Risk stratification and detection of new colorectal neoplasms after colorectal cancer screening with faecal occult blood test: experiences from a Danish screening cohort

Frequency of endoscopic photodocumentation of large colorectal polyps

BACKGROUND AND AIMS

Colonoscopy quality affects colorectal cancer (CRC) incidence and mortality. The U.S. Multi-Society Task Force on Colorectal Cancer strongly recommends photodocumentation (PD) of lesions ≥10 mm in size (ie, large polyps [LPs]) pre-resection and suggests PD postresection to enhance the quality of colonoscopy. No studies have assessed the frequency of LP PD. We evaluated the frequency of and factors associated with PD of LPs.

METHODS

Reports from endoscopists performing ≥50 colonoscopies with LP resection between 2016 and 2021 were reviewed. The frequency of LP PD pre-resection and post-resection and factors associated with PD were collected. A composite score of 2 quality metrics (PD of completeness of examination and bowel preparation quality) was created. Endoscopists were divided into 2 tiers based on the frequency of the score on all included examinations: Tier 1, ≥95% of examinations; and Tier 2, <95% of examinations. Univariate and multivariate analyses were used to assess factors associated with PD.

RESULTS

A total of 1322 colonoscopies, 1693 LPs, and 25 endoscopists were included in this study. PD of LPs occurred in 1392 (82%) pre-resection and in 878 (52%) post-resection. Factors associated with pre-resection PD include endoscopist subspecialty (colorectal surgery vs gastroenterology: odds ratio [OR], .12; 95% confidence interval [CI], .04-.42); >1 LP on examination (2 vs 1 LP: OR, .41 [95% CI, .27-.61]; and ≥3 vs 1 LP: OR, .41 [95% CI, .24-.70]), and longer withdrawal time (OR, 1.02; 95% CI, 1.01-1.04).

CONCLUSIONS

We provide the first data on PD of LP pre-resection and post-resection, which can inform future benchmarking in this area. The implications of PD on metachronous advanced neoplasia need to be studied.

Risk Factors for Metachronous Colorectal Cancer or Advanced Adenomas After Endoscopic Resection of High-risk Adenomas

BACKGROUND & AIMS

Among the characteristics of high-risk adenomas (HRAs), some may predict a higher risk of metachronous advanced lesions. Our aim was to assess which HRA characteristics are associated with high risk of metachronous colorectal cancer (CRC) or advanced adenomas (AAs).

METHODS

We systematically searched Pubmed, EMBASE, and Cochrane for cohort studies and clinical trials of CRC or AA incidence at surveillance stratified by baseline lesion size, histology, and multiplicity. We calculated pooled relative risks (RRs) using a random-effects model. Heterogeneity was assessed with the I² statistic.

RESULTS

Fifty-five studies were included, with 936,540 patients with mean follow-up 5.4 ± 2.9 years. CRC incidence per 1000 person-years was 2.6 (2.1-3.0) for adenomas ≥20 mm, 2.7 (2.2-3.2) for high-grade dysplasia (HGD), 2.0 (1.8-2.3) for villous component, 0.8 (0.1-1.4) for ≥5 adenomas, 1.0 (0.7-1.2) for ≥3 adenomas. Metachronous CRC risk was higher in adenomas ≥20 mm vs 10 to 19 mm (RR, 2.08; 95% confidence interval [CI], 1.20-3.61), HGD vs low-grade dysplasia (RR, 2.89; 95% CI, 1.88-4.44), villous vs tubular (RR, 1.75; 95% CI, 1.33-2.31). No significant differences in CRC risk were found in ≥3 adenomas vs 1 to 2 (RR, 1.24; 95% CI, 0.84-1.83), nor in ≥5 adenomas vs 3 to 4 (RR, 0.79; 95% CI, 0.30-2.11). Compared with normal colonoscopy, RR for CRC risk was 2.61 (95% CI, 2.06-3.32) for ≥10mm, 6.62 (95% CI, 4.60-9.52) for HGD, 3.58 (95% CI, 2.24-5.73) for villous component, and 2.03 (95% CI, 1.40-2.94) for ≥3 adenomas. Similar trends were seen for metachronous AAs.

CONCLUSION

Metachronous CRC risk is highest in patients with baseline adenomas with ≥20 mm or HGD. Multiplicity does not seem to be associated with substantially higher CRC risk in the near term.

Adenoma Detection Rate and Clinical Characteristics Influence Advanced Neoplasia Risk After Colorectal Polypectomy

BACKGROUND AND AIMS

Postpolypectomy risk stratification for subsequent metachronous advanced neoplasia (MAN) is imprecise and does not account for colonoscopist adenoma detection rate (ADR). Our aim was to assess association of ADR with MAN and create a prediction model for postpolypectomy risk stratification incorporating ADR and other factors.

METHODS

We conducted a retrospective cohort study of individuals with baseline polypectomy and subsequent surveillance colonoscopy from 2004 to 2016 within the U.S. Department of Veterans Affairs (VA). Clinical factors, polyp findings, and baseline colonoscopist ADR were considered for the model. Model performance (sensitivity, specificity, and area under the curve) for identifying individuals with MAN was compared with 2020 U.S. Multi-Society Task Force on Colorectal Cancer (USMSTF) surveillance recommendations.

RESULTS

A total of 30,897 individuals were randomly assigned 2:1 into independent model training and validation sets. Increasing age, male sex, diabetes, current smoking, adenoma number, polyp location, adenoma ≥10 mm or with tubulovillous/villous features, and decreasing colonoscopist ADR were independently associated with MAN. A range of 1.48- to 1.66-fold increased risk for MAN was observed for ADR in the lowest 3 quintiles (ADR <19.7%-39.3%) vs the highest quintile (ADR >47.0%). When the final model selected based on the training set was applied to the validation set, improved sensitivity and specificity over 2020 USMSTF risk stratification were achieved (P = .001), with an area under the curve of 0.62 (95% confidence interval, 0.60-0.64).

CONCLUSIONS

Colonoscopist ADR is associated with MAN. Combining clinical factors and ADR for risk stratification has potential to improve postpolypectomy risk stratification. Improving ADR is likely to improve postpolypectomy outcomes.

Colonoscope retraction technique and predicting adenoma detection rate: a multicenter study

BACKGROUND AND AIMS

The success of preventing colorectal cancer relies on the expertise of the colonoscopists. Studies suggest that the retraction technique is a powerful indicator of expertise in distinguishing endoscopists with various adenoma detection rates (ADRs). We aimed to develop a retraction technique score and explore the correlation between endoscopists' retraction technique and their ADRs.

METHODS

In a prospective, multicenter study, 8 colonoscopist nurses and physicians with various ADRs were included. Data from patients admitted for a colonoscopy, as part of the Danish nationwide screening program, were gathered directly from the Olympus ScopeGuide system (UPD-3; Olympus Optical, Tokyo, Japan) providing XYZ-coordinates from the coils along the length of the colonoscope. Motor skill measures were developed based on tip retraction, retraction efficiency, and retraction distance. The principal component analysis was used to study the association among the 3 measures and the historical ADR to create a combined score, the colonoscopy retraction score (CoRS).

RESULTS

Three hundred thirty-three recordings were analyzed. We demonstrated a significant and strong correlation between CoRS and ADR (.90, P < .01). Conversely, withdrawal time did not correlate significantly with ADR (.33, P = .42). In procedures without polypectomies or biopsy sampling, a significant and strong correlation was found between CoRS and ADR (.88, P < .01) and between withdrawal time and ADR (.75, P = .03).

CONCLUSIONS

This study presents a novel, real-time computerized and unbiased assessment tool for colonoscopy withdrawal. CoRS strongly correlated with ADR with and without therapeutic interventions during withdrawal and could be used to ensure quality instead of minimal withdrawal time. (Clinical trial registration number: NCT03587935.).

Surveillance Recommendation for Colonoscopy after Polypectomy

The incidence and mortality of colorectal cancer (CRC) have declined over the past several decades, largely due to improvement and uptake in screening, particularly with colonoscopy. The US Multi-Society Task Force on CRC published guidelines for surveillance after polypectomy in 2012, which were updated in 2020 with some important changes, and this review will provide an updated overview of evidence and outcomes of surveillance after polypectomy. Notable modifications to surveillance guidelines include increasing interval time between colonoscopies from 5 to 7 to 10 years for 1 to 2 low-risk adenomas (<10 mm) and from 3 years to 3 to 5 years when 3 to 4 low-risk adenomas are identified.

Tailoring Surveillance Colonoscopy in Patients With Advanced Adenomas

BACKGROUND & AIMS

Patients with advanced colorectal adenomas (AAs) are directed to undergo intensive surveillance. However, the benefit derived from surveillance may be outweighed by the risk of death from non-colorectal cancer (CRC) causes, leading to uncertainty on how best to individualize follow-up. The aim of this study was to derive a risk prediction model and risk index that estimate and stratify the risk for non-CRC cancer mortality (NCM) subsequent to diagnosis and removal of AA.

METHODS

We conducted a retrospective cohort study of veterans ≥40 years old who had colonoscopy for diagnostic or screening indications at 13 Veterans Affairs Medical Centers between 2002 and 2009 and had 1 or more AAs. The primary outcome was NCM using a fixed follow-up time period of 5 years. Logistic regression using the lasso technique was used to identify factors independently associated with NCM, and an index based on points from regression coefficients was constructed to estimate risk of 5-year NCM.

RESULTS

We identified 2943 veterans with AA (mean age [standard deviation] 63 [8.6] years, 98% male, 74% white), with an overall 5-year mortality of 16.7%, which was nearly all due to NCM (16.6%). Age, comorbidity burden, specific comorbid conditions, and hospitalization within the preceding year were independently associated with NCM. The risk prediction model had a goodness of fit (calibration) P value of .41 and c-statistic (discrimination) of 0.74 (95% confidence interval, 0.71-0.76). On the basis of comparable 5-year risks of NCM, the scores comprised 3 risk categories: low (score of 0-1), intermediate (score of 2-4), and high (score of ≥5), in which NCM occurred in 6.5%, 14.1%, and 33.2%, respectively.

CONCLUSIONS

We derived a risk prediction model that identifies veterans with advanced adenomas who are at high risk of NCM within 5 years, and who are thus unlikely to benefit from further surveillance.

Nomograms to predict cancer-specific mortality in colon adenocarcinoma with different types of villous architecture

PURPOSE

The role of villous architecture in the prognosis of colon adenocarcinoma remains unclear. This study aimed to investigate the prognostic factors of colon adenocarcinoma with different types of villous architecture and to establish nomograms for predicting cancer-specific mortality.

METHODS

This retrospective study included 10,427 patients with colon adenocarcinoma arising in adenomas with villous architectures. The patients were stratified into the tubulovillous adenocarcinoma cohort and villous adenocarcinoma cohort. The prognostic risk factors, which were incorporated into nomograms for survival prediction, were determined by the log-rank test and Cox hazard models. The Harrell's Concordance Index (C-index) and calibration curve were utilized to evaluate the prediction accuracy.

RESULTS

The pathological type of villous architecture was independently associated with the mortality of the entire population. Age, race, tumor size, T/N/M stage, and chemotherapy were independent risk factors of mortality in both cohorts. Interestingly, tumor differentiation was a prognostic factor for tubulovillous adenocarcinoma rather than villous adenocarcinoma, while the retrieved lymph node number was a prognostic factor for villous adenocarcinoma rather than tubulovillous adenocarcinoma. Survival analysis showed that the mortality rate of villous adenocarcinoma was higher than that of tubulovillous adenocarcinoma (HR 1.361, P < 0.001). We then established nomograms to predict the mortality of both cohorts and found excellent discrimination and predictive accuracy (C-index 0.842 and 0.821).

CONCLUSION

Villous architecture is a determinant of colon adenocarcinoma outcomes, which might prompt reports of villous architecture in colon adenocarcinoma specimens by pathologists. Our population-based nomograms could be useful for predicting the survival of patients with colon adenocarcinoma and guiding individualized treatments.

The Microbiome Colorectal Cancer Puzzle: Initiator, Propagator, and Avenue for Treatment and Research

The human gut microbiome has an ever-increasing role in the instigation and progression of colorectal cancer (CRC). Recent investigations have focused on identifying the key causative bacterial species and the composition and structure of the microbiome as a whole that ultimately lead to tumorigenesis in the colon. Understanding the bacterial mechanisms that promote CRC provides a rich area for the development of new screening modalities and therapeutics that may improve patient outcomes. This article reviews the various mechanisms that bacteria in the gut use to induce and/or promote tumor formation, discusses the application of the microbiome in the prevention and therapy of CRC, and provides directions for future research endeavors aiming to develop a more complete understanding of this complex phenomenon.

Microbiome in Colorectal Cancer: How to Get from Meta-omics to Mechanism?

Mounting evidence from metagenomic analyses suggests that a state of pathological microbial imbalance or dysbiosis is prevalent in the gut of patients with colorectal cancer. Several bacterial taxa have been identified of which representative isolate cultures interact with human cancer cells in vitro and trigger disease pathways in animal models. However, how the complex interrelationships in dysbiotic communities may be involved in cancer pathogenesis remains a crucial question. Here, we provide a survey of current knowledge of the gut microbiome in colorectal cancer. Moving beyond observational studies, we outline new experimental approaches for gaining ecosystem-level mechanistic understanding of the gut microbiome's role in cancer pathogenesis.

Long-term risk of colorectal cancer after screen-detected adenoma: Experiences from a Danish gFOBT-positive screening cohort

Fecal occult blood test (FOBT) screening for colorectal cancer (CRC) is implemented in several countries. Approximately half of all FOBT-positive persons have screen-detected adenomas. Despite removal of these, patients with large/multiple adenomas have increased risk of later developing new advanced adenomas and CRC. International guidelines exist for colonoscopic surveillance following adenoma removal. These divide patients into low-, intermediate- and high-risk groups. We followed 711 FOBT-positive patients with screening adenoma identified during population-based CRC screening in two Danish counties in 2005-2006. As reference population, we included 1,240,348 persons in the same age group from the rest of Denmark not included in the screening. We estimated the long-term CRC risk stratified by adenoma findings during screening and compared to the reference group. After 12 years follow-up, the CRC incidence among all adenoma patients was 322 cases per 100,000 person-years (95% confidence interval [CI]: 212-489) ranging from 251 (95% CI: 94-671) to 542 (95% CI: 300-978) cases per 100,000 person-years in the low- and high-risk groups, respectively. In the reference population, the CRC incidence was 244 (95% CI: 242-247) per 100,000. Patients with screen-detected high-risk adenomas after a positive FOBT had an almost doubled risk of CRC compared to the reference population (adjusted hazard ratio [aHR] 1.95, 95% CI: 1.08-3.51), and the incidence in those with no follow-up visits was over 3.6 (aHR 3.64, 95% CI: 1.82-7.29) times the incidence in the reference population. The increased CRC risk could be controlled if high-risk patients underwent follow-up colonoscopy (aHR 0.87, 95% CI: 0.28-2.69).

Factors related to the participation and detection of lesions in colorectal cancer screening programme-based faecal immunochemical test

Background

The overall aim of this study was to describe trends in participation rates and detection of lesions in a colorectal cancer (CRC) screening programme, during three rounds, using faecal immunochemical test (FIT).

Methods

National registers were used to collect data on invitations for CRC screening in the Basque Country (Spain) from 2009 to 2014. Information about participation, age, gender and lesions in each round were collected.

Results

A total of 961.533 individuals were included in the analysis; respectively, 584.950, 298.143 and 78.440 in the first, second and third rounds. The average participation rate was 68.4% (66.8, 70.4 and 72.3%, respectively by round; P < 0.001) and the positivity rate was 6.3% (7, 5.5 and 5.4%, respectively by round; P < 0.001). The participation rate increased significantly with age and was found to be higher in women versus men. A total of 15.144 advanced adenomas and 2.131 CRCs were diagnosed, leading to a detection rate of 23.9 and 3.4‰, respectively. Regarding gender, men had the highest rates in all periods and rounds. The detection rate of advanced neoplasia was lower in the regular when compared with irregular paricipants.

Conclusions

In a CRC screening, this organization obtained high FIT participation rates. Older participants and women were associated with a higher participation. The detection rate of lesions was higher in men, independent on age and round.

Colorectal cancer screening program using FIT: quality of colonoscopy varies according to hospital type

Background and study aims  To compare the quality of colonoscopy in a population-based coordinated program of colorectal cancer screening according to type of hospital (academic or non-academic). Patients and methods  Consecutive patients undergoing colonoscopy after positive FIT (≥ 20 ug Hb/g feces) between January 2009 and September 2016 were prospectively included at five academic and seven non-academic public hospitals. Screening colonoscopy quality indicators considered were adenoma detection rate, cecal intubation rate, complications and bowel preparation quality. Results  A total of 48,759 patients underwent colonoscopy, 34,616 (80 %) in academic hospitals and 14,143 in non-academic hospitals. Among these cases, 19,942 (37.1 %) advanced adenomas and 2,607 (5.3 %) colorectal cancers (CRCs) were detected, representing a total of 22,549 (46.2 %) cases of advanced neoplasia. The adenoma detection rate was 64 %, 63.1 % in academic hospitals and 66.4 % in non-academic hospitals ( P  < 0.001). Rates of advanced adenoma detection, cecal intubation and adequate colonic preparation were 45.8 %, 96.2 % and 88.3 %, respectively, and in all cases were lower (implying worse quality care) in academic hospitals (45.3 % vs 48.7 %; odds ratio [OR] 0.87, 95 % confidence interval [CI] 0.84 - 0.91; 95.9 % vs 97 %; OR 0.48, 95 % CI 0.38 - 0.69; and 86.4 % vs 93 %; OR 0.48, 95 % CI 0.45 - 0.5; respectively; P  < 0.001 in all cases). In 13 patients, all in the academic hospital group, CRC was diagnosed after colonoscopy (0.26 cases × 1000 colonoscopies). Rates of CRC treated by endoscopy were similar in both types of hospital (30 %). The rate of severe complication was 1.2 % (602 patients), with no significant differences by hospital type: bleeding occurred in 1/147 colonoscopies and perforation in 1/329. One patient died within 30 days after screening colonoscopy. Conclusions  The quality of colonoscopy was better in non-academic hospitals. The rate of detection of advanced neoplasia was higher in non-academic hospitals and correlated with the rate of post-colonoscopy CRC.