Interval appendicectomy after conservative management of complicated appendicitis: Balancing recurrence, neoplasm risk, and surveillance strategies.

Abstract

Introduction: Non-operative management (NOM) of complicated appendicitis is increasingly accepted, but the role of interval appendicectomy (IA) remains contentious. Contemporary evidence has shifted decision-making from recurrence risk alone toward age-linked neoplasm risk and radiological features.

Objective: To synthesise contemporary randomised trials, prospective cohorts, and meta-analyses on recurrence after NOM of periappendiceal abscess, appendiceal tumour prevalence, and the diagnostic performance and harms of surveillance strategies (cross-sectional imaging and colonoscopy), to inform a pragmatic risk-stratified framework.

Results: Recurrence after successful NOM is commonly reported at 12-24% and is concentrated within the first six months. In adults presenting with periappendiceal abscess, appendiceal tumour prevalence rises with age, reaching approximately 5-10% in patients aged 35-39 and 14-20% in cohorts of patients aged ≥40 years. Interval CT/MRI findings identify higher-risk patients in whom IA should be prioritised. Colonoscopy is best used selectively, particularly when caecal pathology is suspected, imaging is equivocal, or IA is not planned in older patients.

Conclusion: Interval appendicectomy should generally be considered for patients aged ≥40 years and for any patient with persistent symptoms or concerning radiological findings, while recognising that decisions must be individualised with shared decision making. Younger patients with complete radiological resolution and no red-flag features can usually be observed with structured imaging follow-up. A risk-stratified clinical algorithm is proposed to guide post-NOM management.