Radio-guided surgery with the use of [99mTc-EDDA/HYNIC]octreotate in intra-operative detection of neuroendocrine tumours of the gastrointestinal tract.

PURPOSE: Radio-guided surgery (RGS) is an intra-operative localising technique which enables identification of tissue "marked" by a specific radiotracer injected before surgery. It is mainly used for sentinel node mapping and for detection of parathyroid adenomas and other tumours, including neuroendocrine tumours of the gastrointestinal tract (GEP-NET). The aim of this study was to determine whether intra-operative radio-detection with the use of [(99m)Tc-EDDA/HYNIC]octreotate, a new somatostatin analogue, is able to reveal an unknown primary and secondary sites, thereby improving surgical treatment and the final outcome of GEP-NET. METHODS: The study group included nine patients with suspected GEP-NET (four carcinoids, five pancreatic NET) localised with somatostatin receptor scintigraphy (with [(99m)Tc-EDDA/HYNIC]octreotate), who had negative results on other pre-operative imaging tests. At surgery, suspected tumours were measured in situ and ex vivo and precise exploration of the abdominal cavity was performed with the intra-operative scintillation detector (Navigator). RESULTS: Intra-operative gamma counting localised three carcinoids. In one patient SRS was false positive (owing to inflammatory infiltration). Compared with SRS, RGS revealed additional lymph node metastases in one case. RGS resulted in successful localisation of all pancreatic NET (the smallest lesion was 8 mm in diameter). CONCLUSION: [(99m)Tc-EDDA/HYNIC]octreotate SRS followed by RGS is a promising technique to improve the rate of detection and efficacy of treatment of GEP-NET, especially in the presence of occult endocrine tumours. The imaging properties of [(99m)Tc-EDDA/HYNIC]octreotate and the 1-day imaging protocol offer opportunities for more widespread application of this tracer followed by RGS in oncology.

99mTc-EDDA/HYNIC-octreotate in detection of atypical bronchial carcinoid.

UNLABELLED: Pulmonary carcinoids cause serious difficulties in imaging diagnostics in all stages of the disease. SRS holds great promise for detecting occult primary tu and metastatic lesions. (99m)Tc-EDDA/HYNIC-octreotate, a new scintigraphic agent, should significantly improve sensitivity of the diagnostics of carcinoids due to better affinity to SSR2 than (111)In-Octreoscan and the higher count rate obtained from (99m)Tc over (111)In. We present a case of a 40-year-old women operated on because of lung carcinoid tumour in 2002. The symptoms did not resolve after the operation and 5-OHIAA was still elevated. The thorax spiral CT revealed the focal lesion beneath carina. (111)In-Octreoscan and (99m)Tc-EDDA/HYNIC-octreotate SRS revealed two focal lesions in the mediastinum. (99m)Tc-EDDA/HYNIC-octreotate detected two additional lesions in the lower part of the right lung. Target/non-target count ratios of the lesions were as follows: (99m)Tc-EDDA/HYNIC-octreotate scans - 2,9, (111)In-Octreoscan- 2,1. PET-FDG examination revealed no pathology. Owing to severe bone pains and carcinoid symptoms the patient was referred for the 90Y-DOTA-octreotate treatment. CONCLUSIONS: SRS with a new 99mTc marked somatostatin analogue - octreotate allows for a more sensitive detection of metastatic leasions in carcinoid tumours. The usefulness of 18F-FDG PET, widely used as a powerful imaging technique in clinical oncology, is limited in detection of carcinoid tumours due to the low proliferative activity.

99mTc-EDDA/HYNIC-octreotate scintigraphy, an efficient method for the detection and staging of carcinoid tumours: results of 3 years' experience.

PURPOSE: At all stages of the disease, serious difficulties are encountered in the imaging diagnosis of carcinoids. Somatostatin receptor scintigraphy (SRS) holds great promise for detecting primary tumours and metastases. 99mTc-EDDA/HYNIC-octreotate should significantly improve the diagnosis of carcinoids in comparison with 111In-Octreoscan owing to the better affinity for SSR2 and the higher count rate. The aim of this study was to assess the diagnostic efficiency of 99mTc-EDDA/HYNIC-octreotate scintigraphy in the detection and staging of carcinoid tumours. METHODS: The study population comprised 75 patients (age 48.5+/-15.5 years): 46 with histological confirmation of carcinoid and 29 with suspected disease. 99mTc-EDDA/HYNIC-octreotate (740 MBq) SRS and CT were performed in all patients. Fifteen patients were examined with 111In-Octreoscan. RESULTS: High-quality 99mTc-EDDA/HYNIC-octreotate images were obtained in all cases, with maximum tumour tracer accumulation 4 h p.i. The mean target/non-target ratios for whole body (WB) and SPECT scans were, respectively, as follows: primary lesions: 4.5 and 10.2; metastases: liver, 3.1 and 12.3; abdominal focal lesions, 2.7 and 5.8; lung, 2.7 and 8.3; mediastinum, 3.4 and 7.6; bones, 6.8 and 19.0. 99mTc-EDDA/HYNIC-octreotate WB scans revealed more metastases than 111In-Octreoscan, with better individual separation. 99mTc-EDDA/HYNIC-octreotate SRS revealed new metastatic lesions in seven patients with confirmed carcinoid, and in four with dissemination the primary focus was found. Five patients qualified for radioguided surgery and 11 were referred to 90Y-DOTA-TATE therapy. The sensitivity of SRS in comparison with CT was higher for primary lesions and liver and abdominal lymph node metastases. In the subgroup of patients with suspected neuroendocrine tumours, two duodenal carcinoids, one thymic carcinoid and one ileal carcinoid were found. CONCLUSION: 99mTc-EDDA/HYNIC-octreotate, with high imaging quality, is an excellent alternative to 111In-Octreoscan for staging of carcinoids, and it seems to be the method of choice for detection of the primary focus in patients with metastases from an unknown primary tumour.