Distal Adenomas Research Articles

Endoscopist characteristics that influence the quality of colonoscopy.

Several factors have been shown to be related to colonoscopy quality; however, little is known about the effects of endoscopist factors. This study analyzed the influence of endoscopist-related characteristics on quality indicators for colonoscopy. The study included 48 endoscopists who each performed at least 20 colonoscopies in the colonoscopy arm of a randomized controlled trial comparing fecal immunochemical test vs. colonoscopy in colorectal cancer screening. These endoscopists performed a total of 3838 procedures in the trial. The following were calculated for each endoscopist: adenoma detection rate (ADR), advanced ADR, proximal ADR, distal ADR, and adenoma per colonoscopy rate (APCR). The characteristics of endoscopists were assessed with regard to colonoscopy quality using multivariate regression analysis. Endoscopist characteristics included age, sex, exclusive endoscopy practice, years as a physician, years as a specialist, specialty, total (life-long) number of colonoscopies performed, annual colonoscopy volume, number of hours/week dedicated to endoscopy and number of educational activities in the previous year. Factors associated with ADR were age of the endoscopist (odds ratio [OR] 1.11, 95 % confidence interval [CI] 1.01 - 1.21; P = 0.01) and life-long number of colonoscopies (OR 1.06, 95 %CI 1.01 - 1.11; P = 0.01). Only exclusive dedication to endoscopy practice was found to be independently related to proximal ADR (OR 1.71, 95 %CI 1.15 - 2.74; P = 0.001). Life-long number of colonoscopies was independently related to detection of distal adenomas (OR 1.07, 95 %CI 1.01 - 1.13; P = 0.01). None of the analyzed endoscopist characteristics was associated with advanced ADR or APCR. This study found that the experience of the endoscopist and exclusive dedication to endoscopy practice, but not annual colonoscopy volume, were associated with better colonoscopy quality.

Interendoscopist variability in proximal colon polyp detection is twice higher for serrated polyps than adenomas.

AIMTo assess the interendoscopist variability in the detection of colorectal polyps according to their location and histological type.METHODSThis study was a retrospective analysis of prospectively collected data from a regional colorectal cancer (CRC) screening program; 2979 complete colonoscopies from 18 endoscopists were included. Variability in performance between endoscopists for detection of at least one adenoma (A), one proximal adenoma (PA), one distal adenoma (DA), and one proximal serrated polyp (PSP) was assessed by using multilevel logistic regression models.RESULTSThe observed detection rates among the 18 endoscopists ranged from 24.6% to 47.6% (mean = 35.7%) for A, from 19.1% to 39.0% (mean = 29.4%) for DA, from 6.0% to 22.9% (mean = 12.4%) for PA, and from 1.3% to 19.3% (mean = 6.9%) for PSP. After adjusting for patient-level variables (sex, age), the interendoscopist detection rates variability achieved a significant level for A, PA, and PSP but not for DA (P = 0.03, P = 0.02, P = 0.02 and P = 0.08, respectively). This heterogeneity, as measured by the variance partition coefficient, was approximately threefold higher for PA (6.6%) compared with A (2.1%), and twofold higher for PSP (12.3%) compared with PA.CONCLUSIONThese results demonstrate significant interendoscopist variability for proximal polyp particularly for serrated polyps, but not for distal adenoma detection. These findings contribute to explain the decreased effectiveness of complete colonoscopies at preventing proximal CRCs and the need to carefully assess the proximal colon during scope procedure.

Risk stratification of individuals with low-risk colorectal adenomas using clinical characteristics: a pooled analysis

ObjectiveFor individuals with 1–2 small (<1 cm) low-risk colorectal adenomas, international guidelines range from no surveillance to offering surveillance colonoscopy in 5–10 years. We hypothesised that the risks for metachronous...

Colonic Diverticula Are Not Associated With an Increased Risk of Colorectal Adenomas.

Patients with missed colorectal cancer have been reported to be more likely to have colonic diverticulosis. Such an association could be due to either higher risk of neoplasia or difficulty examining the colon in patients with diverticulosis. The aim of this study was to determine whether colonic diverticula are associated with an increased risk for colonic neoplasia. We analyzed data from a prospective study of patients undergoing screening colonoscopy that included detailed assessment of all colonic diverticula and colorectal polyps. We used logistic regression to estimate odds ratios and 95% confidence intervals while adjusting for confounding variables. Our analyses included 624 participants. Of these, 216 (35%) had one or more colorectal adenomas. Diverticula on colonoscopy were not associated with an increased risk of adenomas (odds ratio (OR) 1.0, 95% confidence interval (CI) 0.7-1.4) or advanced adenomas (OR 0.8, 95% CI 0.4-1.5). Those with the greatest burden of diverticula (10 or more) did not have an increased risk of adenomas (OR 1.1, 95% CI 0.7-1.8) compared with no diverticula. Colonic diverticula were not associated with an increased risk of proximal (OR 1.0, 95% CI 0.6-1.6) or distal adenomas (OR 1.0, 95% CI 0.6-1.7). Patients with colonic diverticula do not have an increased risk of colorectal adenomas or advanced adenomas.

Dietary fiber intake and risk of colorectal cancer and incident and recurrent adenoma in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

Dietary fiber has been associated with a reduced risk of colorectal cancer. However, it remains unclear at which stage in the carcinogenic pathway fiber may act or which food sources of dietary fiber may be most beneficial against colorectal cancer development. The objective was to prospectively evaluate the association between dietary fiber intake and the risk of incident and recurrent colorectal adenoma and incident colorectal cancer. Study participants were identified from the intervention arm of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Participants received flexible sigmoidoscopy at baseline and 3 or 5 y after. Dietary fiber intake was measured by using a self-reported dietary questionnaire. The colorectal cancer, incident adenoma, and recurrent adenoma analyses were based on 57,774, 16,980, and 1667 participants, respectively. Unconditional logistic regression was used to assess the risk of incident and recurrent adenoma, and Cox proportional hazards models were used to assess the risk of colorectal cancer across categories of dietary fiber intake, with adjustment for potential confounders. Elevated total dietary fiber intake was associated with a significantly reduced risk of incident distal colorectal adenoma (ORhighest vs. lowest tertile of intake: 0.76; 95% CI: 0.63, 0.91; P-trend = 0.003) but not recurrent adenoma (P-trend = 0.67). Although the association was not statistically significant for colorectal cancer overall (HR: 0.85; 95% CI: 0.70, 1.03; P-trend = 0.10), a reduced risk of distal colon cancer was observed with increased total fiber intake (HR: 0.62; 95% CI: 0.41, 0.94; P-trend = 0.03). Protective associations were most notable for fiber originating from cereals or fruit. This large, prospective study within a population-based screening trial suggests that individuals consuming the highest intakes of dietary fiber have reduced risks of incident colorectal adenoma and distal colon cancer and that this effect of dietary fiber, particularly from cereals and fruit, may begin early in colorectal carcinogenesis. This trial was registered at clinicaltrials.gov as NCT01696981.

Parathyroid Hormone is Related to Dysplasia and a Higher Rate of Distal Colorectal Adenoma in Women but Not Men.

Molecular and clinical observations provide evidence for a potential role of parathyroid hormone (PTH) in colorectal cancer development. We therefore aimed to assess the association of PTH with regard to colorectal cancer precursor lesions. A cohort of 1432 participants, 777 men, 58.4 ± 9.6 years and 701 women, 59.1 ± 10.6 years, undergoing screening colonoscopy were allocated to PTH serum concentrations either above or below 55 ng/L. The number, localization, size, and histology of the polypoid lesions detected during screening colonoscopy were recorded according to PTH serum concentrations. Serum PTH concentrations were not different between men and women. Women with PTH serum concentrations above the cut-off had significantly more adenomas (13/40; 32.5%) of the distal colon compared to women below the cut-off (91/659; 13.8%; P = 0.001). Additionally, the rate of dysplasia in adenomas of the distal colon was higher in women with high compared to low PTH concentrations (P = 0.001). These findings remained robust after adjustments for serum vitamin D, age, plasma creatinine, BMI, diabetes, and liver steatosis. No associations were observed between serum PTH concentrations and colorectal lesions in men. These data suggest that elevated PTH serum concentrations might have a role in colorectal cancer development as indicated by higher rates of adenomas, specifically with dysplasia, in women. The role of PTH in colon carcinogenesis and its sex specificity deserve further study.

Parathyroid hormone is related to dysplasia and a higher rate of distal colorectal adenoma in women

Background: Molecular and clinical observations provide evidence for a potential role of parathyroid hormone (PTH) in colorectal cancer development. No study has been performed to assess the association of PTH with regard to colorectal cancer precursor lesions.

Establishing the link between hepatitis B virus infection and colorectal adenoma.

Chronic hepatitis B (CHB) infection has been associated with malignancy, most notably hepatocellular carcinoma. Previous research has shown that hepatitis C is associated with increased colorectal adenomas and neoplasia. Currently, there are no studies on the association of CHB and colorectal adenomas. We aimed to identify a possible link between CHB and colorectal adenoma. A retrospective chart review was performed on 588 consecutive patients undergoing screening or diagnostic colonoscopy that were previously screened or diagnosed with hepatitis B. Comparisons between categorical variables were analyzed with Chi Square test and t-test for continuous variables. Unconditional logistic regression was used to generate age-, gender-and race-adjusted odds ratios and their 95% confidence intervals (CI) comparing medication users with non-users. Statistical analyses were performed with SAS 9.3 software. A total of 487 patients were analyzed in the control group vs. 71 in the hepatitis B group. The adenoma detection rate was 23.9% in hepatitis B vs. 15.9% in the non-hepatitis B group for all cause colonoscopy; however this did not reach statistical significance. There was a significantly higher number of adenomas present in the distal colon compared to control (OR =2.16; 95% CI, 1.06-4.43; P=0.04). There were no significant findings between hepatitis B infection with size, multiplicity or presence of proximal adenomas. There was a significant difference noted in regards to smoking history, BMI and age between two groups. Although the adenoma detection rate was higher in hepatitis B population vs. the non-hepatitis B group this did not reach statistical significance. However, we did find an association between CHB infection and the presence of distal colorectal adenomas. Larger prospective studies are needed to strengthen our findings along with future studies examining hepatitis B virus (HBV) and mechanisms inducing colorectal carcinogenesis.

Coffee intake and the risk of colorectal adenoma: The colorectal adenoma study in Tokyo

Coffee is a commonly consumed beverage which contains several potential anticarcinogenic and chemopreventive compounds, and has been hypothesized to have protective effects in colorectal neoplasia. However, the limited available data on coffee consumption in relation to colorectal adenoma (CRA), a precursor lesion to most colorectal cancers, remain largely inconsistent. In this study, we evaluated the association of coffee intake with the risk of CRA in a middle-aged Japanese population. Study subjects were selected from examinees who underwent total colonoscopy as part of a cancer screening program and responded to self-administered dietary and lifestyle questionnaires. A total of 738 patients with adenoma and 697 controls were included in the study. Coffee intake was assessed with a food frequency questionnaire, and divided into quartiles based on the distribution among controls. Unconditional logistic regression models were used to estimate odds ratio (OR) and 95% confidence interval (CI) of CRA, with adjustment for potential confounding factors. High coffee consumption was associated with a reduced risk of CRA, with a multivariate-adjusted OR for the highest versus lowest quartile of coffee intake of 0.67 (95% CI = 0.48-0.93; ptrend = 0.02). The inverse association of coffee intake was limited to proximal (OR = 0.64; 95%CI = 0.44-0.95; ptrend = 0.04) and distal colon adenoma (OR = 0.62; 95%CI = 0.39-0.99; ptrend = 0.06), and appeared to be more evident with small (OR = 0.68; 95%CI = 0.49-0.96; ptrend = 0.04) and single adenomas (OR = 0.65; 95%CI = 0.44-0.95; ptrend = 0.02). Green tea intake was not found to be associated with CRA risk. This study provides support for the protective effect of coffee drinking on colon adenomas, a precursor of colon cancer.

Occurrence of Distal Colorectal Neoplasia Among Whites and Blacks Following Negative Flexible Sigmoidoscopy: An Analysis of PLCO Trial.

It is unclear whether the higher rate of colorectal cancer (CRC) among non-Hispanic blacks (blacks) is due to lower rates of CRC screening or greater biologic risk. We aimed to evaluate whether blacks are more likely than non-Hispanic whites (whites) to develop distal colon neoplasia (adenoma and/or cancer) after negative flexible sigmoidoscopy (FSG). We analyzed data of participants with negative FSGs at baseline in the Prostate, Lung, Colorectal, and Ovarian (PLCO) cancer screening trial who underwent repeat FSGs 3 or 5 years later. Subjects with polyps or masses were referred to their physicians for diagnostic colonoscopy. We collected and reviewed the records of diagnostic evaluations. Our analytic cohort consisted of 21,550 whites and 975 blacks. We did a comparison by race (whites vs. blacks) in the findings of polyps or masses at repeat FSG, the follow-up of abnormal test results and the detection of colorectal neoplasia at diagnostic colonoscopy. At the follow-up FSG examination, 304 blacks (31.2 %) and 4183 whites (19.4 %) had abnormal FSG, [adjusted relative risk (RR) = 1.00; 95 % confidence interval (CI), 0.90-1.10]. However, blacks were less likely to undergo diagnostic colonoscopy (76.6 % vs. 83.1 %; RR = 0.90; 95 % CI, 0.84-0.96). Among all included patients, blacks had similar risk of any distal adenoma (RR = 0.86; 95 % CI, 0.65-1.14) and distal advanced adenoma (RR = 1.01; 95 % CI, 0.60-1.68). Similar results were obtained when we restricted our analysis to compliant subjects who underwent diagnostic colonoscopy (RR = 1.01; 95 % CI, 0.80-1.29) for any distal adenoma and (RR = 1.18; 95 % CI, 0.73-1.92) for distal advanced adenoma. We did not find any differences between blacks and whites in the risk of distal colorectal adenoma 3-5 years after negative FSG. However, follow-up evaluations were lower among blacks.

Circulating levels of vitamin D and colorectal adenoma: A case-control study and a meta-analysis.

To examine the association between circulating 25-hydroxyvitamin D [25(OH)D] levels and colorectal adenoma in a case-control study and a meta-analysis. We conducted a matched case-control study (112 cases and 112 matched controls) and combined 15 studies, including our study, in a meta-analysis. The study-specific odds ratios (ORs) and 95% confidence intervals (CIs) were pooled using a random-effects model. In total, 5454 colorectal adenomas and 6656 controls were included in the meta-analysis. In a meta-analysis including 14 previous studies and our study, we observed a significant inverse association between circulating 25(OH)D levels and colorectal adenoma (OR = 0.68; 95%CI: 0.54-0.82) when comparing the highest category with the lowest category. Stratification by adenoma location (proximal or distal adenoma) showed similar estimates. When we stratified by study region, the ORs (95%CIs) were 0.70 (0.52-0.88) in the US and 0.66 (0.34-0.97) in Asia. These data suggest an inverse association between circulating 25(OH)D levels and colorectal adenoma in both Western and Asian populations.

Patient age and duration of colonoscopy are predictors for adenoma detection in both proximal and distal colon

To investigate the relation of patient characteristics and procedural parameters to the endoscopic detection rate of colonic adenomas. Further to study, which factors may be capable to predict the localization of adenomatous lesions. We used the data base of a prospective randomized colonoscopy study (The ColoCap trial) to identify patients being diagnosed with colon adenoma. Logistic regression analysis was conducted to reveal predictors for adenoma detection in the entire colon and also with respect to the proximal and distal part. Covariates including age, gender, duration of colonoscopy and comorbidities were defined to determine association between predictors and adenoma detection. Equal numbers of adenomas were detected in the proximal and distal side of the splenic flexure [126 (57%) vs 94 (43%), P = 0.104]. Simultaneous occurrence of adenomas in both sides of the colon was rare. The appearance of both proximal and distal adenoma was associated with increasing age (P = 0.008 and P = 0.024) and increasing duration of colonoscopy (P < 0.001 and P = 0.001). Male gender was a predictor for adenoma detection in the proximal colon (P = 0.008) but statistical significance was slightly missed with respect to the distal colon (P = 0.089). Alcohol abuse was found to be a predictor for the detection of distal adenoma (P = 0.041). Increasing age and longer duration of colonoscopy are factors with a strong impact on adenoma detection both in the proximal and distal colon. Since proximal adenomas occurred in absence of distal adenomas, complete colonoscopy should be performed for screening.

Reexamining Risk Factors for High-Grade Dysplasia in Colorectal Polyps

Introduction: High-grade dysplasia (HGD), the penultimate cancer antecedent, represents the most advanced histologic stage in premalignant polyps. Given trends in polyp classification and detection rates, we sought to reexamine demographic and polyp factors associated with risk of HGD across the major polyp types. Methods: Endoscopy and pathology reports were appraised on all polyps removed in 2012 to reflect current practice. Patients with high-risk conditions for cancer were excluded. Multivariate analyses were used to identify independent risk factors. Results: From 2012, 6,067 polyps met inclusion criteria. Low-grade dysplasia (LGD) and HGD were respectively present in 0% and 0% of 1,497 hyperplastic polyps, 12% and 0.4% of 1,024 sessile serrated polyps (SSPs), and 97.2% and 2.7% of 3,546 adenomas. Among SSPs, independent risk factors for any dysplasia included polyp size (p<0.0001) and patient age (p=0.012) but not sex, site, or configuration. Among adenomas, independent risk factors for HGD included polyp size (p<0.0001), histologic architecture (p<0.0001), and site (p=0.02), but not age or configuration. The largest proportional and absolute increase in HGD occurred at a size cutoff of >15 mm (Figure 1); 76% of HGD occurred above this size. Adenomas with tubulovillous or villous architecture were more likely than tubular adenomas to harbor HGD (OR 3.75; 95% CI 2.21, 6.37). HGD was less likely in proximal than distal adenomas (OR 0.51; 95% CI 0.29, 0.9).Figure 1Conclusion: Most HGD is found in large adenomas. While our findings generally corroborate historically shown risk factors for HGD, the abrupt rise in HGD prevalence noted at and above 15 mm suggests a potential opportunity for definitional refinement or stratification of “advanced” adenoma based on size.

Establishing the Link Between HBV Infection and Colorectal Adenoma

Introduction: Chronic hepatitis B (CHB) infection has been associated with malignancy, most notably hepatocellular carcinoma. Previous research has shown that hepatitis C is associated with increased colorectal adenomas and neoplasia. Currently, there are no studies on the association of CHB and colorectal adenomas. We aimed to identify a possible link between CHB and colorectal adenoma. Methods: A retrospective chart review was performed on 555 consecutive patients undergoing screening or diagnostic colonoscopy that were previously screened or diagnosed with hepatitis B. Comparisons between categorical variables were analyzed with the Chi-squared test and t-test for continuous variables. Unconditional logistic regression was used to generate age-, gender-, and race-adjusted odds ratios (ORs) and their 95% confidence intervals (CIs). Statistical analyses were performed with SAS 9.3 software. Results: Four hundred eighty-four patients were analyzed in the control group (non-hepatitis B) versus 71 in the CHB group. The adenoma detection rate was 23.9% in CHB versus 15.9% in the non-hepatitis B group for all-cause colonoscopy; however, this did not reach statistical significance. There was a significantly higher number of adenomas present in the distal colon compared to control (OR 2.16; 95%CI 1.06-4.43; p=0.04; Table 1). There were no significant associations found between CHB infection with size, multiplicity, or presence of proximal adenomas. There was a significant difference in regards to BMI, smoking history, and diabetes between the 2 groups (Table 2).Table 1: Presence of Adenomas in CHB vs. Control GroupTable 2: BMI, Smoking History, and Diabetes Between CHB vs. Control GroupConclusion: Although the adenoma detection rate was higher in the CHB population, this did not reach statistical significance. However, we did find an association between CHB infection and the presence of distal colorectal adenomas. Larger prospective studies are needed to strengthen our findings along with future studies examining HBV and mechanisms inducing colorectal carcinogenesis.

Abstract 2159: A prospective study of non-steroidal anti-inflammatory drug use and colorectal adenoma and colorectal cancer

Abstract Background: Use of non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen, has been shown to yield a chemopreventive effect against colorectal cancer. Whether NSAIDs protect against the initiation vs. the progression of colorectal cancer remains a debate. To explore its role in the course of colorectal carcinogenesis, we evaluated the associations of NSAIDs with incident adenoma, recurrent adenoma, and colorectal cancer in the context of a large population-based screening trial, where participants were randomized to undergo endoscopic examinations in a controlled setting. Methods: We prospectively evaluated the associations between self-reported baseline NSAIDs use and risk of incident distal adenoma (1,127 cases), recurrent adenoma (755 cases), and colorectal cancer (840 cases) among men and women, ages 55-74, enrolled between 1993-2001, and randomized to receive flexible sigmoidoscopy screening (n=77,445) as part of the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. Incident adenoma cases were those with a negative sigmoidoscopy at baseline, but then were found to have adenoma on a follow-up sigmoidoscopy 3 or 5 years later. Recurrent adenoma cases were identified via an ancillary study nested within the PLCO among participants who had an adenoma at baseline and another adenoma on a surveillance colonoscopy 6 months to 10 years after their baseline screen. Participants were followed for cancer incidence for the median of 11.9 years following the baseline screen. All diagnoses of colorectal adenoma and cancer were pathologically confirmed through medical record review. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for adenoma incidence and recurrence and hazard ratios (HRs) and 95% CIs for colorectal cancer incidence using multivariable-adjusted models. Results: Compared to no or infrequent use (&amp;lt;4 times/month), we found aspirin use ≥2 times/day to be associated with a reduced risk of incident adenoma (OR=0.72, 95% CI:0.52-1.00). Although not significantly associated with recurrent adenoma (OR=1.00) or colorectal cancer (OR=0.80), a marginally significant dose trend was observed for colorectal cancer (P=0.05). Similarly, ibuprofen use ≥2 times/day was associated with a reduced risk for incident adenoma (OR=0.72, 95% CI:0.54-0.97), but not associated with adenoma recurrence or cancer. No systematic differences in risk patterns were found by anatomic site, i.e., proximal colon, distal colon or rectum. Conclusion: Our data suggest that use of aspirin and ibuprofen significantly reduces adenoma initiation, but benefit against progression to adenoma recurrence or cancer growth may be weaker. Given the recognized adverse effects of NSAIDs, such as gastric ulcer perforation and upper gastrointestinal bleeding, any chemopreventive recommendations associated with NSAID use need to be tailored by individual cost-benefit assessment. Citation Format: Wen-Yi Huang, L. Joseph Su, Christine C. Johnson, Mark P. Purdue, Sonja I. Berndt. A prospective study of non-steroidal anti-inflammatory drug use and colorectal adenoma and colorectal cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2159. doi:10.1158/1538-7445.AM2014-2159

Which adenomas are detected by fecal occult blood testing? A state-wide analysis from Bavaria, Germany.

Guaiac-based fecal occult blood tests (gFOBTs) are the most widely used noninvasive tests for colorectal cancer screening. While it is well known that they detect only a minority of colorectal adenomas, evidence for the characteristics of adenomas associated with detection is sparse. We derived estimates of the positive likelihood ratio (LR+), a summary measure of diagnostic performance, according to adenoma characteristics by comparing findings at colonoscopy among 19,208 and 181,128 participants who underwent colonoscopy to follow-up a positive gFOBT and as a primary screening examination, respectively, in Bavaria, Germany, in 2007-2009. Age and sex-adjusted estimates of LR+ (95% confidence intervals, 95% CI) ranged from 1.09 (1.05-1.13) for adenomas <1 cm to 2.52 (2.30-2.75) for adenomas >2 cm, and were much higher for pedunculated adenomas (1.96, 95% CI 1.85-2.08) than for flat or sessile adenomas (1.11, 95% CI 1.02-1.21 and 1.12, 95% CI 1.08-1.16, respectively). Villous or tubulovillous structure and dysplasia were likewise associated with a higher chance to be detected by gFOBT. Diagnostic performance was worse for proximal than for distal adenomas (age and sex adjusted LR+:1.16, 95% CI 1.09-1.23 and 1.35, 95% CI 1.29-1.41, respectively) which was explained by the lower proportions of large, pedunculated and nontubular adenomas in the proximal colon. Size, pedunculated shape, and nontubular histology are the key determinants of detection which also explain lower detection rates of adenomas located in the proximal colon.

Characteristics of adenomas detected by fecal immunochemical test in colorectal cancer screening.

Fecal immunochemical test (FIT) diagnostic accuracy for colorectal adenoma detection in colorectal cancer screening is limited. We analyzed 474 asymptomatic subjects with adenomas detected on colonoscopy in two blinded diagnostic tests studies designed to assess FIT diagnostic accuracy. We determined the characteristics of adenomas (number, size, histology, morphology, and location) and the risk of metachronous lesions (according to European guidelines). Finally, we performed a logistic regression to identify those variables independently associated with a positive result. Advanced adenomas were found in 145 patients (75.6% distal and 24.3% only proximal to splenic flexure). Patients were classified as low (59.5%), intermediate (30.2%), and high risk (10.3%) according to European guidelines. At a 100-ng/mL threshold, FIT was positive in 61 patients (12.8%). Patients with advanced adenomas [odds ratio (OR), 8.8; 95% confidence interval (CI), 4.76-16.25], distal advanced adenomas (OR, 6.7; 95% CI, 1.9-8.8), high risk (OR, 20.1; 95% CI, 8.8-45.8), or intermediate risk lesions (OR, 6; 95% CI, 2.9-12.4) had more probabilities to have a positive test. The characteristics of adenomas independently associated were number of adenomas (OR, 1.22; 95% CI, 1.04-1.42), distal flat adenomas (OR, 0.44; 95% CI, 0.21-0.96), pedunculated adenomas (OR, 2.28; 95% CI, 1.48-3.5), and maximum size of distal adenomas (mm; OR, 1.24; 95% CI, 1.16-1.32). European guidelines classification and adenoma location correlates with the likelihood of a positive FIT result. This information allows us to understand the FIT impact in colorectal cancer prevention. Likewise, it should be taken into account in the development of new colorectal adenomas biomarkers.

Adenoma and sessile serrated polyp detection rates: variation by patient sex and colonic segment but not specialty of the endoscopist.

Adenoma detection rate is an important quality indicator. High adenoma detection rate is related to fewer interval cancers. Interval cancers arise from sessile serrated polyps, often in the proximal colon. The detection of adenomas and sessile serrated polyps by location may enhance colonoscopy efficacy. The aim of this study was to determine entire colon and segmental adenoma and sessile serrated polyp detection rates and to assess the impact of endoscopist specialty on polyp detection. Colonoscopies performed by 65 multispecialty endoscopists were studied. This study was conducted at an academic medical center. Average-risk outpatients undergoing screening colonoscopy were selected. Polyp detection rates were determined by sex, colon segment, and each endoscopist. Included were 2167 patients. Adenoma and sessile serrated polyp detection rates were 25% and 2% and not significantly different by specialty of the endoscopist. The adenoma detection rate was higher in men (31%) than in women (20%), including each segment in the colon. It was higher proximally (20%) than distally (16%) (p = 0.027) in men, but no different in proximal (11%) and distal colon (11%) (p = 0.66) in women. Sessile serrated polyp detection was the same in men and women at 2% (p = 0.84) and 3-fold higher in the proximal than in the distal colon (1.4% vs 0.5%), but only significantly so in women (p = 0.041). We found a poor correlation between adenoma and sessile serrated polyp detection rates (r = 0.35). This study was limited by its retrospective nature. Prevalent adenomas are detected more often in men than in women, including overall and by colon segment. The proximal adenoma detection rate is significantly higher than the distal adenoma detection rate in men, but segmental rates are similar in women. Sessile serrated polyp detection rates are low, albeit 3-fold higher in the proximal colon, and are found as frequently in men and women. High-quality colonoscopy, as evidenced by adenoma detection rate, varies by endoscopist but is independent of colonoscopist subspecialty.

Findings in the Distal Colorectum Are Not Associated With Proximal Advanced Serrated Lesions

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. 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. 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. 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.

Visceral abdominal fat measured by computed tomography is associated with an increased risk of colorectal adenoma

We investigated whether visceral adipose tissue (VAT) measured by computed tomography (CT) is a risk factor for colorectal adenoma. For a total of 1,328 patients (857 without adenoma, 471 with colorectal adenoma) undergoing colonoscopy and CT, associations between colorectal adenoma and body mass index (BMI), VAT area and subcutaneous adipose tissue (SAT) were assessed using odds ratios (ORs) with 95% confidence intervals (CIs) adjusted for age, sex, family history, smoking, alcohol intake, diabetes mellitus, aspirin use and nonsteroidal anti-inflammatory drug use. Multivariate analysis showed that colorectal adenoma was marginally associated (p=0.06) with BMI, but not with SAT, while it was significantly associated with VAT and the VAT to SAT ratio (VAT/SAT) for both categorical data and trend (p<0.05). When the obesity indices were considered simultaneously, colorectal adenoma remained significantly associated with VAT and VAT/SAT (p<0.05), but not BMI and SAT. In patients with colorectal adenoma, the adjusted OR for the highest quartiles of VAT and VAT/SAT was 1.90 (95% CI 1.16-3.13) and 2.25 (95% CI 1.49-3.41), respectively, compared to the lowest quartiles. Only VAT area was significantly associated with colorectal adenoma in both men and women (p<0.05). Proximal, multiple and advanced adenomas had significantly higher VAT areas (p<0.05) than distal, solitary and nonadvanced adenomas. Our findings implicate abdominal VAT in the development and progression of colorectal adenoma, and it was better obesity index for colorectal adenoma than BMI in both sexes.