title: The role of 68Ga-DOTATATE PET in patients with neuroendocrine tumors and negative or equivocal findings on 111In-DTPA-octreotide scintigraphy.
abstract: (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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Neuroendocrine Tumour Unit, Royal Free Hospital, London, UK.
authors.forename: Rajaventhan
authors.initials: R
authors.lastname: Srirajaskanthan
authors.forename: Irfan
authors.initials: I
authors.lastname: Kayani
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: Quigley
authors.forename: Jade
authors.initials: J
authors.lastname: Soh
authors.forename: Martyn E
authors.initials: ME
authors.lastname: Caplin
authors.forename: Jamshed
authors.initials: J
authors.lastname: Bomanji
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001692:Biological Transport; D006801:Humans; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D015282:Octreotide / Q000031:analogs & derivatives*; D009942:Organometallic Compounds / Q000378:metabolism; D004369:Pentetic Acid / Q000031:analogs & derivatives*; D049268:Positron-Emission Tomography; D017481:Receptors, Somatostatin / Q000378:metabolism; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D009942:Organometallic Compounds; D017481:Receptors, Somatostatin; C071632:SDZ 215-811; D004369:Pentetic Acid; C513399:gallium Ga 68 dotatate; D015282:Octreotide