Medicine: Cancer Shield: A way to block malignancies

A way to block malignancies

Could there be a pill to prevent cancer? Since the 1970s, experiments with lab animals and studies of cancer rates in different countries have suggested that certain vitamins or related compounds could at least lower the risk of getting some forms of the disease. That evidence has prompted a series of large trials in humans to see if these substances can throw a shield around potential cancer victims.

Last week brought the first modest success story in this new field of "chemo-prevention." Dr. Waun Ki Hong and colleagues from the University of Texas in Houston reported evidence that some cancers can...