Abstract P5-14-09: Prospective cohort study of febrile neutropenia in breast cancer patients with neoadjuvant and adjuvant chemotherapy: CSPOR-BC FN Study

Background: Febrile neutropenia (FN) is one of the greatest concerns when maintaining chemotherapy dosage for early breast cancer patients. However, the incidence proportion of FN remains unclear because of the empirical prescription of oral antibiotics, the use of G-CSF, and the absence of body temperature examination and hematology test. Therefore, we performed a prospective cohort study of FN in breast cancer patients receiving adjuvant or neoadjuvant chemotherapy. Methods: Breast cancer patients were prospectively enrolled from August 2015 to July 2017. The regimens included 4 cycles of FEC (epirubicin 100 mg/m²), E(A)C (epirubicin 90 mg/m² or doxorubicin 60 mg/m²), and TC (docetaxel 75 mg/m²). Considering the current practice of empirically prescribing oral antibiotics without hematology tests, we followed 2 groups and surveyed FN using 2 different definitions: true FN (T-FN): ≥ 37.5°C and grade 4 neutropenia by a hematologic test with a visit to the hospital (visiting group), and surrogate FN (S-FN): ≥ 37.5°C and oral antibiotic intake without a mandatory visit to the hospital (non-visiting group). The primary objective was to investigate the FN incidence of each regimen during the first 4 cycles. The overall incidence proportion of FN was calculated as (patients with T-FN or S-FN) / (total patients). The proportion of T-FN or S-FN in each group was also examined. In the secondary analysis, the risk factors of FN and the safety of FN management in the non-visiting group were investigated. Multiple logistic regression analysis was performed to assess the risk factors. As we assumed that FN occurs in 20% of the patients by these regimens, the planned sample size based on the confidence intervals was 1000. This trial was registered as UMIN 000017857. Results: A total of 1005 female patients with Stage I to III breast cancer were enrolled. Of these patients, 25 were excluded because of incomplete treatments or other regimens administered. There were 477 patients in the visiting group and 503 patients in the non-visiting group. The numbers of patients in each regimen were 338 in FEC, 335 in E(A)C, and 307 in TC. The overall incidence proportions of FN were 22.5%, 27.5%, and 33.9% in FEC, E(A)C, and TC, respectively. The incidence proportions of T-FN were 27.7%, 22.4%, and 36.6%; those of S-FN were 17.3%, 32.4%, and 31.5%. Pegfilgrastim (PEG-G) was used in the 1st cycle more frequently in the non-visiting group than in the visiting group: in FEC, E(A)C, and TC, 39.0%, 11.8%, and 52.1% in the non-visiting group; 4.71%, 1.82%, and 14.1% in the visiting group, respectively. The risk factors of FN were regimen (TC: OR: 2.67, 95%CI: 1.36-5.26), age (u003e 65 OR: 2.24, 95%CI: 1.34-3.75), neutrophil count at registration (/1000/μl: OR: 0.8, 95%CI: 0.67-0.95), pre-/post-operation (pre-: OR: 0.51, 95%CI: 0.29-0.88), and PEG-G (OR: 0.04, 95%CI: 0.01-0.34). There were no significant differences in the frequency of grade 3 adverse events, hospitalization, intake of oral antibiotics, and relative dose intensity between the visiting group and the non-visiting group. Therapeutic daily G-CSF was more frequently used in the visiting group than in the non-visiting group. Conclusions: FN occurred at a rate higher than 20% in these 3 regimens, most frequently in TC. Neutrophil count at registration was found to be one of the risk factors of FN. The current practice of prescribing antibiotics without hematologic tests is acceptable for FN management because the outcomes were not significantly different between the visiting group and the non-visiting group. Citation Format: Takashi Ishikawa, Kentaro Sakamaki, Kazutaka Narui, Hideki Nishimura, Takafumi Sangai, Kentaro Tamaki, Yoshie Hasegawa, Ken-ichi Watanabe, Nobuyasu Suganuma, Shintaro Michishita, Sadatoshi Sugae, Tomohiko Aiharya, Koichiro Tsugawa, Hiroshi Kaise, Hirofumi Mukai. Prospective cohort study of febrile neutropenia in breast cancer patients with neoadjuvant and adjuvant chemotherapy: CSPOR-BC FN Study [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-14-09.