Fig. 2

Directed Acyclic Graph (DAG) that represents the causal relationships between EFS outcome (T), RDI-exposure (A), pre-/post-assignment confounders (\(\varvec{L}\)), and HRe as effect modifier (V). The exposure-effect modification pathway \(A\times V \rightarrow T\) (in purple) is depicted in DAG (a) using the “arrow-on-arrow" representation proposed by [34], whereas in DAG (b) including the additional node with both A and V as parents, as suggested by [35]