Concordance of histological classification of lung cancer with special reference to adenocarcinoma in Osaka, Japan, and the North-West Region of England.

In routinely collected data adenocarcinoma of the lung appeared to be 3 times more frequent in Osaka, Japan, than in the North-Western (NW) Region of England (Manchester). Before embarking on comparative epidemiological studies, it was decided to investigate the comparability of histological diagnosis. Specimens from 60 NW Region lung cancer patients and 52 Osaka patients were exchanged and reviewed. The entire material was then independently assessed by the WHO Collaborating Centre for Histological Classification of Tumours. The interpretation of the WHO Classification (WHO, 1981) by the NW Region and by Osaka was upheld by the WHO Collaborating Centre in 89% and 93% of all cases and in 97% and 100% of adenocarcinoma cases respectively. Agreement between the 2 centres was 88% for the main cell types. Differences in the frequency of adenocarcinoma of lung between the NW Region and Osaka are thus not due to diagnostic artefact and require further exploration. The aetiological implications of the finding that many Chinese and Japanese women with lung adenocarcinoma do not smoke (77% in Osaka) are discussed.