Diagnostic Outcomes among Patients with Positive Multi-Cancer Early Detection Test Results

Multi-cancer early detection (MCED) tests represent a significant technological advancement, allowing for the detection of multiple cancers through a single screening test. In December 2023, Dana-Farber Cancer Institute (DFCI) initiated an MCED clinical and research program to serve patients receiving positive MCED test results and further study MCED tests in clinical practice. Prospective case series reporting on patients with a signal detected by the Grail Galleri MCED test who presented for diagnostic evaluation at DFCI between December 2023 and January 2025. Primary outcomes were confirmation of cancer diagnosis, time to diagnostic resolution, and accuracy of the cancer signal origin (CSO) suggested. Of the 14 patients with a positive MCED test, 78.6% had a confirmed cancer diagnosis, whereas 21.4% were false positives. The median age was 62.5 years, with 64.3% male and 85.7% White, non-Hispanic. The median time from MCED test result to presentation at the DFCI MCED clinic was 28 days. The median time from MCED clinic presentation to diagnostic resolution was 20 days. Among confirmed cases, 54.5% were solid tumors and 45.5% were hematologic malignancies. More than 90% of detected malignancies lack current screening guidelines. Six cancers were diagnosed at stage I/II, and five at III/IV. Most patients with a cancer signal detected on a MCED test were true positives with a cancer consistent with the CSO reported. Patients had their MCED test results quickly adjudicated when presenting to a dedicated clinical program supporting a role for cancer diagnostic expertise in evaluating MCED tests.

MCED tests are a new and evolving technology that may help detect cancer early on. Here, we report the experience of a dedicated cancer clinic in evaluating patients with a positive cancer signal from an MCED test.