The odds of relapse after chemotherapy treatment in young patients with B-precursor acute lymphoblastic leukemia (B-ALL) are significantly reduced by administering additional courses of chemotherapy. B-ALL is one of the most common cancers in children younger than 15 years.

This trial involved nearly 500 patients with B-ALL. The participants received an initial course of induction chemotherapy. After 1 month of treatment, bone marrow samples from the patients were tested for levels of leukemia that were below microscopic detection.

Thirty-five patients were deemed to have a very high risk of relapse because they retained relatively high numbers of leukemia cells. An additional 16 patients were also considered very high risk because their leukemia cells had certain chromosomal abnormalities. These 51 patients then received an intensified treatment regimen.

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The intensified regimen consisted of two additional rounds of chemotherapy using agents not typically given to patients with newly diagnosed B-ALL. This was followed by an intensified consolidation phase of therapy to keep the disease in remission, and a standard maintenance phase to further deter relapse.

The investigators estimate that, 5 years after reaching complete remission, the rate of event-free survival was 76% for these very high risk patients. By contrast, less than half of similar patients who receive standard chemotherapy reach the 5-year mark without relapsing.

“Pediatric patients with B-ALL traditionally receive a standard course of chemotherapy if their risk of relapse is low, and a slightly intensified course if their risk is higher,” said the study’s lead author, Lynda Vrooman, MD, of Dana-Farber/Children’s Hospital Cancer Center. “In this study, we identified a new risk group—those with a very high risk of relapse—and studied the effect of a novel, even more intensive chemotherapy regimen on their outcome.”

“Though it involved a relatively small number of patients, the new trial is one of the first to show improved outcomes for this set of patients as a result of an intensified chemotherapy protocol,” said senior author Lewis Silverman, MD, also of Dana-Farber/Children’s Hospital Cancer Center. Trial leaders will continue to track the study participants to gauge the durability of the remissions produced by the intensified treatment.

This trial was presented at the 2012 American Society of Hematology annual meeting in Atlanta, Georgia, December 8-11, 2012.