Researchers announced that a large clinical trial of nearly 15,000 older male doctors followed for more than a decade found that those taking a daily multivitamin experienced 8 percent fewer cancers than the subjects taking dummy pills. J. Michael Gaziano, HMS professor of medicine at Brigham and Women’s Hospital and the VA Boston Healthcare System, is the lead author. David Chapin, HMS assistant clinical professor of obstetrics, gynecology and reproductive biology at Beth Israel Deaconess Medical Center, participated in the trial.