colon have been investigated, with all showing increased polyp detection.