Ross Gilmore/RedfernsOlivia Newton-John is a breast cancer survivor who has been cancer free since 1992. However, her rep confirms to ABC News that the disease has returned, 25 years later.

A message on Olivia’s official website explains that the back pain Olivia she’d been suffering, which caused her to postpone the first part of her current tour, has been revealed to be breast cancer that has metastasized to her sacrum, the bone at the base of the spine.

The singer will now undergo “a short course of photon radiation therapy,” the statement says, as well as natural wellness therapies. In the meantime, she’s postponed some concert dates to undergo the treatment, but feels confident she’ll be able to make them up later in the year. The rescheduled dates will be posted on her website.

In a statement, Olivia says, “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.”

Ticket holders should contact the venues directly about refunds.

Last year, Olivia collaborated with singer-songwriters Beth Nielsen Chapman and Amy Sky on Liv On, described as a “grief and healing” album. The songs were inspired by all three women’s experiences with loss and illness.

Here are all of Newton-John’s postponed dates:

6/1 — Niagara Falls, ON, Canada, Fallsview Casino Resort
6/2 — Niagara Falls, ON, Canada, Fallsview Casino Resort
6/3 — Northfield, OH, Hard Rock Northfield Park
6/4 — Greensburg, PA, Palace Theatre
6/8 — Stafford, TX, Stafford Centre
6/9 — Hot Springs, AR, Oaklawn Gaming and Racing Complex
6/10 — Wichita Falls, TX, Memorial Auditorium
6/11 — Midland, TX, Wagner Noel Performing Arts Center

Here are all the North American shows still on Olivia’s schedule:

8/24 — Evansville, IN, Victory Theatre
8/25 — Waukegan, IL, Genesee Theater
8/26 — Springfield, MO, Gillioz Theater
8/27 — Joliet, IL, Rialto Square Theatre
10/7 — Pala, CA, Pala Casino Spa Resort
10/20 — Richmond Hill, ON, Canada, Richmond Hill Centre for the Performing Arts*

* = LIV ON concert (with Olivia, Amy Sky & Beth Nielsen Chapman)

Copyright © 2017, ABC Radio. All rights reserved.