An amendment added to the House version of a must-pass national defense bill calls for more research and scrutiny into cancer concerns among troops who worked with America's nuclear missiles. A provision added by Rep. Don Bacon, R-Neb., in the House draft of the annual legislation seeks to review the occupational health and safety conditions of the facilities where troops oversee and work on the Minuteman III intercontinental ballistic missile. The issue hit close to home for the retired Air