Lymph Node Identification Using Magtrace and Magseed Before Chemotherapy

This is an interventional single arm study. The aim is to see if sentinel lymph nodes marked with a magnetic tracer injected before preoperative chemotherapy can be detected at surgery three to six moths later. The investigators also want to see if they can find the same nodes with a tracer injected before chemotherapy as with a tracer injected after chemotherapy. The hypothesis is that the chemotherapy might affect the lymph drainage and the nodes marked before the chemotherapy are the true sentinel lymph nodes. Furthermore, in patients with known lymph node metastases before chemotherapy one metastasis is marked with a magnetic clip before the chemotherapy. This is a well known method but it has not been done in combination with the magnetic tracer. We will show that this is feasible. All patients included in the study will receive their treatments according to the current standard national guidelines as both the magnetic tracer and the routinely used radioactive tracer are used in parallel. The magnetic clip is also used at several sites in Sweden today.