Infiltration of CD4, CD8, CD56, and Fox-P3-positive lymphocytes in breast carcinoma tissue after neoadjuvant chemotherapy with or without trastuzumab

The interplay between the immune response and neoadjuvant therapy in breast cancer

Treatment of early breast cancer is currently experiencing a rapid evolution because of important insight into tumor subtypes and continuous development and improvement of novel therapeutics. Historically considered non-immunogenic, breast cancer has seen a paradigm shift with increased understanding of immune microenvironment, which have revealed extensive heterogeneity in tumor-associated inflammation. Notably, the more aggressive breast cancer subtypes, including triple-negative and HER2-positive, have exhibited favorable responses to combined chemo-immunotherapy protocols. Neoadjuvant therapy has emerged as the standard of care for these tumors, with pathological complete response used as a surrogate endpoint for long-term clinical outcomes and coincidently expediting new drug approval. The neoadjuvant setting affords a unique opportunity for in vivo treatment response evaluation and effects on the tumor microenvironment. In this review, the predictive and prognostic value of the tumor immune microenvironment before, during, and after treatment across various therapeutic regimens, tailored to distinct breast cancer subtypes, is carefully examined.

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.

Combination Immunotherapy Strategies in Breast Cancer

Purpose of Review

We summarize combination immunotherapy strategies for the treatment of breast cancer, with a focus on metastatic disease. First, a general overview of combination approaches is presented according to breast cancer subtype. Second, additional review of promising combination approaches is presented.

Recent Findings

Combination strategies utilizing chemotherapy or radiotherapy with immune checkpoint inhibition are being evaluated across multiple phase III trials. Dual immunotherapy strategies, such as dual immune checkpoint inhibition or combined co-stimulation/co-inhibition, have supportive preclinical evidence and are under early clinical investigation. Modulation of the immune microenvironment via cytokines and vaccination strategies, as well as locally focused treatments to enhance antigenic responses, are active areas of research.

Summary

Pre-clinical and translational research sheds new light on numerous ways the immune system may be modulated to fight against cancer. We describe current and emerging combination approaches which may improve patient outcomes in metastatic breast cancer.