EP2010 - Molecular Residual Disease Accuracy in Colon Cancer Monitoring: A single center retrospective study

Purpose/Background: Circulating tumor DNA (ctDNA) collected from a blood sample, is a non-invasive tool used to monitor malignancy progression and recurrence. Signatera, a molecular diagnostic assay, detects molecular residual disease (MRD) through a tumor specific approach to identify circulating tumor DNA (ctDNA) in the bloodstream. The presence of this specific ctDNA indicates residual or recurrent malignancy, and provides physicians with a non-invasive method of cancer surveillance. At Wellspan York Hospital, the colorectal surgical group often utilizes ctDNA as one tool in monitoring disease in colon cancer patients. A single center retrospective study was performed to determine the accuracy of this data in determining disease progression or recurrence, compared to more traditional surveillance methods such as imaging and colonoscopy findings.

Methods/Interventions: Patients from the oncology department registry who underwent intervention by the colorectal surgery group between 2018 to 2025 were extracted for analysis. Patients included in this study were diagnosed with colon adenocarcinoma, underwent resection of their tumor or other appropriate medical treatment, and have been monitored utilizing ctDNA studies. Exclusion criteria included patients who did not undergo resection, patients deemed to be poor surgical candidates, or patients undergoing treatment for concurrent cancer.

Results/Outcomes: Patient data collected between 2018-2025 was reviewed for colon cancer diagnosis, treatment measures, and ctDNA collection. Due to a protracted data acquisition and expansion of desired time range for the project, our data analysis is not yet complete. While data collection is not complete, over 500 charts are being reviewed. Based on preliminary data review thus far, there does not appear to be a significant discrepancy in the accuracy of disease detection utilizing molecular residual disease in patients monitored with ctDNA studies. However there have been instances found of patients having negative ctDNA studies, with positive biopsy findings which sparked the inspiration for this study.

Conclusion/Discussion: Upon initial analysis, there does not appear to be a significant difference in the accuracy of molecular residual disease detection in colon cancer patients monitored with ctDNA studies at our institution. Further data analysis is ongoing, with subgroup analyses to follow. As rates of colon and rectal cancer continue to increase in younger populations, the development and utilization of non-invasive surveillance methods remains an increasingly important component of cancer care.