About CARET: Rationale

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Rationale for Study

Design

• Eligibility Criteria

• Recruitment

• Intervention

• Follow-up

• Data Collection

Primary Publications

Rationale for Study

Lung cancer is a highly lethal disease with an 80-90% mortality rate. In 2005, it was estimated that approximately 170,000 Americans would be diagnosed with lung cancer and 155,000 would die. In the United States, lung cancer is the most common cause of cancer death in men and women, exceeding the combined total for breast, prostate, and colon cancers. Lung cancer is also one of the few diseases with a well-defined etiology: inhalation of tobacco smoke. While tobacco use has become less common over the past 25 years, approximately 25% of the American public still currently use tobacco. Moreover, former smokers continue to be at elevated risk; and the majority of Americans who now develop lung cancer are former smokers. Thus, even if cigarette smoking could be eliminated as an environmental carcinogen, lung cancer would remain a problem for the foreseeable future.

Over the past 20 years there has been intense interest in cancer chemoprevention, the use of agents to prevent, arrest, or reverse the development of cancers. On the basis of epidemiological observations and in vivo animal studies, dietary micronutrients (including beta-carotene and vitamin A) were some of the first agents to attract wide interest as potential lung cancer prevention agents. The Beta-Carotene and Retinol Efficacy Trial (CARET) was one of several trials started in the early 1980s to assess the chemopreventive efficacy and safety of beta-carotene and vitamin A.