Interval Appendicectomy after Conservative Management of Complicated Appendicitis: Balancing Recurrence, Neoplasm Risk, and Surveillance Strategies.

BACKGROUND

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.

SUMMARY: Recurrence after successful NOM is commonly reported at 12-24% and is concentrated within the first 6 months. In adults presenting with periappendiceal abscess, appendiceal tumour prevalence rises with age, reaching approximately 5-10% in patients aged 35-39 years and 14-20% in cohorts aged ≥40 years. Interval CT or MRI findings, including dilated or cystic morphology, mural abnormalities, calcification, mucin, or a base mass, 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.

KEY MESSAGES: IA should generally be considered in patients aged ≥40 years and in those with persistent symptoms or concerning radiological findings, while recognising that decisions must be individualised and made through 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.