Appendectomy and Colorectal Cancer

Chinese University of Hong Kong (Other)
Overall Status
Active, not recruiting ID

Study Details

Study Description

Brief Summary

Colorectal cancer (CRC) is one of the most common cancer worldwide. Initiation and progression of CRC involve complex interactions among genetic, epigenetic and environmental factors. Given that hereditary and familial CRC only accounts for 2% to 5% of cases, environmental factors are the key triggers of CRC. Emerging evidence has indicated that gut microbes are an important environmental factor promoting CRC development. Gut dysbiosis has been shown to promote colorectal carcinogenesis in mice. Several individual bacterial species, such as the enterotoxigenic Bacteroides fragilis (ETBF), Fusobacterium nucleatum and Peptostreptococcus anaerobius, could exert carcinogenic effects by inducing direct DNA damage, oxidative damage and activating oncogenic signaling pathways. Recent studies have shown that the appendix plays an important role in maintaining homeostasis and biodiversity of gut microbiome by providing an ideal ecological niche for commensal bacteria and production of immunoglobulin A. Considering the key role of microorganisms in gastrointestinal pathophysiology, absence of appendix may result in disruption of microbiome homeostasis, which could potentially influence the risk of developing CRC. In terms of epidemiological evidence, the association of appendectomy with the risk of CRC development has been controversial, and to date no consensus has been attained. Although gut microorganisms could be a crucial pivot between appendectomy and risk of subsequent CRC development, the direct contribution of appendectomy and the underlying mechanisms are still largely unexplored. In this study, we aim to study

  1. the association between appendectomy and colorectal cancer, and

  2. the role of appendectomy in CRC risk through causing gut microbial dysbiosis.

Condition or Disease Intervention/Treatment Phase

    Study Design

    Study Type:
    Actual Enrollment :
    180000 participants
    Observational Model:
    Time Perspective:
    Official Title:
    Altered Gut Microbiome Composition by Appendectomy Contributes to Colorectal Cancer
    Actual Study Start Date :
    Jun 1, 2022
    Anticipated Primary Completion Date :
    May 31, 2025
    Anticipated Study Completion Date :
    May 31, 2025

    Arms and Interventions

    Arm Intervention/Treatment
    Non-appendectomy controls

    Appendectomy cases

    Outcome Measures

    Primary Outcome Measures

    1. Appendectomy is associated with risk of subsequent CRC incidence [3 years]

      Individuals underwent appendectomy from January 2000 to December 2020 will be retrieved from a population-based database (CDARS) in Hong Kong. For the control group, individuals without appendectomy between 2000 and 2020 based on the same exclusion criteria will be identified from the total population register of CDARS. For each case of appendectomy, we will select two matched referential individuals from the pool based on the year of birth and gender to study the association between appendectomy and CRC risk.

    Eligibility Criteria


    Ages Eligible for Study:
    N/A and Older
    Sexes Eligible for Study:
    Inclusion Criteria:
    • Individuals underwent appendectomy from January 2000 to December 2020
    Exclusion Criteria:
    1. patients with the age ≤18 years at enrollment;

    2. Patients with any malignant diseases or inflammatory bowel disease history before enrollment;

    3. Patients with hereditary syndromes of colorectal adenomas or polyps (familial adenomatous polyposis, Lynch syndrome, etc.);

    4. Patients that underwent appendectomy for appendiceal neoplasms.

    Contacts and Locations


    Site City State Country Postal Code
    1 Institute of Digestive Disease, The Chinese University of Hong Kong Sha Tin Hong Kong 00000

    Sponsors and Collaborators

    • Chinese University of Hong Kong


    None specified.

    Study Documents (Full-Text)

    None provided.

    More Information


    None provided.
    Responsible Party:
    Jun YU, Professor, Chinese University of Hong Kong Identifier:
    Other Study ID Numbers:
    • 2022.203
    First Posted:
    Oct 19, 2023
    Last Update Posted:
    Oct 19, 2023
    Last Verified:
    Oct 1, 2023
    Studies a U.S. FDA-regulated Drug Product:
    Studies a U.S. FDA-regulated Device Product:
    Additional relevant MeSH terms:

    Study Results

    No Results Posted as of Oct 19, 2023