Lung cancer is characterized by a varied histologic background and as a result has a wide range of histologic types compared to cancer of other organs. There is remarkable difference in malignancy according to histologic type, therefore a definitive diagnosis before treatment is essential to determine therapeutic strategy. Recently definitive diagnostic rates of 99% have been obtained by various diagnostic procedures. The value of surveys especially those including sputum cytology is discussed. Also laser therapy with Nd-YAG laser and/or administration of hematoporphyrin derivative plus photoradiation by an argon dye laser and tumor localization with fluorescence photoradiation by a krypton ion laser are discussed.
