Dexamethasone in the maintenance phase of acute lymphoblastic leukaemia treatment: is the risk of lethal infections too high?

We report an increased incidence of infectious deaths during maintenance treatment of the ninth protocol for acute lymphoblastic leukaemia of the Dutch Childhood Oncology Group (DCOG-ALL-9). The main difference in maintenance treatment between DCOG-ALL-9 and the DCOG-ALL-7 and DCOG-ALL-8 protocols is the interruption of methotrexate and 6-mercaptopurine by vincristine (2mg/m(2) weekly) and dexamethasone (6mg/m(2) daily) for 14 days every 7 weeks in the DCOG-ALL-9 protocol. The 1107 children treated with the DCOG-ALL-7, DCOG-ALL-8 or DCOG-ALL-9 protocol were included and screened for infectious death during maintenance treatment (July 1988-July 2002). Seven of the 510 children died of severe infections during the maintenance phase of DCOG-ALL-9, compared to none of the 597 patients during the DCOG-ALL-7 and DCOG-ALL-8 protocols (1.37% versus 0.0%; p=0.013). Results from the current study suggest that repeated, prolonged exposure to dexamethasone results in an increase of lethal infections from 0% to 1.37%. In the dosing-schedule used, the advantage of dexamethasone may not outweigh the higher risk of infectious death.