Discouraging news to report, as Def Leppard guitarist Vivian Campbell has revealed that his cancer has returned. The veteran rocker was diagnosed with Hodgkin's lymphoma in 2013, but the cancer went into remission later that year and again in 2014. He underwent stem cell treatment with hopes that it would prevent the cancer from returning, but unfortunately he is once again battling the disease.

The guitarist, who was also famously in the band Dio during the band's formative years, wrote the following message on Facebook: "I'm saddened by the fact that my cancer has returned. However, I'm beyond consolation that it's return will prevent me from being able to do my job for a while. I’m still working on a schedule of treatment with my doctors, but I will see you all very soon. My apologies."

No need to apologize, Vivian, as we're all rooting for you to beat this cancer. Def Leppard are slated to kick off an extensive North American summer tour with Styx and Tesla this Tuesday, June 23. While Def Leppard haven't announced a replacement for Campbell, it is believed Trixter's Steve Brown will fill his shoes as he did last year when Campbell underwent stem cell treatment.

See Where Vivian Campbell Ranks on Our List of the Top 50 Hard Rock + Metal Guitarists