Active surveillance for low-grade appendiceal mucinous neoplasm (LAMN)

Area of Science:

• Gastroenterology
• Oncology
• Surgical Pathology

Background:

• Low-grade appendiceal mucinous neoplasm (LAMN) lacks standardized management guidelines, particularly for incidentally discovered cases.
• The risk of pseudomyxoma peritonei progression necessitates careful monitoring strategies.

Purpose of the Study:

• To evaluate the efficacy of an active surveillance (AS) strategy for incidentally diagnosed LAMN.
• To assess the role of MRI in predicting disease progression in LAMN patients.

Main Methods:

• Thirty patients with incidentally diagnosed LAMN and low risk for pseudomyxoma progression were enrolled.
• Active surveillance included physical examination, tumor markers, and abdominopelvic MRI every 6 months initially, then annually for 10 years.
• Inclusion criteria required LAMN confirmation, limited extra-appendiceal mucin, normal tumor markers, and normal baseline MRI.

Main Results:

• 87% of patients exhibited no disease progression on MRI during a median follow-up of 3.1 years.
• 13% of patients progressed to pseudomyxoma peritonei (PMP).
• MRI in the first postoperative year accurately predicted prognosis in 97% of cases.

Conclusions:

• Active surveillance, guided by MRI, is a safe and effective management option for incidental LAMN.
• Early MRI findings are highly predictive of long-term disease outcomes in LAMN patients.