Outcomes in participants with a false positive multi-cancer early detection (MCED) test: Results from >4 years follow-up from DETECT-A, the first large, prospective, interventional MCED study.

Abstract

3039 Background: Recommended standard of care (SOC) early detection tests are solely available for four cancer types and fewer than 20% of incident cancers in the US are being diagnosed as a result of screening. Advances in detection of tumor-derived analytes in the blood are enabling the development of MCED tests that may expand early cancer detection. While MCED tests are being designed with high specificity, false positive (FP) results remain a concern for clinicians and patients alike, as no long-term outcomes of individuals with a FP MCED test have been reported. DETECT-A was the first prospective interventional clinical trial to evaluate an MCED blood test. The test used was an early version of CancerSEEK, evaluated in 9,911 women without history of cancer ( Science, 369:6499, 2020). This prospectively planned analysis evaluates cancer incidence among DETECT-A participants with FP results, with the intention of providing key long-term data on test effectiveness. Methods: This analysis included 98 DETECT-A participants with FP results, where a FP was defined as a positive CancerSEEK result with subsequent PET-CT and clinical evaluation with no evidence of cancer within 1 year of the initial CancerSEEK test. Sixty-three of 98 participants had no follow-up procedure performed after imaging, and 35 subjects had noninvasive/minimally invasive follow-up procedures performed. Electronic medical records were analyzed from January 2020 through November 2022 for cancer diagnosis, treatment, remission, recurrence, and mortality. Results: Ninety-six of 98 participants with a FP result remained free of cancer with a median follow-up of 4.3 years (IQR: 3.9-4.9) from the initial CancerSEEK test. One stage I breast cancer and one stage III ovarian cancer were diagnosed 2.7 and 2.9 years respectively from the initial CancerSEEK test. Conclusions: Patients with a negative PET-CT and initial clinical evaluation after a positive CancerSEEK test had low (<1% per year) risk for cancer in the ensuing four years after the initial CancerSEEK test. If confirmed, this result should prove reassuring to clinicians and to patients who have no evidence of cancer on comprehensive imaging following a positive MCED test. Further, these results provide preliminary support for the recommendation that patients who participate in MCED testing and receive a FP result can safely return to routine care after comprehensive anatomic and functional imaging and clinical evaluation reveal no suspicion of cancer.