Somatostatin receptor scintigraphy with [111In-DTPA-d-Phe1]- and [123I-Tyr3]-octreotide: the Rotterdam experience with more than 1000 patients

Abstract

Various tumours, classically specified as either neuroendocrine or non-neuroendocrine, contain high numbers of somatostatin receptors, which enable in vivo localization of the primary tumour and its metastases by scintigraphy with the radiolabelled somatostatin analogue octreotide. In addition granulomas and autoimmune processes can be visualized because of local accumulation of somatostatin receptor-positive activated mononuclear leucocytes. In many instances a positive scintigram predicts a favourable response to treatment with octreotide. It is tempting to speculate that octreotide labelled with an appropriate radionuclide might be used in cancer therapy. The successful application of radiolabelled octreotide in scintigraphy indicates the possible usefulness of other radiolabelled peptides, either native peptides or derivatives of these, in, for example, nuclear oncology. The small size of these peptides, e.g. bombesin and substance P, is of the utmost importance for a relatively fast blood clearance, thus leading to low background radioactivity. In this way peptides are powerful alternatives to (fragments of) monoclonal antibodies, the application of which to scintigraphic localization of specific cell surface antigen-bearing tumours is plagued by slow blood clearance and, hence, high background levels.

Peptide receptor radionuclide therapy with 177Lu-octreotate in patients with foregut carcinoid tumours of bronchial, gastric and thymic origin

“…These tumours often express somatostatin receptor subtype 2, which can be visualised with 111 In-octreotide scintigraphy (somatostatin receptor scintigraphy, SRS) [1]. If SRS is positive, peptide receptor radionuclide therapy with radiolabelled somatostatin analogues, e.g.…”

Comparison of 68Ga-DOTANOC and 68Ga-DOTATATE PET/CT Within Patients with Gastroenteropancreatic Neuroendocrine Tumors

“…68 Ga-DOTANOC has high affinity for somatostatin receptor subtypes 2, 3, and 5 (sst 2,3,5 ). It has a wider receptor binding profile than 68 Ga-DOTATATE, which is sst 2 -selective.…”

“…To date, 5 somatostatin receptor subtypes (sst 1 -sst 5 ) have been identified, all of which are expressed with differing frequencies in GEP-NETs. For example, sst 2 and sst 5 are expressed at a high density in 70%-100% of GEP-NETs (1). These receptors have been used as a target for diagnostic and therapeutic radiotracers.…”

“…Although most NETs express sst 2 , the distribution and density of sst 2 is often variable and sometimes too low for effective somatostatin receptor targeting (1). This is likely the reason for the wide sensitivity range (60%-100%) of 111 In-DTPA-octreotide scintigraphy and SPECT in the detection of NETs (5). One possible approach to overcoming this problem is the use of radiolabeled tracers with affinity to more than one somatostatin receptor subtype.…”

“…One possible approach to overcoming this problem is the use of radiolabeled tracers with affinity to more than one somatostatin receptor subtype. Gastrinomas, ileal carcinoids, and VIPomas express sst 2 or sst 5 with an incidence of almost 100% (1). [DOTA, 1-Nal 3 ]-octreotide (DOTANOC) is a peptide that promises to target a broader range of somatostatin subtype receptors, including sst 2 , sst 3 , and sst 5 (6,7).…”