Is it possible to completely avoid removing the lymph nodes in the armpit?

Breast cancer (mammary carcinoma) is a malignant disease of the breast tissue characterized by the uncontrolled proliferation of breast cells. Treatment is divided into several phases and depends largely on how widespread the tumor is (stages 1–4) and the characteristics of the cancer cells in the initial tissue sample. This also includes whether hormone receptors are detectable on the surface of the cancer cells (estrogen receptor-positive, progesterone receptor-positive) and the increased presence of the HER2 receptor (HER2-positive). If none of these receptors are present, the cancer is referred to as triple-negative breast cancer. Treatment usually involves an initial round of chemotherapy (neoadjuvant), followed by surgery on the breast and lymph nodes, and then further treatment (adjuvant), which is determined by the risk of recurrence. The removal of axillary lymph nodes is currently under critical review, as it can cause side effects for the patient while its benefits remain uncertain. There are different approaches here: In one approach, only so-called sentinel lymph nodes—which are thought to be most likely to contain tumor cells—are removed; alternatively, suspicious lymph nodes or even all axillary lymph nodes are removed. Since neoadjuvant chemotherapy is now highly effective, it might be possible to forego lymph node removal entirely if the lymph nodes were not obviously affected at the onset of the disease.

The goal of the EUBREAST-01 study is to investigate whether lymph node removal can be completely avoided if, following neoadjuvant chemotherapy, complete regression of the tumor in the breast can be observed on imaging. To this end, patients will undergo breast-conserving surgery without the removal of sentinel lymph nodes. The study consists of a single arm; accordingly, all patients receive the same treatment and are aware of it (open-label). After surgery, patients will be followed for at least three years. The study will investigate whether the cancer recurs during this period and how the treatment strategy affects survival.

To participate in the study, patients must be at least 18 years old and have triple-negative or HER2-positive breast cancer. Patients must have shown complete tumor regression following neoadjuvant chemotherapy. Patients whose cancer has already spread to other parts of the body, or who have had another type of cancer within the last five years, are not eligible to participate.