"It has been an intense journey," said the Chicago-born star after undergoing surgery. "But l am feeling great and ready to start the next chapter.
"You just gotta do what you gotta do," she added. "And I'm cancer free forever, breast cancer free at least, and that has been all worth the struggle."
The Left Outside Alone singer is now the second woman to have been given German GQ's humanitarian award after Annie Lennox received the honour in 2010.
Annie, who was recognised for her work raising HIV awareness, had previously collaborated with Anastacia and 22 other female artists to create a fundraising single called Sing that was released on World AIDS day.