The Relationship between Distal Findings and Proximal Neoplasia in Colorectal Cancer Screening: A Systematic Review and Meta-Analysis
Invited conference paper presented and published in conference proceedings

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AbstractImportance: Flexible sigmoidoscopy (FS) and colonoscopy are recommended as screening tests of choice for colorectal cancer (CRC). FS is now gaining popularity in some European countries and Asia Pacific regions since it can be performed by primary care professionals. Whether screening participants with distal hyperplastic polyps (HPs) detected by FS should be followed by subsequent colonoscopy, however, is still controversial as previous studies presented mixed findings.
Objective: to evaluate the association between distal HPs and proximal neoplasia (PN)/advanced proximal neoplasia (APN) in asymptomatic, average-risk patients undergoing endoscopic CRC screening.
Data Sources: Ovid Medline, EMBASE and the Cochrane Library from inception to 31 July 2016.
Data Extraction and Synthesis: We included all screening studies that examined the relationship between different distal findings and PN/APN for average-risk, asymptomatic subjects. Data were independently extracted by two reviewers and in cases of disagreement, consensus was made via referral to a third reviewer.
Main Outcomes and Measures: We pooled absolute risks and odds ratios with a random effects meta-analysis. Four subgroup analyses were performed according to study characteristics. Heterogeneity was characterized with the I2 statistics.
Results: Twenty-eight eligible studies were finally identified, including a total of 104,961 subjects (Figure 1). Overall, the prevalence of colorectal neoplasia was 25.0%; advanced colorectal neoplasia 4.9%; PN 13.2% and APN 2.2%. When compared with normal distal findings, distal HP was not associated with PN (OR=1.16, 95% 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%) (Figure 2), whilst subjects with distal non-advanced or advanced adenoma had higher odds of PN and 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 better endoscopy quality control measures. There was no significant heterogeneity when the associations between distal HP and PN (I2=40%, p=0.28) /APN (I2=5%, p=0.39) were examined. The Egger’s regression tests showed that publication bias did not exist (all p > 0.50).
Conclusions and Relevance: The presence of distal HP is not associated with PN/APN in asymptomatic screening population. Our findings do not support routine colonoscopy workup for subjects with distal HPs detected by sigmoidoscopy, and provided concrete evidence in support of the US Preventive Services Task Force Recommendation Statements published in 2016. We anticipate that this clinical implication has a substantial potential to reduce unnecessary colonoscopy procedures, complications and healthcare costs, particularly in regions where colonoscopic capacity may be limited.
All Author(s) ListJason LW Huang, YH Wang, Johnny Y Jiang, CP Yu , YL Wu , P Chen, XQ Yuan , Miaoyin Liang, Harry HX Wang, Martin CS Wong
Name of ConferenceDigestive Disease Week, 2017
Start Date of Conference06/05/2017
End Date of Conference09/05/2017
Place of ConferenceChicago
Country/Region of ConferenceUnited States of America
Proceedings TitleGastroenterology
Series TitleAGA Abstracts
Number in Series83
Volume Number152
Issue Number5
PublisherSpringer Nature
Place of PublicationUS
Pagess21 - s22
LanguagesEnglish-United States
Keywordscolorectal cancer screening; distal finding; proximal neoplasia; meta-analysis

Last updated on 2021-17-06 at 00:39