Background: The role of interval appendectomy in adults after non-operative management of acute appendicitis (AA) is unclear. We hypothesize that recurrent appendicitis is uncommon in patients managed without appendectomy (NA) during their index hospitalization for AA.

Methods: Clinical presentation, cancer treatment, and follow-up were collected from the electronic medical records of patients with CT scan confirmed AA from July 1999 through July 2009 at a tertiary cancer center. Medians of continuous data were compared using the Wilcoxon rank sum test.

Results: Seventy-five of 109 AA patients (68.8%) underwent appendectomy during the index hospitalization (IHA). Three IHA patients had more than 48 hours of medical management of AA prior to appendectomy. Thirty-four of 109 AA patients (31.2%) were NA. The median index hospitalization length of stay of the NA patients 6 days (0-55) and the median age was 59 (18-80). The reasons for NA were presence of an abscess or phlegmon (N=14), mild symptoms (13), high surgical risk (3), end stage cancer (3), and patient declining surgery (1). Among NA patients, 8 had percutaneous drainage of an abdominal abscess, the median duration of IV antibiotics was 5 days (0-55) and the median total duration of IV + PO antibiotics was 12 days (0-55). 35% of NA patients and 35% of IHA patients had received chemotherapy in the prior 30 days. During the index hospitalization for AA there were 6 deaths (3 IHA, 3 NA), 4 patients died of sepsis and 2 of cancer progression. At a median follow up of 19 months (range 1-103), 4 of the 31 NA patients who survived initial hospitalization had recurrent AA (12.9%) at 2, 2, 3 and 3 months after the first episode of AA [Figure]. Each had radiologic or symptomatic resolution of AA between episodes. Five NA patients had planned interval appendectomy (16.1%) at 1-7 months post AA and 22 remained asymptomatic without interval appendectomy (70.9%). Three of 22 subsequently asymptomatic patients suffered cancer related death less than 1 year after AA.

Conclusion: Among patients at a cancer center managed non-operatively at the time of the initial episode of AA, recurrent AA was early (< 4 months) but uncommon. Interval appendectomy should be used judiciously in this patient population.