[Chemoprevention of lung cancer. A review about previous studies, results and future developments].

Despite improvements in the early detection of lung tumors, mortality from this type of disease is increasing world wide and the 5-year-survival rate still ranges below 10 %. The approach of chemoprevention offers the possibility to interfere with the process of cancerogenesis by the use of natural or synthetic chemical compounds and either to prevent DNA damage or to stepp the proliferation of premalignant cells that are already in place. With regard to bronchial carcinoma, chemoprevention in the first place implies cessation of smoking but the currently used procedures are not extremely efficient and many ex-smokers experience an increased risk of acquiring a lung tumor over a prolonged period of time (secondary prevention). In the past 20 years many details of the process of tumorigenesis have been revealed and this knowledge has promoted the targeted use of chemopretective compounds. In addition to the classics in the fields, such as vitamin A, beta-carotene, vitamins E, C and B12 as well as selenium, the last years have brought the development of new compounds, such as retinoids, dithiols, cyclooxygenase inhibitors, epidermal growth factors and others, the mechanismen of action of which provide interesting new approaches. In addition, the introduction of biomarkers, either genetic alterations or proliferation or differentiation, allows to monitor the process of tumorigenesis in its different stages, from early to late, and thereby offers the perspective to perform studies on chemoprevention more rapidly and effectively as in previous years. Thus, in combination with optimized, controlled study designs it is to be expected that in near future clinical studies on the effects on chemoprotective compounds will yield decisive data on their efficacy in chronic smokers as well as ex-smokers.