Research papers: Lung CancerChemoprevention of lung cancers: lessons from CARET, the beta-carotene and retinol efficacy trial, and prospects for the futureOmenn, Gilbert S.Author Information University of Michigan, Ann Arbor, Michigan, USA Correspondence and requests for reprints to Gilbert S. Omenn, MD, PhD, University of Michigan, Ann Arbor, MI 48109-0656, USA Tel: +1 734 763 7583; fax: +1 734 647 8148; e-mail: email@example.com Received 25 August 2005 Accepted 28 September 2005 European Journal of Cancer Prevention: June 2007 - Volume 16 - Issue 3 - p 184-191 doi: 10.1097/01.cej.0000215612.98132.18 Buy Metrics Abstract The objective of this paper was to review the strategies for lung cancer chemoprevention. A retrospective assessment of the major findings from the most informative lung cancer chemoprevention clinical trials [alpha-tocopherol (vitamin E), beta-carotene trial and β-carotene and retinol efficacy trial] was employed. Both trials and many others showed no benefit from what was once the prime candidate for lung cancer chemoprevention, β-carotene. Furthermore, both trials found that β-carotene, alone or in combination with vitamin E or retinyl palmitate, increased the incidence of lung cancers and the total and cardiovascular mortality rates. In conclusion, design, conduct, documentation, relationships with participants, and preparedness for unexpected findings are all important for chemoprevention research. Trials are necessary to test inferences from observational epidemiology and animal models. Multiple classes of promising agents are available for evaluation and for eventual randomized trials. © 2007 Lippincott Williams & Wilkins, Inc.