Comparison of infusion-related reactions to chemotherapy versus targeted therapy: A four-year experience at the Medical Day Hospital of the Fondazione IRCCS Istituto Nazionale Tumori Milano

BACKGROUND: Infusion reactions (IRs) are a significant concern in oncology due to unpredictable onset and a lack of standardized management guidelines. OBJECTIVES: To compare the incidence, severity and management of IRs related to chemotherapy and targeted therapies in real-world practice, based on the experience of Medical Day Hospital at the Fondazione IRCCS Istituto Nazionale Tumori in Milan. METHODS: A retrospective analysis of 73,057 non-investigational drug preparations (39,468 chemotherapies; 33,589 targeted therapies) was conducted between 2020 and 2023. The primary endpoint was the incidence of IRs per administration. Statistical comparison was performed using the Chi-square test. RESULTS: A total of 646 IRs were observed (0.88%). The median age was 61 years (range 19-90), 75 % female and 25% male. The incidence was significantly higher for chemotherapy (1.17%) compared to targeted therapies (0.55%; p < 0.0001). The most problematic chemotherapies were paclitaxel (reaction risk 2.77%) and oxaliplatin (5.18%). For targeted therapies, rituximab (2.37%) and nivolumab (0.52%) showed the highest risk. Most reactions (97.4%) were mild (G1-G2) according to CTCAE 5.0. CONCLUSIONS: Chemotherapy remains associated with a significantly higher risk of IRs compared to targeted therapies. Although clinical presentations are similar, distinct pathophysiological mechanisms require tailored management and risk assessment.