Introduction: Neuroendocrine tumors (NET) are a heterogeneous group of malignant gastrointestinal tumors. Usually they exhibit functional or non-functional but progressive disease. Liver metastases (MTS) are usual, and can be present together with the primary tumor at the time of diagnoses. Although liver transplantation has been controversial, over the last decade there has been more evidence in favor of performing it under restrictive criteria. Here we present our initial experience with liver transplantation (LTx) for unresectable liver metastasis of NET, under selective criteria established by a multidisciplinary surgical, oncological and liver transplant program.
Material and Methods: Patients with NET referred to our center are evaluated and discussed in a unique committee and entered in a prospective database. Variables analyzed were: location and treatment of the primary tumor, pre-transplant management, time in waiting list, pathologicalfindings of the primary tumor and the liver explants, post Tx immunosuppressive treatment, overall patient survival and recurrence rate.
Results: Between 2009-2017, four patients were considered candidates and evaluated for LTx for unrespectable liver MTS. Letters of appeal were send to the local procurement organization (INCUCAI), and approved for equal score than the one given for HCC. Three of them had intestinal NET (iNET) and 1 was a pancreatic NET (pNET), 2 were male; the median age at diagnosis was 42±7.88 years, and median age at LTx was 44±7 years. All patients had the primary tumor resected by partial enterectomies or distal pancreatectomy. All patients received systemic treatment previous to LTx including somatostain analogs (3), everolimus (1), chemoembolization (1). The mean time between primary tumor treatment and LTx was 682±37 days; mean time in waiting list was 119±62.5 days. Three patients received whole cadaveric grafts, 1 right lobe split. Pathology analysis of the primary tumor were: low grade NET with Ki 67 < 2%;average # of mitosis: 2.5/10 HPF, lymphovascular invasion (LVI) was present in 2, perineural invasion (PNI) in one; the explanted livers showed grade 1 NET in 3 cases, Ki 67 <2% and 4 mitosis/10 HPF (min 1, max 16), LVI was diagnosed in one case. Primary immunosuppression used were: tacrolimus (3)and everolimus (1). Overall patient survival was 100% at a median follow up of 3 years. One patient experienced disease recurrence (25%), being the only case with LVI. Conclusions: Although the series is small, the uses of a selective candidate selection together with the possibility of providing priority on the waiting list, have allowedto obtained survival benefit comparable to other LTx indication for cancer.