Role of high definition colonoscopy in colorectal adenomatous polyp detection

≥3 Nonadvanced Adenomas are More Common in the Era of Contemporary Colonoscopy and Not Associated With Metachronous Advanced Neoplasia

INTRODUCTION

Data from standard definition colonoscopy era demonstrate patients with an advanced adenoma (≥10 mm, villous features or high-grade dysplasia) or ≥3 nonadvanced adenomas are considered high-risk for metachronous advanced neoplasia (MAN). Low-risk adenoma (LRA) patients are those with 1 to 2, <10 mm tubular adenomas. High definition colonoscopy, split-dose bowel preparation, and attention to adenoma detection enhance diminutive adenoma detection. We compared baseline adenoma characteristics between patients undergoing colonoscopy in a historic cohort (HC) and contemporary cohort (CC) to determine if number of patients with ≥3 nonadvanced adenomas are increased in CC, and if those features are associated with MAN in CC.

MATERIALS AND METHODS

Patients undergoing their first colonoscopy in HC (<2006) and CC (≥2006) at age 50 and above were identified through natural language processing. Multivariable regression analysis compared baseline adenoma characteristics between HC and CC, and determined the association between baseline characteristics and MAN in CC patients.

RESULTS

In total, 255,074 colonoscopies were performed between 1990 and 2015. A total of 9773 colonoscopies performed in the HC and 59,531 in the CC were included. At baseline, CC patients were more likely to have ≥3 nonadvanced adenomas [odds ratio (OR): 2.1, 95% confidence interval (CI): 1.7-2.6]. In 3,377 CC patients undergoing follow-up colonoscopy, the risk of MAN did not differ between patients with LRA versus those with ≥3 nonadvanced adenomas (6.3% vs. 4.6%, OR: 1.4, CI: 0.58-3.5) including 3-4 (6.1%, OR: 1.4, CI: 0.52-3.6) and ≥5 (7.7%, OR: 1.8, CI: 0.23-14.6), although few patients had ≥5 nonadvanced adenomas.

CONCLUSIONS

Colonoscopy in the contemporary era increases detection of patients with ≥3 nonadvanced adenomas, which do not increase the risk of MAN compared with LRA patients. A similar surveillance to LRA patients should be considered for those patients.

Identification of key candidate genes and pathways associated with colorectal aberrant crypt foci-to-adenoma-to-carcinoma progression

AIM

The present study aimed to detect key candidate genes and pathways involved in colorectal aberrant crypt foci-to-adenoma-to-carcinoma progression.

BACKGROUND

Although colorectal cancer (CRC) is the third most common type of cancer, the involved signaling pathways and driver-genes remain largely unclear. CRC begins with the malignant transformation of precancerous lesions including aberrant crypt foci (ACF) and benign adenomatous polyp or adenoma.

METHODS

A list of formerly reported ACF, adenoma, and CRC-associated proteins was obtained from GeneCards, and then the data in online David Bioinformatics Resources was analyzed. The protein-protein interactions were surveyed utilizing String database and Cytoscape software. After hubs and bottlenecks were recognized, the key genes and pathways were identified through different bioinformatics analysis.

RESULTS

The most important pathways associated with colorectal aberrant crypt foci-to-adenoma progression were attributed to "pathways in cancer" and "chemokine signaling pathway" and those in adenoma-to-carcinoma progression were related to "pathways in cancer," "chemokine signaling pathway," and "Ras signaling pathway." The genes participating in these pathways are key ones. Furthermore, PRKACB, CUL2, and GSK3B were significant as the seed in the clusters related to adenoma and GNB1, RALBP1, ROCK1, and IKBKG in the clusters related to cancer.

CONCLUSION

The key candidate genes and pathways in progress CRC formed precursor lesions were identified by integrated bioinformatics analysis. The results could lead to a better understanding of the cause and underlying molecular events as well as detection of therapeutic targets for CRC.

Afro-Caribbeans Have a Lower Prevalence of Advanced Colon Neoplasia than African-Americans

BACKGROUND/AIMS

The black population in the USA is a heterogeneous group composed of smaller subgroups from different origins. The definition of black in many colorectal cancer (CRC) risk studies is vague, and differences in CRC risk comparing black subpopulations have not been evaluated. The aim of the study is to compare advanced colorectal neoplasia (ACN) between two subgroups of black populations: African-American (AA) and Afro-Caribbean (AC). A secondary aim was to determine whether there are differences in prevalence of adenomas.

METHODS

This was a retrospective study of 3797 AA and AC patients undergoing first time screening colonoscopy in two different institutions in the USA.

RESULTS

Overall adenoma prevalence was 29.3% for the entire population with 29.5% in AAs and 29.0% in AC with no statistically significant difference between the study groups (AOR: 1.02; 95% CI 0.88-1.18, P = 0.751). However, ACN was significantly higher in the AA group (11.8%) compared to AC (9.0%) (AOR: 1.30, 95% CI 1.02-1.66, P = 0.034). It was observed that AAs had ACN at a higher BMI than AC. After adjusting for BMI/ethnicity interactions, the difference in ACN between both groups became more significant (AOR: 1.93, 95% CI 1.16-3.23, P = 0.012).

CONCLUSIONS

AAs have a higher risk of ACN than AC. Current recommendations to start screening in average-risk AAs at an earlier age may not apply to other black subgroups.

Can technology increase adenoma detection rate?

Colorectal cancer is the third most common cancer worldwide and the second most common cause of cancer-related death in Europe and North America. Colonoscopy is the gold standard investigation for the colon but is not perfect, and small or flat adenomas can be missed which increases the risk of patients subsequently developing colorectal cancer. Adenoma detection rate is the most widely used marker of quality, and low rates are associated with increased rates of post-colonoscopy colorectal cancer. Standards of colonoscopy and adenoma detection vary widely between different endoscopists. Interventions to improve adenoma detection rate are therefore required. Many devices have been purported to increase adenoma detection rate. This review looks at current available evidence for device technology to improve adenoma detection rate during colonoscopy.

Enhanced flat adenoma detection rate with high definition colonoscopy plus i-scan for average-risk colorectal cancer screening

BACKGROUND AND AIM

The usefulness of high definition colonoscopy plus i-scan (HD+i-SCAN) for average-risk colorectal cancer screening has not been fully assessed. The detection rate of adenomas and other measurements such as the number of adenomas per colonoscopy and the flat adenoma detection rate have been recognized as markers of colonoscopy quality. The aim of the present study was to compare the diagnostic performance of an HD+i-SCAN with that of standard resolution white-light colonoscope.

METHODS

This is a retrospective analysis of a prospectively collected screening colonoscopy database. A comparative analysis of the diagnostic yield of an HD+i-SCAN or standard resolution colonoscopy for average-risk colorectal screening was conducted.

RESULTS

During the period of study, 155/163 (95.1%) patients met the inclusion criteria. The mean age was 56.9 years. Sixty of 155 (39%) colonoscopies were performed using a HD+i-SCAN. Adenoma-detection-rates during the withdrawal of the standard resolution versus HD+i-SCAN colonoscopies were 29.5% and 30% (p = n.s.). Adenoma/colonoscopy values for standard resolution versus HD+i-SCAN colonoscopies were 0.46 (SD = 0.9) and 0.72 (SD = 1.3) (p = n.s.). A greater number of flat adenomas were detected in the HD+i-SCAN group (6/60 versus 2/95) (p < .05). Likewise, serrated adenomas/polyps per colonoscopy were also higher in the HD+i-SCAN group.

CONCLUSIONS

A HD+i-SCAN colonoscopy increases the flat adenoma detection rate and serrated adenomas/polyps per colonoscopy compared to a standard colonoscopy in average-risk screening population. HD+i-SCAN is a simple, available procedure that can be helpful, even for experienced providers. The performance of HD+i-SCAN and substantial prevalence of flat lesions in our average-risk screening cohort support its usefulness in improving the efficacy of screening colonoscopies.

Expert opinions and scientific evidence for colonoscopy key performance indicators

Colonoscopy is a widely performed procedure with procedural volumes increasing annually throughout the world. Many procedures are now performed as part of colorectal cancer screening programmes. Colonoscopy should be of high quality and measures of this quality should be evidence based. New UK key performance indicators and quality assurance standards have been developed by a working group with consensus agreement on each standard reached. This paper reviews the scientific basis for each of the quality measures published in the UK standards.

High-definition colonoscopy increases adenoma detection rate

BACKGROUND

The adenoma detection rate (ADR) is a quality indicator for colonoscopy. High-definition (HD) imaging has been reported to increase polyp detection rates.

OBJECTIVE

The primary objective of this study was to compare polyp detection rate (PDR) and adenoma detection rate (ADR) before and after the implementation of HD colonoscopy.

METHODS

A retrospective chart review was performed on patients aged 48-55 years old, who underwent first-time screening colonoscopy. The first group underwent standard-definition (SD) colonoscopy in the first 6 months of 2011. The second group underwent screening with HD colonoscopy during the first 6 months of 2012. We compared age, gender, PDR, ADR, and average sizes of adenomatous polyps between gastroenterologist and colorectal surgeon and among physicians themselves. Statistical analysis was performed with Fischer's exact test and Pearson Chi-square.

RESULTS

A total of 1268 patients were involved in the study (634 in each group). PDR (35.6 vs. 48.2 %, p < 0.001) and ADR (22.2 vs. 30.4 %, p = 0.02) were higher in the HD group. The average size of an adenomatous polyp was the same in the two groups (0.58 vs. 0.57, p = 0.69). However, this difference was not seen among colorectal surgeons PDR (35.7 vs. 37 %, p = 0.789), ADR (22.9 vs. 24.5 % p = 0.513), but clearly seen among gastroenterologist, PDR (35.6 vs. 53.1 % p < 0.001) and ADR (21.9 vs. 32.9 % p < 0.001). When polyps were categorized into size groups, there was no difference in ADR between the two timeframes (<5 mm in size (41.5 vs. 35.4 %), 5-10 mm (49.3 vs. 60.1 %) and >10 mm (9.2 vs. 4.5 %), p = 0.07). Polyps were most commonly seen in the sigmoid colon (26.1 vs. 24.7 %). There was no difference in the rate of synchronous polyp detection between modalities (25.6 vs. 29 %, p = 0.51). Withdrawal time was the same in both procedure (9.2 vs. 8.5 min, p = 0.10).

CONCLUSION

Screening colonoscopy with high-definition technology significantly improved both PDR and ADR. In addition, high-definition colonoscopy may be particularly useful and advantageous among less experienced endoscopists in various community settings. However, there needs to be application to specific patient populations in future studies to assess for any statistical differences between standard- and high-definition modalities to determine clinical utility.

Can adjusting BMI for age and sex provide for a better predictor of colonic neoplasia?

OBJECTIVE

The aim of this study was to evaluate the influence of BMI on colonic neoplasia in average-risk patients aged between 40 and 59 years, analyzed by sex.

METHODS

A total of 4443 patients aged between 40 and 59 years undergoing a first-time screening or average-risk colonoscopy were included in this study. Data on demographics, smoking, and BMI were collected and correlated to the presence of adenomas and advanced adenomas.

RESULTS

We evaluated 1197 colonoscopies in patients aged between 40 and 49 years, and 3246 in those aged between 50 and 59 years. Among men between 40 and 49 years, increasing BMI [odds ratio (OR)=1.05, 95% confidence interval (CI): 1.00-1.09] and BMI of at least 27 (OR=1.95, 95% CI: 1.15-3.29) were predictors of adenomas. Younger men with a BMI of at least 27 were more likely to have proximal adenomas (OR=2.23, 95% CI: 1.14-4.37) but not advanced adenomas. There was no relation between BMI and adenomas in younger women. Among women aged between 50 and 59 years, increasing BMI (OR=1.03, 95% CI: 1.01-1.05) and a BMI of at least 24 (OR=1.43, 95% CI: 1.06-2.94) was found to be correlated with adenomas, and increasing BMI was also found to be associated with proximal adenomas (OR=1.67, 95% CI: 1.13-2.45). Among men aged between 50 and 59 years, there was no relation between BMI and adenomas, but there was a positive correlation for advanced adenomas (OR=1.05, 95% CI: 1.002-1.09). Among women aged between 50 and 59 years, BMI was not predictive of advanced adenomas.

CONCLUSION

The association between BMI and adenoma differs by age and sex. If BMI is utilized to refine screening practices for colorectal cancer, its influence on sex and age should be taken into account.

Optimized sedation improves colonoscopy quality long-term

Background. Quality monitoring and improvement is prerequisite for efficient colonoscopy. Aim. To assess the effects of increased sedation administration on colonoscopy performance. Materials and Methods. During Era 1 we prospectively measured four colonoscopy quality indicators: sedation administration, colonoscopy completion rate, adenoma detection rate, and early complications rate in three cohorts: cohort A: intention for total colonoscopy cases; cohort B: cohort A excluding bowel obstruction cases; cohort C: CRC screening-surveillance cases within cohort B. We identified deficiencies and implemented our plan to optimize sedation. We prospectively evaluated its effects in both short- (Era 2) and long-term period (Era 3). Results. We identified that sedation administration and colonoscopy completion rates were below recommended standards. After sedation optimization its use rate increased significantly (38.1% to 55.8% to 69.5%) and colonoscopy completion rate increased from 88.3% to 90.6% to 96.4% in cohort B and from 93.2% to 95.3% to 98.3% in cohort C, in Eras 1, 2, and 3, respectively. Adenoma detection rate increased in cohort C (25.9% to 30.6% to 35%) and early complications rate decreased from 3.4% to 1.9% to 0.3%. Most endoscopists increased significantly their completion rate and this was preserved long-term. Conclusion. Increased sedation administration results in long-lasting improvement of colonoscopy quality indicators.

Ancillary imaging techniques and adenoma detection

Advancements in image technology have allowed recognition of mucosal architecture in more detail and may improve adenoma detection. This review provides a technical overview on individual imaging technologies and their effect on detection of adenomas. Only high-definition endoscopy has been shown to improve detection of small adenomas. None of the digital chromoendoscopy technologies improves adenoma detection. Limited studies on autoimmunfluorescence imaging in conjunction with high-definition endoscopy may improve detection of small adenomas.

Comparison of adenoma detection rate in Hispanics and whites undergoing first screening colonoscopy: a retrospective chart review

BACKGROUND

Current guidelines recommend screening colonoscopy beginning at age 50 in the average-risk population. Race has been shown to influence the risk of colorectal cancer, thus leading to the recommendation of initiating screening in blacks at the age of 45. Few data exist on the prevalence of colon polyps among U.S. Hispanics.

OBJECTIVES

To compare the adenoma detection rate (ADR) between Hispanics and whites undergoing a first screening colonoscopy at our referral center.

DESIGN

Observational study.

SETTING

Single endoscopy unit, tertiary care teaching hospital.

PATIENTS

Patients 50 years of age or older undergoing their first screening colonoscopy whose race was determined as white or Hispanic from June 2007 to August 2010.

MAIN OUTCOME MEASUREMENT

ADR by race.

RESULTS

There was no statistically significant difference in the ADR among Hispanics and whites (45% and 48%, respectively; P = .2). No difference was found when comparing the ADR in Hispanic and white males (50% and 55%, respectively; P = .2), Hispanic and white females (40% in both groups), or in the 50- to 59-year-old subgroup (42% in Hispanics, 45% in whites, P = .4). There was no difference in the prevalence of advanced adenomas (3% in Hispanics, 4% in whites, P = .3). The prevalence of proximal polyps in Hispanics and whites was similar (18% and 19%, respectively, P = .8).

LIMITATIONS

Retrospective design, self-identification of race/ethnicity, underrepresentation of certain Hispanic subgroups.

CONCLUSIONS

We found a similar ADR among Hispanics and whites undergoing their first screening colonoscopy. These findings have important implications for colorectal cancer screening recommendations, suggesting that the current guidelines are appropriate for Hispanics.

Endoscopic techniques for improving colorectal adenoma detection: Recent progress

Colorectal cancer (CRC) is one of the most common malignant neoplasms worldwide and develops mostly from precancerous lesions such as colorectal adenomas. Therefore, early detection and resection of colorectal adenomas is key to preventing CRC. At present, colonoscopy is acknowledged as the gold standard for the diagnosis and treatment of colorectal lesions; however, conventional colonoscopy is still associated with a certain rate of missed lesions. It is reported that the missed detection rate is 6% when adenomas are more than 1 cm, 13% for adenomas 6-9 mm, and 27% for adenomas less than 5 mm. The missed detection rate for right colonic adenomas is higher than that for left colonic adenomas. The missed diagnosis of colorectal adenomas or malignant tumors invariably increases surgical rate and mortality. Currently, great efforts have been made to improve the detection rate of colorectal adenomas. This paper will briefly review recent advances in endoscopic techniques for improving the detection rate of colorectal adenomas.

High-definition colonoscopy with i-Scan: Better diagnosis for small polyps and flat adenomas

AIM: To investigate if high-definition (HD) colonoscope with i-Scan gave a higher detection rate of mucosal lesions vs standard white-light instruments.

METHODS: Data were collected from the computerized database of the endoscopy unit of our tertiary referral center. We retrospectively analyzed 1101 consecutive colonoscopies that were performed over 1 year with standard white-light (n = 849) or HD+ with i-Scan (n = 252) instruments by four endoscopists, in an outpatient setting. Colonoscopy records included patients’ main details and family history for colorectal cancer, indication for colonoscopy (screening, diagnostic or surveillance), type of instrument used (standard white-light or HD+ plus i-Scan), name of endoscopist and bowel preparation. Records for each procedure included whether the cecum was reached or not and the reason for failure, complications during or immediately after the procedure, and number, size, location and characteristics of the lesions. Polyps or protruding lesions were defined as sessile or pedunculated, and nonprotruding lesions were defined according to Paris classification. For each lesion, histological diagnosis was recorded.

RESULTS: Eight hundred and forty-nine colonoscopies were carried with the standard white-light video colonoscope and 252 with the HD+ plus i-Scan video colonoscope. The four endoscopists did 264, 300, 276 and 261 procedures, respectively; 21.6%, 24.0%, 21.7% and 24.1% of them with the HD+ plus i-Scan technique. There were no significant differences between the four endoscopists in either the number of procedures done or the proportions of each imaging technique used. Both techniques detected one or more mucosal lesions in 522/1101 procedures (47.4%). The overall number of lesions recognized was 1266; 645 in the right colon and 621 in the left. A significantly higher number of colonoscopies recognized lesions in the HD+ plus i-Scan mode (171/252 = 67.9%) than with the standard white-light technique (408/849 = 48.1%) (P < 0.0001). HD+ with i-Scan colonoscopies identified more lesions than standard white-light imaging (459/252 and 807/849, P < 0.0001), in the right or left colon (mean ± SD, 1.62 ± 1.36 vs 1.33 ± 0.73, P < 0.003 and 1.55 ± 0.98 vs 1.17 ± 0.93, P = 0.033), more lesions < 10 mm (P < 0.0001) or nonprotruding (P < 0.022), and flat polyps (P = 0.04). The cumulative mean number of lesions per procedure detected by the four endoscopists was significantly higher with HD+ with i-Scan than with standard white-light imaging (1.82 ± 2.89 vs 0.95 ± 1.35, P < 0.0001).

CONCLUSION: HD imaging with i-Scan during the withdrawal phase of colonoscopy significantly increased the detection of colonic mucosal lesions, particularly small and nonprotruding polyps.