Lung cancer diagnosis: evaluation of diagnostic techniques.

In 200 patients with histologically proven lung cancer, retrospective analysis of the relative diagnostic value of sputum cytology, bronchial washings cytology, bronchial biopsy, scalene node biopsy, mediastinoscopy and thoracotomy was undertaken. Bronchial biopsy proved positive in 80 percent of patients with central tumours (those lying between the origin of a main brochus and the origins of lobar segmental bronchi) against 35 percent of patients with peripheral tumours (those lying distal to the origins of the lobar segmental bronchi). Sputum cytology was positive in 27 percent of patients so investigated and bronchial washings cytology in 14 percent--both techniques being more effective with central tumours. Thoracotomy, as the sole method of obtaining histological confirmation of the clinical diagnosis, accounted for 20.5 percent of all cases, being used more often in patients with peripheral tumours. In 15 percent the first histologically positive result came from distal spread. The relative indications for needle biopsy and endobronchial fibroscopy are discussed.