Multivariable Cox models
Using a CS cut point of 12 at diagnosis and 0 at EOI, a backward-selected Cox model showed that CS at diagnosis, EOI CS, MYCN status, and receipt of immunotherapy were each independently prognostic of EFS. CS >12 at diagnosis was associated with a >14-fold higher risk of an event (n=68; p<0.0001), while EOI CS >0 was associated with a 3-fold higher risk of an event (p=0.0149), MYCNamplification was associated with a 21-fold higher risk of an event (p<0.0001), and non-receipt of immunotherapy was associated with a 4-fold higher risk of an event (p=0.0008).
For OS, using the same factors as for EFS, a backward-selected Cox model indicated that CS at diagnosis, MYCN status, and immunotherapy were prognostic of OS, with CS >12 at diagnosis,MYCN amplification, and no immunotherapy corresponding to an increase in the risk of death of 12.821 (n=68; P<0.0001), 15.167 (P<0.0001), and 4.557 (P=0.0006), respectively.