Study Findings May Reveal a ‘Crystal Ball’ for Cancer
Oct 5, 2023
Karin Fleming
Caucasian male in blue T-shirt and glasses places hands on rock outcrop during hike

Dr. Charles McDonnell has glimpsed the future—in the blood of an individual originally undiagnosed with cancer but who later developed the disease in his tongue and kidney.

Dr. McDonnell recalls this “medical magic” of early cancer detection in Sutter patient Louis “Lou” Sall, a 66-year-old Sacramento resident.

“Because the cancer was diagnosed early, Mr. Sall received the chemotherapy and radiation treatment that stopped cancerous cells from spreading to other organs.  After oncology treatments, Mr. Sall is in remission and was restored to full health,” says the radiation oncologist with Sutter Medical Group in Roseville, a suburb outside of California’s capital city.

Researchers at Sutter Study Galleri, a Blood Test for Early Cancer Detection
Sall is among the 1,623 individuals who participated in the PATHFINDER 1 study at Sutter Medical Center, Sacramento. Sutter Health was the first site to enroll a participant to the nationwide study sponsored by GRAIL, LLC.

PATHFINDER 1 tested the effectiveness of GRAIL’s Galleri™ technology. It is a multi-cancer early detection (MCED) test that can detect more than 50 cancers. Many of those cancers, which include those of the pancreas, lymphatic system and bladder, currently don’t have a screening test to detect them in early stages.

Findings from PATHFINDER 1 were recently published in the medical journal Lancet. Results showed:

  • Use of Galleri™ more than doubled the number of cancers found among PATHFINDER study participants compared to traditional screening tests
  • 71% of study participants with MCED-detected cancers had cancer types for which healthcare providers don’t currently screen
  • Cancers detected by Galleri™ included the most lethal forms, as well as those in early stages that are more likely to be effectively treated
  • The Galleri™ test identifies the cancer via a “signal,” otherwise known as the presence of small pieces of the tumor’s DNA. For patients who tested positive for a cancer signal, the Galleri™ test identified the cancer signal origin with a high degree of accuracy (approximately 90%).

Today’s Research, Tomorrow’s Healthcare Solutions
“These results are like a ‘window’ to begin seeing the future of early cancer detection,” says Dr. McDonnell. “They show researchers and physicians how adding this technology to standard screening methods may significantly enhance our ability to catch cancers early. This means we can prevent unnecessary deaths and healthcare costs from cancers detected too late when treatment is unlikely to be effective.”

But Dr. McDonnell notes that, while the study results are promising, they aren’t definitive. Galleri™ and other investigational MCEDs are still in the early stages of development.

“It may likely be many months before Galleri™ or other MCED tests are approved by the U.S. Food and Drug Administration. And more research is needed to determine their effectiveness in people from different races and ethnicities,” says Dr. McDonnell.

More Big Steps Toward Early Cancer Detection:  PATHFINDER 2
To help advance findings from PATHFINDER 1, Sutter is offering eligible patients enrollment to the PATHFINDER 2 study across eight sites in the greater Sacramento region, at Sutter Memorial Medical Center in Modesto and at Sutter’s Palo Alto Medical Foundation in Palo Alto.

While blood tests to detect or monitor cancer progression are not new, existing cancer screening tests typically look for a single cancer at a time (e.g., lung cancer). The PATHFINDER 2 study is assessing whether the Galleri™ test will safely aid early detection of multiple types of cancer with a single blood draw before symptoms present.

The study is also assessing patients’ adherence to standard-of-care cancer screening tests.

Blood samples are collected from eligible Sutter patients who consent to participate in the study. The blood samples are analyzed for the cancer signal. If a study participant tests positive for a cancer signal, they are provided a diagnostic work-up, counseled on the results of their blood test and followed during workup to diagnose their cancer. This may include imaging studies, laboratory tests and/or biopsies.

If no cancer signal is detected, the study participant will be counseled to continue their guideline-recommended screening. PATHFINDER 2 researchers at Sutter will follow study participants’ health for three years to assess their cancer status and the use of routine guideline-recommended cancer screening.

Who Can Enroll in Pathfinder 2?
Individuals who did not participate in the earlier GRAIL-sponsored studies at Sutter entitled STRIVE or PATHFINDER 1, who haven’t been diagnosed with cancer in the last three years and who are 50-79 years of age, are potentially eligible to enroll in the PATHFINDER 2 study.

“Insights from the PATHFINDER study may improve how we screen for cancers and expand the types of cancer for which we can screen. Sutter’s participation in this study could help pioneer breakthroughs in early detection that may help save lives around the world,” says Dr. McDonnell. “We anticipate this trial may allow us to personalize cancer screening and may eventually enable earlier, safer care for those patients found to have cancer.”

To learn more about PATHFINDER 2 and to see if you qualify, please contact the study team at or call 916-746-2161.

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