Doctors paid millions of dollars by Medtronic failed to identify a significant cancer risk with the company's spine surgery product in a 2009 paper about results of a large clinical trial. The surgeons left out important data and claimed there was no significant link between the product and cancer. The company and doctors had become aware of information on an additional cancer case, which pushed the concern to a critical level, at least two months before the paper was published, a Journal Sentinel/MedPage Today investigation found. Independent researchers say they had an ethical duty to report the cancer risk. The breach is the latest conflict-of-interest controversy facing Medtronic, which is under investigation by a U.S. Senate committee and the U.S. Justice Department for its marketing of the spine surgery product known as bone morphogenetic protein-2, or BMP-2.