Reproducibility of diagnosis and its influence on the distribution of lungcancer by histologic type in Osaka, Japan

The histologic types of lung cancer cases diagnosed in 1979-1980 (n=799) an d 1987 (n=587) were independently reviewed by two pathologists in order to investigate the reproducibility of the diagnosis of the histologic type whe n the WHO classification (1981) was used, The specimens from 354 surgical c ases and biopsy or cytology specimens from 1032 non-surgical cases were rev iewed. The inter-observer agreement was 87.9% (kappa=0.79) for surgical cas es and 81.4% (kappa=0.72) for non-surgical cases. When compared to the orig inal diagnosis, the agreement was 86.8% (kappa=0.78) for surgical and 86.4% (kappa=0.79) for non-surgical cases in 1979-1980 and the agreement was 92. 8% (kappa=0.87) for surgical and 89.1% (kappa=0.83) for non-surgical cases in 1987, By histologic type, no difference in the agreement was observed ex cept for large cell carcinoma. The distribution of histologic types after t he review differed only slightly (less than 6%) from the original distribut ion, This suggests that in Osaka, Japan, the diagnosis based on the WHO cla ssification (1981) had only a limited influence on the distribution of hist ologic types, and is not a major reason for the changing trends in lung can cer incidence by histologic type.