Newton-John was diagnosed with stage 4 metastatic breast cancer in 2017, nearly 30 years after her first diagnosis.

In 2017, Newton-John's cancer returned and it had spread to other parts of her body, so she had radiation therapy to treat it. Newton-John battled stage 4, metastatic breast cancer, which means the cancer had spread to distant areas of the body.

Newton-John was in remission for breast cancer until 2013, when it had metastasised outside of her breasts. By 2017, it had progressed to stage 4 breast cancer, spreading to her spine.