Impact of primary tumor resection and metastasectomy among gastroentero-pancreatic neuroendocrine tumors with liver metastases only on survival

Background: Despite recommendations for primary tumor resection (PTR) with or without liver resection (LR) in the patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs) and isolated liver metastases, there are conflicting data for their impact on overall survival (OS).Methods: 2320 patients with GEP-NETs and isolated liver metastases were identified from NCDB. Multiple imputations were used to accommodate missing data, and inverse probability of treatment weighting (IPTW) was conducted to minimize bias.Results: Patients with PTR had a greater OS than those without PTR (3-year rate of 88.6% vs. 69.9%, P < 0.001), which was preserved in the adjusted analysis (IPTW-adjusted HR = 0.387, 95% CI: 0.264-0.567; P < 0.001). Patients with LR had a greater OS than those without LR (3-year rate 87.7% vs. 75.2%, P = 0.003), which was also preserved in adjusted analysis (IPTW-adjusted HR = 0.450, 95% CI: 0.229-0.885; P = 0.021). Patients undergoing both PTR and LR had the greatest survival advantage than those with other surgical interventions (P < 0.001).Conclusions: Either PTR or LR is associated with improved survival for GEP-NET patients with isolated liver metastases. However, there remains significant selection bias in the current study, and caution should be exercised when selecting patients for resection.