Philippa RoxbyHeath ReporterLaura MarstonLaura now feels good six years after her diagnosis of advanced tongue cancerHundreds of thousands of people with advanced head and neck cancer could live longer without their cancer returning thanks to an immunotherapy drug, a clinical trial suggests.This is the first sign of a breakthrough for patients with this difficult-to-treat cancer for 20 years, say scientists behind the research.Laura Marston, 45, from Derbyshire, says she is "amazed she's still h...