Impact of a Prior Nonpancreatic Malignancy on Survival Outcomes of Patients With Stage IV Pancreatic Neuroendocrine Tumor: A Population-Based and Propensity Score Matching Study.

Objective: The aim of the study was to investigate the impact of a previous nonpancreatic malignancy on the survival outcomes in patients with a stage IV pancreatic neuroendocrine tumor (PanNET).
Methods: The Surveillance, Epidemiology, and End Results database was reviewed, and patients diagnosed with a stage IV PanNET between 2004 and 2015 were selected. Patients were divided into 2 groups according to the presence or absence of a previous nonpancreatic malignancy. Clinicopathological characteristics and survival outcomes were compared.
Results: A total of 1582 patients with stage IV PanNET were identified, of whom 116 (7.3%) had a prior malignancy. Prostate (33.62%), breast (17.24%), and gastrointestinal (12.07%) malignancies were the most common. Most prior malignancies (84.48%) were localized and regional. Patients with intervals of 36 months or less, 36 to 60 months, 60 to 120 months, and more than 120 months account for 25.86%, 14.66%, 31.03%, and 28.45% of all cases, respectively. Before and after propensity score matching, there was no significant difference detected regarding survival outcomes.
Conclusions: Stage IV PanNET patients with a history of a prior cancer had comparable survival outcomes with patients without such history. These patients could be candidates for clinical trials if otherwise appropriate, and aggressive and potentially curative therapies should be offered.