The 71-year-old rocker pulled out of a charity gig and dates on The Who's 50th anniversary tour after he was struck down with the potentially deadly illness.
Roger has now revealed he spent four weeks in hospital as he battled the condition, and he was convinced he was going to die.
"I crawled into the hospital on my hands and knees," he tells Britain's The Sun newspaper. "I started talking gobbledygook (nonsense), I couldn't get anyone's name right and my legs went all funny. I virtually stopped working... It was touch and go there for a few days. I've never known pain like it.
"I know it sounds weird but an incredible peace came over me, which I can still tap into now... I guess when you face adversity you learn something and you gain something.
"It was touch and go. But out of all that I came to terms with my own mortality... I was ready to go, and if I had to go I would have gone with a smile on my face."
Roger has since returned to work to launch The Sun's Christmas appeal for his Teenage Cancer Trust charity, but he is still not completely recovered.
He adds, "I've still got aches and pains in my legs. It feels like the bottom half of my legs don't belong to me - like to learning to walk again."
The Who's postponed tour dates have been rescheduled for February (16).