Campbell made the revelation during an interview with Palm Beach, Florida radio station Gater 98.7, according to a transcription from Ultimate Classic Rock. The guitarist told the station that the Hodgkin's lymphoma "seems to be, kind of, coming back again."

"But I'm not concerned about it," he added. "I mean, it's just a process. I mean, it always was a little bit touch-and-go. But, you know, it's just a process to get through. I mean, like I said, it's absolutely nothing I'm concerned about, but it's something I need to start the process, I need to get a handle on, so that I am free and clear to tour this summer. So, all good. You know what I mean?"