Primary tumor resection improves survival of gastrointestinal neuroendocrine carcinoma patients with nonresected liver metastases

Background The role of primary tumor resection (PTR) in the survival of gastrointestinal neuroendocrine carcinoma (GI‐NEC) patients with liver metastases only remains poorly defined. Therefore, we investigated the impact of PTR on the survival of GI‐NEC patients with nonresected liver metastases. Methods GI‐NEC patients with a liver‐confined metastatic disease diagnosed between 2016 and 2018 were identified in the National Cancer Database. Multiple imputations by chained equations were used to account for missing data, and the inverse probability of treatment weighting (IPTW) method was used to eliminate selection bias. Overall survival (OS) was compared by adjusted Kaplan–Meier curves and log‐rank test with IPTW. Results A total of 767 GI‐NEC patients with nonresected liver metastases were identified. Among all patients, 177 (23.1%) received PTR and had a significantly favorable OS before (median: 43.6 months [interquartile range, IQR, 10.3–64.4] vs. 8.8 months [IQR, 2.1–23.1], p