Abstract 566P
Background
4AC-4T (Doxorubicin/cyclophosphamide (60/600 mg/m2) followed by paclitaxel (175 mg/m2)) dose dense chemotherapy is widely used in early-stage breast cancer. However, when giving this regimen in developing countries, there is a limited access to Peg-filgrastim, and the optimal and cost-effective duration of filgrastim for primary prophylaxis of febrile neutropenia (FN) is unknown.
Methods
This is a prospective cohort study on 93 breast cancer patients who were treated with (neo)adjuvant 4AC-4T dose dense regimen at Vietnam National Cancer Hospital from 06/2023 to 06/2024. The patients received filgrastim on day 3, 4, 5, 6, 7 after AC and day 3, 4 after T. Additional dose(s) of filgrastim was given if neutropenia of grade ≥2 was recorded on day 1 of the following cycle, and chemotherapy will be given ≥24 hours later. Rate of FN and neutropenia were assessed.
Results
The median age of patients was 48 (IQR 40-53) years old, 60.2% and 39.8% patients received 4AC-4T in adjuvant and neoadjuvant settings respectively. A total of 744 cycles of chemotherapy were given, in which FN occurred in 4 cycles (0.54%), all of which were during 4AC. Grade 1, 2, 3, 4 neutropenia were recorded after 58 (7.80%), 62 (8.33%), 26 (3.49%) and 6 (0.81%) cycles respectively, most of which occurred during 4AC (41, 48, 22, and 4 events respectively). One, two and three doses of filgrastim were added at the begining of the next cycle to correct the neutropenia after 91 (12.23%), 21 (2.82%) and 6 (0.81%) cycles, respectively. Among 4 patients who had FN, one case was treated in as outpatient and 3 cases required hospitalization.
Conclusions
This shorter duration of primary prophylaxis filgrastim allowed most patients to underwent 4AC-4T dose dense regimen without complications, which could reduce cost and side effects of G-CSF, but a closer monitoring should be given after AC. There should be larger randomized study to further evaluate the effectiveness of this schedule, especially in resource limited settings.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.