The 75-year-old justice returned to her home in Washington Friday, after being released from the Memorial Sloan-Kettering Cancer Center in New York, the court said.
The one-centimeter growth that doctors initially spotted during a CT scan in late January turned out, upon analysis, to be benign. But a second, even smaller tumor found by her surgeon, Dr. Murray Brennan, during the operation was malignant, the court said. Doctors classified the cancer as early stage, or Stage 1.
Tests on Ginsburg's lymph nodes revealed no cancer and doctors found no spread of it elsewhere, the court said.
Brennan removed Ginsburg's spleen and a portion of the pancreas on Feb. 5.
Ginsburg has indicated she will be at the court when the justices next hear arguments on Feb. 23.
Cancer specialists said that it is possible Ginsburg may avoid chemotherapy because of the small size of the tumor and the absence of cancer in her lymph nodes.
"Many would elect not to do anything further here," said Dr. Suresh Chari, a gastroenterologist at the Mayo Clinic in Rochester, Minn.
The course of her illness so far strongly suggests the benefits of early detection, even though in this case it was incidental. Ginsburg had been suffering no symptoms and was undergoing a routine physical when doctors spotted a growth on her pancreas.
As a survivor of colon cancer, Ginsburg would be expected to have regular checkups that look for growths in that part of the body. Doctors removed a cancerous growth from her colon in 1999 and she underwent chemotherapy and radiation, without missing a day on the bench.
Last week, when Brennan began the surgery and found the second, malignant growth, the tumor's small size and location allowed him to perform the easier of the operations most commonly used on pancreatic cancer patients.
"She couldn't have asked for a better way of picking this up," said Dr. Chandra Are, a surgeon at the University of Nebraska Medical Center who said he trained under Brennan. "She was very lucky."
Pancreatic cancer has very poor survival rates - just 5 percent of patients live five years after their diagnosis. But that owes largely to the relatively late discovery of the cancer.
The numbers look better, though not great, for those whose cancer is caught early enough for surgery, followed by chemotherapy. Five-year survival grows to 20 percent to 24 percent, according to the American Cancer Society.
But cancer specialists said the numbers can exceed 50 percent when growths are smaller than 1 centimeter and lymph nodes are free of cancer. That describes Ginsburg's situation.
"The prognosis is extremely good," Chari said.