Treatment of advanced neuroendocrine tumours with the radiolabelled somatostatin analogue octreotide

Abstract

Neuroendocrine tumours (NET) have a particular tendency to express functional receptors and/or uptake mechanisms. Radionuclides, such as 111 In-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 111 In-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.

Disappearance of a growth hormone secreting macro adenoma during long-term somatostatin analogue administration and recurrence following somatostatin withdrawal

“…[4][5][6] Somatostatin analogues, being major inhibitors of cell growth, are used in a variety of clinical conditions related to the gastrointestinal tract, pancreas, neuroendocrine system, diabetic retinopathy and thyroid eye disease. [7][8][9] With regard to pituitary adenomas, therapy with somatostatin analogues has been effective, not only in GH secreting adenomas, but also in thyrotropin secreting pituitary adenomas, 10 in prolactinomas 11 and in non-functioning, normotopic or orthotopic pituitary adenomas. 12 In this report, we describe a patient in whom long term (62 months) lanreotide-L.A.R administration resulted in complete disappearance of a GH secreting macroadenoma, followed by recurrence of the adenoma six months post therapy discontinuation.…”

<p>Therapies targeting the signal pathways of pheochromocytoma and paraganglioma</p>

“…I 131 -metaiodoenzylguanidine (I 131 -MIBG) is a kind of radiopharmaceutical which acts as a norepinephrine analog taken up by cells in the sympathomedullary system19 and high doses of I 131 -MIBG can prolong survival and relieve symptoms 20. Since PCC expresses somatostatin receptors, radiopharmaceuticals based on the somatostatin analogs octreotide and lanreotide have also begun to be used 21. However, these treatments are only suitable for cancer patients who have high intake of radionuclides and there is still insufficient evidence to determine radionuclide therapy doses and normal tissue tolerated doses.…”

“…When tested temozolomide in PCC/PGL patients, 67% of the patients showed clinical benefits and 80% of them showed tumors of low-level MGMT 24. Moreover, the CVD regimen (a combination of cyclophosphamide, vincristine, and dacarbazine) recommended for chemotherapy had an effective rate of about 50%, but most of them relapsed within 2 years 21. A meta-analysis showed that about 37% of the patients had partial response on reducing tumor volume after using chemotherapy drugs 20.…”

Recent advances in radiological and radionuclide imaging and therapy of neuroendocrine tumours

“…an effective radiation dose to the tumour without damage to non-tumour tissues (25,91). Tumour heterogeneity may cause incomplete responses unless the radiation delivered can kill the nearby tumour cells that are target-negative; this depends on the cross-fire from the radioisotope localized in or on the target-positive tumour cells (23,92).…”