Functional Status and Postoperative Outcomes After Left Pancreatectomy for Pancreatic Neuroendocrine Tumors: An Exploratory Analysis from the Prospective SPANDISPAN Study

<jats:p>Background: Whether tumor functional status influences postoperative outcomes after left pancreatectomy (LP) for pancreatic neuroendocrine tumors (pNETs) remains unknown. We evaluated the association between functional status, perioperative management, and postoperative outcomes in a prospective nationwide cohort of patients undergoing LP for pNET. Methods: This prespecified analysis of the prospective multicenter SPANDISPAN study included consecutive patients undergoing elective LP at 41 Spanish hospitals between February 2022 and January 2023. Of 98 patients with pNET, functional status was available in 88 (14 functioning and 74 non-functioning tumors). Perioperative characteristics, spleen preservation, and postoperative outcomes were compared according to tumor functional status. Results: Spleen preservation was performed in 28.6% of functioning and 18.9% of non-functioning tumors (p = 0.472; risk difference 9.7 percentage points, 95% CI [confidence interval] −15.6 to 34.9). Patients with functioning tumors had lower rates of clinically relevant postoperative pancreatic fistula (7.1% vs. 36.5%; p = 0.032; risk difference −29.3 percentage points, 95% CI −46.7 to −12.0), shorter length of hospital stay (median 4 vs. 7 days; p = 0.036), and no 90-day readmissions (0% vs. 31.1%; p = 0.017; risk difference −31.1 percentage points, 95% CI −41.6 to −20.5). Tumor functional status was not significantly associated with the use of spleen-preserving resection. Conclusions: Functional status is associated with clinically relevant differences in postoperative outcomes after LP for pNET. Patients with functioning tumors experienced lower postoperative morbidity than those with non-functioning tumors, whereas no statistically significant association was detected between tumor functional status and spleen preservation. These exploratory findings suggest that tumor functional status may warrant consideration as an additional factor in perioperative risk stratification and patient counseling, pending confirmation in larger, adequately powered studies; spleen preservation should continue to be guided by established oncological criteria.</jats:p>