Clinical and biological features prognostic of survival after relapse or progression of INRGSS stage MS pattern neuroblastoma: A report from the International Neuroblastoma Risk Group (INRG) project.

Patients diagnosed in and after 2001 have substantially better post-event OS compared to before 2001. In those diagnosed in and after 2001, most well-accepted prognostic factors for OS at diagnosis are also prognostic of post-event OS. Future studies may evaluate strategies to improve outcomes in this rare population.