[Principles of histological diagnosis and clinical staging evaluation for lung cancer]

In the histological diagnosis, it is important to consider the presence of borderline lesions, the possibilities of multiple primary lung cancers and the differential diagnosis between small cell carcinoma and non-small cell carcinomas. In the definite diagnosis, moreover, it is necessary to refer to the special staining procedures, including immuno-histochemistry. In clinical trials, one must evaluate the precise clinical staging in addition to the pathological qualification for enrolled cases. On the other hand, the staging evaluation should be minimal in the practical treatment. It should be noticed that the staging procedure between non-small cell carcinoma and small cell carcinoma is different.