WASHINGTON, D.C. / RankWire.AI / – According to recent findings, patients who had their appendix removed due to acute appendicitis experienced fewer subsequent diagnoses of colorectal cancer compared to those treated solely with antibiotics. This retrospective analysis drew from a substantial international health database, comparing matched groups. Researchers identified colorectal cancer in 0.7% of individuals who underwent an appendectomy, whereas the rate was 1.7% among those who received only antibiotics. This difference indicated a 58% lower relative risk in the group that had surgery.
Utilizing the TriNetX Global Collaborative Network, researchers accessed data from 168 healthcare organizations. They selected patients diagnosed with acute appendicitis who either received surgical removal or antibiotic therapy. After matching patients based on relevant criteria, each initial group comprised 15,774 individuals. The final analysis involved 15,616 patients who had an appendectomy and 15,295 who were treated with antibiotics, after excluding those with prior colorectal cancer diagnoses. The records showed 110 cases of colorectal cancer following appendectomy, compared to 254 cases in the antibiotic-only group.
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. However, the study has not yet undergone peer review by a medical journal, which limits the strength of the conclusions that can be drawn. While the study suggests an association between the type of treatment and later colorectal cancer diagnosis, it does not prove that appendectomy directly prevents colorectal cancer.
Comparison of Surgical and Antibiotic Approaches
Acute appendicitis results from inflammation of the appendix, a small organ located near the junction of the small and large intestines. Traditionally, many cases are managed through surgical removal, known as an appendectomy. In recent years, antibiotics have also become an accepted treatment option for selected patients. Valentine Nfonsam, senior author and professor as well as executive vice chair of surgery at Morehouse School of Medicine, emphasized that antibiotic therapy remains a vital choice despite the new study’s findings.
In addition, the researchers explored factors that could influence the development of colorectal cancer after treatment for appendicitis. Sometimes, appendicitis occurs in individuals with an undiagnosed colorectal tumor, especially when a tumor on the right side of the colon causes obstruction and inflammation of the appendix. Surgery allows for tissue examination, which can reveal abnormalities and prompt further diagnostic testing that is not typically performed immediately with antibiotic-only treatment.
Associations, Not Causation, in Cancer Risk
The appendix plays a role in immune function through its lymphoid tissue and is linked to the gut microbiome, comprising bacteria and other microorganisms within the digestive system. The recent study did not determine whether these biological functions account for the observed differences in colorectal cancer diagnoses, nor whether inflammation or microbial alterations are causal factors. Consequently, researchers refrain from suggesting that appendectomy acts as a preventive measure against colorectal cancer.
Previous research has yielded mixed results regarding the relationship between appendectomy and colorectal cancer. A 2024 prospective study tracked over 224,000 participants across three large cohorts for up to 32 years, finding no evidence that appendectomy increases long-term colorectal cancer risk or precancerous lesions. This new investigation addresses a different question by comparing patients with appendicitis who underwent surgery with those receiving antibiotics alone. Researchers note that age, family history, and genetic factors remain well-established contributors to colorectal cancer risk.