Current Treatment and Future Trends of Immunotherapy in Breast Cancer

Immunotherapy continues to redefine the solid tumor treatment landscape, with inhibitors of the PD-L1/PD-1 immune checkpoint having the most widespread impact. As the most common cancer diagnosed worldwide, there is significant interest in the development of immunotherapy for the treatment of breast cancer in both the early and metastatic settings. Recently reported results of several clinical trials have identified potential roles for immunotherapy agents alone or in combination with standard treatment for early and metastatic disease. While trials to date have been promising, immunotherapy has only been shown to benefit a select group of patients with breast cancer, defined by tumor subtype, PD-L1 expression, and line of therapy. With over 250 trials ongoing, emerging data will enable the further refinement of breast cancer immunotherapy strategies. The integration of multiple putative biomarkers and consideration of dynamic markers of early response or resistance may inform optimal patient selection for immunotherapy investigation and integration into clinical practice. This review will summarize the current evidence for immune-checkpoint blockade (ICB) in the treatment of early and metastatic breast cancer, highlighting current and potential future biomarkers of therapeutic response.

Automated summary

Immunotherapy has a significant impact on breast cancer treatment, but is only effective for a select group of patients. Ongoing clinical trials and emerging data will help refine the treatment strategies. This review summarizes the evidence for immune checkpoint blockade in early and metastatic breast cancer and discusses current and potential future biomarkers for therapeutic response.