Rectosigmoid findings are not associated with proximal colon cancer: Analysis of 6196 consecutive cases undergoing total colonoscopy

Association of preserved vegetable consumption and prevalence of colorectal polyps: results from the Lanxi Pre-colorectal Cancer Cohort (LP3C)

PURPOSE

Although fresh vegetable consumption has been linked with a lower risk of colorectal polyps, a precursor lesion for colorectal cancer (CRC), the association between preserved vegetable consumption and colorectal polyps is unknown. We aimed to assess the association of preserved vegetable intake with the prevalence of colorectal polyps with the consideration of subsites, sizes and multiplicity of polyps.

METHODS

We analyzed the cross-sectional data from 40-80 years Chinese at a high risk of CRC from the Lanxi Pre-colorectal Cancer Cohort (LP3C) baseline survey, which was conducted between March 2018 and December 2019. Dietary information was obtained via a validated food frequency questionnaire. Multivariate logistic regression was employed to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) of preserved vegetable consumption and the prevalence of colorectal polyps.

RESULTS

Of 6783 eligible participants in 2018-2019 survey of LP3C, 2064 prevalent colorectal polyp cases were identified. In the multivariable-adjusted model, preserved vegetable consumption was positively associated with the prevalence of colorectal polyps (OR for fourth vs. first quartile: 1.18; 95% CI 1.01-1.36; P trend = 0.02). The similar association was also detected for small polyps [OR_{Q4 vs Q1} (95% CI): 1.17 (1.00-1.37); P trend = 0.03]. The similar trend was detected for multiple polyps [OR _{Q4 vs Q1} (95% CI):1.27 (0.98-1.64); P trend = 0.04], proximal colon polyps [OR_{Q4 vs Q1} (95% CI): 1.12 (0.90-1.38); P trend = 0.07], and single polyp [OR_{Q4 vs Q1} (95% CI) for 1.15 (0.98-1.35); P trend = 0.06]. No significant association was observed for distal colon [OR_{Q4 vs Q1} (95% CI) 1.19 (0.98-1.45); P trend = 0.09]. Replacing one serving per day of preserved vegetables with fresh vegetables was related to 20%, 23%, and 37% lower prevalence of overall, small, and multiple polyps, respectively.

CONCLUSIONS

Preserved vegetable consumption was associated with a higher prevalence of colorectal polyps in a Chinese population at a high risk of CRC. Replacing preserved vegetables with fresh vegetables may be conducive to lower prevalent colorectal polyps.

Risk stratification for advanced proximal colon neoplasm and individualized endoscopic screening for colorectal cancer by a risk-scoring model

BACKGROUND

Only 30% to 40% of patients with advanced proximal neoplasms (APN) have distal colon neoplasms.

OBJECTIVE

To develop a risk score model for APN and propose an individualized screening protocol for colorectal cancer.

DESIGN

Retrospective cohort study.

SETTING

Tertiary-care center.

PATIENTS

Derivation cohort (6200 adults) and validation cohort (1389 adults).

INTERVENTION

Screening colonoscopy.

MAIN OUTCOME MEASUREMENTS

An APN risk score model was developed from the derivation cohort (6200 adults) and was tested in the validation cohort (1389 adults), who underwent screening colonoscopy.

RESULTS

Age, male sex, and smoking were clinical risk factors for APN. The presence of a distal neoplasm was a sigmoidoscopic risk factor for APN. We calculated APN risk scores (0-8) based on these variables and classified patients as low risk (0-2) or high risk (3-8). In the validation cohort, the relative risk of APN was 3.5-fold higher in the high-risk group than in the low-risk group. Our model suggests that colonoscopy should be performed as an initial screening test in patients with a high clinical risk for APN. Sigmoidoscopy should be performed initially in patients with low clinical risk for APN followed by supplementary colonoscopy in those with high APN risk scores based on both clinical and sigmoidoscopic risk factors. This protocol detected APN in 22 of 34 APN+ patients (64.7%) with little increase in the endoscopy burden, whereas only 16 of 34 APN+ patients (47.1%) would be identified by initial sigmoidoscopy followed by colonoscopy only in cases with distal neoplasms.

LIMITATIONS

Retrospective design.

CONCLUSION

Our APN risk score model provides an algorithm for efficient screening of colorectal cancer by sigmoidoscopy and colonoscopy.

The relationship between distal and proximal colonic neoplasia: a meta-analysis

OBJECTIVES

To investigate the association between proximal colonic neoplasia and distal lesions as a function of the lesion type. The extent to which health, demographic, and study characteristics moderate this association was also examined.

DATA SOURCES

Google Scholar, Web of Science, Scopus, and PubMed.

STUDY ELIGIBILITY CRITERIA

Studies allowing the calculation of OR of proximal neoplasia (PN) and proximal advanced neoplasia (PAN) for distal hyperplastic polyps (HP), nonadvanced adenomas (NAA), adenomas (AD), and advanced neoplasia (AN); also, studies for which the proportions of subjects with isolated (i.e., not accompanied by distal lesions) PN (IPN) and PAN (IPAN) over the total number of subjects with PN or PAN could be calculated.

STUDY APPRAISAL AND SYNTHESIS METHODS

Thirty-two studies were included for calculating OR between proximal neoplasia and distal lesions and 40 studies for proportions of IPN and IPAN. Subgroup analyses were conducted for presence of symptoms, prevalence of PN and PAN, age, proportion of males, geographic region, study design, and demarcation point.

RESULTS

The association between distal lesions and proximal neoplasia increased with the severity of the distal lesions. Odds of PN were higher in subjects with HP compared to subjects with a normal distal colon. Odds of PN and PAN were higher in subjects with NAA, AD, and AN than in subjects with a normal distal colon. PAN were more strongly associated with distal lesions in asymptomatic populations, in young populations, and in populations with a low prevalence of PAN. In approximately 60% of the subjects with PN and PAN, these neoplasia were isolated.

LIMITATIONS

The present results may be affected by publication bias and dichotomization in the subgroup analyses. Limitations related to the individual studies include self-selection, lesion misclassification and misses, and technological advances leading to changes in the detection of lesions during the time span of the included studies.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

All types of distal lesions are predictive of PN. All types of distal neoplasia are predictive of PAN. The association between distal lesions and proximal neoplasia increases with the severity of the distal lesion. The association between distal lesions and proximal advanced neoplasia is stronger in low-risk groups as compared to high-risk groups.

Prevalence of colorectal neoplasms in Asian Americans

PURPOSE

To determine the yield of colonoscopy in a predominantly Asian American gastroenterology practice in California from 8/2003 to 2/2005.

RESULTS

A total 2,723 subjects were included: 87% were Asian and 13% were non-Asian. Advanced neoplasia prevalence was 12% in Asian men and 9% in non-Asian men (P = 0.21), and 8% and 7% in women (P = 0.62). Similar results were found in asymptomatic patients (13% and 13%, P = 0.99, for men; 8% and 6%, P = 0.46, for women). Factors associated with presence of advanced neoplasia were total number of polyps and presence of right-sided lesions. Asian men were more likely to have neoplasia overall compared with non-Asian men with odds ratio (OR) of 2.14 (1.23-3.72); however, there were no significant differences in the prevalences of advanced neoplasia in the two groups.

CONCLUSIONS

Colorectal neoplasia is as prevalent in Asian Americans and preventive guidelines for colorectal cancer should also be advocated for this ethnic group.

Clinical significance of distal colon polyps for the prediction of an advanced proximal neoplasm: the KASID prospective multicenter study

BACKGROUND/AIMS

The possibility of proximal lesion without distal polyps is a weak point of sigmoidoscopic colon cancer screening, but the clinical significance of distal findings for advanced proximal neoplasm (APN) is uncertain. The aim of this study was to assess the significance of a distal finding as a predictor of APN.

MATERIALS AND METHODS

Asymptomatic patients > or =50 years old were enrolled from among patients who underwent polypectomy at 11 tertiary medical centers during the Korean Association for the Study of Intestinal Disease prospective study conducted between July 2003 and March 2004. Polyps located distal to the splenic flexure were defined as distal polyps. An advanced neoplasm was defined as a polyp of > or =10 mm in size, and/or with villous features, and/or with high-grade dysplasia, or invasive cancer. Age, gender, and distal polyp size, appearance, and histology were analyzed as risk factors of APN. The sensitivity and positive predictive value of distal polyps for APN were calculated.

RESULTS

Data from 826 patients were analyzed. Mean patient age was 60.1 years (range 50-86), and 71.3% were men. APN was found in 98 patients, and 45 (45.9%) patients had no distal polyps. Risk factors of APN were a male gender, distal polyp size, and an advanced distal neoplasm. Sensitivities of a distal polyp of > or =10 mm and of an advanced distal neoplasm for APN were both 38.8% with positive predictive values of 13.3 and 14.4%, respectively.

CONCLUSIONS

Although distal colon findings were found to be helpful for predicting APN in asymptomatic patients aged > or =50 years, APN without distal polyps requires careful consideration.

Risk of advanced proximal adenoma and cancer according to rectosigmoid findings in the Korean population

Colorectal cancer is one of the leading causes of cancer death in the United States and Europe. Recently, the incidence of colorectal cancer has been increasing remarkably in Korea. To reduce the high incidence, screening of colorectal cancer in asymptomatic individuals has been advocated. Sigmoidoscopy is simpler, faster, and better tolerable than total colonoscopy, but the scope cannot reach the proximal colon segment and, therefore, may miss proximal colon cancer. In the present study, we intended to investigate the prevalence of proximal adenoma and cancer according to the findings in rectosigmoid colon and to find their risk factors. Data were collected retrospectively from 1541 consecutive patients who underwent total colonoscopy at the Department of Gastroenterology, Hanyang University, between October 2003 and December 2004. Neoplasms were classified as diminutive adenoma (< or =5 mm), small adenoma (6-9 mm), advanced adenoma (> or =10 mm, with villous component or high-grade dysplasia), and cancer. The sites of neoplasms were defined as rectosigmoid (rectum and sigmoid colon) and proximal (from cecum to descending colon) colon. The prevalence of advanced proximal adenoma was associated with severe rectosigmoid findings. On the other hand, the prevalence of proximal colon cancer did not show such a tendency. Among the 131 patients with proximal advanced adenoma, 66% had no neoplasm in the rectosigmoid colon. Moreover, among the 27 patients with proximal cancer, 52% had no neoplasm in the rectosigmoid colon. Multivariate logistic regression analysis revealed that age, gender, and advanced rectosigmoid adenoma were the risk factors of advanced proximal adenoma, but nothing was associated with the risk for proximal colon cancer. Advanced rectosigmoid adenoma may be the predictor of advanced proximal adenoma, especially in old males. However, nothing is related to the risk for proximal colon cancer. Therefore, colonoscopy may be more adequate for colorectal cancer screening than sigmoidoscopy in the Korean population.