Lesson from COVID-19 outbreak; importance of standard precautions to febrile neutropenia prevention in patients with breast cancer who received adjuvant chemotherapy: a retrospective observational study.

Purpose: Intensive cytotoxic chemotherapy increases the risk of infection in patients with cancer by inducing bone marrow suppression and mucosal injury. Febrile neutropenia (FN) is the most important clinical adverse event in patients with cancer receiving cytotoxic chemotherapy. To prevent FN, standard precautions including hand and respiratory hygiene are generally recommended, but the exact effect of non-pharmacologic intervention has not been clearly proven in the clinical setting. We aimed to compare the incidence of FN between the pre-coronavirus disease 19 (COVID-19) era vs. the post-COVID-19 era. Methods: We retrospectively enrolled patients with breast cancer who received an adriamycin and cyclophosphamide (AC) regimen containing adjuvant chemotherapy at Jeju National University Hospital. We compared the incidence of FN between the pre- and post-COVID-19 period and analyzed characteristics of the event and other clinical risk factors. Results: In total, 149 patients were enrolled, including 94 who received AC chemotherapy in the pre-COVID-19 era and 55 who received it in the post-COVID-19 era. Sixteen patients (10.7%) experienced FN. Fourteen (14.9%) and 2 events (3.6%) occurred in pre-COVID-19 and post-COVID-19 eras, respectively. The post-COVID-19 era was the only risk factor for FN (P = 0.032). Conclusion: We found an association between FN occurrence and the COVID-19 outbreak, providing indirect evidence of the importance of non-pharmacological measures to reduce FN risk in patients with breast cancer. Further research is required to confirm the standard precautions for FN prevention in patients with cancer.