He's been battling the disease throughout the recording process of Def Leppard's self-titled 11th album. And he says he's hopeful of good news come December.

Campbell tells radio station 100.7 WZXL: "I'm taking this drug called pembrolizumab. I'm part of a phase two clinical trial. I don't actually know if it's working yet. I'll find out in early December.

"My doctors and I are going to sit down and have a look and see if it's holding the cancer at bay or shrinking the tumours. If it is, I'll be able to continue this treatment for a couple of years, which will be the best possible outcome. If not, then I've got to reconsider my options.