OBSERVER VARIABILITY IN HISTOPATHOLOGICAL REPORTING OF NON-SMALL-CELLLUNG-CARCINOMA ON BRONCHIAL BIOPSY SPECIMENS

Aims-To evaluate the ability of histopathologists to sub-classify non- small cell lung carcinomas on bronchial biopsy material using the curr ent World Health Organisation (WHO) classification. Methods-Twelve his topathologists each reviewed 100 randomly selected bronchial biopsy sp ecimens which had originally been reported as showing non-small cell l ung carcinoma. For each case, two sections were circulated, one staine d by haematoxylin and eosin and the other by a standard method for muc in (alcian blue/periodic acid Schiff). The participants were allowed t o indicate their degree of confidence in their classification of each case. A standard proforma was completed and the results were analysed using kappa statistics. Results-Where the participants were confident in their classification, they were actually quite good at sub-classify ing the non-small cell carcinoma sections (kappa=0.71, standard error= 0.058). Overall, however, the results were only fair (kappa=0.39, stan dard error=0.034). Conclusions-The majority of non-small cell lung car cinomas can be correctly categorised on adequate bronchial biopsy mate rial. Where a confident diagnosis was made, both squamous carcinoma (k appa=0.73) and adenocarcinoma (kappa=0.83) were well recognised.