Chemoprevention of lung cancer: Current status and future prospects

Lung cancer is the leading cause of cancer death in the United States. The current mainstays of lung cancer therapy are surgery, radiation and chemotherapy. These interventions have produced slight declines in mortality rates in the last 5 years however, it appears unlikely that marked improvements will occur in the near future. This grim overview argues strongly for new, emerging approaches for controlling this disease. Chemoprevention is the use of specific natural or synthetic substances with the objective of reversing, suppressing or preventing carcinogenic progression to invasive cancer. Whether primary, secondary or tertiary settings, prevention has the highest potential to improve the dismal statistics associated with this cancer. Several randomized clinical or translational chemoprevention trials have been conducted. All have so far produced either neutral or harmful primary endpoint results showing that lung cancer was not prevented by alpha-tocopheral, beta-carotene, retinal, retinyl palmitate, N-acetylcysteine or isotretinoin in smokers. Secondary results supporting treatment with isotretinoin in 'never' and former smokers and data from prevention trials involving selenium and vitamin E however, are encouraging and offer a promising direction for future clinical study. Other areas of promise for future lung cancer chemoprevention study include the study of molecular markers of risk and drug activity, molecular targeting study, improved imaging techniques and new drug delivery systems.