Miller, R.

ABSTRACT Background and Objectives 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. Methods 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. Results 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). Conclusions 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.

Background: Upfront resectable pancreatic ductal adenocarcinoma (PDAC) is defined by the NCCN as disease with ≤180° portomesenteric vein (PMV) abutment. However, the clinical significance of PMV abutment in this cohort remains unexplored, and we sought to investigate its impact. Methods: This multi-institutional study included patients who underwent pancreatoduodenectomy (PD) for upfront resectable PDAC from 2002 to 2023. Patients with PDAC with ≤180° PMV abutment were compared with those without. Overall survival (OS) was compared and stratified based on whether patients underwent upfront surgery or neoadjuvant therapy (NAT). Results: Among 1,446 patients included, 521 (36.0%) had PMV abutment. Median OS for patients with PMV abutment was 28.8 months compared with 31.2 months for those without ( P =.17). In a stratified analysis of patients who underwent upfront surgery, patients with PMV abutment had worse OS (19.2 vs 27.6 months; P <.05) and lower R0 resection rates (63.1% vs 87.2%; P <.05) compared with those without. However, in patients who underwent NAT, this difference in R0 resection rate was not observed (91.4% vs 94.0%, respectively; P =.27). Furthermore, there was no significant difference in median OS with NAT (42.5 vs 51.6 months, respectively; P =.48). Conclusions: In this largest cohort to date of patients with upfront resectable PDAC, PMV abutment was associated with worse OS compared with no PMV abutment when an upfront resection strategy was used. The use of NAT in patients with PMV abutment mitigated this survival difference with increased R0 resection rates. These findings suggest that patients with upfront resectable PDAC with PMV abutment benefit from a NAT approach for optimal survival outcomes, and that the current criteria guidelines need to be redefined.