Peptide Receptor Radionuclide Treatment and (131)I-MIBG in the management of patients with metastatic/progressive phaeochromocytomas and paragangliomas.

BACKGROUND AND OBJECTIVES: Radionuclide therapy has been used to treat patients with progressive/metastatic paragangliomas (PGLs) and phaeochromocytomas (PCCs). The aim of the present study is to retrospectively compare the therapeutic outcomes of these modalities in patients with progressive/metastatic PCCs and PGLs. METHODS: Patients with progressive/metastatic PGLs and PCCs that were subjected to radionuclide treatment in our department were retrieved from our department's database for the period 1998-2013. Overall survival (OS), progression free survival (PFS), event free survival (EFS), and response to treatment were calculated. Treatment toxicity was documented. RESULTS: Twenty-two patients with progressive/metastatic PGLs or PCCs were treated with either (131)I-MIBG, (90)Y-DOTATATE or (177)Lu-DOTATATE. A total of 30 treatments were administered (16 treatments with (131)I-MIBG, 2 with (177)Lu-DOTATATE, and 12 with (90)Y-DOTATATE. Patients treated with PRRT had increased PFS and response to treatment compared to (131)I-MIBG treated patients (P < 0.05). However, difference in OS was non significant (P = 0.09). There was no difference in major toxicities between groups. When comparing only patients with PGLs, OS, PFS, EFS, and response to treatment were significantly higher in the PRRT treatment group. CONCLUSION: PRRT treatment offers increased OS, PFS, EFS, and response to treatment compared to (131)I-MIBG therapy in patients with progressive/malignant PGLs.

Use of molecular imaging to differentiate liver metastasis of colorectal cancer metastasis from neuroendocrine tumor origin.

Synchronous malignant neoplasms in a single patient are well documented in the literature. It is also recognized that there is increasing incidence of synchronous non-neuroendocrine neoplasm in patients with neuroendocrine tumor (NET). We present a case, of a patient with synchronous colorectal cancer and pancreatic NET, both cancers presenting with liver metastasis. By using 18F-FDG PET and 68Ga-DOTATATE PET imaging, we showed 2 different tumor types within the liver, which was subsequently confirmed on liver biopsy. This case report shows the utility of molecular imaging using different PET peptides. These newer modalities are useful in understanding the biology of the NET and in determining the best patient management.

Technetium-99m-labelled sulesomab (LeukoScan) in the evaluation of soft tissue infections.

OBJECTIVE: To perform a retrospective review of all patients receiving technetium-99m ((99m)Tc)-labelled sulesomab over a 4-year period to determine if soft tissue infections can be accurately identified. METHODS AND MATERIALS: We reviewed the results of 124 (99m)Tc-sulesomab studies performed over a 4-year period. Of these, 34 were performed for undiagnosed fever in which soft tissue infection was suspected to be the main cause. The patients' clinical notes, microbiology reports and other imaging findings were reviewed to determine the clinical outcome following the scan. The scans were regarded as being true-positives if (i) uptake correlated with the site from which fluid or tissue was obtained and which grew bacteria, and/or (ii) the site of abnormality was reported as having an infection on other imaging or (iii) there was a clinical correlation with the referring clinician's evaluation of the patient. Planar imaging was performed using standard protocols, together with single-photon emission computed tomography (if required) at 1 and 4 h after injection of 20-30 mCi (740-1,110 MBq) (99m)Tc-sulesomab. RESULTS: Three patients were unevaluable. In the remaining 31 patients, 21 (99m)Tc-sulesomab studies were regarded as true-positives and 6 patients had true-negative scans. One patient had a false-positive scan (abnormal uptake with negative microbiology) and 3 had false-negative scans (infection confirmed but a negative scan). CONCLUSION: In suspected soft tissue infection, (99m)Tc-sulesomab imaging has a sensitivity of 88% with a specificity of 86% and overall accuracy of 87%. (99m)Tc-sulesomab provides an accurate method of imaging for suspected soft tissue infection, which is also fast and convenient, as cell labelling is not required.

Utility and limitations of 3,3-diphosphono-1,2-propanodicarboxylic acid scintigraphy in systemic amyloidosis.

AIMS: Technetium-99m-labelled 3,3-diphosphono-1,2-propanodicarboxylic acid ((99m)Tc-DPD) is a sensitive method for imaging cardiac transthyretin (ATTR) amyloid. We report utility and limitations of (99m)Tc-DPD scintigraphy in 321 patients with suspected cardiac amyloidosis. METHODS AND RESULTS: The cohort included wild-type ATTR (ATTRwt) amyloidosis in 94 (29%), ATTR-Val122Ile amyloidosis in 38 (12%), hereditary ATTR (ATTRmt) amyloidosis in 46 (14%), primary light-chain (AL) amyloidosis in 44 (14%), secondary (AA) amyloidosis in three (1%), other hereditary amyloidosis types in nine (3%), undetermined types in two (0.5%), and 85 (26.5%) patients in whom systemic amyloidosis was ultimately excluded. All 158 patients with ATTR amyloidosis with clinical cardiac involvement had cardiac (99m)Tc-DPD uptake, with median Grade 2 intensity. Thirteen further ATTR amyloidosis patients without clinical evidence of cardiac involvement also demonstrated (99m)Tc-DPD cardiac uptake. Eighteen of 35 (51%) AL patients with cardiac involvement had (99m)Tc-DPD cardiac uptake (median Grade 1 intensity). SPECT imaging indicates that the apparent reciprocal reduction in bone uptake is due to masking of bone uptake by extensive soft-tissue uptake in ATTR amyloidosis, especially ATTRwt, and ATTR-Val122Ile types. CONCLUSION: (99m)Tc-DPD scintigraphy is a highly sensitive technique for imaging cardiac ATTR amyloidosis and is an important investigation in the diagnostic pathway of patients with cardiac amyloidosis. It is not specific for ATTR in isolation but must be interpreted in a broad clinical context to avoid dangerous diagnostic errors. Diffuse skeletal muscle uptake identifies muscle as a hitherto unrecognized site that merits investigation as a target organ in ATTR amyloidosis.

The role of 68Ga-DOTATATE PET in patients with neuroendocrine tumors and negative or equivocal findings on 111In-DTPA-octreotide scintigraphy.

UNLABELLED: (111)In-diethylenetriaminepentaacetic acid (DTPA)-octreotide scintigraphy is currently the nuclear medicine imaging modality of choice for identifying neuroendocrine tumors. However, there are cohorts of patients in whom scintigraphy findings are negative or equivocal. We evaluated the role of (68)Ga-DOTATATE PET in a selected group of patients with negative or weakly positive findings on (111)In-DTPA-octreotide scintigraphy to determine whether (68)Ga-DOTATATE PET is able to detect additional disease and, if so, whether patient management is altered. METHODS: Fifty-one patients with a histologically confirmed diagnosis of neuroendocrine tumors were included. Of the 51 patients, 35 who were negative and 16 equivocal for uptake on (111)In-DTPA-octreotide scintigraphy underwent (68)Ga-DOTATATE PET. Findings were compared using a region-by-region analysis. All findings were verified with CT or MRI. After (68)Ga-DOTATATE PET, all cases were reviewed to determine whether the (68)Ga-DOTATATE PET findings resulted in any alteration in management, in terms of suitability for peptide receptor therapy, somatostatin analogs, and surgery. RESULTS: Of the 51 patients, 47 had evidence of disease on cross-sectional imaging or biochemically. (68)Ga-DOTATATE PET was positive in 41 of these 47 patients (87.2%). No false-positive lesions were identified. (68)Ga-DOTATATE PET detected 168 of the 226 lesions (74.3%) that were identified with cross-sectional imaging. (68)Ga-DOTATATE PET identified significantly more lesions than (111)In-DTPA-octreotide scintigraphy (P < 0.001). There was no correlation between (68)Ga-DOTATATE uptake and histologic grade of neuroendocrine tumors. (68)Ga-DOTATATE imaging changed management in 36 patients (70.6%), who were subsequently deemed suitable for peptide receptor-targeted therapy. CONCLUSION: In patients with negative or equivocal (111)In-DTPA-octreotide findings, (68)Ga-DOTATATE PET identifies additional lesions and may alter management in most cases.