For patients who undergo surgery to remove colorectal cancer that has spread to the liver, the critical question has always been: who actually needs chemotherapy afterward, and who can be spared its toxicity? A blood-based molecular test may finally offer a reliable answer, potentially reshaping how oncologists make one of the most consequential post-surgical decisions in gastrointestinal cancer care.
This prospective analysis from the CIRCULATE-Japan GALAXY study enrolled 298 patients with resected colorectal liver metastases (CRLM) between 2020 and 2024, measuring circulating tumor DNA (ctDNA) two to ten weeks after surgery using a personalized, tumor-informed assay. Analyses were stratified by whether patients received neoadjuvant chemotherapy before surgery or proceeded directly to resection. In the upfront surgery cohort of 191 patients, those who tested positive for molecular residual disease (MRD) via ctDNA faced dramatically worse disease-free survival (hazard ratio 4.14) and overall survival (hazard ratio 9.13) compared to MRD-negative patients. Critically, MRD status also appeared to identify which patients derived meaningful benefit from adjuvant chemotherapy — a distinction that has eluded the field for decades.
This finding carries real clinical weight. Adjuvant chemotherapy after CRLM resection has never demonstrated a consistent overall survival advantage in randomized trials, yet it remains widely used, exposing many patients to significant side effects without clear benefit. The ctDNA-guided stratification approach seen here aligns with emerging evidence across multiple solid tumor types — including stage II-III colon cancer data from DYNAMIC and COBRA trials — suggesting that MRD-negative patients may safely forgo chemotherapy while MRD-positive patients represent a genuinely high-risk group worth treating aggressively. Key limitations include the observational, non-randomized nature of the chemotherapy comparison within this cohort, meaning residual confounding cannot be excluded. The relatively modest sample size and the single-country design also warrant caution before broad clinical adoption. Nevertheless, this study is more than incremental — it provides prospective, biomarker-stratified evidence that could anchor future randomized trials and nudge practice toward precision-guided adjuvant decision-making in CRLM.