Ruth Bader Ginsburg treated for cancer

US Supreme Court Justice Ruth Bader Ginsburg speaks after receiving the American Law Institute"s Henry J. Friendly Medal in Washington, DC, on May 14, 2018.Image copyrightAFP

US Supreme Court Justice Ruth Bader Ginsburg has received treatment for a cancerous tumour on her pancreas, a court spokeswoman says.

She "tolerated treatment well" and the tumour was "treated definitively", the court added in a statement.

Ms Ginsburg, 86, has survived previous battles with cancer, as well as fractured ribs from falls.

As the most senior liberal justice, her health is watched closely as a possible indicator of changes to the court.

Justices on the highest court in the US serve for life or until they choose to retire, and supporters have expressed concern that if anything were to happen to Ms Ginsburg then a more conservative justice could replace her.

Donald Trump has appointed two judges since becoming president, and the current court is seen to have a 5-4 conservative majority in most cases.

Ms Ginsburg received three weeks of radiation therapy in New York in August after the tumour was discovered, the court said.

"The abnormality was first detected after a routine blood test in early July, and a biopsy performed... she cancelled her annual summer visit to Santa Fe, but has otherwise maintained an active schedule," the statement said.

"The tumour was treated definitively and there is no evidence of disease elsewhere in the body... no further treatment is needed at this time."

Ms Ginsburg is the oldest sitting justice on the Supreme Court. She was nominated by President Bill Clinton in 1993 - becoming the second woman ever to join the court.

Before she became a justice, she had a background in civil rights law - fighting gender discrimination and arguing six cases before the Supreme Court.

She has become an icon for liberals - in recent years, she has been the subject of a biopic, On the Basis of Sex, a documentary, and a bestselling book called Notorious RBG.

She received treatment for colon cancer in 1999, and pancreatic cancer in 2009. In December, she had surgery to remove two cancerous nodules from her lung.

She has refused to retire from her role, once saying in an interview: "As long as I can do the job full steam, I will be here."