Cobalt-57 bleomycin scanning for lung cancer detection: a prospective study in thoracic surgery

Patients displaying an abnormal chest X-ray, in some cases, cause a difficult diagnostic problem. A differential diagnosis between benign and malignant lesions is important to determine the choice of treatment i.e. whether or not to perform a thoracotomy. In a prospective study, we have examined the role of 57Co-bleomycin scanning for prethoracotomy assessment of 60 patients with a high clinical probability of lung cancer. For these patients, a sensitivity of 89%, a specificity of 84% and an accuracy of 88% were found. However, as a consequence of the six false-negative scans (two in-situ carcinomas and four stage I carcinomas), bleomycin scanning cannot be regarded as adequate for obviating thoracotomy in patients with a high clinical probability of lung cancer but a negative scan. Nevertheless, the technique is useful for the assessment of tumour size and for the detection of hilar, mediastinal and extra-thoracic metastases, with consequences for TNM staging. It has been found that the tumour dimension correlates well with the actual anatomo-pathologic size determined after surgical examination (r2 = 0.65 and p less than 0.01). Therefore, with an accuracy around 90% for the diagnosis of lung cancer, 57Co-bleomycin scanning offers a major tool for use in clinical investigation.