CRP as a Marker for the Success of Immunotherapy in Breast Cancer

Breast cancer (mammary carcinoma) is a malignant disease of the mammary gland tissue characterized by the uncontrolled proliferation of mammary gland cells. Treatment of the disease depends on numerous factors, such as the person’s overall health, the stage of the disease, the tumor’s growth rate (Ki-67 index), the presence of detectable hormone receptors on the surface of the cancer cells (estrogen receptor-positive, progesterone receptor-positive), and the increased presence of HER2 receptors on the cells (HER2-positive). Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer that lacks both hormone receptors and HER2 receptors on the cell surface. As a result, common targeted therapies are not an option, and standard treatment usually consists of chemotherapy. In recent years, immunotherapy using so-called immune checkpoint inhibitors (ICI) has been incorporated into treatment, both for early-stage and for advanced or metastatic TNBC.

The aim of this study is to investigate whether the blood marker C-reactive protein (CRP), a marker of inflammation, is suitable as an easily measurable predictor of treatment success. Preliminary evidence from other types of cancer, such as lung or kidney cancer, suggests that a mild inflammatory response may be associated with a better response to immunotherapy. The study design is observational and prospective. Thus, the drug itself is not being tested; rather, blood values and disease progression in the patients are being recorded during and after therapy. There are two groups: a control group receiving chemotherapy alone and an experimental group receiving chemotherapy plus immunotherapy. In addition to CRP, other laboratory values important for the immune response are determined from the blood samples. The study will run for a total of 10 years, including treatment and follow-up phases, to assess the long-term benefits of CRP measurement.

Women 18 years of age or older with confirmed triple-negative breast cancer (TNBC) in the early or advanced/metastatic stage are eligible to participate. For metastatic TNBC, evidence of PD-L1 positivity is also required for the immunotherapy group. Patients must not have previously received immunotherapy or prior systemic treatment during the early stages of their cancer.