Blood Test Identifies Colorectal Cancer Patients Who Benefit from Post-Surgery Chemotherapy

New research presented at the ESMO Gastrointestinal Cancers Congress 2026 and published in JAMA Oncology indicates that a blood test can help identify patients with colorectal cancer that has spread to the liver who are most likely to benefit from chemotherapy after surgery. The Phase II GALAXY study found that patients with detectable circulating tumor DNA (ctDNA) after surgery had significantly better outcomes with adjuvant chemotherapy. This method could potentially spare other patients unnecessary treatment.

Context

Colorectal cancer is a leading cause of cancer-related deaths worldwide, and adjuvant chemotherapy is commonly used to prevent recurrence after surgery. However, not all patients respond positively to this treatment, leading to a need for more precise methods of determining who will benefit. The GALAXY study presents a significant advancement in this area by utilizing circulating tumor DNA as a biomarker.

Why it matters

Identifying which colorectal cancer patients will benefit from chemotherapy post-surgery can improve treatment outcomes and reduce unnecessary side effects. This blood test offers a more personalized approach to cancer care, allowing for tailored treatment plans. Enhanced patient selection could lead to better resource allocation in healthcare settings.

Implications

If adopted widely, this blood test could change the standard of care for colorectal cancer patients, leading to improved survival rates. Patients identified as unlikely to benefit from chemotherapy could avoid its associated risks and costs. On a broader scale, this approach may influence how cancer treatments are personalized across various types of cancer.

What to watch

Following this research, further studies may focus on validating the effectiveness of the blood test in larger, diverse populations. Regulatory approvals for clinical use could be sought, which would impact treatment protocols. Additionally, healthcare providers may begin to adopt this method in clinical practice if proven reliable.