Necessity of posttreatment surveillance for low-grade appendiceal mucinous neoplasms.

Background And Objectives: Low-grade appendiceal mucinous neoplasms (LAMNs) are generally treated by surgical resection, but posttreatment surveillance protocols are not well-established. The objectives of this study were to characterize posttreatment surveillance and determine the risk of recurrence following surgical resection of LAMN.

Methods: Patients who underwent surgical resection of localized LAMNs in an 11-hospital regional healthcare system from 2000 to 2019 were identified. Posttreatment surveillance regimens were characterized, and rates of disease recurrence were evaluated.

Results: A total of 114 patients with LAMNs were identified. T-category was pTis for 92 patients (80.7%), pT3 for 7 (6.1%), pT4a for 14 (12.3%), and pT4b for 1 (0.9%). Two patients (1.8%) had a positive resection margin. Posttreatment surveillance was performed for 39 (34.2%) patients and consisted of office visits for 32 (82%) patients, computerized tomography imaging for 30 (77%), magnetic resonance imaging for 5 (13%), colonoscopy for 15 (38%), and serum tumor marker measurement for 12 (31%). After a mean follow-up duration of 4.7 years, no patients experienced tumor recurrence.

Conclusions: Posttreatment surveillance is common among patients with LAMNs. However, no patients experienced tumor recurrence, regardless of T-category or margin status, suggesting that routine surveillance following surgical resection of LAMN may be unnecessary.