Neutropenia-Associated Outcomes in Patients With Breast Cancer Receiving Myelosuppressive Chemotherapy With Reduced Doses of Pegfilgrastim

BACKGROUND: Pegfilgrastim can be utilized to prevent neutropenia-associated complications in patients receiving myelosuppressive chemotherapy for breast cancer. A common adverse event associated with pegfilgrastim is bone pain. Clinicians may opt to reduce the dose of pegfilgrastim when administering it to patients with previous severe or refractory bone pain. There is limited and conflicting evidence with regard to the safety and efficacy of this practice. The purpose of this study was to investigate the impact of administering reduced doses of pegfilgrastim on neutropenia-associated outcomes in patients with breast cancer receiving myelosuppressive chemotherapy. METHODS: A retrospective chart review was conducted at a large, multistate health system with several different medical oncology practice sites. The primary outcome was the incidence of febrile neutropenia. Secondary outcomes included the incidence and severity of neutropenia, hospitalization for febrile, use of intravenous antimicrobials for febrile, delays in chemotherapy or dose reductions in chemotherapy secondary to neutropenia or febrile, rationale for dose reduction of pegfilgrastim, and improvement in bone pain. RESULTS: A total of 80 patients received reduced dose pegfilgrastim. Most patients had their doses reduced secondary to bone pain (54%) or leukocytosis (14%). One (1.25%) patient experienced febrile neutropenia that did not require hospitalization or intravenous antimicrobials. Chemotherapy treatment delays and dose reductions secondary to neutropenia or febrile neutropenia occurred in 1 (1.25%) and 2 (2.5%) patients, respectively. CONCLUSION: Reduced doses of pegfilgrastim in patients receiving myelosuppressive chemotherapy for breast cancer resulted in a low incidence of neutropenia-associated events, including febrile neutropenia and grade 3/4 neutropenia.