International study comparing radiotherapy and complete surgical removal of the axillary lymph nodes in patients with breast cancer and affected lymph nodes

In this study, all participants suffering from breast cancer with lymph node involvement will first have the affected lymph nodes and the axillary sentinel lymph nodes removed ("less invasive axillary surgery"/"focused axillary surgery"). Then, in some patients, all the lymph nodes in the armpit are also surgically removed, while in others the armpit is additionally irradiated instead, which is done as part of routine breast or chest irradiation.

Intervention studied

In the trial group, patients do not receive further surgical removal of all lymph nodes in the armpit (standard therapy). Instead, they receive radiotherapy to the armpit at a later stage. This is carried out at the same time as radiotherapy of the breast or chest, which is planned for all patients regardless of group allocation.

Criteria for participation

• Node-positive breast cancer (histologically or cytologically proven in both the primary tumor and lymph nodes)
• Eligible for a primary ALND or SLN procedure and either newly diagnosed or isolated recurrence in the breast/second ipsilateral breast cancer after previous breast-conserving surgery and sentinel procedure and disease-free for at least 3 years and without previous axillary dissection or axillary RT.
• No neoadjuvant treatment with the exception of bridge therapy of less than 3 months.

Exclusion criteria

• Stage IV breast cancer.
• Clinical breast cancer N3c without axillary involvement (clinical breast cancer N3a and clinical breast cancer N3b are permissible).
• Clinical breast cancer N2b (clinical breast cancer N2a is permitted).
• Contralateral breast cancer within 3 years.