Campbell tells the Daily Herald, "So I went to Dublin and started to record with the band [in February], we started work on a new record, and as soon as I got back from that, I did another surgical biopsy and that showed that the cancer had definitely come back," he explained.

"I'm actually doing this new high-tech chemo treatment, I'm about halfway through it already, and it's really kind of easy going. It's the first new drug that's been discovered for Hodgkin's since 1977 and they made this discovery in 2011, and it's actually being pioneered here at City of Hope, so I'm part of this research clinical trial that's going on.

"It's very, very benign chemo, actually it just targets -- I don't know how it works, obviously I'm not a medical person, but somehow or other it just manages to target the cancer cells. It's not like old-school, carpet-bomb chemo where it kills all the fast-growing cells, so I haven't experienced any hair loss or any issues with my skin or nails or anything this time around, which is good. And assuming that works, I'm going to have to continue a couple of treatments, actually, over the course of the [KISS] tour, so that's awkward to work around, but not impossible."