Liquid biopsies using circulating tumor DNA for surveillance of gastrointestinal cancers in Hispanics: first real-world data report

Background: Malignant tumors release circulating tumor DNA (ctDNA) into the bloodstream, providing insights into tumor-specific mutations and pathways driving cancer progression.ctDNA testing is currently approved as a type of liquid biopsy to monitor disease burden and detect minimal residual disease (MRD).This study aimed to evaluate the adoption of ctDNA testing in a community oncology practice and assess the overall diagnostic performance of ctDNA and its association with disease progression in stage IV colorectal cancer (CRC), as determined by imaging studies.Patients and methods: This retrospective study analyzed the medical records of 88 patients with gastrointestinal cancers (80 CRC, 5 gastric, 3 esophageal) who underwent ctDNA molecular testing between January 2020 and April 2022.Electronic medical records from patients aged 21 years who had two or more ctDNA tests with concurrent imaging studies or a pathology-confirmed CRC, gastric cancer, or esophageal cancer diagnosis were evaluated.Results: At baseline, 47 (53.4%) patients had negative and 41 (46.6%) had positive results.Most patients had CRC (90.1%).In stage IV CRC, ctDNA was increasing before radiologic progression in all documented cases (100%), with a median lead time of 2.5 months (range 0.5-15 months).In early-stage CRC (I-III), ctDNA preceded radiologic progression in 40% of cases, with a median lead time of 6 months (range 6-10 months).Conclusions: Using real-world data, we report the first-time results of the ctDNA testing adoption in a community oncology setting among patients with gastrointestinal cancers, predominantly CRC.Our findings suggest that integration of ctDNA testing may support disease monitoring in routine clinical practice.