Clearance of ctDNA and presence of MRD in the ctDNA reveal patterns of response and predict outcome. (A) Line and dot graph showing pretreatment and follow-up ctDNA levels (log hGE/mL, y-axis) in serially analyzed samples. Lines connect serial samples drawn from the same patient. Color of the lines is according to clinical response determined after 6 cycles of therapy. Quantification of ctDNA performed only if MRD^ctDNA was deemed positive. (B) Swimmer plot of the study patients with a cfDNA sample analyzed after 6 months of therapy. Patients (rows) are grouped according to their MRD^ctDNA status. The x-axis represents follow-up time. (C) Kaplan-Meier survival estimate for PFS according to MRD^ctDNA status after 6 cycles of therapy for evaluable patients. (D) Kaplan-Meier survival estimate for PFS according to MRD^ctDNA status and PET-CT response. Patients with both ctDNA clearance and PET-CT CR after 6 cycles are compared with patient with MRD^ctDNA positivity or incomplete PET-CT responses (PR or SD). PD, progressive disease; PR, partial response.