Background: Mechanical obstruction of the appendiceal lumen is proposed as a possible factor in the pathogenesis of acute appendicitis. Hence, patients over the age of 40 are often referred to a follow-up colonoscopy after admission for acute appendicitis. The use of CT scans question whether routine colonoscopy still has a place in follow-up for these patients.
Methods: All patients aged over 40 years with confirmed acute appendicitis admitted to St. Olav's Hospital in the period from 2010 to 2015 were included in this retrospective study. Findings and distribution of significant colorectal neoplasms (cancer and advanced adenomas) within three years after the admission were evaluated.
Results: Fifty-four (7.4%) of the 731 patients were found to have colonic neoplasms; 9 patients (1.2%) were found to have colorectal cancer of which 7 were located on the right side, 22 patients (3.0%) were found to have advanced adenomas and 23 patients (3.1%) were found to have non-advanced adenomas. The sensitivity and specificity for CT to discover cancer was 0.25 and 0.97, respectively. A total of 316 patients (43.2%) had colonoscopy within three years after admission.
Conclusion: There may be an increased risk of colorectal neoplasms in patients over the age of 40 admitted with acute appendicitis. There seems to be an increased proportion of right-sided cancer relatively to other colonic locations. The sensitivity for CT scans to discover colorectal cancer in this group is low. Further studies are needed to decide whether routine colonoscopy is indicated after acute appendicitis in patients over 40 years.
Keywords: Acute appendicitis; colonoscopy; colorectal cancer.