How Postoperative ctDNA Results Influence Treatment Decisions Following CRC Resection
Experts discuss the pivotal role of ctDNA in postoperative colorectal cancer care, using it alongside pathology and staging to personalize recurrence risk assessment and guide adjuvant therapy decisions, particularly in nuanced cases where ctDNA results and clinical risk factors may not align.
Circulating tumor DNA (ctDNA) plays a central role in post-operativeostoperative discussions about recurrence risk and treatment planning. Many patients naturally ask whether the surgery removed all of the cancer, and while although the surgical margins and pathology might suggest complete resection, ctDNA testing introduces a deeper layer of analysis. A positive ctDNA result indicates minimal residual disease, meaning microscopic cancer remains in the body despite clean margins. In such cases, adjuvant chemotherapy is strongly recommended, and the explanation is framed in accessible language, such as describing “cancer in the blood,” to help patients understand the significance.
When a patient is ctDNA-negative and has a low-risk stage II cancer, surveillance without further treatment is often the path forward. This group benefits from reassurance that their risk of recurrence is low and that close monitoring will be maintained. However, challenges arise when ctDNA results are negative, but the patient has higher-risk features, such as a stage III classification or concerning pathological findings. In these discordant cases, decision-making becomes more nuanced and requires shared input from both physician and patient.
For patients in this gray area, personality and preferences help guide the treatment approach. The conversation often involves a “what if” scenario—asking the patient to consider how they might feel if cancer recurs in the future and they had opted against chemotherapy. This reflective approach allows patients to weigh the emotional and clinical implications of their choices. Ultimately, ctDNA adds a valuable, individualized layer to risk assessment, but it is used in conjunction with traditional staging and patient values to tailor decisions around adjuvant therapy.
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