Phase II, open-label, multicentre national study. Patients with metastatic neuroendocrine carcinomas of extrapulmonary origin will be eligible. Treatment will be performed as indicated in the section "Investigational drug and reference therapy". Cisplatinum and everolimus dosing is based upon earlier phase 1 studies (Fury et al. 2012). CTs will be done at 9 weekly intervals (after 3 courses of chemotherapy;). Patients will be treated until documented progression according to RECIST 1.1. Enrolment is expected to take between 14 - 16 months. The total study duration is estimated to be 2 to 3 years until publication. Three NET centres in The Netherlands will participate, (Erasmus Medical Center in Rotterdam, Netherlands Cancer Institute in Amsterdam and , the University Medical Center of Groningen) A pre-treatment (and optional post-treatment) tumour biopsy will be included for DNA/RNA analyses and organoid culture. An additional 5cc of blood will be withdrawn as a germline DNA reference. A second 5 cc of blood will be included for measuring circulating tumour transcripts to identify all types of GEP-NET (NETTest).