[Incidence of bacteremia among histologic groups of hematologic malignancies]

Subgroups having dissimilar prognoses are being identified among cancer patients with infection. Previous studies have suggested that these differences may be related to the histologic diagnosis, but this issue has not as yet been demonstrated.

We reviewed the medical records of all patients admitted with acute leukemia (AL) or lymphoma (ML) from 1988 to 1998. Incidence of bacteremia was calculated for the following subgroups: acute lymphocytic leukemia (ALL), acute myelocytic leukemia (AML), AML following refractory anaemia with excess blasts (AML-RAEB), high-grade ML (HGML), intermediate-grade ML (IGML), low-grade ML (LGML) and indeterminate ML (IML). Kaplan-Meier curves of time to the first positive blood culture were constructed and compared by means of log-rank test.

In the period covered there were 244 new diagnoses of AL or ML: 62 AML, 32 ALL, 20 AML-RAEB, 78 HGML, 7 IGML, 37 LGML and 6 IML. At the end of the study period, 44 patients were alive, 147 were known to have died at a certain date and 53 had been formally lost to follow-up (most of them, transferred for hospice care). Among 684 blood cultures, there were 51 contaminations and 155 significant isolates. Among the latter, gram-positive bacteria were isolated in 74 and gram-negative bacteria in 47; in 27 cases more than 1 bacterial species were recovered. Fungi were isolated in 7 cases. The incidence of bacteremia expressed as cases per 1000 patient-days was 5.80 for AML, 5.03 for AML-RAEB, 1.56 for ALL, 0.21 for HGML and 0.40 for the remaining ML. Time to the first positive blood culture was significantly shorter for AML than for any other group, and was shorted for ALL and AML-RAEB than for ML.

Differences in the incidence of bacteremia were observed among histologically-defined groups of unselected patients with hematologic malignancies.