biostudies-literatureUnknownSinicrope FANCI NIH HHS<h4>Purpose</h4>Detection of molecular residual disease using circulating tumor DNA (ctDNA) may enable postoperative risk stratification and guide adjuvant therapy. We evaluated the prognostic value of a tissue-free, epigenomic ctDNA assay in patients with stage III colon cancer (CC) enrolled in a phase III adjuvant chemotherapy trial.<h4>Methods</h4>Plasma samples were collected after surgery and before adjuvant infusional fluorouracil, leucovorin, and oxaliplatin alone or combined with cetuximab. ctDNA was analyzed using a tissue-free assay; in ctDNA-positive patients, tumor fraction (TF) was quantified and genotyping was performed with a 739-gene panel. Associations with disease-free survival (DFS), time to recurrence (TTR), and overall survival (OS) were assessed using multivariable Cox models adjusted for covariates.<h4>Results</h4>Among 2,260 evaluable patients, 461 (20.4%) were ctDNA-positive with significantly higher detection in advanced T-/N-stage, high-grade, obstruction/perforation, and <i>BRAF</i>^<i>V600E</i> tumors. At a median follow-up of 6.1 years, ctDNA positivity was independently associated with shorter TTR (hazard ratio [HR], 5.96 [95% CI, 5.11 to 6.96]), DFS (HR, 5.03 [95% CI, 4.36 to 5.81]), and OS (HR, 4.45 [95% CI, 3.76 to 5.27]; all <i>P</i> < .0001). The 5-year DFS was 27.7% (95% CI, 23.8 to 32.2) <i>v</i> 77.1% (95% CI, 75.1 to 79.1) in ctDNA-positive versus ctDNA-negative patients, and adverse prognostic impact was greater in lower T/N stage, low-risk, and dMMR subsets (interaction <i>P</i> = .0012-.041). Among ctDNA-positive patients, TF was nearly double in those who recurred or died (<i>P</i> = .0002) and stratified patients for TTR, DFS, and OS (all adjusted <i>P</i> < .002). Genotyping identified mutations in <i>FLT1</i> (OR, 8.99) and <i>PREX2</i> (OR, 7.73) genes that were most strongly associated with recurrence (<i>P</i> < .03).<h4>Conclusion</h4>Evaluation of ctDNA in resected stage III CC using a tissue-free assay provided robust and independent prognostic value. Higher ctDNA burden, dMMR, and specific mutations defined poor prognostic groups among ctDNA-positive patients.Journal of clinical oncology : official journal of the American Society of Clinical OncologyJCO2502086https://www.ebi.ac.uk/biostudies/studies/S-EPMC12866954biostudies-literatureTissue-Free Circulating Tumor DNA Assay and Patient Outcome in a Phase III Trial of FOLFOX-Based Adjuvant Chemotherapy (Alliance N0147).PMC12866954U10 CA180882U24 CA196171Sharma NAlberts SRRich TSinicrope FAShi QSegovia DHardin AfalseTissue-Free Circulating Tumor DNA Assay and Patient Outcome in a Phase III Trial of FOLFOX-Based Adjuvant Chemotherapy (Alliance N0147).<h4>Purpose</h4>Detection of molecular residual disease using circulating tumor DNA (ctDNA) may enable postoperative risk stratification and guide adjuvant therapy. We evaluated the prognostic value of a tissue-free, epigenomic ctDNA assay in patients with stage III colon cancer (CC) enrolled in a phase III adjuvant chemotherapy trial.<h4>Methods</h4>Plasma samples were collected after surgery and before adjuvant infusional fluorouracil, leucovorin, and oxaliplatin alone or combined with cetuximab. ctDNA was analyzed using a tissue-free assay; in ctDNA-positive patients, tumor fraction (TF) was quantified and genotyping was performed with a 739-gene panel. Associations with disease-free survival (DFS), time to recurrence (TTR), and overall survival (OS) were assessed using multivariable Cox models adjusted for covariates.<h4>Results</h4>Among 2,260 evaluable patients, 461 (20.4%) were ctDNA-positive with significantly higher detection in advanced T-/N-stage, high-grade, obstruction/perforation, and <i>BRAF</i>^<i>V600E</i> tumors. At a median follow-up of 6.1 years, ctDNA positivity was independently associated with shorter TTR (hazard ratio [HR], 5.96 [95% CI, 5.11 to 6.96]), DFS (HR, 5.03 [95% CI, 4.36 to 5.81]), and OS (HR, 4.45 [95% CI, 3.76 to 5.27]; all <i>P</i> < .0001). The 5-year DFS was 27.7% (95% CI, 23.8 to 32.2) <i>v</i> 77.1% (95% CI, 75.1 to 79.1) in ctDNA-positive versus ctDNA-negative patients, and adverse prognostic impact was greater in lower T/N stage, low-risk, and dMMR subsets (interaction <i>P</i> = .0012-.041). Among ctDNA-positive patients, TF was nearly double in those who recurred or died (<i>P</i> = .0002) and stratified patients for TTR, DFS, and OS (all adjusted <i>P</i> < .002). Genotyping identified mutations in <i>FLT1</i> (OR, 8.99) and <i>PREX2</i> (OR, 7.73) genes that were most strongly associated with recurrence (<i>P</i> < .03).<h4>Conclusion</h4>Evaluation of ctDNA in resected stage III CC using a tissue-free assay provided robust and independent prognostic value. Higher ctDNA burden, dMMR, and specific mutations defined poor prognostic groups among ctDNA-positive patients.2026-01-01T00:00:00Z2026 Jan2026-07-02T03:17:11.869Z2026-07-02T03:09:00.03ZS-EPMC128669544161622410.1200/JCO-25-0208610.1200/jco-25-02086