PLANAR CO-57 BLEOMYCIN SCINTIGRAPHY COMPARED WITH CT-SCAN IN THE DIAGNOSIS AND STAGING OF LUNG-CANCER

Objectives: Cobalt-57 bleomycin accumulates in tumour cells and is a d iagnostic aid for discriminating malignant and benign lesions. Publish ed data indicate that planar cobalt-57 bleomycin scintigraphy (bleo-sc an) is a sensitive and specific test in the diagnosis and staging of l ung cancer. CT-scan was however not used in these studies. We tested t he value of bleo-scan and compared the results with those of computed tomography (CT-scan). Methods: Bleo-scan and CT-scan were obtained fro m patients who were consecutively investigated because of a suspicious lesion on their chest X-ray. Results: In 59 patients carcinoma of the lung was diagnosed 49 times (83%). The sensitivity of bleo-scan was 9 0%, specificity was 30% and positive predictive value (PPV) 86%. CT-sc an could not discriminate between malignant and benign lesions. Thirty -two of the 41 patients with non-small-cell lung cancer had pathologic al examination of mediastinal lymph nodes, revealing metastases in 47% of the patients. Bleo-scan and CT-scan, respectively, had a sensitivi ty of 53 and 87%, a specificity of 77 and 82%, and negative predictive values (NPV) of 65 and 87%. In the 49 lung cancer patients distant me tastases were detected at 11 sites in 10 patients. Bleo-scan gave fals e-negative and false-positive results. Conclusions: Bleo-scan in (susp ected) lung cancer adds too little to the diagnostic procedure to make it a routine procedure. CT-scan gives indispensable information about possible mediastinal involvement.