Management of fever of unknown origin in patients with neoplasms and neutropenia.

During 81 febrile episodes, 76 cancer patients with neutropenia were randomly allocated to continue or discontinue antibiotics 4 days after initiation of carbenicillin and cephalothin therapy, if no infection had been demonstrated. During 56 episodes, the patients became afebrile, after initiation of antibiotics. Infection as a cause of fever was identified in 21% of the episodes. The cause of fever could not be identified in 72% of the episodes. Three of 30 patients randomized to discontinue antibiotics developed infection which ultimately caused their death. During 25 episodes, the patients remained febrile. Infection was the ultimate cause of fever in 40% of the episodes. The cause of fever could not be identified in 48%. The majority of infections documented in this group responded when gentamicin was added. Antibiotic therapy with carbenicillin and cephalothin is effective initial therapy for fever due to presumptive infection. If, after 4 days of therapy, no infection is documented and the patient is responding, the antibiotics should be continued for an additional 3 to 5 days. However, for patients not responding after the initial 4 days of therapy, the addition of gentamicin is indicated.