Rajan, S.S., Lyman, G.H., Stearns, S.C., & Carpenter, W.R. (2011). Effect of primary prophylactic granulocyte-colony stimulating factor use on incidence of neutropenia hospitalizations for elderly early-stage breast cancer patients receiving chemotherapy. Medical Care, 49, 649–657.

The purpose of the study was to study the effect of administration of primary prophylactic (PPG) colony-stimulating factory and duration of administration on the occurrence of chemotherapy-induced neutropenia hospitalization in older adult patients with breast cancer.

The study sample included women older than age 66 years. Women with stage 0 were excluded because stage 0 does not require chemotherapy, and women with stage 4 were excluded because stage 4 palliative therapy is very different from standard first-course administration.

The SEER data from 16 registries (1994–2002) was used. The outcome of interest was neutropenia hospitalizations defined as ICD9 code 288.0X in the first, third or sixth months after the first course of chemotherapy.  Administration of G-CSF had to be initiated within five days after the first course of chemotherapy as primary prophylaxis. G-CSF was defined according to procedures codes.

• The total sample was 10,441 patients aged 66 years and older.
• All participants were female
• All had stage l, ll, or lll breast cancer
• Patients had to be receiving chemotherapy with in six months of diagnosis.
• Neutropenia hospitalization had to occur within the first three or six months.
• Exclusion criteria: Chemotherapy initiation after six months.
   

Inpatient

Observational study

• End result Medicare data from 1994–2003
• Outcomes and treatment defined by ICD9 diagnosis and procedure codes
   

Administration of PPG-CSF during the first course of chemotherapy reduced neutropenia hospitalizations by 16% with in first three months and 17% within the first six months of chemotherapy. Hospitalization rates within the first three months of chemotherapy initiation were three times higher in women receiving less than five days of PPG-CSF compared to women receiving PPG-CSF for five or more days. Hospitalization rates within the first one and six months were also lower with longer PPG-CSF.

PPG-CSF use is associated with reductions in patient healthcare utilization.

• No controls.
• The study does not focus on incidence of neutropenia and, rather, worked on severity
• Many mild cases of neutropenia go unreported as ANC less than 2,000.
• Neutropenia hospitalization was taken as a dependant variable for the study and patients with mild neutropenia would not be taken as a part of the study,
• Retrospective data analysis only
   

PPG-CSF received during the first three months, particularly after five days of initiation of the therapy, and to be taken for at least five days, would reduce the risk of neutropenia hospitalization among older adult patients with breast cancer.