DETECTION OF LYMPH-NODE METASTASES IN LUNG-CANCER - COMPARISON OF I-131 ANTI-CEA-ANTI-CA-19-9 IMMUNOSCINTIGRAPHY VERSUS COMPUTED-TOMOGRAPHY

Mediastinal lymph node metastasis is one of the most important prognos tic variables of lung cancer. We designed a study to compare immunosci ntigraphy (IS) using iodine-131 anticarcinoembryonic antigen (CEA) and anti-carbohydrate 19-9(CA 19-9) monoclonal antibody and computed tomo graphy (CT-scan), in the setting of mediastinal staging. Seventeen pat ients were involved in a prospective, blind study, to compare IS with CT-scan imaging of the mediastinum. Sensitivity and specificity of bot h methods were analyzed with reference to pathological staging by medi astinal lymph node sampling. IS imaging was not possible in two patien ts owing to a thyroid uptake and one patient refused surgery. Among th e 14 evaluable patients, sensitivity and specificity were 0.83 and 0.1 2 for IS, and 0.66 and 0.50 for CT-scan, respectively. We used differe nt thresholds of positivity for both methods in order to evaluate the sensitivity-specificity relationship. When compared with that of IS, t he area under the receiver operating characteristic (R.O.C.) curves of the CT-scan was bigger. Although one patient had pathologically confi rmed N2 with negative CT-scan and positive IS, the results