The wisest strategy is to take all this information with a grain of salt. But the wheels of science grind slowly, and a healthy dose of skepticism, along with patience, is a good thing. The best evidence is the blinded clinical trial, in which researchers divide up the study group, with half getting the treatment and half receiving a dummy pill. In laboratory research, experiments on laboratory animals are used just as preliminary tests to see if a treatment is toxic or has an effect on living tissue before research is pursued in humans. However, new therapies often behave much differently in humans than they do in lab rats, or in tissue in a petri dish.
Expert opinion is considered the least reliable.
But that doesn't mean they're right. The National Breast Cancer Coalition offers an intensive five-day educational program for breast cancer survivors that teaches them how to critically analyze scientific literature, familiarizes them with the language and concepts of science and helps them become more sophisticated consumers and advocates. The Cochrane Collaboration is an international consortium of groups in Great Britain, Australia, Canada and the United States that analyzes and evaluates medical evidence. The San Francisco Cochrane Center is gearing up to do consumer education programs in the Bay Area and may do them in Southern California in the future. To get more information than is provided in news reports, you can find medical studies in the Journal of the American Medical Assn.