For the first time in her Supreme Court career, Justice Ruth Bader Ginsburg missed a session of oral arguments Monday.

Ginsburg, who joined the court in 1993, is still recuperating from cancer surgery. She has had several health scares during her time on the Supreme Court, but has not missed a day of scheduled oral arguments until now. The court has arguments scheduled for Tuesday and Wednesday as well, and it is unclear when she will return.

“Justice Ginsburg is unable to be present today,” Chief Justice John G. Roberts Jr. announced as the court began its session. But she is working from home, and Roberts said she will participate in the two cases scheduled for oral argument by reading briefs, filings and a transcript of the sessions.

She had surgery Dec. 21 for two malignant nodules in her left lung, the 85-year-old justice’s third bout with cancer.

The pulmonary lobectomy was performed at Memorial Sloan Kettering Cancer Center in New York. She was released several days later and has been working at home, according to court spokeswoman Kathleen Arberg.

The two nodules in the lower lobe of her left lung were discovered during tests performed at George Washington University Hospital after Ginsburg fell and broke three ribs on Nov. 7.

In a pulmonary lobectomy, a lobe of the lung is completely removed. The right lung has three lobes, the left has two.

Ginsburg was treated for colorectal cancer in 1999, and pancreatic cancer was discovered at a very early stage 10 years later. She scheduled treatment for both during the court’s off days.

Near the end of 2014, she had a heart stent implanted.

Cancer specialists say the kind of surgery Ginsburg underwent is performed only when the doctors are convinced the cancer has not spread to other organs — in that case, the treatment would be a systemic therapy like chemotherapy.

The court has not said whether further treatments are planned.

Ginsburg is the oldest member of the court, and the longest-serving of the court’s four liberals.

“As long as I can do the job full steam, I will do it,” Ginsburg said last year.

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