The Australian singer and actress, who first found fame in the hit movie-musical Grease, told Australia’s 7 network that she was “treating it naturally and doing really well”.
Newton-John, who turns 70 in a few weeks, was diagnosed with breast cancer in 1992 and a tumour was found in her shoulder five years ago.
This time she said she had taken a slightly different approach, fighting the disease with a mixture of radiation treatment and a healthier diet – she has lost weight after cutting out sugar completely.
She also said she is taking cannabis oil to help control her pain.
Newton-John said that her husband John Easterling had been growing the plant, something she said he could do legally in California, where the couple live.
“I’m very lucky to live in a state where it’s legal and I have a husband who is a plant medicine man – how lucky is that?” she said.