Performance of multicancer early detection blood test in cancer survivors from the PATHFINDER study

Cancer survivors are at risk for recurrence and second primaries, yet often lack clear guidance for long-term surveillance. Analysis among 1609 survivors who particpated in the prospective PATHFINDER study evaluated a blood-based multicancer early detection (MCED) test. Participants had completed treatment for their original cancer ≥ 3 years before inclusion and had no suspicion of cancer. Previous cancers included breast (47%), melanoma (10%), prostate (9%), colorectal (4%), and lymphoma (4%). Average time since diagnosis was 11.2 years. The MCED detected a cancer signal in 1.2% (n=20). Ten new cancer diagnoses occurred: 5 second primaries (stage I uterine, stage II sarcoma, stage III ovarian, stage IV lymphoma, and stage IV colorectal) 8 to 15 years after the original diagnosis, and 5 recurrences (breast cancer) 4 to 11 years after the original diagnosis. The authors conclude that these results suggest that MCED testing could fill a critical gap in long-term cancer surveillance for survivors.