P35: Slow Adoption of Observation for Small Pancreatic Neuroendocrine Tumors

Friday, March 24, 2023

1:26 PM – 1:31 PM

Location: SSO HUB Pan-Tumor Zone: CRS, HPB, Pan-Tumor & Upper GI

Poster Presenter(s)

Aaron T. Scott, MD

Fellow
City of Hope National Medical Center, United States

Disclosure information not submitted.

Author(s)

Aaron T. Scott, MD

Fellow
City of Hope National Medical Center, United States

Disclosure information not submitted.
Matthew Hernandez, MD

Fellow
City of Hope, United States

Disclosure information not submitted.
AL

Aaron Lewis, MD

Assistant Clinical Professor
City of Hope, United States

Disclosure information not submitted.
DL

Daneng Li, MD

Associate Professor
City of Hope, United States

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Laleh Melstrom, MD MSCI

Chief of Surgical Oncology, Associate Professor of Surgery and Immuno Oncology
City of Hope Medical Center
La Verne, California, United States

Disclosure information not submitted.
GS

Gagandeep Singh, MD

Professor
City of Hope National Medical Center, California, United States

Disclosure information not submitted.
Yuman Fong, MD

Sangiacomo Chair and Chairman
City of Hope Medical Center
Duarte, CA, California, United States

Disclosure information not submitted.
Mustafa Raoof, MD, FACS

Assistant Professor
Department of Surgery, Cancer Genetics and Epigenetics
Duarte, California, United States

Disclosure information not submitted.

Introduction: Growing evidence suggests that small (<2 cm), asymptomatic, non-functional pancreatic neuroendocrine tumors (PNETS) typically follow an indolent course, and that observation should be considered. However, resection rates remain high despite major society guidelines recommending observation. We aim to describe trends in the adoption of non-operative management, and to identify factors associated with resection.

Methods: The National Cancer Database (NCDB) was reviewed from 2004 – 2019 and patients with well-differentiated, non-metastatic PNETs <2 cm were selected. Demographic factors associated with resection were identified and significance was calculated using the Chi-squared test, T-test and binary logistic regression. Survival was analyzed using the Kaplan Meier method.

Results: A total of 8,507 patients with small, non-functional PNETs were identified, of whom 5,891 underwent surgery and 2,616 were observed. The mean age of surgical patients was 59.8 versus 65 for those observed (p < 0.001). 65% of tumors < 1 cm were resected compared to 69% of 1 - 1.5 cm tumors and 73% of 1.6 - 2 cm tumors (p < 0.001). The overall resection rate remained stable from 2004 to 2011, with 82% of patients in this time period treated surgically. From 2012 to 2019 the resection rate decreased from 79% to 53%. Overall survival was longer in the post-2011 cohort, during which time the resection rate was 66%, compared to the pre-2011 cohort during which time the resection rate was 82% (HR 1.17, p< 0.001), and the median survival was not reached in either group. Among surgical patients, 30- and 90-day mortality rates were 1% and 1.7% respectively, and the 30-day unplanned readmission rate was 8.2%. On multivariable analysis, older age at diagnosis, male sex, facility type, later year of diagnosis, and smaller tumor size were all significantly associated with non-operative management.

Conclusions: Pancreatic surgery for small PNETs is associated with unclear benefit and well described risks. Despite data suggesting that observation is a reasonable strategy, most patients in the NCDB with these tumors still undergo resection. Consistent with recent national guidelines, there has been an increasing trend toward observation of small PNETs in recent years. This decrease in resection rate has not resulted in worse overall survival.

Learning Objectives:

describe trends in resection rates for small pancreatic neuroendocrine tumors in the US.
describe national guidelines for the management of small pancreatic neuroendocrine tumors.
identify factors predictive of resection in small pancreatic neuroendocrine tumors.