Guidelines for prevention of Pneumocystis carinii pneumonitis in children and adolescents with cancer.

Pneumocystis carinii pneumonitis (PCP) is one of the most important opportunistic infections in children and adolescents with cancer. Its high frequency and a considerable mortality have led to primary chemoprophylaxis in patients with hematological malignancies and following allogeneic hematopoietic stem cell transplantation. Although less well characterized, patients with autologous stem cell transplantation and patients with dose-intensive chemotherapy for pediatric solid tumors may have a similarly high risk for PCP based on their profound T-cell depletion. For more than two decades, effective chemoprophylaxis for PCP has been available. Trimethoprim and sulfamethoxazole (TMP/SMX) is the prophylactic modality of first choice. The combination has been shown to be almost 100% efficacious in pediatric cancer patients at highest risk, and it is usually well tolerated in this setting. Secondary alternatives to TMP/SMX include oral dapsone, oral atovaquone, and aerosolized pentamidine-isethionate. These modalities are less effective than TMP/SMX, and have been evaluated predominantly in HIV-infected patients. This article reviews epidemiology and current approaches to chemoprophylaxis for PCP in children and adolescents with cancer and/or hematopoietic stem cell transplantation, and provides evidence-based guidelines for indications and modalities of PCP prophylaxis in this population.