Oral antibiotic prophylaxis in patients with cancer: a double-blind randomized placebo-controlled trial

In an attempt to reduce the incidence of fever and infection, we randomized patients with cancer to receive trimethoprim/sulfamethoxazole plus erythromycin (TMP/SMX + E) versus placebos after each cycle of chemotherapy (no crossover) and to continue until granulocytopenia (polymorphonuclear leukocytes less than 500/mm3) resolved or the patient became febrile. We evaluated 541 episodes (150 patients); 249 episodes (77 patients) with TMP/SMX + E and 292 episodes (73 patients) with placebos. The patients' median age was 17 years. Thirty percent of the patients had leukemia, 23% had lymphoma, and 47% had solid tumors. Compliance with prescribed medication was prospectively rated as excellent in 60.6%, good in 11.7%, poor in 11.1%, and unknown in 16.6%; compliance was better for the placebo group (P = 0.001). The overall incidence of fever or infection was 22.1% for the TMP/SMX + E group versus 26.9% for the placebo group. When only episodes with excellent compliance in which granulocytopenia was documented were compared, the incidence of fever or infection was 18.1% for the TMP/SMX + E group vs 32.2% for the placebo group (P = 0.009), with bacterial infection occurring in 3.8% of the TMP/SMX + E group vs 11.9% of the placebo group (P = 0.019), and unexplained fever in 10.5% of the TMP/SMX + E group vs 19.6% of the placebo group (P = 0.037). Patients with good or poor compliance showed no significant benefit from the TMP/SMX + E, and patients with excellent compliance did best, regardless of whether they were receiving antibiotics or placebos, suggesting that patient compliance is an important independent variable. The incidence of fever or infection was significantly lower for patients with leukemia with excellent compliance who received antibiotics (P = 0.037) than for patients with lymphomas or solid tumors. Oral antibiotic prophylaxis reduced the incidence of fever and infection in some granulocytopenic patients, but the benefit was limited and restricted to patients whose compliance was complete.