Background: Chemotherapy for breast cancer is associated with a high risk of neutropenia. Pegfilgrastim reduces the risk of neutropenic fever but commonly causes bone pain.
Objective: Evaluate whether a reduced dose of pegfilgrastim (3 mg) reduced the frequency of bone pain without compromising efficacy.
Methods: Records reviewed from breast cancer patients who received at least one 3 mg dose of pegfilgrastim, white blood count (WBC), and absolute granulocyte counts (AGC) were collected. Musculoskeletal pain scale was collected at each visit.
Results: 265 treatments from 36 women were analyzed. There was no difference in post-treatment AGC between 3 versus 6 mg. Leukocytosis (WBC > 20,000 cells/cu mm) was more likely for those treated with 6 mg (chi-square 5.265, p = 0.0215). There was higher change in bone pain in patients who received 6 mg doses compared to none or 3 mg.
Limitations: In this retrospective, non-randomized study, we found the majority of patients received the reduced 3 mg dose after intolerance to the 6 mg dose. It is unknown if smaller or larger doses than 3 mg would achieve similar results or whether 3 mg dose would be effective as an initial therapy or for patients receiving different chemotherapy regimens. Pain is observed despite premedication with naproxen and/or loratidine.
Conclusion: Reduced dose of pegfilgrastim 3 mg was less likely to cause bone pain. The reduced dose was not associated with a significant difference in post-treatment AGC or rate of serious infection.
Keywords: Breast cancer; Chemotherapy; Neutropenia; Pegfilgrastim.