[Efficacy of conversion therapy and direct surgical resection in patients with metastatic pancreatic neuroendocrine tumors].

Objective: To explore the prognosis of Chinese patients with metastatic pancreatic neuroendocrine tumor (PanNET) treated with conversion therapy and surgical resection. Methods: The pathological data and prognostic information was retrospectively collected of patients with metastatic PanNET treated in Fudan University Shanghai cancer center from January 2010 to May 2021, and propensity score matching was used to analyze the prognosis difference between conversion treatment followed surgery and direct surgery. Results: There were 58 males and 43 females in 101 patients with metastatic PanNET. The age raged from 18 to 74 years, with a median age of 51 years. A total of 88 patients received primary tumor with liver metastases resection, 1 receied of primary tumor resection and 12 received primary tumor resection and combined organs or extrahepatic metastases. Multivariate analysis showed that R2(HR=1.943,95%CI:1.262-2.990,P=0.003)resection and G3(HR=1.876,95%CI:1.001-3.516,P=0.05) were independent risk factors for postoperative progression of metastatic patients. There were 63 patients (62.4%) who had received direct surgery, and 38 patients (37.6%) who had received preoperative conversion therapy. The conversion therapy had a higher proportion of T3/T4 stage (68.1% vs 39.7%, P=0.007), resection with combined organs/extrahepatic metastasis (26.3% vs 9.5%, P=0.005) and R2 resection (71.1% vs 42.9%, P=0.005). The median progression-free survival (mPFS) between conversion therapy and direct surgery had no statistically significant, but after the propensity score matching the mPFS of the conversion therapy group was significantly longer than direct surgery group (HR=0.442,95%CI:0.207-0.943,P=0.027). Conclusions: Conversion therapy for partially metastatic PanNET is better than that of direct surgery. Radical resection and grade are independent prognostic factors for metastatic PanNET after resection.