Pharmacological therapy consists of long-lasting octreotide injections, Iodine-131 metaiodobenzylguanidine (
131I-MIBG), interferon-α (IFN-α) or targeted chemo- and radiotherapy. Octreotide is a somatostatin analogue and appears to be an efficacious treatment for carcinoid syndrome, reducing symptoms in more than 70% of patients [
52,
53]. Some patients with partial response after local ablation have relief of symptoms by additional treatment with octreotide [
37]. Prolonged symptomatic relief can be provided by
131I-MIBG therapy. In individual cases, improved quality of life may be obtained [
54]. Even improved survival was seen by symptomatic response to
131I-MIBG treatment [
55]. The clinical benefit of IFN-α treatment has been limited by their modest anti-tumour effect as well as serious side-effects [
56,
57]. In addition, combination treatment with octreotide and IFN-α showed little advantage. Biochemical responses were observed in 72–77%, however no objective tumour regression was observed [
57,
58]. A promising approach is the concept of somatostatin receptor (SSTR)-mediated chemo-or radiotherapy of SSTR-expressing metastatic carcinoid. Currently, clinical trials with cytotoxic compounds, such as methotrexate and doxorubicin, linked to an analog of somotostatin are under way [
59,
60]. Also promising is targeted SSRT-mediated radiotherapy using radionuclides such as
90Y and
177Lu. Experimental studies in patients who have somatostatin-positive tumours show complete remission by the use of tetra-azacyclododecane tetra-acetic acid Tyr
3-octreotide [
61]. After surgical reduction of tumour load, repeated intermediate-dosage
90Y, Tyr-octreotide,
177Lu or
131I-MIBG treatment appears to be a reliable and well-tolerated radionuclide therapy and might be a useful adjunct in patients with malignant neuroendocrine carcinoma, providing long-lasting palliation and prolonged survival [
62].