644 Background: liver metastases (LM) from well-differentiated gastroenteropancreatic neuroendocrine tumors (wd-GEP-NET) can develop in 28-77% of patients (pts) in their lifetime. Multiple treatments can provide radiological and symptomatic response. Our aim was to evaluate responses to locoregional (LRT) and systemic (SYST) treatments in wd-GEP-NET with LM. Methods: we included consecutive records of pts with confirmed histological diagnosis of wd-GEP-NET and radiological LM, treated at our institution between 2008-2019. Relevant variables were retrospectively extracted from electronic records. Radiological response was assessed with RECIST 1.1 by radiological independent review. Results: 55 pts, 45.5% male. Median age at LM diagnosis 49 years (IQR 41-63). Primary tumor sites: 49% pancreatic, 27.3% small intestine, 11% unknown, 12.7% others. WHO 2019 grade 1, 2 and 3 in 52.7, 41.8 and 1.8%, respectively. Twentynine tumors (52.7%) were functional, with carcinoid syndrome in n20. At LM diagnosis, 91% of pts had symptomatic disease: hormonal n8, local n4, systemic n4, hormonal + local n4, local + systemic n22, hormonal + systemic n5, hormonal + local + systemic n5. LM tumoral burden was <10% in 22%, 11-50% in 43.6, > 50% in 30.9% of pts. 49.1% of pts had extra hepatic metastatic disease. LRT to LM was administered to 32 pts: TAE/TACE n26, ablation n8. SYST to 22 pts: somatostatin analog n15, Lutetium-177 n4, chemotherapy n2, everolimus n1. 1 pt did not receive treatment. Response to treatments is shown. In the LRT group, -- pts developed complications: n16 postembolization syndrome, n2 infections, n3 liver failure, n7 others. There was 1-procedure-related death. Conclusions: Patients treated with LRT at our institution achieved similar efficacy and safety results compared to those reported by previous studies.[Table: see text]

454 Background: Pancreatic cancer remains a highly lethal disease. There is no consensus on treatment sequences and chemotherapy (CT) regimen in BRPC and LAPC. Our aim was to describe the multimodal treatment and outcomes in our population. Methods: We retrospectively reviewed medical records of patients (pts) with BRPC/LAPC and histological diagnosis of adenocarcinoma evaluated at Instituto Nacional de Ciencias Médicas y Nutrición from January 2011-December 2016. Clinical and pathological variables at diagnosis and treatment were recorded. Overall survival (OS) was estimated using Kaplan-Meier method and compared by Log-rank test. Results: 69 pts were evaluated, 39% (27) did not receive treatment. We analyze 42 treated pts. BRPC 33%/LAPC 67%. Median age was 58.8 y/o, 54.8% were female. Symptoms at diagnosis: 79% abdominal pain, 76% weight loss, 55% jaundice. ECOG performance status (PS): 0 (17%), 1 (69%) and 2 (14%). Main location was pancreatic head (76%). Median laboratory values: total bilirubin 1.04 mg/dL (0.2-25), albumin 4.1 g/dL (2.4-5.1), CA 19.9 182.8 U/mL (0.8-4028). Laparotomy at diagnosis was performed in 21%. All pts received induction CT (iCT). FOLFIRINOX was the most common regimen (37%), followed by FOLFOX4 (34%). The best overall response with iCT was stable disease (62%), progressive disease was observed in 24%. iCT followed by chemoradiation (CRT) could be delivered to 48% (20/42). Capecitabine-based CRT was preferred (94%). Six pts (14%) underwent surgical resection after multimodal treatment (36% BRPC, 3.5% LAPC), 5 pts achieved R0 resection. The resection rate with single-agent iCT was 0% vs 20% with combination iCT. Median OS was 15.6 months (m): 14.4 m for BRPC and 15.5 m for LAPC. Median OS according iCT: gemcitabine 7.8 m, fluorouracil 13.7 m, FOLFOX4 15.5 m and FOLFIRINOX 24.6 m. Univariate analysis identified ECOG PS (0-1 vs 2, P = 0. 014) and age ( < 59 vs ³59, P = 0.002) as significantly associated with survival. Conclusions: Early administration of combination CT followed by CRT and/o surgical resection in selected pts improves oncological outcomes in pts with BRPC/LAPC. In pts with good PS, iCT with FOLFIRINOX is the preferred regimen given best results.