Correlation of MTV with ctDNA at baseline, 1 month, and 3 months. The correlation of baseline MTV with ctDNA strengthened in the focused cohort (B) compared with the entire cohort (A). The correlation was moderate at 1 month (C) and the strongest at 3 months (D). For patients with evidence of disease, there was no correlation at 1 month (E), but the correlation persisted at 3 months (F).