Appendiceal Neoplasm in Conservatively Managed Acute Appendicitis: A Retrospective Observational Study

Introduction Appendiceal neoplasms are more prevalent in patients ≥ 40 years old who present with complicated appendicitis, especially if managed conservatively. Routine interval appendicectomy is not recommended. Follow-up bowel screening using both a CT scan and colonoscopy is recommended. Following the COVID-19 pandemic, many units have increased their utilization of non-operative management of acute appendicitis (NOM). This provides an optimal population sample to study the incidence of unexpected appendiceal malignancy compared to a similar cohort that underwent operative management. The primary outcomes of interest include the incidence of appendiceal malignancy following NOM, efficacy of bowel screening, and rates of re-admission. Methods A retrospective, observational study on patients admitted with acute appendicitis from January 2020 to December 2021. All patients diagnosed with acute appendicitis aged 40 years and older were included in the study, while those under 40 or without a diagnosis of acute appendicitis were excluded. Results We had 211 cases of acute appendicitis. 125 (59%) of which were managed operatively, while 86 cases (41%) were managed NOM. We found six cases (7%) of appendiceal malignancy in the NOM cohort, compared to two cases (1.6%) in the operatively-managed cohort. A routine follow-up colonoscopy failed to reveal any sinister pathology. All six cases underwent interval appendicectomy through which the malignancy was detected. 39 cases (45%) of NOM had at least one episode of re-admission, with 32 (37%) of them being in the first year. Conclusion NOM of acute appendicitis in adults ≥ 40 years old is associated with an increase in unexpected appendiceal malignancy, none of which were detected on follow-up colonoscopy. We emphasize the need for closer surveillance and potentially more aggressive follow-up strategies, including routine interval appendicectomy, for older patients undergoing NOM of acute appendicitis.