How often should peripheral blood BCR-ABL fusion protein be monitored in pediatric/AYA patients with Ph+ ALL, and how should this be used to guide treatment?

How often do you monitor BCR-ABL fusion protein in pediatric and AYA patient with Ph+ ALL?

• After induction and then if negative, only if there is concerns for relapse
• After each phase of treatment until patient is MRD negative
• Only at diagnosis
• Other