Abstract
There is no quarrel that prevention is preferable for fighting cancer compared to treating the disease in a late stage. Prevention studies, however, can be difficult and challenging to design and to conduct due to the low incidence rate, long process of cancer development, large sample size, extended study duration, cost, and the requirement of well tolerated or little toxicity of the chemopreventive agents. In the past 30 years, much effort has been devoted to chemoprevention in breast, colon, head/neck, lung, skin, and prostate cancers, etc. An overview of the successes and failures of the chemoprevention trials will be given. In order to do better, we must make improvements in the following areas: (1) Identify high risk individuals. Individual cancer risk models are available in breast and lung cancers for example but need to be refined. (2) Focus on subjects with premalignant lesions or intra-epithelial neoplasm as they are ideal candidates for prevention trials. (3) Identify subjects with molecular targets. For targeted agent trials, selecting subjects most likely to respond based on the agent's mechanism of action can dramatically increase the study efficiency. (4) Identify and validate the intermediate or surrogate endpoints for cancer development. (5) Apply efficient and flexible designs such that correct answers can be reached with a smaller number of patients in a shorter period of time. Adaptive randomization can also allow more subjects to be treated with better treatments in the trial based on cumulative information. (6) Balance the risk benefit ratio. It is evident that all treatments come with certain side effects. Seeking favorable efficacy and toxicity tradeoff is critically important for developing successful prevention strategies. More effective chemoprevention studies can be designed and implemented through the lessons learned.
Citation Format: J. Jack Lee. Report card for chemoprevention trials: The good, the bad and the ugly: How can we do better? [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr ED01-01.
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