Fungal infections in the cancer patient.

Fungal infections are increasing in frequency, especially among patients with haematological malignancies. The fungi which cause most of the infections in cancer patients are Candida spp. and Aspergillus spp. These fungi seldom infect individuals with normal host defence mechanisms. Many factors predispose patients to fungal infection, including neutropenia, lymphopenia, gastro-intestinal ulceration, intravenous catheters and adrenal corticosteroid therapy. Candida spp. cause 5 major types of infection: dermatitis, thrush, gastro-intestinal, primary organ and disseminated infection. Aspergillus spp. and Phycomycetes cause pulmonary, disseminated or rhino-cerebral infection. Cryptococcus neoformans usually causes meningitis but may cause pneumonia or disseminated infection. The diagnosis of fungal infection is often made only at postmortem examination, because it is difficult to isolate the aetiological agent from sites of infection. Amphotericin B remains the mainstay of antifungal therapy, but is seldom effective in the patient with compromised host defences. Successful management of these infections in the future will depend upon improvement in diagnostic capabilities as well as the introduction of more effective and less toxic antifungal agents.