The singer was diagnosed with the disease for the second time earlier this year.
Anastacia revealed on Tuesday that she underwent a double mastectomy and that she is “in the final stages” of recovery.
“I was diagnosed with breast cancer for the second time earlier this year and am currently in the final stages of recovery after undergoing a double mastectomy,” she said in a statement. “It has been an intense journey but I am feeling great and ready to start the next chapter.”
“Breast Cancer Awareness Month gives all who are facing this disease a chance to gain strength and support from each other. Early detection has saved my life twice. I will continue to battle and lend my voice in any way I can.”
The 45-year-old was first diagnosed with breast cancer in 2003.
This year in February, when she received the second diagnosis, she was forced to cancel her European tour.