(dtpa-phe(1))-octreotide and Pheochromocytoma

This paper is a critical review of the literature on NET radionuclide therapy with (111)In-DTPA(0)-octreotide (Octreoscan) and (131)I-MIBG, focusing on efficacy and toxicity. Some potential future applications and new candidate therapeutic agents are also mentioned. Octreoscan has been a pioneering agent for somatostatin receptor radionuclide therapy. It has achieved symptomatic responses and disease stabilization, but it is now outperformed by the corresponding β-emitter agents (177)Lu-DOTATATE and (90)Y-DOTATOC. (131)I-MIBG is the radionuclide therapy of choice for inoperable or metastatic phaeochromocytomas/paragangliomas, which avidly concentrate this tracer via the noradrenaline transporter. Symptomatic, biochemical and tumour morphological response rates of 50-89%, 45-74% and 27-47%, respectively, have been reported. (131)I-MIBG is a second-line radiopharmaceutical for treatment of enterochromaffin carcinoids, mainly offering the benefit of amelioration of hormone-induced symptoms. High specific activity, non-carrier-added (131)I-MIBG and meta-astato((211)At)-benzylguanidine (MABG) are tracers with potential for enhanced therapeutic efficacy, yet their integration into clinical practice awaits further exploration. Amongst other promising agents, radiolabelled exendin analogues show potential for imaging and possibly therapy of insulinomas, while preclinical studies are currently evaluating DOTA peptides targeting the CCK-2/gastrin receptors that are overexpressed by medullary thyroid carcinoma cells.

Topics: 3-Iodobenzylguanidine; Carcinoid Tumor; Carcinoma, Neuroendocrine; Humans; Iodine Radioisotopes; Neuroendocrine Tumors; Octreotide; Paraganglioma; Pentetic Acid; Pheochromocytoma; Radiopharmaceuticals; Receptors, Somatostatin; Thyroid Neoplasms

Current therapeutic approaches in neuroendocrine tumours include surgery, radiotherapy and polychemotherapy. Different metabolic patterns of neuroendocrine tumours allow the use of a wide range of diagnostic options in nuclear medicine, due to the presence of a wide spectrum of radiotracers electively concentrating in these neoplasms. Nuclear medicine, and in particular 111In Octreotide (OCT) scintigraphy, 123I Methaiodobenzylguanidine (MIBG) and pentavalent 99mTc-DMSA (V-DMSA), together with biohumoral markers, are currently able to locate tumours also not detectable using traditional diagnostic techniques. Somatostatin analogs, such as octreotide have become increasingly important over the years in the treatment of patients with neuroendocrine tumours. At present the therapeutic use of somatostatin analogs can be schematised as 1) pharmacological treatment (with cold octreotide); 2) surgical treatment (radioguided surgery); 3) radiometabolic treatment (with marked octreotide). The development of new synthetic molecules and new radiocompounds will probably open up interesting scenarios in the near future.

Topics: Adrenal Gland Neoplasms; Adrenalectomy; Antineoplastic Agents, Hormonal; Carcinoma, Medullary; Carcinoma, Non-Small-Cell Lung; Combined Modality Therapy; Humans; Indium Radioisotopes; Lung Neoplasms; Neoplasm Proteins; Neuroendocrine Tumors; Octreotide; Pentetic Acid; Pheochromocytoma; Radionuclide Imaging; Radiopharmaceuticals; Receptors, Somatostatin; Somatostatin; Surgery, Computer-Assisted; Thyroid Neoplasms; Thyroidectomy; Tomography, X-Ray Computed

The medical approach to patients with secreting or clinically non-functioning pituitary adenoma as made considerable progress thanks to the use of new somatostatin analogs. They were first used to treat acromegaly in the mid 1980s and numerous studies have shown a reduction in GH concentration in over 90% of acromegalic patients. Good results were obtained using slow-release analog treatment also in TSH-secreting adenomas, whereas the therapeutic efficacy of these peptides in clinically non-functioning adenomas is still controversial. Treatment with somatostatin analogs improves symptoms, normalises hormone secretion and in some cases may induce a reduction in the volume of pituitary adenomas. Scintigraphy with octreotide may help to select patients who respond to this form of treatment.

Topics: Acromegaly; Adenoma; Adolescent; Adrenal Gland Neoplasms; Adult; Aged; Antineoplastic Agents, Hormonal; Carcinoma; Humans; Indium Radioisotopes; Insulin-Like Growth Factor I; Kidney Neoplasms; Melanoma; Middle Aged; Octreotide; Pentetic Acid; Peptides, Cyclic; Pheochromocytoma; Pituitary Neoplasms; Predictive Value of Tests; Prolactinoma; Radionuclide Imaging; Radiopharmaceuticals; Sensitivity and Specificity; Somatostatin; Thymoma; Thymus Neoplasms; Thyroid Neoplasms; Thyrotropin; Treatment Outcome

Cardiac pheochromocytoma is an exceedingly rare and unusual clinical entity. Only 37 previous surgically treated adult patients were found in review of the surgical literature. We report the case of a 13-year-old boy who had a cardiac pheochromocytoma that was localized by the 111-indium diethylenetriamine pentaacetic acid octreotide scintigraphy scan and confirmed by magnetic resonance imaging after computed tomographic and B1-iodine-metaiodobenzylguanidine scans had failed. At operation, a 6-cm pheochromocytoma of the left atrium was found and successfully resected with reconstruction of the left atrium using autologous pericardium.

Topics: Adult; Child; Heart Neoplasms; Humans; Indium Radioisotopes; Male; Octreotide; Pentetic Acid; Pheochromocytoma; Sensitivity and Specificity; Tomography, Emission-Computed, Single-Photon

We investigated the role of radiolabeled somatostatin analogs (SAs) in adrenal imaging. We evaluated 15 patients (6 men and 9 women, mean age 47 +/- 17 years) with imaging-detected adrenal tumors. Patient population was divided into two groups on the basis of the nature of adrenal lesions. Group 1 consisted of patients with benign adrenal lesions (n = 10). Group 2 consisted of patients with malignant adrenal lesions (n = 5). Pathology examinations were obtained in 13 cases: 7 pheochromocytomas, 2 adenomas, 2 cysts, 1 carcinoma, and 1 fibro-histiocytoma. One patient had a proven diagnosis of non-small-cell lung cancer associated with the presence of a right adrenal mass. The last patient had a clinical diagnosis of Werner syndrome associated with the presence of a large left adrenal mass. All patients underwent scientigraphic studies using radiolabeled SAs, of which indium-111 (In-111) pentetreotide was used in 11 cases and technetium-99m (Tc-99m)-labeled peptides (P-587 or P-829) were used in the remaining four cases. No significant labeled SAs uptake was observed in the majority (8 of 10, 80%) of the benign adrenal lesions (Group 1); however, increased uptake was found in two benign pheochromocytomas. Conversely, significant labeled SAs uptake was observed in the majority (4 of 5, 80%) of the malignant adrenal lesions (Group 2); however, the last lesion (carcinoma) did not show abnormal uptake. Results of this study show that the majority of benign adrenal tumors do not concentrate radiolabeled SAs; conversely, the majority of malignant adrenal lesions show significant SAs uptake, suggesting the presence of somatostatin receptors. This finding may allow the use of somatostatin as a treatment agent in malignant adrenal tumors. Thus, the main role of labeled SAs in adrenal imaging consists of lesion characterization rather than tumor detection and localization.

Topics: Adrenal Gland Neoplasms; Adult; Aged; Female; Humans; Indium Radioisotopes; Iodine Radioisotopes; Male; Middle Aged; Octreotide; Pentetic Acid; Pheochromocytoma; Radionuclide Imaging; Somatostatin; Technetium Compounds

An account is given of the results observed with I-131 MIBG scintigraphy in four patients (1 bladder pheochromocytoma, 3 neuroblastomas) chosen on account of their particular clinical and diagnostic interest from a series of 41 apudoma patients examined by means of this technique. In the first patient, the unusual site of the tumor in the posterior wall of the bladder meant that its detection by I-131 MIBG was only possible after catheterization of the bladder. In the second patient, uptake in the metastasis was only evident after removal of the primary tumor. In the third patient, the scintiscan revealed several metastases (some in bone) not detected by CT. In the fourth patient (congenital neuroblastoma), enhanced uptake accompanied the appearance of high plasma catecholamine and urinary vanillylhandelic acid values, suggesting a functional switch from a nonsecreting to a secreting form. a supplementary In-111 DTPA-Octreotide (OCT) scintiscan of this patient demonstrated the presence of somatostatin receptors on the neuroblasts. Thus, this examination would seem particularly useful for the differentiation of nonsecreting neuroblastomas. Its employment in assessment of the therapeutic capacity of OCT itself is also suggested.

Topics: 3-Iodobenzylguanidine; Adolescent; Adrenal Gland Neoplasms; Child, Preschool; Humans; Indium Radioisotopes; Infant; Iodine Radioisotopes; Iodobenzenes; Neuroblastoma; Octreotide; Pentetic Acid; Pheochromocytoma; Radionuclide Imaging; Thoracic Neoplasms; Urinary Bladder Neoplasms

The results of in vivo somatostatin scintigraphy were correlated with those of MIBG from 14 patients, aged 22-66 yr, with metastatic pheochromocytoma (10 patients), malignant paraganglioma (3 patients) and metastatic ganglioneuroblastoma (1 patient). Twelve patients had elevated catecholamine excretion. A dynamic study and serial whole-body scans (4-48 hr) were obtained after injection of 130-187 MBq of 111In-DTPA-Phe-1-octreotide. When indicated, SPECT imaging was done. The results were compared to MIBG scans obtained after a diagnostic or a therapeutic dose.. Three patients with more than 20 tumor sites on MIBG scans had only 1-9 sites on 111In-octreotide scintigraphy. Two patients had no MIBG uptake but one had lung uptake on octreotide scintigraphy. In the other 9 patients with a total of 41 foci of MIBG uptake, 33 sites of 111In-octreotide uptake are found. All positive images with octreotide scintigraphy were seen at or before 4 hr, but the contrast improved at 24 hr. Uptake intensity was lower with 111In-octreotide than MIBG and the number of tumor sites was higher with MIBG. However, seven foci were positive only on octreotide scintigraphy and six of them could not be confirmed by other imaging modalities.. Use of octreotide to identify somatostatin receptors seems promising, especially when results from MIBG scans are negative. Moreover octreotide images could aid in determining a treatment regimen as well as establishing the extent of disease and prognosis.

Topics: 3-Iodobenzylguanidine; Adrenal Gland Neoplasms; Adult; Aged; Female; Ganglioneuroblastoma; Humans; Indium Radioisotopes; Iodine Radioisotopes; Iodobenzenes; Magnetic Resonance Imaging; Male; Middle Aged; Neoplasm Metastasis; Octreotide; Paraganglioma; Pentetic Acid; Pheochromocytoma; Radionuclide Imaging; Tomography, X-Ray Computed