Neutropenia is a hematologic adverse event characterized by an absolute neutrophil count (ANC) lower than 1500 cells/mL. This reduction may be due to decreased neutrophil production, accelerated use, a shift in compartments of neutrophils, or a combination of these factors.
Neutropenia is often associated with
infections, which are major causes of morbidity and mortality in patients with
cancer. In patients with
multiple myeloma, the novel agents
thalidomide,
lenalidomide, and
bortezomib have improved outcome, but
chemotherapy-related
neutropenia should be carefully considered.
Chemotherapy-related high-risk factors for severe
neutropenia include regimens with an expected
neutropenia rate of > 50%, such as the 3-drug combinations including
lenalidomide plus
alkylating agents or
doxorubicin, whereas low-risk regimens include combinations of the novel agents with
dexamethasone alone. Patient characteristics, disease stage, type of current and previous treatment, and ANC < 1000 cells/mL at baseline are additional factors that define the risk of severe
neutropenia.
Granulocyte-colony stimulating factor (
G-CSF) should be used to manage
chemotherapy-related
neutropenia so that patients may stay on treatment for a longer time and benefit from it. Primary
G-CSF prophylaxis should be used when high-risk regimens are administered or when low/intermediate-risk regimens are used and additional risk factors are present. Reactive
G-CSF treatment is indicated when patients undergoing low-risk
chemotherapy experience grade 3/4
neutropenia. If ANC restores to > 1000 cells/mL,
therapy can be resumed with no dose modifications. In case of persistence of severe
neutropenia, treatment should be delayed until ANC reaches > 1000 cells/mL, and
dose reductions are necessary.