Risk stratification of surveillance for low-grade appendiceal mucinous neoplasms

Area of Science:

• Gastroenterology
• Surgical Oncology
• Oncology

Background:

• Low-grade appendiceal mucinous neoplasms (LAMNs) can potentially progress to pseudomyxoma peritonei (PMP).
• The incidence and risk factors for LAMN recurrence are not well-defined.
• There is no consensus on the optimal surveillance strategy for LAMN patients.

Purpose of the Study:

• To determine the recurrence rate and identify risk factors for LAMN after surgical resection.
• To evaluate the necessity and duration of surveillance imaging for LAMN.

Main Methods:

• Retrospective analysis of 125 patients with LAMNs confined to the appendix and limited right lower quadrant involvement (1992-2023).
• Assessment of recurrence risk factors using Kaplan-Meier curves and Cox proportional hazards regression.
• Median follow-up of 51.2 months.

Main Results:

• Only 4% of patients experienced recurrence, all progressing to PMP.
• The 5- and 10-year cumulative recurrence incidence rates were 3% and 6%, respectively.
• LAMNs limited to the right lower quadrant and tumor size <2 cm were significant risk factors for recurrence (P < .05). Patients with these factors had a 10-year recurrence risk of 30%, versus 1% for those without.

Conclusions:

• The overall recurrence risk of LAMN after appendectomy is low.
• Appendectomy alone is sufficient treatment for most LAMNs.
• Long-term surveillance is recommended for high-risk patients (right lower quadrant involvement, tumor size <2 cm); others can be observed expectantly.