Comparison of the risk of appendiceal tumors in uncomplicated and complicated appendicitis.

ABSTRACT

BACKGROUND: Interval appendectomy or non-operative management is commonly performed for complicated appendicitis in adult patients. However, these treatments are still controversial because the incidence rate of appendiceal tumors recognized after interval appendectomy is reportedly higher than that after emergency appendectomy. Thus, this study aimed to compare the appendiceal tumor rates between uncomplicated and complicated appendicitis. METHODS: This study was a retrospective review of patients with appendicitis who underwent surgical removal at a single institution over 7.5 years. The primary objective was the comparison of the incidence rate of appendiceal tumors using propensity score matching, and the secondary objective was the same comparison among older patients, defined as patients aged ≥ 60 years. RESULTS: A total of 1277 patients were included. Of these patients, 297 (23.3%) were preoperatively diagnosed with complicated appendicitis. Moreover, 22 (1.7%) patients, including 14 cases of complicated appendicitis and 8 cases of uncomplicated appendicitis, were diagnosed with appendiceal tumors based on pathological examination. No significant difference was found in the incidence rate of appendiceal tumors between the two groups after matching for patients' background, including age, sex, and history of appendicitis by propensity score matching (P = 0.073). However, among patients aged ≥ 60 years, the incidence of appendiceal tumors was significantly higher in complicated than in uncomplicated appendicitis (P = 0.006). CONCLUSIONS: Although the overall risk of appendiceal tumors did not differ between complicated and uncomplicated appendicitis when analyzed by the propensity score matching, in older patients aged ≥ 60 years, the risk increased among those with complicated appendicitis. Therefore, although the incidence is low, complicated appendicitis, particularly, among older patients, should be examined carefully and be performed IA when unusual findings exist.