Risk of Advanced Proximal Neoplasms According to Distal Colorectal Findings: Comparison of Sigmoidoscopy-Based Strategies

Optimal Strategies for Colorectal Cancer Screening

Colorectal cancer (CRC) imposes significant morbidity and mortality, yet it is also largely preventable with evidence-based screening strategies. In May 2021, the US Preventive Services Task Force updated guidance, recommending screening begin at age 45 for average-risk individuals to reduce CRC incidence and mortality in the United States (US). The Task Force recommends screening with one of several screening strategies: high-sensitivity guaiac fecal occult blood test (HSgFOBT), fecal immunochemical test (FIT), multi-target stool DNA (mt-sDNA) test, computed tomographic (CT) colonography (virtual colonoscopy), flexible sigmoidoscopy, flexible sigmoidoscopy with FIT, or traditional colonoscopy. In addition to these recommended options, there are several emerging and novel CRC screening modalities that are not yet approved for first-line screening in average-risk individuals. These include blood-based screening or “liquid biopsy,” colon capsule endoscopy, urinary metabolomics, and stool-based microbiome testing for the detection of colorectal polyps and/or CRC. In order to maximize CRC screening uptake in the US, patients and providers should engage in informed decision-making about the benefits and limitations of recommended screening options to determine the most appropriate screening test. Factors to consider include the invasiveness of the test, test performance, screening interval, accessibility, and cost. In addition, health systems should have a programmatic approach to CRC screening, which may include evidence-based strategies such as patient education, provider education, mailed screening outreach, and/or patient navigation, to maximize screening participation.

Colorectal Cancer Screening Prevalence and Adherence for the Cancer Prevention Project of Philadelphia (CAP3) Participants Who Self-Identify as Black

Introduction

Colorectal cancer is the third leading cause of cancer-related deaths among Black men and women. While colorectal cancer screening (CRCS) reduces mortality, research assessing within race CRCS differences is lacking. This study assessed CRCS prevalence and adherence to national screening recommendations and the association of region of birth with CRCS adherence, within a diverse Black population.

Methods

Data from age-eligible adults, 50–75 years, (N = 357) participating in an ongoing, cross-sectional study, was used to measure CRCS prevalence and adherence and region of birth (e.g., Caribbean-, African-, US-born). Prevalence and adherence were based on contemporaneous US Preventive Services Task Force guidelines. Descriptive statistics were calculated and adjusted prevalence and adherence proportions were calculated by region of birth. Adjusted logistic regression models were performed to assess the association between region of birth and overall CRCS and modality-specific adherence.

Results

Respondents were 69.5% female, 43.3% married/living with partner, and 38.4% had <$25,000 annual income. Overall, 78.2% reported past CRCS; however, stool test had the lowest prevalence overall (34.6%). Caribbean (95.0%) and African immigrants (90.2%) had higher prevalence of overall CRCS compared to US-born Blacks (59.2%) (p-value <0.001). African immigrants were five times more likely to be adherent to overall CRCS compared to US-born Blacks (OR = 5.25, 95% CI 1.34–20.6). Immigrants had higher odds of being adherent to colonoscopy (Caribbean OR = 6.84, 95% CI 1.49–31.5; African OR = 7.14, 95% CI 1.27–40.3) compared to US-born Blacks.

Conclusions

While Caribbean and African immigrants have higher prevalence and adherence of CRCS when compared US-born Blacks, CRCS is still sub-optimal in the Black population. Efforts to increase CRCS, specifically stool testing, within the Black population are warranted, with targeted interventions geared towards US-born Blacks.

Is It Time to Introduce PET/CT in Rectal Cancer Guidelines?

At the moment, international guidelines for rectal cancer suggest to consider F-FDG PET/CT scan in a few conditions: (1) at disease presentation in case of suspected or proven metastatic synchronous adenocarcinoma with potentially curable M1 disease; (2) in the recurrence workup for serial carcinoembryonic antigen level elevation; (3) in the recurrence workup with metachronous metastases documented by CT, MRI, or biopsy; (4) in case of strong contraindication to IV contrast agent administration; and (5) to evaluate an equivocal finding on a contrast-enhanced CT or MRI. PET/CT is not indicated in the follow-up or surveillance of rectal cancer. On the other hand, an attentive evaluation of the literature shows that PET/CT may also be used in some circumstances with significant levels of diagnostic accuracy. This review article aims to emphasize differences between current international guidelines and scientific literature in the role of PET/CT in rectal cancer.

Detection of serrated lesions in proximal colon by simulated sigmoidoscopy vs faecal immunochemical testing in a multicentre, pragmatic, randomised controlled trial

Background

The diagnostic yield of the faecal immunochemical test and sigmoidoscopy in detecting proximal serrated polyps in a colorectal cancer screening programme has not been fully assessed.

Aim

We determined the detection rate of proximal serrated polyps by simulated sigmoidoscopy and faecal immunochemical test compared with total colonoscopy in a population-based, multicentre, nationwide, randomised controlled trial (ColonPrev study).

Methods

Sigmoidoscopy yield was simulated based on the UK-Flexible Sigmoidoscopy Trial for total colonoscopy referral. Definitions were: proximal serrated polyp (proximal serrated polyp): sessile serrated polyp or hyperplastic polyp of any size and proximal at-risk serrated polyp (at-risk proximal serrated polyp): sessile serrated polyp of any size or hyperplastic polyp ≥ 10 mm, both located proximally to the splenic flexure.

Results

A total of 10,611 individuals underwent faecal immunochemical test and 5059 underwent total colonoscopy and were evaluated by simulated sigmoidoscopy. Sigmoidoscopy and faecal immunochemical test were less accurate in detecting proximal serrated polyps (odds ratio: 0.13; 95% confidence interval: 0.10-0.18 and 0.13; 0.09-0.18, p < 0.0001, respectively). Both tests were inferior to colonoscopy in detecting at-risk proximal serrated polyps, and sigmoidoscopy was inferior to faecal immunochemical test in detecting these lesions (odds ratio: 0.17; 95% confidence interval: 0.10-0.30 and 0.25; 0.17-0.37, p < 0.0001, respectively).

Conclusion

Sigmoidoscopy and faecal immunochemical test are less accurate in detecting proximal serrated polyps than colonoscopy, particularly in women.

Flexible sigmoidoscopy in colorectal cancer screening: implications of different colonoscopy referral strategies

Flexible sigmoidoscopy (FS) screening reduces colorectal cancer incidence and mortality. Its potential to detect proximal neoplasms depends on colonoscopy referral. We estimated diagnostic performance of sigmoidoscopy using 12 different referral criteria in detecting colorectal cancer and advanced adenomas. Colonoscopy results from 14,947 participants of screening colonoscopy in Germany were used to derive sensitivity of sigmoidoscopy for colorectal cancer, advanced adenomas (AAs), and any advanced neoplasms in the proximal colon. It was assumed that FS detects the same neoplasms as colonoscopy within its reach and that distal neoplasms would be followed by colonoscopy. In addition, numbers of colonoscopies needed (NCN) to detect one proximal advanced neoplasm were calculated. The most advanced findings during colonoscopy were colorectal cancer in 213 subjects (1.4%), AA in 1539 subjects (10.2%) and non-advanced adenomas in 2988 subjects (19.8%). Without colonoscopy referral, overall sensitivities for any colorectal cancer, advanced adenoma and any advanced neoplasm (proximal or distal) would be 79, 65 and 66%, respectively. These sensitivities could be increased to up to 86, 83 and 84% by the referral strategies investigated. Compared to referral due to advanced adenomas, referral due to non-advanced adenomas would substantially increase the NCN at a modest gain in sensitivity. Sensitivities were higher and NCNs were lower in men than in women for every strategy. In conclusion, colonoscopy referral can substantially increase sensitivity of sigmoidoscopy-based screening, but the gain by referral due to non-advanced adenomas substantially increases NCN compared to referral due to advanced neoplasms only. Major sex differences may call for sex-specific referral strategies.

Screening of colorectal cancer: present and future

INTRODUCTION

Colorectal cancer (CRC) is the third most common cancer in males and second in females, and the fourth most common cause of cancer death worldwide. Currently, about 60-70% of diagnosed cases in symptomatic patients are detected at an advanced stage of disease. Earlier stage detection through the use of screening strategies would allow for better outcomes in terms of reducing the disease burden. Areas covered: The aim of this paper is to review the current published evidence from literature which assesses the performance and effectiveness of different screening tests for the early detection of CRC. Expert commentary: Adequate screening strategies can reduce CRC incidence and mortality. In the last few decades, several tests have been proposed for CRC screening. To date, there is still insufficient evidence to identify which approach is definitively superior, and no screening strategy for CRC can therefore be defined as universally ideal. The best strategy would be the one that can be economically viable and to which the patient can adhere best to over time. The latest guidelines suggest colonoscopy every 10 years or annual fecal immuno-chemical test (FIT) for people with normal risk, while for individuals with high risk or hereditary syndromes specific recommendations are provided.

Distribution of colorectal polyps: Implications for screening

BACKGROUND

During the last decades data from different studies reported modifications of the topographic distribution of colorectal cancers (CRCs), with an increased frequency of tumours in proximal colonic segments. Given the documented link between adenomas and CRC, a proximal migration of adenomas over time could be expected as well.

AIM

To evaluate available evidence about the prevalence of adenomas and of sessile serrated polyps across colonic segments, the changing trends in their distribution across the colon and the diagnostic performance of screening tests currently adopted in population based screening programs for lesions located in different colonic segments.

METHODS

Literature search on PubMed, Embase, and Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects with reference to preferred reporting items for systematic reviews and meta-analysis (PRISMA), considering all adult human studies in English, published between January 2000 and February 2017.

RESULTS

Cross-sectional analysis of endoscopy and pathology data-bases are consistently showing a trend toward an increase with age of the proportion of adenomas located in the proximal colon. Several observational studies analysed the site distribution of adenomas, testing the hypothesis of a proximal shift of these lesions, and most of them reported an increase in the proportion of right-sided adenomas over time, although a similar trend was not confirmed by others. Also the quality of the retrieved evidence was low. Both endoscopy and FIT are showing a different level of sensitivity for lesions arising in different colonic segments, depending also on screenees characteristics.

CONCLUSION

Available evidence is supporting the hypothesis of an increase in the proportion of right-sided adenomas with age, while a similar increase has not been reported for SSP/A, at least among subjects aged 50 or older. The trend toward a proximalization of colorectal adenomas over time, reported by some authors, likely results from improved diagnostic performances and/or the process of population ageing.

The Association between Distal Findings and Proximal Colorectal Neoplasia: A Systematic Review and Meta-Analysis

OBJECTIVES

Whether screening participants with distal hyperplastic polyps (HPs) detected by flexible sigmoidoscopy (FS) should be followed by subsequent colonoscopy is controversial. We evaluated the association between distal HPs and proximal neoplasia (PN)/advanced proximal neoplasia (APN) in asymptomatic, average-risk patients.

METHODS

We searched Ovid Medline, EMBASE, and the Cochrane Library from inception to 30 June 2016 and included all screening studies that examined the relationship between different distal findings and PN/APN. Data were independently extracted by two reviewers with disagreements resolved by a third reviewer. We pooled absolute risks and odds ratios (ORs) with a random effects meta-analysis. Seven subgroup analyses were performed according to study characteristics. Heterogeneity was characterized with the I² statistics.

RESULTS

We analyzed 28 studies (104,961 subjects). When compared with normal distal findings, distal HP was not associated with PN (OR=1.16, 95% confidence interval (CI)=0.89-1.51, P=0.14, I²=40%) or APN (OR=1.09, 95% CI=0.87-1.36, P=0.39, I²=5%), while subjects with distal non-advanced or advanced adenoma had higher odds of PN/APN. Higher odds of PN/APN were observed for more severe distal lesions. Weaker association between distal and proximal findings was noticed in studies with higher quality, larger sample size, population-based design, and more stringent endoscopy quality-control measures. The Egger's regression tests showed all P>0.05.

CONCLUSIONS

Distal HP is not associated with PN/APN in asymptomatic screening population when compared with normal distal findings. Hence, the presence of distal HP alone detected by FS does not automatically indicate colonoscopy referral for all screening participants, as other risk factors of PN/APN should be considered.

Results of total colonoscopy in the diagnosis of polyps. Case studies in Villavicencio, Colombia

Introducción. Cualquier levantamiento por encima del plano normal de la mucosa colónica es considerada proyección polipoidea. A mayor edad es más probable encontrar pólipos; además, los >1 cm de diámetro tienen mayor potencial de desarrollar neoplasia maligna.Objetivo. Establecer la frecuencia de lesiones polipósicas del colon, su tamaño, su localización y los grupos de edades donde están presentes en pacientes a quienes se les realizó colonoscopia en el Hospital Departamental de Villavicencio en el periodo 2009-2014.Materiales y métodos. Se analizaron los resultados de 411 colonoscopias diagnósticas. La recolección de datos y descripción estadística se hizo con el software SPPSS 2011.Resultados. Del total de la muestra, 43 (10.46%) pólipos fueron ≤1cm de diámetro, 16 (4% 3.89%) estuvieron entre 1cm y 2cm, no se encontraron pólipos >2cm y en el resto de resultados no se hallaron estas anomalías. En el grupo de edad de 41 a 50 años se presentaron pólipos en todos los segmentos del colon, pero el de mayor porcentaje (11%) fue el de 71 a 80 años. En el colon izquierdo se presentó el 69% de los pólipos >1cm y el 67% de los <1cm.Conclusión. En grupos de poblaciones <40 años de edad, los hallazgos de pólipos son bajos en colon izquierdo y muy bajos en colon derecho.

Diagnosis reliability of combined flexible sigmoidoscopy and fecal-immunochemical test in colorectal neoplasia screening

Background

Employing colonoscopy, the gold standard in colorectal cancer (CRC) diagnosis testing, for CRC screening presents a significant risk of complications. Alternative methods with a lower invasive-level and fewer risks are proposed in combination, though each with lower diagnosis performance when applied separately. The main objective of this cross-sectional pilot study was to evaluate the feasibility of a CRC screening program using combined flexible sigmoidoscopy and fecal-immunochemical test (FIT).

Methods

The patient population consisted of 2,201 consecutive-case symptomatic patients attending the gastroenterology outpatient clinic with mild complaints between 2012 and 2014. They were referred for FIT. A sample of 252 individuals underwent a subsequent colonoscopy, blind to FIT results, and theoretical sigmoidoscopy was simulated. On a subsample of 57 patients, real sigmoidoscopy was additionally performed. Prior probabilities in terms of patients’ compliance and CRC prevalence were estimated, together with predictive ability of FIT and sigmoidoscopy in screening population. We assessed the merit of a screening strategy employing two-stage serial multiple testing: a) first stage by combining two parallel tests, that is, flexible sigmoidoscopy and FIT and b) colonoscopy as the second diagnosis test. The scheme was validated using the actual predictive values derived from the study population.

Results

Colonoscopy found 75 (29.76%) individuals with advanced neoplasia. FIT was positive in 30.3% of advanced neoplasia cases, while between 23.73% and 28.28% met the theoretical sigmoidoscopy simulation criteria, with good concordance between real and theoretical sigmoidoscopy. The colonoscopy referral compliance rate was 52% among FIT-positives. Sensitivity and specificity of the first-stage test combination were better than sigmoidoscopy alone (McNemar test: P<0.001). Negative predictive values for low prevalence levels were between 81.5% and 90.12%.

Conclusion

Combining less resource challenging and less invasive testing procedures is worthwhile in colorectal neoplasia detection, improving sensitivity and specificity of either test alone, and leading to better posterior probabilities in usual screening scenarios.

Colorectal Cancer Risk Following Adenoma Removal: A Large Prospective Population-Based Cohort Study

BACKGROUND

Randomized controlled trials have demonstrated significant reductions in colorectal cancer incidence and mortality associated with polypectomy. However, little is known about whether polypectomy is effective at reducing colorectal cancer risk in routine clinical practice. The aim of this investigation was to quantify colorectal cancer risk following polypectomy in a large prospective population-based cohort study.

METHODS

Patients with incident colorectal polyps between 2000 and 2005 in Northern Ireland were identified via electronic pathology reports received to the Northern Ireland Cancer Registry. Patients were matched to the Northern Ireland Cancer Registry to detect colorectal cancer and deaths up to December 31, 2010. Colorectal cancer standardized incidence ratios (SIR) were calculated and Cox proportional hazards modeling applied to determine colorectal cancer risk.

RESULTS

During 44,724 person-years of follow-up, 193 colorectal cancer cases were diagnosed among 6,972 adenoma patients, representing an annual progression rate of 0.43%. Colorectal cancer risk was significantly elevated in patients who had an adenoma removed (SIR, 2.85; 95% CI, 2.61-3.25) compared with the general population. Male sex, older age, rectal site, and villous architecture were associated with an increased colorectal cancer risk in adenoma patients. Further analysis suggested that not having a full colonoscopy performed at, or following, incident polypectomy contributed to the excess colorectal cancer risk.

CONCLUSIONS

Colorectal cancer risk was elevated in individuals following polypectomy for adenoma, outside of screening programs.

IMPACT

This finding emphasizes the need for full colonoscopy and adenoma clearance, and appropriate surveillance, after endoscopic diagnosis of adenoma.

Choosing the optimal method in programmatic colorectal cancer screening: current evidence and controversies

Colorectal cancer (CRC) is an important health problem all over the world, being the third most common cancer and the second leading cause of cancer-related death in Western countries. The most important strategy for CRC prevention is screening (i.e. secondary prevention). Since it is widely accepted that adenomas and serrated polyps are the precursors of the vast majority of CRC, early detection and removal of these lesions is associated with a reduction of CRC incidence and, consequently, mortality. Moreover, cancers detected by screening are usually diagnosed at early stages and, therefore, curable by endoscopic or surgical procedures. This review will be address CRC screening strategies in average-risk population, which is defined by those individuals, men and women, 50 years of age or older, without any additional personal or familial predisposing risk factor. In order to maximize the impact of screening and ensure high coverage and equity of access, only organized screening programs (i.e. programmatic screening) should be implemented, as opposed to case-finding or opportunistic screening. For that reason and considering that the optimal approach for colorectal screening may differ depending on the scenario, this review will be focused on the advantages and limitations of each screening strategy in an organized setting.

Likely effect of adding flexible sigmoidoscopy to the English NHS Bowel Cancer Screening Programme: impact on colorectal cancer cases and deaths

Background:

From 2013, once-only flexible sigmoidoscopy (FS) at age 55 is being phased into the England National Health Service Bowel Cancer Screening Programme (NHSBCSP), augmenting biennial guaiac faecal occult blood testing (gFOBT) at ages 60–74. Here, we project the impact of this change on colorectal cancer (CRC) cases and deaths prevented in England by mid-2030.

Methods:

We simulated the life-course of English residents reaching age 55 from 2013 onwards. Model inputs included population numbers, invitation rates and CRC incidence and mortality rates. The impact of gFOBT and FS alone on CRC incidence and mortality were derived from published trials, assuming an uptake of 50% for FS and 57% for gFOBT. For FS plus gFOBT, we assumed the gFOBT effect to be 75% of the gFOBT alone impact.

Results:

By mid-2030, 8.5 million individuals will have been invited for once-only FS screening. Adding FS to gFOBT screening is estimated to prevent an extra 9627 (−10%) cases and 2207 (−12%) deaths by mid-2030. If FS uptake is 38% or 71%, respectively, an extra 7379 (−8%) or 13 689 (−15%) cases and 1691 (−9%) or 3154 (−17%) deaths will be prevented by mid-2030.

Conclusions:

Adding once-only FS at age 55 to the NHSBCSP will prevent ∼10 000 CRC cases and ∼2000 CRC deaths by mid-2030 if FS uptake is 50%. In 2030, one cancer was estimated to be prevented per 150 FS screening episodes, and one death prevented per 900 FS screening episodes. The actual reductions will depend on the FS invitation schedule and uptake rates.

Effectiveness, training and quality assurance of colonoscopy screening for colorectal cancer

Screening for colorectal cancer has been proven to be effective in reducing colorectal cancer incidence and mortality. While the precise benefit of screening exclusively by colonoscopy is not yet known, unarguably, the exam is central to the success of any screening programme. The test affords the opportunity to detect and resect neoplasia across the entire large bowel and is the definitive examination when other screening tests are positive. However, colonoscopy is invasive and often requires sedation as well as extensive bowel preparation, all of which puts the patient at risk. Furthermore, the test can technically be demanding and, unarguably, there is variation in how it is performed. This variation in performance has now been definitively linked to important outcome measures. For example, interval cancers are more common in low adenoma detectors as compared with high adenoma detectors. This review outlines the most current thinking regarding the effectiveness of colonoscopy as a screening tool. It also outlines key concepts to optimise its performance through robust quality assurance programmes and high-quality training.

Diagnostic performance of fecal immunochemical test and sigmoidoscopy for advanced right-sided colorectal neoplasms

BACKGROUND

Colorectal cancer screening effect on right-sided colorectal neoplasia is limited. We compared fecal immunochemical test and simulated sigmoidoscopy diagnostic accuracy for advanced right-sided neoplasia detection.

METHODS

We analyzed 1,292 individuals with complete screening colonoscopy with a fecal immunochemical test determination before colonoscopy. Sigmoidoscopy and "hybrid strategy" (sigmoidoscopy or fecal hemoglobin concentration ≥ 20 µg hemoglobin/g) diagnostic yield were simulated according to UK Flexible Sigmoidoscopy, Screening for COlon REctum (SCORE), and Norwegian Colorectal Cancer Prevention (NORCCAP) trials criteria to complete colonic examination. We compared sensitivity and specificity of both strategies and of "hybrid strategy" for advanced right-sided neoplasia with McNemar test.

RESULTS

An advanced right-sided neoplasia was detected in 47 (3.6 %) subjects. A fecal hemoglobin concentration ≥ 20 µg hemoglobin/g was determined in 6.6 % of the subjects and 10.1, 12.7, and 23.5 % met UK, SCORE, and NORCCAP criteria, respectively. Fecal immunochemical test was statistically more specific than sigmoidoscopy strategies (93.8 %, UK 90.3 %, SCORE 87.7 %, NORCCAP 77.8 %; p < 0.001). In contrast, fecal immunochemical test sensitivity for advanced right-sided neoplasia (17 %) was not statistically different than UK (21.3 %; p = 0.7) or SCORE (23.4 %; p = 0.5), although it was inferior than NORCCAP strategy (42.5 %; p < 0.001). Adding fecal immunochemical test to sigmoidoscopy increased number of positives (8.5-25.7 %), sensitivity (10-30 %), and significantly reduced advanced right-sided neoplasia specificity (p < 0.001).

CONCLUSIONS

Fecal immunochemical test and sigmoidoscopy diagnostic yield for advanced right-sided neoplasia are low. Fecal immunochemical test is more specific than sigmoidoscopy but less sensitive than sigmoidoscopy according to NORCCAP criteria.

Prediction of proximal advanced neoplasia: a comparison of four existing sigmoidoscopy-based strategies in a Chinese population

OBJECTIVE

To compare the performance of existing sigmoidoscopy-based strategies in predicting advanced proximal neoplasia (APN) in an asymptomatic Chinese cohort.

DESIGN

We included all screening participants aged 50-70 years who received colonoscopy between 2008 and 2014 in Hong Kong. Sigmoidoscopy yield was estimated from the colonoscopic findings based on the: (1) UK flexible sigmoidoscopy; (2) Screening for COlon REctum (SCORE); (3) NORwegian Colorectal Cancer Prevention (NORCCAP) trials and (4) US clinical index based on age, gender and distal findings. The sensitivity, specificity, the number of subjects needed to screen (NNS) and the number of subjects needed to refer (NNR) for colonoscopy to detect one APN were evaluated. Binary logistic regression modelling identified the distal findings associated with APN.

RESULTS

From 5879 eligible subjects, 132 (2.2%) had APN. The US strategy achieved the highest sensitivity for APN detection (42.0%) and the UK criteria attained the highest specificity (96%). The US criteria led to the lowest NNS (92 vs 103-267) and the UK criteria required the least NNR (12 vs 16-21). Using the US strategy, the rates of APN detected were 1.4% (low-risk group), 2.2% (intermediate risk) and 5.9% (high risk). The c-statistics of the UK, SCORE, NORCCAP and the US criteria were 0.55±0.03; 0.59±0.03; 0.59±0.03 and 0.62±0.05 respectively.

CONCLUSIONS

The US criteria had the highest sensitivity for detection of APN and lowest NNS and the UK score had the highest specificity and the lowest NNR. The performance of all these four criteria to predict APN is limited, highlighting an urgent need to devise a novel APN prediction system for Asian subjects.

Programmatic screening for colorectal cancer: the COLONPREV study

The COLONPREV study is an ongoing multicenter, nationwide, randomized controlled trial aimed at evaluating the efficacy of once-only colonoscopy and biennial fecal immunochemical testing with respect to the reduction of CRC-related mortality at 10 years in average-risk colorectal cancer screening population. Following a pragmatic approach, this study may contribute to establishing the most cost-effective strategy in a programmatic, population-based setting. In this review, we report the results obtained at the first screening round, as well as others achieved in nested evaluations using the COLONPREV dataset with the aim of clarifying some controversial issues on the different strategies of colorectal cancer screening.

Findings in the distal colorectum are not associated with proximal advanced serrated lesions

BACKGROUND & AIMS

Serrated lesions are an important contributor to colorectal cancer (CRC), notably in the proximal colon. Findings in the distal colorectum are markers of advanced proximal adenomatous neoplasia. However, it is not known whether they affect the odds of advanced proximal serrated lesions.

METHODS

We performed a retrospective cross-sectional study of data from 1910 patients (59.3 ± 8.0 years, 53.8% female) who underwent an average-risk screening colonoscopy from August 2005 through April 2012 at Indiana University Hospital and an associated ambulatory surgery center. Colonoscopies were performed by an endoscopist with high rates of detection of adenomas and serrated polyps. Tissue samples of all serrated polyps (hyperplastic, sessile serrated adenoma/polyp [SSA/P], or traditional serrated adenoma) proximal to the sigmoid colon and serrated polyps >5 mm in the rectum or sigmoid colon were reviewed by a gastrointestinal pathologist and reclassified on the basis of World Health Organization criteria. Advanced serrated lesion (ASL) was defined as SSA/P with cytologic dysplasia, SSA/P ≥10 mm, or traditional serrated adenoma. Advanced conventional adenomatous neoplasia (ACN) was defined as tubular adenoma ≥10 mm, villous histology, high-grade dysplasia, or cancer. The prevalence of proximal ASL and ACN was calculated on the basis of distal colorectal findings. Multivariable logistic regression analysis was performed to determine the age-adjusted and sex-adjusted odds of advanced proximal adenomatous and serrated lesions. Secondary analyses were performed to examine the effect of variable ASL definitions.

RESULTS

Fifty-two patients (2.7%) had proximal ASL, and 99 (5.2%) had proximal ACN. Of the 52 patients with proximal ASL, 27 (52%) had no distal polyps. Of the 99 patients with proximal ACN, 40 (40%) had no distal polyps. Age and type of distal adenomas were significantly associated with proximal ACN. There were no significant associations between distal polyp type and proximal ASL. In secondary analyses, distal SSA/Ps (P = .008) but not distal hyperplastic polyps or conventional adenomas were associated with any proximal SSA/P.

CONCLUSIONS

The findings at flexible sigmoidoscopy that traditionally serve as indications for colonoscopy (conventional adenomas) are likely to be ineffective for detection of proximal ASL. This finding, plus the observation that most patients with proximal ASL have no distal polyps, favors screening colonoscopy over sigmoidoscopy, especially in the elderly. The observation that non-advanced distal SSA/Ps are associated with any proximal SSA/P warrants further study.

Rate of detection of advanced neoplasms in proximal colon by simulated sigmoidoscopy vs fecal immunochemical tests

BACKGROUND & AIMS

We compared the ability of biennial fecal immunochemical testing (FIT) and one-time sigmoidoscopy to detect colon side-specific advanced neoplasms in a population-based, multicenter, nationwide, randomized controlled trial.

METHODS

We identified asymptomatic men and women, 50-69 years old, through community health registries and randomly assigned them to groups that received a single colonoscopy examination or biennial FIT. Sigmoidoscopy yield was simulated from results obtained from the colonoscopy group, according to the criteria proposed in the UK Flexible Sigmoidoscopy Trial for colonoscopy referral. Patients who underwent FIT and were found to have ≥75 ng hemoglobin/mL were referred for colonoscopy. Data were analyzed from 5059 subjects in the colonoscopy group and 10,507 in the FIT group. The main outcome was rate of detection of any advanced neoplasm proximal to the splenic flexure.

RESULTS

Advanced neoplasms were detected in 317 subjects (6.3%) in the sigmoidoscopy simulation group compared with 288 (2.7%) in the FIT group (odds ratio for sigmoidoscopy, 2.29; 95% confidence interval, 1.93-2.70; P = .0001). Sigmoidoscopy also detected advanced distal neoplasia in a higher percentage of patients than FIT (odds ratio, 2.61; 95% confidence interval, 2.20-3.10; P = .0001). The methods did not differ significantly in identifying patients with advanced proximal neoplasms (odds ratio, 1.17; 95% confidence interval, 0.78-1.76; P = .44). This was probably due to the lower performance of both strategies in detecting patients with proximal lesions (sigmoidoscopy detected these in 19.1% of patients and FIT in 14.9% of patients) vs distal ones (sigmoidoscopy detected these in 86.8% of patients and FIT in 33.5% of patients). Sigmoidoscopy, but not FIT, detected proximal lesions in lower percentages of women (especially those 50-59 years old) than men.

CONCLUSIONS

Sigmoidoscopy and FIT have similar limitations in detecting advanced proximal neoplasms, which depend on patients' characteristics; sigmoidoscopy underperforms for women 50-59 years old. Screening strategies should be designed on the basis of target population to increase effectiveness and cost-effectiveness. ClinicalTrials.gov number: NCT00906997.

Advanced proximal neoplasia of the colon in average-risk adults

BACKGROUND

Estimating risk for advanced proximal neoplasia (APN) based on distal colon findings can help identify asymptomatic persons who should undergo examination of the proximal colon after flexible sigmoidoscopy (FS) screening.

OBJECTIVE

We aimed to determine the risk of APN by most advanced distal finding among an average-risk screening population.

DESIGN

Prospective, cross-sectional study.

SETTING

Teaching hospital and colorectal cancer screening center.

PATIENTS

A total of 4651 asymptomatic persons at average risk for colorectal cancer aged 50 to 74 years (54.4% women [n = 2529] with a mean [± standard deviation] age of 58.4 ± 6.2 years).

INTERVENTIONS

All participants underwent a complete colonoscopy, including endoscopic removal of all polyps.

MAIN OUTCOME MEASUREMENTS

We explored associations between several risk factors and APN. Logistic regression was used to identify independent predictors of APN.

RESULTS

A total of 142 persons (3.1%) had APN, of whom 85 (1.8%) had isolated APN (with no distal findings). APN was associated with older age, a BMI >27 kg/m(2), smoking, distal advanced adenoma and/or cancer, and distal non-advanced tubular adenoma. Those with a distal advanced neoplasm were more than twice as likely to have APN compared with those without distal lesions.

LIMITATIONS

Distal findings used to estimate risk of APN were derived from colonoscopy rather than FS itself.

CONCLUSION

In persons at average risk for colorectal cancer, the prevalence of isolated APN was low (1.8%). Use of distal findings to predict APN may not be the most effective strategy. However, incorporating factors such as age (>65 years), sex, BMI (>27 kg/m(2)), and smoking status, in addition to distal findings, should be considered for tailoring colonoscopy recommendations. Further evaluation of risk stratification approaches in other asymptomatic screening populations is warranted.

Risk stratification for advanced colorectal neoplasia according to fecal hemoglobin concentration in a colorectal cancer screening program

BACKGROUND & AIMS

The latest generation of fecal immunochemical tests (FIT) allows for quantitation of hemoglobin in feces, allowing for selection of optimal cut-off concentrations. We investigated whether individuals with positive results from quantitative FITs, in combination with other factors, could be identified as being at greatest risk for advanced colorectal neoplasia.

METHODS

In a retrospective study, we analyzed data from a consecutive series of 3109 participants with positive results from FITs (≥20 μg/g of feces) included in the first round of the Barcelona colorectal cancer screening program, from December 2009 through February 2012. All participants underwent colonoscopy and were assigned to groups with any advanced colorectal neoplasia or with nonadvanced colorectal neoplasia (but with another diagnosis or normal examination findings).

RESULTS

Median fecal hemoglobin concentrations were significantly higher in participants with advanced colorectal neoplasia (105 μg/g; interquartile range, 38-288 μg/g) compared with participants with nonadvanced colorectal neoplasia (47 μg/g; interquartile range, 23-119 μg/g) (P < .001). Positive predictive values for advanced colorectal neoplasia, determined using arbitrary fecal hemoglobin concentrations, differed with sex and age. Multivariate logistic regression analysis identified sex (men: odds ratio [OR], 2.07; 95% confidence interval, 1.78-2.41), age (60-69 y: OR, 1.24; 95% confidence interval, 1.07-1.44), and fecal hemoglobin concentration (>177 μg/g: OR, 3.80; 95% confidence interval, 3.07-4.71) as independent predictive factors for advanced colorectal neoplasia. Combining these factors, we identified 16 risk categories associated with different probabilities of identifying advanced colorectal neoplasia. Risk for advanced colorectal neoplasia increased 11.46-fold among individuals in the highest category compared with the lowest category; positive predictive values ranged from 21.3% to 75.6%.

CONCLUSIONS

Fecal hemoglobin concentration, in addition to sex and age, in individuals with positive results from FITs can be used to stratify probability for the detection of advanced colorectal neoplasia. These factors should be used to prioritize individuals for colonoscopy examination.