WASHINGTON (CNN) -- Supreme Court Justice Ruth Bader Ginsburg was released Friday from a New York hospital, eight days after undergoing surgery for pancreatic cancer.
Justice Ruth Bader Ginsburg also had surgery for colorectal cancer in September 1999.
A statement from the Supreme Court said the disease was caught early and had not spread beyond her pancreas.
"Extraordinarily, the approximately one-centimeter lesion revealed on a late January CAT scan, the discovery of which led to the February 5 surgery, proved benign," said the court statement.
But, in searching the entire pancreas, attending pancreatic surgeon Dr. Murray Brennan identified "a previously undetected single, even smaller tumor which upon examination was found malignant," the statement said.
Doctors at New York's Memorial Sloan-Kettering Cancer Center said the cancer has been determined as TNM [tumor-node-metastasis] Stage 1, the earliest stage of the disease. It is confined to the pancreas and not yet spreading.
It is not common for pancreatic cancer to be found at such an early stage because symptoms often are not evident until it reaches TNM Stage 3 or 4, when the cancer has spread to surrounding tissue or organs such as the bile duct or stomach.
The court statement said part of the justice's spleen was removed along with a portion of her pancreas during last week's surgery. Further tests showed the cancer had not spread to her lymph nodes and no metastasis was found, it said.
Ginsburg, named to the high court in 1993, has said she plans to be on the bench when oral arguments resume February 23. Sources close to her said she has been working on the caseload from her hospital bed and will continue to do so as she recovers in her New York and Washington apartments.
Getting back into her regular routine is very important to the justice, and it would help her cope with future medical treatment, the sources said.
Ginsburg, the only woman on the Supreme Court, entered after a CAT scan "revealed a small tumor, approximately one centimeter across, in the center of the pancreas," a previous news release said.
"Justice Ginsburg had no symptoms prior to the incidental discovery of the lesion during a routine annual checkup in late January at the National Institutes of Health in Bethesda, Maryland," the court said.
Ginsburg previously underwent surgery for colorectal cancer in September 1999. At the time, court sources said she worked on pending cases while in her hospital bed and during her subsequent recovery.
Less than a month later she appeared in public to give a speech and said, "I am still mending but have progressed steadily."
She underwent chemotherapy between October 1999 and June 2000. There was no word on her future course of treatment beyond Thursday's surgery.
"Cancer is a dreadful disease," she told a women's health research dinner in 2001. "The surgery, and what I call the post-operative insurance course [chemotherapy and radiation] are not easy to bear physically and can generate large anxiety."
But, Ginsburg added, "There is nothing like a cancer bout to make one relish the joys of being alive. It is as though a special, zestful spice seasons my work and days. Each thing I do comes with a heightened appreciation that I am able to do it."
Ginsburg's mother died of cancer the day before the future justice graduated from high school. Her husband was diagnosed with cancer while she was in law school, but was successfully treated.
Almost 35,000 Americans are estimated to have died from pancreatic cancer in 2008, making it the fourth leading cause of cancer death overall, according to the American Cancer Society. For all ages combined, the one-year survival rate is 24 percent; the five-year survival rate is 5 percent.
The low survival rate is a result of the disease commonly being undiscovered until the condition is advanced.
She never missed a day on the bench.
Ginsburg, considered one of the more liberal jurists on the bench, was appointed to the Supreme Court in 1993 by President Bill Clinton.
Ginsburg is the second woman to serve on the Supreme Court, following Justice Sandra Day O'Connor, who served from 1981 to 2006. O'Connor was nominated by President Jimmy Carter to the U.S. District Court of Appeals, where she served from 1981 until her nomination to the Supreme Court.