Olivia-Newton John has “Reluctantly” postponed her June concert dates after learning that the back pain she’s been waylaid by recently is caused by breast cancer that has metastasized to her sacrum.

“I decided on my direction of therapies after consultation with my doctors and natural therapists and the medical team at my Olivia Newton-John Cancer Wellness and Research Centre in Melbourne, Australia,” the 68-year-old singer said Tuesday in a statement on social media.

Those therapies include a short course of photon radiation therapy in addition to “Natural wellness therapies,” the statement said.

Newton-John was diagnosed with breast cancer in 1992, at which time she underwent chemotherapy after a modified radical mastectomy with reconstruction.

Three weeks ago, Newton-John postponed her May shows, with her team citing “a bad issue with Olivia’s sciatica.” Now, her June shows in the U.S. and Canada have been put off.

Ticket-holders are being directed to venues for refunds, and any rescheduled dates will be posted on Newton-John’s official website.

“Olivia … is confident she will be back later in the year, better than ever, to celebrate her shows,” the Tuesday statement said.

Olivia Newton John