And he knows he’ll have to undergo exhausting treatment for the rest of his life.
He announced he was suffering from lymphoma in January 2012, just weeks after Sabbath announced they’d be making their first album with Ozzy Osbourne since 1978′s Never Say Die.
In the following months he struggled to continue recording duties while received treatment for his illness – which was partly responsible for the band failing to reach agreement with departed drummer Bill Ward.
Now Sabbath are touring to promote the album, 13 – and Iommi is delighted to be part of it.
He tells MercuryNews.com: “To be honest, I was wondering whether I could do it. I have to treat life very differently now.
“This, for me, has been a big challenge. So far it’s been okay. The medical thing is still going on; it’ll be ongoing, really, for life – it’s not going to go away.
“I go back to England every seven to eight weeks for a treatment, then it takes 10 days, two weeks, to start feeling normal again; then we go back on the road.”
It’s not just Iommi who’s had to take a fresh look at things. “I think my illness, in one way, has helped everybody,” he says. “It’s brought the reality: you don’t really know how long this is going to last.
“It was easy to take things for granted before. I think everyone now appreciates what we’ve got and what we get to do.”
He’s proud of 13 – but insists it was never a case of recording an album for its own sake. “We haven’t done it just to do one. We didn’t need to do one. We wanted to do one for ourselves, and I think it holds up. We love all the stuff.”
Black Sabbath tour the UK at the end of the year – and Geezer Butler has hinted it might be the last time they do:
Dec 10: 02 Arena, London, UK
Dec 12: Odyssey Arena, Belfast, Ireland
Dec 14: Arena, Sheffield, UK
Dec 16: Hydro, Glasgow, UK
Dec 18: Arena, Manchester, UK
Dec 20: LG Arena, Birmingham, UK