[Infection and immunosuppression in cancer patients]

Septicemia in hematologic malignancies and infection of herpes zoster in cancer patients were studied, and trend in organisms in a cancer hospital was investigated. 1) Septicemia in hematologic malignancies. The success rate of antibiotic therapy for septicemia was 76% if the patients were not under antibiotic therapy when septicemia developed. But recovery from septicemia was only 25% if the patients were undergoing antibiotic therapy when septicemia developed. Some 90% of neutropenic patients under 500/microliters, who were not under antibiotic therapy when septicemia developed, recovered from septicemia if the neutrophil count increased in the following 5 days. Change in the neutrophil count was an important factor determining the success or failure of antibiotic therapy for septicemia. The use of granulocyte colony-stimulating factor may prevent chemotherapy-induced neutropenia. Shortening of the period of neutropenia or preventing its occurrence should reduce the incidence and the severity of infection. 2) Infection of herpes zoster in cancer patients. Thirty-four cancer patients were associated with herpes zoster. Eleven of them were patients with malignant lymphoma and ten of them were patients of breast cancer. Most patients were heavily pretreated by chemotherapy and/or radiotherapy before the development of herpes zoster. Marked lymphocytopenia was observed at the onset of herpes zoster. Absolute lymphocyte count was under 1000/microliters in 71% of these patients. Development of herpes zoster in cancer patients was considered to be due to the depression of cell-mediated immunity which was the result of repeated and continued anticancer therapy. Acyclovir was found to be effective to treat herpes zoster in these patients. 3) Trend of organisms detected in cancer hospital. The frequency of organisms isolated from clinical materials in the National Cancer Center Hospital was compared during the period from 1978 to 1982 and the period from 1983 to 1987. The most common organism detected in both periods was P. aeruginosa and no change in frequency was observed. But the frequency of gram-negative bacilli, E. coli, Klebsiella and Serratia, decreased significantly in the latter period while the frequency of gram-positive cocci, Enterococcus and Staphylococcus increased markedly in the latter period. The use of cephems of third generation in the latter period could be one reason for the recent change of organisms detected in the hospital. Appropriate therapy for infection based on the latest and accurate information should be used.