Cranial Radiation Therapy

The proportion of patients receiving cranial radiation therapy has decreased significantly over time. At present, most newly diagnosed children with ALL are treated without cranial radiation therapy. Many groups administer cranial radiation therapy only to those patients considered to be at highest risk of subsequent CNS relapse, such as those with documented CNS leukemia at diagnosis (as defined above) (≥5 WBC/μL with blasts; CNS3) and/or T-cell phenotype with high presenting WBC count.[11] Some centers do not use cranial irradiation for any patients.[12]

In patients who do receive radiation therapy, the cranial radiation dose has been significantly reduced and administration of spinal irradiation is not standard.

Ongoing trials seek to determine whether radiation therapy can be eliminated from the treatment of all children with newly diagnosed ALL without compromising survival or leading to increased rate of toxicities from upfront and salvage therapies.[12,13] A meta-analysis of randomized trials of CNS-directed therapy has confirmed that radiation therapy can be replaced by intrathecal chemotherapy in most patients with newly diagnosed ALL. Additional systemic therapy may be required depending on the agents and intensity used.[14]; [1][Level of evidence B1]