The rock legend, who was diagnosed with Non-Hogkin’s Lymphoma in January 2012, told how recording Sabbath’s new album helped give him focus after he became convinced he’d “had it” and was going to die.
“As soon as they told me that I’d got it I went into shock and I just thought, ‘that’s it, I’ve had it’,” said Iommi as he launched a new campaign in Birmingham.
“When you are diagnosed with it, you think of nothing else but ‘am I going to die? When I’m going to die’, and that’s the way you think.
“But doing the album helped me in some ways, because I had my friends around me, my family around me, and getting my mind off it, because you constantly think about it.”
But for Iommi, considered one of the greatest rock guitarists of all time, writing the latest album was a welcome distraction from his treatment, which could be extremely tiring and painful.
“We were supposed to be going to LA,” he said.
“And because I was so ill all the band came to my house, where I’ve got a studio, and we worked there.
“It was really great, actually, and it brought us together so much. I would come down into the studio and if I said I didn’t feel too good they’d say ‘leave it, let’s do it another day.
“They were really helpful like that.
“With Ozzy, Sharon went through cancer and so seeing her go through that helped a lot as well.
“He would tell me he’d spoken to Sharon about what she’d been through, and he would give me advice.”
Iommi, 67, was invited to experience the isolation box, where the public could listen to cancer survivors share their experience in the busy shopping centre, to evoke emotions of feeling alone in a crowd.
The box included the stories of Niki Meller, from Rednal, and Narinder Wauhar from Sutton Coldfield, who have both battled breast cancer.
Iommi added: “When you get cancer it’s terrible because you tend to isolate yourself, and you can quite easily isolate yourself too much.
“Some people get frightened and locked in this box and they can’t do anything. Because it is daunting.
“And it’s quite true, when you’re diagnosed with something like this, it really is a lonely time. A lot of people do keep it inside, and others can feel like there are dirty because they have it.
“To talk to somebody is probably the best therapy you can have.”