Fig. 2

Clinicopathological correlates and prognostic impact of ctDNA levels. (A) Total number of ctDNA positive and negative plasma samples during treatment (left panel), ctDNA status for each patient at baseline (middle panel), and ctDNA fractions at baseline (right panel), in adjuvant and palliative patients, respectively. NA marks samples with a different, and less sensitive, detection limit. BL = baseline. (B) Kaplan-Meier analysis of overall survival (OS) in strata according to positive vs. negative ctDNA status at baseline in adjuvant patients (left panel) and in palliative patients (right panel). (C) Kaplan-Meier analysis of OS in palliative patients in strata according to high (ctDNA^high) vs. low (ctDNA^low) ctDNA concentrations at baseline, one month and three months of treatment, defined by the calculated optimal prognostic cutoff value at 350 mGEs/ml plasma. (D) From left to right: Distribution of sex, treatment regimen, ECOG performance status and cfDNA levels in ctDNA^low and ctDNA^high patients, respectively. (E) From left to right: Distribution of metastatic status and metastatic sites, liver metastases, lung metastases and peritoneal metastases in the ctDNA^low and ctDNA^high groups, respectively. For (D–E) Fisher’s exact test was used to calculate associations between proportions of categorical variables. (F) Levels of routine clinical parameters CA19-9, CEA, CRP and albumin, and distribution of age in ctDNA^low and ctDNA^high patients, respectively.