WASHINGTON, D.C. / RankWire.AI / – According to recent findings, patients who had their appendix removed due to acute appendicitis exhibited fewer subsequent diagnoses of colorectal cancer compared to those treated solely with antibiotics. The study, which looked back at data from a broad international health database, compared matched groups. Researchers observed a 0.7% occurrence of colorectal cancer in patients who underwent an appendectomy, whereas the rate was 1.7% among those who received only antibiotics. This difference translated into a 58% reduction in relative risk for the surgery group.
The investigation utilized the TriNetX Global Collaborative Network, which aggregated data from 168 healthcare organizations. Researchers identified individuals with acute appendicitis who received either surgical removal or antibiotic therapy. After matching participants based on relevant characteristics, each initial group consisted of 15,774 individuals. The final analysis comprised 15,616 patients who had an appendectomy and 15,295 who were treated with antibiotics only, after excluding those with prior colorectal cancer diagnoses. The records revealed 110 cases of colorectal cancer following appendectomy, compared to 254 cases after antibiotic-only treatment.
The findings were presented at the American College of Surgeons Clinical Congress 2026, held in Washington from September 26 to September 29. The research abstract was reviewed and selected by the Scientific Forum program committee. Nonetheless, no medical journal has peer-reviewed the study as of yet. This limits the strength of the conclusions that can be drawn, as the research shows an association between treatment method and later colorectal cancer diagnosis but does not prove that removing the appendix prevents cancer.
Comparison between surgical and antibiotic treatments examined
Acute appendicitis is a condition characterized by inflammation of the appendix, which is located near the junction of the small and large intestines. Traditionally, many cases are managed with surgical removal, known as an appendectomy. However, antibiotics have also become an accepted treatment option for selected patients. Senior author Valentine Nfonsam, a professor and executive vice chair of surgery at Morehouse School of Medicine, emphasized that antibiotic therapy remains a valuable alternative despite the findings of this study.
The researchers also explored factors that could influence the development of colorectal cancer following appendicitis treatment. For example, sometimes appendicitis occurs in individuals who already have an undiagnosed colorectal tumor. A tumor located on the right side of the colon can block the appendix, leading to inflammation. Surgery provides tissue samples for pathological analysis, which can reveal abnormalities and prompt further diagnostic tests that are not typically performed immediately in cases treated with antibiotics alone.
Study does not confirm a cancer-preventive effect
The appendix contains lymphoid tissue and plays a role in immune functions within the gut. It has also been associated with the gut microbiome, comprising bacteria and other microorganisms in the digestive system. The recent research did not determine whether these biological functions explain the observed differences in colorectal cancer diagnoses. Nor did it establish if inflammation or changes in microbial populations caused the association. Consequently, researchers refrained from suggesting that appendectomy acts as a method to prevent colorectal cancer.
Previous studies have yielded varied results regarding the link between appendectomy and colorectal cancer. For instance, a 2024 prospective analysis followed over 224,000 participants across three large cohorts for up to 32 years. It found no evidence that an appendectomy increased long-term colorectal cancer risk or the risk of colorectal precursors. The current study, however, addresses a different question by comparing patients with appendicitis who underwent surgery to similarly affected patients who received antibiotics alone. Researchers highlighted that age, family history, and genetic predisposition are still well-established factors in assessing colorectal cancer risk.