American Surgical Association

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A Novel Validated Recurrence Risk Score to Guide a Pragmatic Surveillance Strategy after Resection of Pancreatic Neuroendocrine Tumors: An International Study of 1006 Patients
Mohammad Y. Zaidi*1, Alexandra G. Lopez-Aguiar*1, Valentina Andreasi*2, Stefano Partelli*2, George A. Poultsides*3, Mary Dillhoff*4, Flavio H. Rocha*5, Kamran Idrees*6, Clifford S. Cho7, Sharon M. Weber8, Ryan C. Fields*9, Charles A. Staley, III1, Massimo Falconi*2, Shishir K. Maithel*1
1Emory University, Atlanta, GA;2San Raffaele Scientific Institute, Milan, Italy3Stanford University, Stanford, CA;4The Ohio State University, Columbus, OH;5Virginia Mason Medical Center, Seattle, WA;6Vanderbilt University, Nashville, TN;7University of Michigan, Ann Arbor, MI;8University of Wisconsin, Madison, WI;9Washington University School of Medicine, St Louis, MO

Objective: Despite heterogeneous biology, similar surveillance schemas are utilized after resection of all pancreatic neuroendocrine tumors (PanNETs). Given concerns regarding excess radiation exposure and financial burden, our aim was to develop a prognostic score for disease-recurrence to guide individually-tailored surveillance strategies. Methods: All patients with primary nonfunctioning, non-metastatic well/moderately-differentiated PanNETs who underwent curative-intent resection at 9-institutions from 2000-2016 were included (n=1006). A Recurrence Risk Score (RRS) was developed from a randomly-selected derivation-cohort comprised of 67% of patients and verified on the validation-cohort comprised of the remaining 33%. Results: On multivariable analysis, patients within the derivation-cohort (n=681) with symptomatic tumors (jaundice, pain, bleeding), tumors>2cm, Ki67>3%, and LN(+) disease had increased recurrence. Each factor was assigned a score based on their weighted odds-ratio that formed a RRS of 0-10: symptomatic=1, tumor>2cm=2, Ki67 3-20%=1, Ki67>20%=6, LN(+)=1. Patients were grouped into Low (RRS=0-2; n=247), Intermediate (RRS=3-5; n=204), or High (RRS=6-10; n=9) risk groups. At 24mos, 33% of High RRS recurred, while only 2% of Low and 14% of Intermediate RRS recurred (Figure1A). This persisted in the validation-cohort (n=325;Figure1B). Conclusion: This international, novel, internally-validated recurrence risk score accurately stratifies recurrence-free survival for patients with resected pancreatic neuroendocrine tumors. Given their unique recurrence patterns, surveillance intervals of 12-, 6-, and 3-months are proposed for Low, Intermediate, and High RRS patients, respectively, in order to minimize radiation exposure and optimize cost/resource utilization.

* By Invitation


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