Predictive value of Neutrophil-to-Lymphocyte Ratio in patients with Triple Negative Breast Cancer treated with Immune Checkpoint Inhibitors

Triple-negative breast cancer (TNBC) is a fast-growing and aggressive form of breast cancer that does not respond to common treatments like hormone therapy. Hormone therapy is a form of treatment that deprives breast cancer of oestrogen and progesterone, the two main female hormones that it needs to survive and grow. Each year, around 2 million new cases of TNBC are diagnosed worldwide. Many people with advanced TNBC (also known as metastatic TNBC) are treated with a type of drug called immune checkpoint inhibitors (ICIs). Metastatic TNBC means that the cancer has spread from the breast to other parts of the body and is a rare, aggressive form of breast cancer. These medications help the immune system recognize and attack cancer cells. They are called immune checkpoint inhibitors because they block proteins called "checkpoints" on immune cells that act as a brake on the immune system. In doing this they then allow the immune system, specifically T-cells, to continue fighting cancer cells. However, these treatments do not work for everyone. Some patients do not benefit and may still suffer from serious side effects.

Because of this, researchers are trying to find better ways to predict who is most likely to respond to ICI treatment. One possible clue may come from a simple blood test. This test looks at the ratio of two types of white blood cells: neutrophils and lymphocytes. This is known as the neutrophil-to-lymphocyte ratio (NLR). Higher NLR levels have been linked with shorter survival in patients with breast cancer.
Recent research has shown that neutrophils can form structures called neutrophil extracellular traps (NETs), which may play a role in making cancer more resistant to treatments like ICIs. TNBC tumors appear to have more of these NETs compared to other types of breast cancer.
In our study, we want to find out if NLR levels measured before treatment can help predict how well a patient will respond to ICI treatment. We believe that patients with a high NLR might be less likely to benefit from this therapy.

To test this idea, we will review the medical records of patients with metastatic TNBC who have already received ICI-based treatments. We will look at their NLR levels before treatment and compare these levels to how long their cancer stayed under control, using a measurement called progression-free survival (PFS). This means the amount of time during which the cancer does not grow or spread.
If our research finds a strong link between high NLR and poor response to treatment, it could help doctors make better decisions about who should receive ICI therapy. This could improve patient care by making treatments more personalized and reducing unnecessary side effects in those unlikely to benefit.