Updated results from the CIRCULATE-Japan GALAXY study show that a blood test for circulating tumor DNA (ctDNA) can help identify which patients benefit from chemotherapy after surgery for colorectal cancer liver metastases.
Among patients who had surgery first, those with detectable ctDNA after surgery gained major benefits from adjuvant chemotherapy. Their four-year overall survival rate reached 65.3%, compared with 32.9% for patients who did not receive chemotherapy. In contrast, patients with no detectable ctDNA had excellent long-term outcomes without chemotherapy, and additional treatment provided no clear benefit.
Patients who received chemotherapy before surgery were more likely to remain ctDNA-positive after surgery. However, extra chemotherapy after surgery did not improve survival in this group, suggesting their tumors may already be resistant to standard treatment.
The study also found that post-surgery ctDNA status was the strongest predictor of cancer recurrence and survival, outperforming traditional risk factors. These findings support using ctDNA testing to personalize treatment decisions and avoid unnecessary chemotherapy while identifying patients who may need alternative therapies.