J Nucl Med. 2007; 48 (Supplement 2):152P
Oncology: Clinical Diagnosis-Solid Tumors
Ga-68 DOTATOC PET in neuroendocrine tumors: The experience at the National Cancer Institute, Naples, Italy
Raffaella Della Moglie1 and
1 UOC Medicina Nucleare, Ist. Naz. Tumori, Fondazione G. Pascale, Napoli, Italy
Objectives: Imaging of neuroendocrine (NE) tumors with radiolabeled somatostatin analogs has become common practice. We are evaluating the routine use of Ga-68 labeled DOTATOC for imaging these tumor types. Methods: Between May and December of 2006, 91 DOTATOC PET studies were performed at our institution in 80 patients being evaluated for suspicion, follow-up or characterization of NE tumors. Patient population included previous diagnosis of GI tract and pancreatic tumors (21), small cell lung cancer (10), metastatic NE tumors with unknown primary (7), medullary thyroid cancer (10), unexplained elevated chromogranin levels or other neuroendocrine signs and symptoms (18), bronchial carcinoid (4), thymic masses (5), neuroblastoma (2), paraganglioma(1) and Merkel tumor (2). Patients were scanned 25-65 minutes after injection of 2-4 mCi of the radiopharmaceutical with a Siemens ECAT scanner. Results: Pancreas and GI tract tumors showed the highest number of positive cases (14/21). Six out of 10 patients with persistent small cell lung cancer showed elevated tracer uptake on DOTATOC PET scans and 3/4 bronchial carcinoids showed marked tracer accumulation. Nine patients had Octreoscan performed within 1 month of the DOTATOC scan. Findings were concordant in 4 cases whereas the remaining 5 cases showed a higher lesion number in the DOTATOC scans. In no instance did Octreoscan outperform DOTATOC in lesion detection. Physiologic uptake of DOTATOC was often observed in the adrenal glands a finding not usually seen on Octreoscan SPET. Bone metastases appear to be particularly avid for the tracer compared to other nuclear imaging modalities. The procedure is better tolerated by patients as it is carried out in one day with short scanning times. Cost of the procedure is lower than for Octreoscan in terms of scanner time and radiopharmaceutical cost. Conclusions: Our preliminary experience with DOTATOC PET is in accordance with the findings of other groups that this method is a marked improvement compared to scanning with Octreoscan. Our current impression is that PET with DOTATOC or other DOTA coupled somatostatin analogs will likely become the method of choice in imaging NE tumor patients both for diagnostic purposes and for treatment planning.