Sad Last Days: Olivia Newton-John Facing Death's Door As Killer Cancer Returns

Olivia Newton-John’s cancer has returned with a vengeance — as the killer disease spread into the bones of her lower back, RadarOnline.com learned exclusively.

“It’s the beginning of the end for Olivia,” said a source. “This is her final fight and she promises to go out swinging.

“At this point, her goal is to make it to her 70th birthday on Sept. 26th and have a big celebration.”

As RadarOnline.com has reported, the “I Honestly Love You” singer revealed her devastating stage 4 breast cancer diagnosis in May 2017.

At the time, docs gave her “grim odds” at a recovery or long-term survival.

Sadly, now that the cancer has metastasized, friends and colleagues said there’s nothing more modern medicine can do for the talented four-time Grammy winner.

“Her immune system has lost its ability to recognize that cancerous cells are different from her own cells,” explained Dr. Gabe Mirkin, a longevity expert who has not treated Olivia.

“This has allowed her cancer to spread to her bones.”

With no further conventional treatment available, “Olivia is taking herbal medications and just trying to fight the cancer naturally,” said the source.

“She’s trying to remain positive and taking things one day at a time.”

As Olivia faces what’s likely to be her final fight, the gutsy entertainer has told pals she has a secret weapon to help keep her upbeat — her “Grease” co-star and close pal John Travolta!

Now, RadarOnline.com has learned Olivia hopes to make two public appearances on Sept. 11 and 14 in Australia. She’ll discuss her long career in an interview format.

“Olivia has made it clear she will not be singing during the evenings,” said the source. “She will be seated for the interviews because it’s difficult for her to stand for long periods of time.

“This is really her swan 
song. It may be the last time fans could see her alive, on stage.”