Review Treatment of advanced neuroendocrine tumours with the radiolabelled somatostatin analogue octreotide

Neuroendocrine tumours (NET) have a particular tendency to express functional receptors and/or uptake mechanisms. Radionuclides, such as 111In-pentetreotide, a somatostatin analogue, which bind to somatostatin receptors, present an imaging modality that has been used for both the diagnosis and staging of NET. Scintigraphy with 111In-pentetreotide can identify lesions beyond the diagnostic sensitivity of conventional imaging modalities. In addition, NET that demonstrate positive uptake to a diagnostic 111In-pentetreotide can, in theory, be treated with these radionuclides, thus presenting a novel and evolving therapeutic modality in addition to other traditional therapeutic approaches. Although experience with 90Y-DOTA-D-Phe1-Tyr3-octreotide therapy is still limited, preliminary studies have demonstrated useful activity in a variety of NET with limited side-effects. Large phase II clinical trials using 90Y-DOTA-D-Phe1-Tyr3-octreotide therapy are still on-going and the results are expected to be presented soon. In order to improve the response rates obtained, newer somatostatin analogues are being developed and the combination with other â-emitting particles in addition to 90Y is being considered. Key words: neuroendocrine, tumours, radionuclide