Other Removing gut bacteria's potential 'safe house' (appendix) may lower risk of colorectal cancer subtype (May 2024, n=139,406) Appendectomy and Long-term Colorectal Cancer Incidence, Overall and by Tumor Fusobacterium nucleatum Status

Michael Harrop

Active member
Joined
Jul 6, 2023
Messages
466
Location
USA
https://medicalxpress.com/news/2024-05-gut-bacteria-potential-safe-house.html
https://journals.lww.com/annalsofsurgery/abstract/9900/appendectomy_and_long_term_colorectal_cancer.870.aspx

The appendix, once dismissed as an unnecessary human organ, has more recently been shown to play a role in the immune system. However, we lack a clear understanding of how its removal to treat appendicitis affects long-term human health.

Abstract​

Objective:​


To test hypotheses that appendectomy history might lower long-term colorectal cancer risk and that the risk reduction might be strong for tumors enriched with Fusobacterium nucleatum, bacterial species implicated in colorectal carcinogenesis.

Background:​


The absence of the appendix, an immune system organ and a possible reservoir of certain pathogenic microbes, may affect the intestinal microbiome, thereby altering long-term colorectal cancer risk.

Methods:​


Utilizing databases of prospective cohort studies, namely the Nurses’ Health Study and the Health Professionals Follow-up Study, we examined the association of appendectomy history with colorectal cancer incidence overall and subclassified by the amount of tumor tissue Fusobacterium nucleatum (Fusobacterium animalis). We used an inverse probability weighted multivariable-adjusted duplication-method Cox proportional hazards regression model.

Results:​


During the follow-up of 139,406 participants (2,894,060 person-years), we documented 2811 incident colorectal cancer cases, of which 1065 cases provided tissue F. nucleatum analysis data. The multivariable-adjusted hazard ratio of appendectomy for overall colorectal cancer incidence was 0.92 (95% CI, 0.84−1.01). Appendectomy was associated with lower F. nucleatum-positive cancer incidence (multivariable-adjusted hazard ratio, 0.53; 95% CI, 0.33−0.85; P=0.0079), but not F. nucleatum-negative cancer incidence (multivariable-adjusted hazard ratio, 0.98; 95% CI, 0.83−1.14), suggesting a differential association by F. nucleatum status (Pheterogeneity=0.015). This differential association appeared to persist in various participant/patient strata including tumor location and microsatellite instability status.

Conclusions:​


Appendectomy likely lowers the future long-term incidence of F. nucleatum-positive (but not F. nucleatum-negative) colorectal cancer. Our findings do not support the existing hypothesis that appendectomy may increase colorectal cancer risk.
 
Format correct?
  1. Yes
Back
Top