Olivia Newton-John announced on Tuesday that she has relapsed from breast cancer. She explained that the cancer has spread to her sacrum, a bone in her lower back. The singer postponed her national tour in May because of back pains, but it was discovered to be a cancer relapse. Newton-John was diagnosed with breast cancer in 1992 and went under a partial mastectomy, chemotherapy, and breast reconstruction. She will now undergo photon radiation therapy to treat the cancer.