Secondary analysis of prognostic value of combined assessment of circulating tumor DNA and immunoscore in stage III colon cancer

Evaluating immunoscore (IS) and circulating tumor DNA (ctDNA) might improve prognostication and tailoring adjuvant treatments in patients after resection of stage III colon cancer (CC). Combined analyses of two adjuvant phase 3 trials after resection of stage III CC included 554 patients with available ctDNA results after resection but before start of adjuvant treatment. Among these patients, 445 were ctDNA-negative (80.3%) and 109 were ctDNA-positive (19.7). With a median follow-up of 6.7 years, ctDNA was an independent prognostic marker for both time to recurrence and overall survival. IS was not prognostic among ctDNA-positive patients, but remained a significant prognostic tool among ctDNA-negative patients. The authors conclude that ctDNA was detectable in 19.7% of the patients and was confirmed as a major independent prognostic biomarker, whereas IS provided additional prognostic information among ctDNA-negative patients.