Eric A. Klein

Multicancer Early Detection Blood Test Performance in Cancer Survivors From the PATHFINDER Study

PURPOSE Cancer survivors are at risk for recurrence and second primaries, yet often lack clear guidance for long-term surveillance. METHODS We assessed the performance of a blood-based multicancer early detection (MCED) test in 1,609 survivors who participated in PATHFINDER, a prospective study of adults without current suspicion of cancer. RESULTS Previous cancers included breast (47%), melanoma (10%), prostate (9%), colorectal (4%), and lymphoma (4%). Average time since diagnosis was 11.2 years, and a cancer signal was detected in 1.2% (20/1,609). Ten new cancer diagnoses occurred: 5 second primaries (stage I uterine, stage II sarcoma, stage III ovarian, stage IV lymphoma, and stage IV colorectal) 8-15 years after original diagnosis and five recurrences (breast cancer) 4-11 years after original diagnosis. Test performance metrics were similar in those with and without previous cancer history. CONCLUSION These findings highlight the potential of MCED tests to address a significant unmet need in long-term surveillance of survivors.