Rothé F, et al. - In this exploratory companion study to the PePITA trial (a prospective, multicenter, non-randomized study whose primary objective is to predict the outcome of adjuvant therapy in colon cancer), researchers assessed the prognostic and predictive significance of circulating tumor cell (CTC) detection prior to therapy and after one course of preoperative FOLFOX. Thirty-six of the first 58 patients that participated in PePiTA trial were included in the CTC companion study. Two patients had ≥1 CTC/22.5 ml at baseline (6, 95% CI: 1–19%) and only 5 patients (14, 95% CI = 5–30%) had ≥1 CTC/22.5 ml blood in at least one of the two timepoints. They terminated the inclusion of patients in the PePiTA CTC substudy because the detection rate of patients with CTCs at baseline was lower than expected. Due to the limited sample size, the prognostic and predictive value of CTCs in locally advanced colon cancer could not be investigated. For the identification of the most reliable prognostic/predictive biomarker in early-stage colon cancer, further standardized studies are required.