Benefit of Primary Tumor Resection in Stage IV, Grade 1 and 2, Pancreatic Neuroendocrine Tumors: A Propensity-Score Matched Cohort Study.

Objective: To determine the association of primary tumor resection in stage IV pancreatic neuroendocrine tumors (Pan-NET) and survival in a propensity-score matched study. Background: Pan-NET are often diagnosed with stage IV disease. The oncologic benefit from primary tumor resection in this scenario is debated and previous studies show contradictory results. Methods: Patients from 3 tertiary referral centers from January 1, 1985, through December 31, 2019: Uppsala University Hospital (Uppsala, Sweden), Sahlgrenska University Hospital (Gothenburg, Sweden), and Brigham and Women's Hospital/Dana-Farber Cancer Institute (Boston, USA) were assessed for eligibility. Patients with sporadic, grade 1 and 2, stage IV pan-NET, with baseline 2000-2019 were divided between those undergoing primary tumor resection combined with oncologic treatment (surgery group [SG]), and those who received oncologic treatment without primary tumor resection (non-SG). A propensity-score matching was performed to account for the variability in the extent of metastatic disease and comorbidity. Primary outcome was overall survival. Results: Patients with stage IV Pan-NET (n = 733) were assessed for eligibility, 194 were included. Patients were divided into a SG (n = 65) and a non-SG (n = 129). Two isonumerical groups with 50 patients in each group remained after propensity-score matching. The 5-year survival was 65.4% (95% CI, 51.5-79.3) in the matched SG and 47.8% (95% CI, 30.6-65.0) in the matched non-SG (log-rank, Conclusions: Resection of the primary tumor in patients with stage IV Pan-NET and G1/G2 grade was associated with prolonged overall survival compared to nonoperative management. A surgically aggressive regime should be considered where resection is not contraindicated.