# Real-world evidence of febrile neutropenia-related hospitalization on patients with perioperative chemotherapy for early breast cancer in Japan

## TL;DR

This study examines how febrile neutropenia-related hospitalizations affect early breast cancer patients in Japan who receive chemotherapy before or after surgery.

## Contribution

The study provides real-world evidence on febrile neutropenia-related hospitalization in early breast cancer patients undergoing perioperative chemotherapy in Japan.

## Key findings

- Febrile neutropenia-related hospitalization occurred in 5.73% of patients and 0.80% of chemotherapy cycles.
- Fourth-generation cephalosporins were the most commonly used intravenous antibacterial drugs during hospitalization.
- The median cost of hospitalization was 189 thousand yen, and granulocyte-colony stimulating factor was used in 67.28% of affected patients.

## Abstract

To clarify particularly how febrile neutropenia-related hospitalization (FNH) affects patients’ daily lives, by analyzing real-world data on FNH among patients with early breast cancer (EBC) receiving perioperative chemotherapy in Japan.

This retrospective nationwide large-scale database study was conducted using anonymized claims data from 2010 to 2020. The patients with EBC who had available surgical records were included. Men, those aged < 18 years, and those who had not available chemotherapy records were excluded. FNH was defined as hospitalization during perioperative chemotherapy for EBC, with administration of intravenous antibacterial drugs and a diagnosis of FN, sepsis, infection, or fever.

The analysis population included 33,310 EBC patients with a mean age of 56.9 years, who received a total of 267,535 perioperative chemotherapy cycles. FNH occurred in 1,910 patients (5.73%) and 2144 chemotherapy cycles (0.80%). Median duration of FNH was 6.0 days. Fourth-generation cephalosporins were the most used intravenous antibacterial drugs (50.42%). Median duration of intravenous antibacterial drugs administration was 4.0 days. Therapeutic granulocyte-colony stimulating factor (G-CSF) was used in 1285 patients (67.28%). Median cost for FNH was estimated to be 189 thousand yen in 1,474 chemotherapy cycles with FNH, in which patients received intravenous antibacterial drugs administration for 3–8 days.

This nationwide real-world data analysis revealed the incidence, duration, treatment patterns, and medical cost of FNH in patients with EBC receiving perioperative chemotherapy in Japan. These findings indicate that FNH imposes a considerable burden on patients’ daily lives, including time and financial impacts, contributing to the implementation of appropriate shared decision-making for primary G-CSF prophylaxis.

The online version contains supplementary material available at 10.1007/s12282-025-01714-6.