Impact of neoadjuvant chemotherapy on perioperative immune function in breast cancer patients: a propensity score-matched retrospective study.

To evaluate the impact of neoadjuvant chemotherapy on perioperative immune function in breast cancer patients, focusing on CD3, CD4, CD8, and natural killer (NK) cells, as well as the CD4/CD8 ratio. We retrospectively reviewed medical records of breast cancer patients who underwent surgery with or without neoadjuvant chemotherapy at our medical center from January 2020 to December 2022. Patients were matched 1:1 based on propensity scores. Immune cell proportions and the CD4/CD8 ratio were compared on preoperative day one and postoperative days one and seven. Among matched patients, immune cell proportions and the CD4/CD8 ratio did not significantly differ between those who received neoadjuvant chemotherapy and those who did not at any of the three time points. Similar results were observed in chemotherapy-sensitive patients compared to the entire group of patients who did not receive neoadjuvant chemotherapy. However, chemotherapy-insensitive patients had significantly lower proportions of CD4 and NK cells, as well as a lower CD4/CD8 ratio, at all three time points compared to patients who did not receive neoadjuvant chemotherapy. Neoadjuvant chemotherapy may impair immune function in chemotherapy-insensitive patients, but not in those who are sensitive to the treatment.