Risk of Appendiceal Neoplasm in Periappendicular Abscess in Patients Treated With Interval Appendectomy vs Follow-up With Magnetic Resonance Imaging

Abstract

IMPORTANCE The step after conservative treatment of periappendicular abscess arouses controversy, ranging from recommendations to abandon interval appendectomy based on low recurrence rates of the precipitating diagnosis to performing routine interval appendectomy owing to novel findings of increased neoplasm risk at interval appendectomy. To our knowledge, there are no randomized clinical trials with sufficient patient numbers comparing these treatments. OBJECTIVE To compare interval appendectomy and follow-up with magnetic resonance imaging after initial successful nonoperative treatment of periappendicular abscess. DESIGN, SETTING, AND PARTICIPANTS The Peri-Appendicitis Acuta randomized clinical trial was a multicenter, noninferiority trial conducted in 5 hospitals in Finland. All patients between age 18 and 60 years with periappendicular abscess diagnosed by computed tomography and successful initial nonoperative treatment from January 2013 to April 2016 were included. Data analysis occurred from April 2016 to September 2017. INTERVENTIONS Patients were randomized either to interval appendectomy or follow-up with magnetic resonance imaging; all patients underwent colonoscopy. MAIN OUTCOMES AND MEASURES The primary end point was treatment success, defined as an absence of postoperative morbidity in the appendectomy group and appendicitis recurrence in the follow-up group. Secondary predefined end points included neoplasm incidence, inflammatory bowel disease, length of hospital stay, and days of sick leave. RESULTS A total of 60 patients were included (36 men [60%]; median [interquartile range] age: interval appendectomy group, 49 [18-60] years; follow-up group, 47 [22-61] years). An interim analysis in April 2016 showed a high rate of neoplasm (10 of 60 [17%]), with all neoplasms in patients older than 40 years. The trial was prematurely terminated owing to ethical concerns. Two more neoplasms were diagnosed after study termination, resulting in an overall neoplasm incidence of 20% (12 of 60). On study termination, the overall morbidity rate of interval appendectomy was 10% (3 of 30), and 10 of the patients in the follow-up group (33%) had undergone appendectomy. CONCLUSIONS AND RELEVANCE The neoplasm rate after periappendicular abscess in this small study population was high, especially in patients older than 40 years. If this considerable rate of neoplasms after periappendicular abscess is validated by future studies, it would argue for routine interval appendectomy in this setting.

Diagnosis and treatment of acute appendicitis: 2020 update of the WSES Jerusalem guidelines

“…Adult patients with complicated AA treated with interval appendectomy can be diagnosed with appendiceal neoplasm in up to 11% of cases, in contrast to 1.5% of the patients who have early appendectomy [217]. Recently, the RCT by Mällinen et al comparing interval appendectomy and follow-up with MRI after initial successful nonoperative treatment of periappendicular abscess was prematurely terminated owing to ethical concerns following the unexpected finding at the interim analysis of a high rate of neoplasm (17%), with all neoplasms in patients older than 40 years [218]. If this significant rate of neoplasms after periappendicular abscess is validated by future studies, it would argue for routine interval appendectomy in this setting.…”

Risk of appendiceal cancer in patients undergoing appendectomy for appendicitis in the era of increasing nonoperative management

“…Variables specific to the patient's perioperative presentation were included, such as preoperative WBC count level, presence of preoperative sepsis or shock, preoperative imaging of either imaging confirmed or imaging indeterminate appendicitis, and specimen pathology results. WBC count was evaluated within clinically important parameters as a categorical variable using traditional cut-offs of below normal (<4.5), normal (4.5-11), elevated (11)(12)(13)(14)(15)(16)(17)(18)(19)(20), and significantly elevated (>20). The primary goal of this study was to determine independent risk factors associated with the pathologic diagnosis of cancer after appendectomy in patients with imaging-confirmed or indeterminate appendicitis with additional focus on the contribution of age to the final model.…”

Appendiceal Adenocarcinoma Found by Surgery for Acute Appendicitis is Associated with Older Age – A Retrospective Cohort Study

“…Healthcare providers have been eager to adapt this new modality without consideration for possible long-term outcomes, and oncologic rami cation. To date, the only gold standard con rmatory test for appendiceal cancer is appendectomy that is usually performed for the presentation of acute appendicitis (21)(22)(23). In a recent prospective study of acute complex appendicitis, patients with complicated appendicitis who underwent either surveillance or interval appendectomy were found to have an exceedingly high rate of malignancy that even resulted in premature discontinuation of a prospective study (10,(24)(25)(26).…”