"I'm saddened by the fact that my cancer has returned," says Campbell. "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."

Def Leppard are scheduled to kick off a North American tour with Styx and Tesla in Tampa, FL on June 23. At press time, the band had yet to announce plans for the trek without Campbell; last fall, the group brought in Steve Brown of Trixter to perform a series of dates in his absence from the lineup.