Immunoscintigraphy of lung cancer using 111In-labelled antiCEA F023C5-F(ab')2 fragments.
Forty-one patients with known lung carcinoma or suspicion of bearing this disease were studied with 111In-antiCEA F023C5-F(ab')2. Five patients with positive results were further studied to assess in vivo specificity using 111In-4C4-F(ab')2 (MoAb antihepatitis). Immunoscintigraphic results have been compared to immunohistochemistry in 16 patients. Tumour visualization with non-specific MoAb was present in all five patients although the maximum tumour/background (T/B) ratio obtained was 1.51. Therefore a 'specificity criterion' has been applied to examinations performed with MoAb antiCEA. There was considered to be a positive result when the T/B ratio was greater than 1.60. Results obtained in this way for thoracic lesions were 25/34 true positive (TP) (73%) and 6/7 true negative (TN) (86%). When studies were analysed visually only, the results were 32/34 TP (94%) and 3/7 TN (43%). In addition, immunoscintigraphic results are more concordant with immunohistochemical results when the specificity criterion is applied. In metastatic lesions results were 9/13 TP (69%) with only 1/3 TP (33%) for liver metastasis (anatomic site of lowest detection ability). SPECT imaging did not improve results over planar images, although it clearly contributed to a better anatomic location of lesions. The constant presence of non-specific uptake in thoracic lesions makes it necessary to establish a T/B ratio limit in order to obtain adequate specificity with the immunoscintigraphic technique.
Torres
M
M
Nuclear Medicine Service, Medical School, Hospital Reina Sofia, Cordoba, Spain.
Jiménez-Heffernan
A
A
Valverde
A
A
González
F M
FM
Latre
J M
JM
Llamas
J M
JM
Baamonde
C
C
López-Rubio
F
F
Mateo
A
A
D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000556:secondary; D000310:Adrenal Gland Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary; D002272:Carcinoembryonic Antigen / Q000032:analysis; D018288:Carcinoma, Small Cell / Q000000981:diagnostic imaging / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000473:pathology / Q000556:secondary; D006801:Humans; D007150:Immunohistochemistry; D007205:Indium Radioisotopes; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D016719:Radioimmunodetection; D012888:Skull Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary
D002272:Carcinoembryonic Antigen; D007205:Indium Radioisotopes