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 prognostic variables of lung cancer. We designed a study to compare immunoscintigraphy (IS) using iodine-131 anticarcinoembryonic antigen (CEA) and anti-carbohydrate 19-9(CA 19-9) monoclonal antibody and computed tomography (CT-scan), in the setting of mediastinal staging. Seventeen patients were involved in a prospective, blind study, to compare IS with CT-scan imaging of the mediastinum. Sensitivity and specificity of both methods were analyzed with reference to pathological staging by mediastinal lymph node sampling. IS imaging was not possible in two patients owing to a thyroid uptake and one patient refused surgery. Among the 14 evaluable patients, sensitivity and specificity were 0.83 and 0.12 for IS, and 0.66 and 0.50 for CT-scan, respectively. We used different thresholds of positivity for both methods in order to evaluate the sensitivity-specificity relationship. When compared with that of IS, the area under the receiver operating characteristic (R.O.C.) curves of the CT-scan was bigger. Although one patient had pathologically confirmed N2 with negative CT-scan and positive IS, the results