Nutritional aspects regarding lung cancer chemoprevention.

Lung cancer is still one of the major causes of cancer-related deaths and its mortality figures argue powerfully for new approaches to control this leading cancer threat. Chemoprevention can be defined as the use of specific agents to reverse, or prevent premalignancy from progressing to invasive cancer. The use of foods and dietary supplements present a safe chemopreventive strategy. Data for this review were identified by searches of PubMed and references from relevant articles. Articles were identified by use of the search terms "lung cancer", "chemoprevention", "carcinogenesis", and "retinoids". Only papers published in English were included. Trials in lung cancer chemoprevention have so far produced either neutral or harmful primary endpoint results, whether in the primary, secondary, or tertiary settings. Lung cancer was not prevented by beta-carotene, alpha-tocopherol, retinol, retinyl palmitate, N-acetylcysteine, or isotretinoin in smokers. Ongoing trials may help define new avenues for chemoprevention. The concept of chemoprevention in lung cancer is still in its infancy, but in the future it may have a significant impact on the incidence and mortality of lung cancer. In addition to epidemiologic studies, basic science research to detect mechanisms and evaluate the chemopreventive potential of food components is necessary. The overwhelming evidence of a major role of nutrition in carcinogenesis, the many leads that nutritional intervention may reduce cancer incidence, and the growth and increasing sophistication of clinical trials networks point to a very promising future for nutritional intervention trials leading to substantial public benefit.