Abstract 213P
Background
Hepatic manifestations of neuroendocrine neoplasms (NEN) are most commonly diagnosed as metastases from other organs or from an unknown primary. However, the current WHO classification defines primary hepatic NEN (PHNEN) arising in the liver as a distinct entity. With only a few cases of PHNEN reported and difficulty to discern them from hepatic metastases, evidence on optimal management is very limited.
Methods
In order to explore the clinical characteristics and treatment outcomes of PHNEN, we performed a retrospective review of the combined prospective and retrospective databases of two high-volume NEN centers for PHNEN presenting between 08/1996 and 10/2023.
Results
Among over 2000 patients in the databases, 38 patients with PHNEN could be identified. Median follow-up was 40.7 months. Histologies were NET G1 (n=6), NET G2 (n=17), NET G3 (n=3), NEC G3 (n=11) and MiNEN (n=1). Four patients presented with synchronous extrahepatic metastases, mostly lymph nodes. Resection of the hepatic primary was performed in 23 patients with a median recurrence-free survival of 115.9 months. Five patients received liver transplantation. First-line somatostatin analogue (SSA) treatment was administered to three evaluable patients, all with stable disease (SD) as best response for 14.0, 35.0 and 36.0 months respectively. Of four evaluable patients under peptide receptor radionuclide therapy (PRRT), two showed a partial remission (PR), one an SD and one a mixed response. Platinum-based chemotherapy was applied in nine NEN G3 patients with only two PRs and one SD as best responses and the remaining tumors progressing, with a median progression-free survival of 2.5 months. The median overall survival of the whole cohort was 133.9 months, with 4.2 months in NEC G3 and MiNEN vs. 133.9 months in NET G1-3 (p<0.0001).
Conclusions
PHNEN are an exceptional but distinct disease. While both SSAs and PRRT showed encouraging activity, efficacy of platinum-based chemotherapy in G3 PHNEN was limited. Prognosis was largely determined by grading and differentiation. Further molecular characterization of the patient cohort is ongoing.
Legal entity responsible for the study
National Center for Tumor Diseases (NCT) Heidelberg.
Funding
Has not received any funding.
Disclosure
L. Apostolidis: Financial Interests, Personal, Invited Speaker: Ipsen, BMS; Financial Interests, Personal, Advisory Board: Novartis. L. de Mestier du Bourg: Financial Interests, Personal, Advisory Board: Novartis; Financial Interests, Personal, Expert Testimony: Ipsen, Esteve. All other authors have declared no conflicts of interest.