A U.S. consumer group called for an urgent Food and Drug Administration review of the safety of aspartame on Monday, but the FDA said there was no immediate need to do so despite a new study showing the sweetener may cause cancer. Italian researchers published a new study last week that showed aspartame -- widely used in soft drinks -- might cause leukemia, lymphoma and breast cancer in rats. "This is the second study by the same lab showing that aspartame causes cancer in rats," Center for Science in the Public Interest executive director Michael Jacobson said in a telephone...