title: Immunoscintigraphy of adenocarcinomas by means of radiolabeled F(ab')2 fragments of an anti-carcinoembryonic antigen monoclonal antibody: a multicenter study.
abstract: F(ab')2 fragments of anti-carcinoembryonic antigen (CEA) monoclonal antibody F023C5, determined to be more suitable than intact IgG and Fab fragments for immunoscintigraphy, were labeled with 131I or conjugated to DTPA for instant 111In-labeling, and administered i.v. (2-3 mCi/0.5 mg) to 509 patients in 11 nuclear medicine departments: 284 patients had gastrointestinal adenocarcinomas, 204 had nongastrointestinal adenocarcinomas and 21 were control; serum CEA was elevated in 169 patients, normal in 115, and not determined in 225. The following results were obtained: (a) no adverse reactions; (b) tumor imaging in 324 patients (in particular, in 81.5% CEA-seropositive and in 69.0% CEA-seronegative patients); (c) no significant difference in sensitivity among the results of the 11 departments; (d) no significant difference in overall sensitivity between 131I-and 111In-labeled immunoradiopharmaceuticals; (e) the fraction of documented lesions imaged was 73.3% in CEA-seropositive and 53.7% in CEA-seronegative patients; (f) the detection of liver metastases was hampered, particularly when using the 111In-labeled reagent, by nonspecific radioactivity uptake; (g) the major cause of negative immunoscintigraphy results was a lack of CEA in tumor lesions, as documented by immunohistochemistry; (h) lesion size is also important since the sensitivity was 64% for lesions up to 2 cm in diameter and 84% for larger lesions; (i) many "unexpected" radiolocalizations were recorded. Most were identified as occult tumor lesions. In 35 patients, this finding contributed to the early detection of tumor recurrences.
authors.affiliation: Dipartimento di Biologia e Genetica, Università di Milano, Italy.
authors.forename: A G
authors.initials: AG
authors.lastname: Siccardi
authors.forename: G L
authors.initials: GL
authors.lastname: Buraggi
authors.forename: L
authors.initials: L
authors.lastname: Callegaro
authors.forename: A C
authors.initials: AC
authors.lastname: Colella
authors.forename: P G
authors.initials: PG
authors.lastname: De Filippi
authors.forename: G
authors.initials: G
authors.lastname: Galli
authors.forename: G
authors.initials: G
authors.lastname: Mariani
authors.forename: R
authors.initials: R
authors.lastname: Masi
authors.forename: R
authors.initials: R
authors.lastname: Palumbo
authors.forename: P
authors.initials: P
authors.lastname: Riva
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000378:metabolism; D002272:Carcinoembryonic Antigen / Q000276:immunology*; D005189:False Positive Reactions; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000378:metabolism; D007074:Immunoglobulin G / Q000378:metabolism; D007205:Indium Radioisotopes / Q000378:metabolism; D007457:Iodine Radioisotopes; D015337:Multicenter Studies as Topic; D009382:Neoplasms, Unknown Primary / Q000000981:diagnostic imaging; D011877:Radionuclide Imaging; D014018:Tissue Distribution
chemical_list: D002272:Carcinoembryonic Antigen; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D007205:Indium Radioisotopes; D007457:Iodine Radioisotopes