Implementation and evaluation of multi-cancer early detection testing at the Dana-Farber Cancer Institute: A retrospective analysis of clinical outcomes and diagnostic pathways.

11159 Background: Early detection and interception of cancer is a growing field at the intersection of primary care and oncology. Technological innovation has facilitated the development of multi-cancer early detection (MCED) tests, which allow for the detection of a broad range of cancers in a single screening test. These tests are entering clinical practice as laboratory developed tests but little has been reported about their implementation. In 2023, Dana-Farber introduced an MCED Program to facilitate the evaluation of patients who have received MCED testing and to study novel MCED strategies. Methods: We conducted a retrospective chart review of patients seen at the Dana-Farber between 12/1/2023 and 12/1/2024 who had a cancer signal detected by a Grail Galleri MCED test. Results: Thirteen patients were evaluated for a positive cancer signal detected by the Grail Galleri MCED test. The median age was 62.7 (54.9-81.4), 61.5% (8/13) were male, and 84.6% (11/13) were white. Following diagnostic evaluation 76.9% (10/13) had a confirmed cancer diagnosis and 23.1% (3/13) were deemed false positives. The time from MCED test result to presentation at DFCI was a median of 25 days (6-368) and the median time to conduct the diagnostic evaluation was 23 days (5-104), which was shorter in true positive cases (15 days) compared to false positives (98 days). A total 6 of the 10 (60%) signal detected cases were solid tumors which included triple negative breast, testicular, liver, cholangiocarcinoma, tonsillar, and lung (non-smoker); and 4 (40%) cases were hematologic malignancies (3 lymphoma, 1 myeloma). Of the malignancies detected, 9 (90%) have no current screening guidelines. Screening mammography was up to date in the patient found to have triple negative breast cancer. Six cancers (60%) were diagnosed at stage I/II and 4 (40%) were stage III/IV. All 3 false positive cases received a repeat MCED test a median of 118 days (87-161) after the initial test and all had no signal detected at re-test. The median number of tests/procedures to reach diagnostic resolution was 4 for true positive cases (2-7) and 5 for false positive cases (4-6). All patients required advanced imaging. The first or second cancer signal origin was accurate in 90% (9/10). There were no issues encountered obtaining prior authorizations for diagnostic tests and no adverse events were reported. Conclusions: The majority of patients that presented with a positive MCED test were true positives with a cancer consistent with the cancer signal origin. Patients with signal detected tests were quickly adjudicated in our clinical program, although some patients initially experienced significant delays in finding a provider to work-up their test result. These findings support a role for dedicated cancer diagnostic clinical expertise in the evaluation of MCED tests.