Model performance for each survival outcome (PFS, OS) and plasma collection (BL thru C8D1) estimated by rank concordance (c-index) calculated from leave-one-out-cross-validation (LOOCV) to fit an elastic net model with ctDNA features. Bar height indicates c-index estimate, error bars indicate the standard error of the c-index, and two-sided P values are shown comparing each model’s c-index to random classifier. Each model is built using patients in the training subset at-risk for the relevant landmarked survival endpoint, where the numbers from left to right are: 240, 240, 237, 237, 206, 202, 201, 196, 146 and 136. The exact P values from left to right are 6.69 x 10 -5, 9.50 x 10 -10, 1.06 x 10 -5, 7.97 x 10 -9, 2.87 x 10 -9, 4.16 x 10 -6, 3.35 x 10 -7, 0.000797098, 6.54 x 10 -8, 3.18 x 10 -7.
