Pancreatic cancer can be in the body for decades before actually making a person ill, which could create earlier opportunities to spot and treat it, U.S. scientists say. Genetic analysis of tumors suggests the first mutations might happen before the disease becomes lethal, although it’s fatal in 95 per cent of cases, the BBC reports, adding that in the UK, survival rates haven’t improved for 40 years. By the time it’s diagnosed, it’s often aggressive and unresponsive. On average, each metastatic tumor has 61 cancer-related mutations, two-thirds of which had been present in the original pancreatic tumor. On average, researchers estimate it took 11.7 years for a single gene mutation in a pancreas cell to become a “mature” pancreatic tumor.