Accuracy of morphological diagnosis of lung cancer in a department of respiratory medicine.

In view of the importance of determination of cell type in patients with bronchial carcinoma who are to be given chemotherapy a series of 140 histologically proved cases was analysed to assess the accuracy of pretreatment diagnosis by cytology and bronchial biopsy. Final histological diagnosis was made after thoracotomy (131 cases) or necropsy (9 cases). Before treatment, malignancy was diagnosed in 71% of cases with 91% accuracy in cell typing. Diagnostic yield was greatest in squamous carcinoma (81%) and least with adenocarcinoma (50%). Large-celled and small-celled anaplastic carcinomas gave yields of 61% and 68% respectively. Accuracy of cell typing was high (90-97%) except for large-celled anaplastic carcinoma (71%). All diagnostic methods were not employed in every case. In patients supplying samples the diagnosis was made by sputum cytology in 57%, by rigid bronchoscopy cytology in 57%, by fibreoptic bronchoscopy cytology in 71% and biopsy in 53%. Causes of diagnostic failures and possible means of increasing accuracy of pretreatment diagnosis were discussed.