Grail has announced final results from the interventional Pathfinder study, which evaluated multi-cancer early detection (MCED) screening using a blood test and the clinical care pathways following a “cancer signal detected” MCED test result in 6,662 individuals aged 50 years or older, an age group at elevated risk for cancer.
The Guardian reports that the new test has been described as a potential “gamechanger” by NHS England, which is due to report results from a major trial involving 165,000 people next year. Doctors hope the test will save lives by detecting cancer early enough for surgery and treatment to be more effective, but the technology is still in development.
Results were presented in a proffered paper session at the European Society for Medical Oncology (ESMO) Congress 2022 in Paris.
Key findings included:
- Adding multi-cancer early detection (MCED) screening to standard of care screening more than doubled the number of cancers detected
- 71% of participants with MCED-detected cancers had cancer types with no routine screening tests available
- Approximately half of the MCED-detected new cancers were stage I or II
- MCED-predicted cancer signal origin had 97.1% accuracy and enabled targeted diagnostic evaluatons
- MCED screening was implemented in adults with elevated cancer risk without study-related serious adverse events
- Participants reported high satisfaction and low negative psychological impact with MCED screening.
“The Pathfinder study is an exciting first step towards fundamental change in the approach to cancer screening. The study found cancer in about 1% of participants including types for which there is no established screening method. The study demonstrated the feasibility of this paradigm and solid test performance,” said Deb Schrag, MD, MPH, chair, Department of Medicine at Memorial Sloan Kettering Cancer Center in New York. “Although continued public health efforts to optimise adherence to existing screening strategies that have been proven effective are critical, this study provides a glimpse of what the future may hold—the opportunity for screening using blood tests to detect various types of cancers at their earliest and most treatable stages.”
“When added to standard of care screening, MCED testing more than doubled the number of cancers detected compared to standard screening alone. In fact, Galleri detected more cancers than all US Preventive Services Task Force-recommended standard single-cancer screenings combined. These included Stage I cancers of the liver, small intestine, and uterus, and Stage II pancreatic, bone, and oropharyngeal cancers,” said Jeffrey Venstrom, MD, chief medical officer at GRAIL. “This is particularly notable given the Pathfinder population was heavily screened with higher-than-average rates for mammography, colonoscopy, and low-dose CT lung scans.”
A cancer signal was detected in 92 participants, two of whom began workup prior to the return of their MCED test results. Of these, 35 participants were diagnosed with 36 cancers. Among the confirmed cancers, 71% (25/35) of participants had cancer types that have no routine cancer screening available. Nearly half (48%) of the non-recurrent cancers were found in early-stages (Stage I or II). Standard of care screening identified 29 cancers, and another 56 cancers were diagnosed because symptoms appeared or tumors were found incidentally or from monitoring for cancer recurrence.
The cancer signal origin prediction had a 97% accuracy and directed physician clinical workup, leading to resolution of the cancer diagnosis in less than three months for most participants with a true positive signal (73%), and in less than two months for half of them. The median time to diagnostic resolution was longer for false positive results (162 days); 44% of these participants had scheduled follow-up imaging or procedures three or more months later, contributing to the longer time to resolution.
Most participants underwent imaging procedures, such as scans or MRIs, following true and false-positive results. As expected, most true positive participants (82%) underwent an invasive procedure to confirm a cancer diagnosis. Three underwent endoscopies triggered by the predicted cancer signal origin, and 24 had procedures triggered only by abnormal imaging, physical, or laboratory findings, including three surgical biopsies. A smaller proportion of false positive participants had invasive procedures (30%). Five had procedures triggered by CSO predictions (five endoscopies, one endometrial biopsy and one pap smear), and 12 had procedures triggered only by abnormal imaging, physical, or laboratory findings, or by their medical history. No study-related serious adverse events were reported as a result of MCED testing in the study, and there were no adverse events reported from diagnostic workups.
“The refinements we made to the earlier version of Galleri resulted in clinically expected outcomes and had the intended result of reducing false positives from hematological signals,” added Venstrom. “While Pathfinder was not designed to determine sensitivity or the number of cancer types detected by Galleri, 11 different cancer types were detected in this study that have no standard screening today, and the false positive rate was less than 1%. In the much larger CCGA case-control study, the Galleri test detected over 50 types of cancer.”
For more information, visit grail.com.