Pneumocystis carinii pneumonia during maintenance treatment of childhood acute lymphoblastic leukemia

Background Pneumocystis carinii pneumonia (PCP) is a wellknown risk among patients with deficient T‐cell function such as children treated for acute lymphoblastic leukemia (ALL). The purpose of this study was to estimate the risk for PCP during maintenance treament (MT) to identify patients at risk who could benefit from prophylaxis. Procedure We registered all episodes of PCP during MT in 71 children diagnosed between January 1992 and June 1997 with non‐B‐cell ALL at The Copenhagen University Hospital. Sulphametoxazole and trimetroprim (SMX/TMP) prophylaxis against PCP was given during induction and consolidation therapy but stopped prior to MT with oral methotrexate/6‐mercaptopurine. Patients with standard (SR), intermediate (IR), and high risk (HR) ALL started MT at 3, 8, and 15 months from diagnosis, respectively. Results The HR group had a cumulated risk of 70% for developing PCP, whereas the risk for PCP in children with IR and the SR was 11 and 8%, respectively (P