The Supreme Court Justice was treated for lung cancer last year.

Supreme Court Justice Ruth Bader Ginsburg has again had a recurrence of cancer. Ginsburg has undergone three weeks of radiation therapy for pancreatic cancer.

An abnormality was first detected after routine bloodwork Ginsburg, 86, had in July. A biopsy later confirmed there was a malignant tumor on her pancreas, according to a statement from the U.S. Supreme Court.

On top of the radiation, Ginsburg — or RBG as she’s been famously nicknamed — also had a stent inserted in her bile duct likely to keep the duct open.

Ginsburg’s bout with pancreatic cancer comes less than a year after she underwent surgery for lung cancer. It’s unclear if the two cancers are related or occurred independent of one another, according to health experts.

While Ginsburg’s condition is stable and the Supreme Court justice is already back in action, she will need to closely monitor her health to ensure the cancer doesn’t recur.

“The tumor was treated definitively and there is no evidence of disease elsewhere in the body,” the U.S. Supreme Court stated. “Justice Ginsburg will continue to have periodic blood tests and scans.”

Ginsberg has battled various cancers in her life, including colon, lung, and pancreatic cancer.

She was first diagnosed and successfully treated for pancreatic cancer back in 2009.

People who’ve previously been diagnosed with cancer typically must undergo years of routine bloodwork and testing to ensure the cancer hasn’t recurred or spread.

Doctors occasionally use tumor markers — a type of test that tracks chemicals in your blood made by tumor cells — to understand how treatments are working, predict a person’s chance of recovery, and monitor the cancer for recurrence.

In Ginsburg’s case, doctors were likely using tumor markers to ensure the pancreatic cancer wasn’t coming back, health experts believe.

“The most likely scenario is she was getting routine tumor marker follow up because of her history of having had pancreas cancer,” suspects Dr. Elliot Newman, the chief of surgical oncology, pancreas, and hepatobiliary surgery at Lenox Hill Hospital.

Interestingly, many oncologists may stop testing tumor markers if someone is cancer-free for 5 years.

It’s also very rare for a cancer survivor to have normal tumor marker levels for 10 years and then experience a sudden increase, as the case may be with Ginsburg, according to Dr. Anton Bilchik, a surgical oncologist, professor of surgery, chief of gastrointestinal research, and chief of medicine at John Wayne Cancer Institute at Providence Saint John’s Health Center, told Healthline.

Doctors may have also identified the cancer via a liver function test, or a blood test that essentially assesses the overall health of the liver.

“Other blood tests such as an increase in liver function tests, specifically bilirubin [a chemical made by the liver], would suggest that the tumor may be obstructing (blocking) the bile duct and therefore causing the liver enzymes to increase,” Bilchik told Healthline.

All things considered, the routine bloodwork helped Ginsburg’s doctors catch the cancer early and treat it quickly.

“The advantage in RBG of detecting an early increase allowed for immediate treatment, which has a better chance of controlling the growth of the tumor,” Bilchik said.

Although tumor marker tests have the potential to accurately identify cancer, they can also pick up on tumor markers that are produced by healthy, noncancerous cells in the body. This can cause tumor marker levels to look abnormally high in people who don’t have cancer, resulting in false positives.

For this reason, tumor marker tests typically aren’t enough to make a concrete cancer diagnosis, according to the Mayo Clinic.

“Many have asked over the years about routinely drawing the tumor markers but it’s not cost effective, often leads to false positives, and is not routinely recommended because these tests are not sensitive or specific enough,” Newman explained.

Researchers are currently working to develop more tests that can effectively pick up on more types of cancer and provide earlier detection.

“More recently, a lot of research has gone into developing more sensitive tests such as circulating tumor cells which can detect the DNA of tumor cells at its earliest stage,” Bilchik said.

While these tests are commercially available, they need to be studied further to validate their usefulness in detecting all types of cancer.

According to Newman, finding a test that is sensitive and specific enough is the holy grail when it comes to diagnosing and treating cancer.

Supreme Court Justice Ruth Bader Ginsburg recently underwent three weeks of radiation to treat pancreatic cancer. An abnormality was first detected during routine bloodwork in July, and a biopsy confirmed a cancerous tumor on her pancreas. This is Ginsburg’s fourth bout with cancer, and second go with cancer of the pancreas. Health experts suspect doctors were using tumor markers, a routine blood test, to ensure the cancers were not recurring.