Of the 554 patients with available ctDNA results, 445 were ctDNA-negative (80.3%) and 109 were ctDNA-positive (19.7%); baseline characteristics showed more T4/N2 and venous embolism/lymphatic invasion/perineural invasion1 in ctDNA-positive patients. With a median follow-up of 6.7 years, the 2-year TTR rate was 43.5% (95% CI, 34.1 to 52.6) for ctDNA-positive patients and 88.1% (95% CI, 84.7 to 90.8) for ctDNA-negative patients (P < .0001). ctDNA was confirmed as an independent prognostic marker for both TTR (adjusted hazard ratio [adjHR], 5.21 [95% CI, 3.59 to 7.58]; P < .001) and OS (adjHR, 4.84 [95% CI, 3.40 to 6.89]; P < .001). ctDNA remained the most significant prognostic factor irrespective of disease stage, treatment duration, and IS results. IS was not prognostic in ctDNA-positive patients but remained a significant prognostic tool for ctDNA-negative patients.

CONCLUSION In this combined analysis of two adjuvant trials dedicated to patients with stage III CC after surgery, ctDNA was detectable in 19.7% of the patients and was confirmed as a major independent prognostic biomarker. IS seems to bring additional prognostic information in the 80.3% of patients who are ctDNA-negative.