Potter, Donald Dean

BACKGROUND: Children continue to undergo right hemicolectomy (RHC) for neuroendocrine tumors (NET) of the appendix based on adult guidelines. Appendectomy alone is recommended for the pediatric population; however, there are no data on safety of this approach in the setting of positive margins. This study aimed to determine the association between tumor characteristics and survival in a national cohort, hypothesizing that survival would be excellent despite high-risk features including positive margins on appendectomy. STUDY DESIGN: Patients 18 years of age or younger with NET of the appendix were identified in the National Cancer Database from 2004 to 2022 using ICD-O-3 codes. Characteristics of patients who underwent definitive appendectomy vs RHC were compared using chi-square tests. Five-year survival was determined for appendectomy patients with and without high-risk size, margin, and lymph node (LN) features. RESULTS: Of 1,339 patients, 1,156 (86%) underwent appendectomy and 183 (14%) RHC. Median age in both groups was 15 (13 to 17) years. Patients who underwent RHC had larger tumors (24% vs 4%, greater than 2 cm, p < 0.001), more lymphovascular invasion (31% vs 10%, p < 0.001), and were more likely to undergo LN assessment (82% vs 10%, p < 0.001) with a higher LN positivity rate (31% vs 16%, p = 0.006). There was no difference in margins status (p = 0.76). The 5- and 10-year survival was excellent regardless of tumor characteristics for patients overall (99.9% and 99.4%, respectively) and for those who underwent definitive appendectomy (99.9% and 99.2%). CONCLUSIONS: These data further support appendectomy as definitive management for children with appendiceal NET. Additional resection does not confer a survival benefit even in the setting of positive margins.