Key measures to focus cancer prevention

Several measures that are currently poorly defined in many of our studies that focus on prevention are now a priority for us to achieve the goal of preventing the majority of cancer. These are summarized below and in a recent article (http://bit.ly/aI2jAr)

Prevention Questions	Cohort	Methods issues
Which exposure?	Refined measures	Validation and error correction strategies.
Change by how much?	Observational cohorts ideally across broad range of exposure	Consortium adds value of broader exposure (e.g., EPIC and diet pooling project).
Among whom? At what age must exposure be changed?	Level of exposure. Time course of exposure and disease development	Consortium adds power to evaluate effects of age. Intermediate endpoints refine temporal relations.
How long must change be sustained?	Duration of altered exposure to modify cancer incidence	Repeated assessment, updating exposure, refines measures of duration and continuing adherence.
Does risk reduction persist after cessation of exposure?	Updated exposure in cohort essential to address this question.	Follow-up of participants after intervention in trail setting adds insights here too.