Journal Review in Colorectal Surgery: ctDNA in Colorectal Cancer and Anal Squamous Cell Cancer

Circulating tumor DNA (ctDNA), a minimally invasive blood-based biomarker, has emerged as one of the most promising advances in cancer surveillance. Today, we will explore how ctDNA is transforming the management of colorectal cancer and anal squamous cell cancer across the disease continuum—from risk stratification and adjuvant therapy decision-making to surveillance and early detection of recurrence. Through landmark clinical trials, real-world applications, and emerging research, we will examine how ctDNA is helping move cancer care closer to the goal of truly personalized medicine.Hosts: ·       Dr. Janet Alvarez - General Surgery Resident at New York Medical College/Metropolitan Hospital Center·       Dr. Wini Zambare – General Surgery Resident at Weill Cornell Medical Center/New York Presbyterian·       Dr. Philip Bauer, Assistant Professor of Surgery, Division of Colon and Rectal Surgery, The Ohio State University Wexner Medical Center, Arthur G. James Cancer Hospital·       Dr. J. Joshua Smith MD, PhD, Chair, Department of Colon and Rectal Surgery at MD Anderson Cancer CenterGuests:Dr. Paul Romessor ·      Director of Colorectal and Anal Cancer, Department of Radiation Oncology·      Associate Attending Radiation OncologistMemorial Sloan Kettering Cancer CenterDr. Jeanne Tie ·      Medical Oncologist | Lower GI Unit ·      Lower GI Research Lead ·      Chair | Lower GI Working Party | GI Cancer TrialsPeter MacCallum Cancer Centre Dr. Takayuki Yoshino·      Professor, Global Center of Research Excellence for Advanced Medicine (G-CORE),Keio University School of Medicine·      Executive Advisor to Hospital East Director·      Director, Department of Global Oncology·      Chief, Department of Gastrointestinal OncologyNational Cancer Center Hospital EastLearning Objectives:·      Describe the biological basis and clinical applications of circulating tumor DNA (ctDNA) as a biomarker of minimal residual disease (MRD) in colorectal cancer.·      Interpret the prognostic significance of postoperative and longitudinal ctDNA testing and its role in predicting recurrence risk across stages of colorectal cancer.·      Evaluate evidence from landmark clinical trials, including DYNAMIC and GALAXY, supporting ctDNA-guided treatment de-escalation and escalation strategies in colorectal cancer.·      Discuss emerging applications of ctDNA monitoring in personalized cancer care, including surveillance, treatment response assessment, and future clinical trial directions. References:·      Ando, K. et al. (2026). Molecular Residual Disease and Recurrence in Rectal Cancer Patients Undergoing Upfront Surgery: A Prospective Cohort Study. Annals of Surgery. https://pubmed.ncbi.nlm.nih.gov/39854721/ (Note: If direct access is limited, the article is available via PMC: PMC12695342)·      Romesser, P. B. et al. (2026). Tumor-informed circulating tumor DNA stratifies recurrence risk and survival in anal squamous cell carcinoma. Nature Communications. https://pubmed.ncbi.nlm.nih.gov/38347209/·      Tie, J. et al. (2025). Circulating tumor DNA analysis guiding adjuvant therapy in stage II colon cancer: 5-year outcomes of the randomized DYNAMIC trial. Nature Medicine. https://pubmed.ncbi.nlm.nih.gov/39943485/·      Tie, J. et al. (2025). Circulating tumor DNA-guided adjuvant therapy in locally advanced colon cancer: the randomized phase 2/3 DYNAMIC-III trial. 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