Sheryl Crow's embraced her ''freedom'' when she was diagnosed with cancer.

The 55-year-old singer - who has adopted sons Wyatt, 10, and Levi, seven - was treated for breast cancer in 2006 and discovered she had a benign brain tumour in 2011 but she tries not to worry about her health and instead focus on the positives in her life.

She said: ''I don't think about it anymore. I don't think about whether my cancer's coming back or if my brain tumour's growing or anything like that.

''I'm busy with my kids - my objective is to be here as long as I can for them and to enjoy every second of it.

''But I would say that my life was really changed when I got diagnosed. It gave me the freedom to just say, 'Hey, let's get on with life. If you wanna have kids, either adopt or go have one, get some sperm, whatever.'

''I also learned how to let myself off the hook, and it really made my life a lot better.''

The 'If It Makes You Happy' singer has a poor memory and jokingly admitted she blames that on her brain tumour, which she has not needed treatment for.

She told Rolling Stone magazine: ''I like to blame my lack of memories on having a brain tumour, but unfortunately I can't, 'cause it doesn't have any side effects [laughs].''

Since becoming a mother, Sheryl has adapted her work schedule to suit their needs and admitted Wyatt was more upset than she was when she quit touring temporarily to give them stability.

She said: ''Everything revolves around what's good for them. I quit touring a couple of years ago.

''[Wyatt] cried. He was like, 'We're not going on the tour bus?'

''But the main thing really is that my work, my so-called inspiration, has been relegated to school hours. I made a record I love between school drop-off and dinnertime. Not many rock stars can say that.''