De-Escalating Surgery for 1-2 cm Appendiceal Neuroendocrine Tumors: A North American Multi-Center Analysis

NCCN guidelines recommend right hemicolectomy (RHC) for appendiceal neuroendocrine tumors (aNETs) > 2 cm and observation for < 1 cm. However, optimal surgical management of 1-2 cm tumors remains controversial. This study compared long-term survival and recurrence between patients undergoing RHC versus appendectomy (APY) for 1-2 cm aNETs.

Patients with pathologically confirmed 1-2 cm aNETs treated at three Mayo Clinic sites (1972-2024) were included. Primary outcomes were recurrence and all-cause mortality after resection. Associations with lymph node (LN) metastasis were assessed in patients with lymphadenectomy.

Sixty-five patients were identified: 29 (45%) underwent APY, 35 (54%) RHC, and one ileocecectomy. Median age at diagnosis was 39 years; 71% were female and 94% white. LN positivity was 15.2% for tumors with nodes examined. Tumor size > 1.5 cm, stage T3/T4, and lymphovascular invasion were not associated with nodal metastasis. No survival differences were observed between APY and RHC. LN positivity did not impact survival. No recurrences occurred during a median follow-up of 6.25 years (IQR 2.44-12.63).

Among patients with 1-2 cm aNETs, RHC conferred no survival benefit over APY. Absence of recurrence and the limited prognostic value of nodal disease suggest APY alone may suffice for this population.