Axillary Reverse Mapping: Preventing Lymphedema Among Patients With Breast Cancer

Kelly Hunt, MD, MD Anderson Cancer Center, Houston, TX, discusses the practice of axillary reverse mapping as a method to prevent lymphedema for patients with breast cancer.

Dr Hunt explained the differences between axillary reverse mapping and complete axillary node dissection, with a focus on the advantages axillary reverse mapping can provide in terms of preserving lymph nodes or lymphatics for this patient population.

Transcript

I'm Kelly Hunt, and I'm the professor and chair of the Department of Breast Surgical Oncology at the MD Anderson Cancer Center.

What is axillary reverse mapping?

Auxiliary reverse mapping is a technique whereby a dye is injected into the upper arm, and that helps to facilitate identification of lymphatics and lymph nodes that are primarily draining that upper extremity. It helps the surgeon to identify and potentially preserve those lymph nodes, or in some cases remove the lymph nodes but preserve the lymphatics, and then reconstruct the lymphatics so that the lymphatic drainage of the upper arm is preserved.

What is axillary reverse mapping’s role in lymphedema prevention for patients with breast cancer?

The concern is that over the past couple of decades, with breast cancer treatment, there's been less need for complete axillary lymph node dissection. With the use of axillary lymph node dissection, we do see the development of lymphedema in a significant proportion of patients. For early-stage breast cancer patients, it ranges quite a bit depending on the study and how the measurements were taken of the upper extremity, but it's somewhere between 20% to 40%. Then for patients who have lymph node-positive disease, where they receive chemotherapy, auxiliary lymph node dissection, and often radiation therapy as well, the rates of lymphedema are as high as 60% at 3 years from some of the prospective studies that we've done. The rate of lymphedema is still quite high. Now again, we can sometimes avoid auxiliary lymph node dissection depending on the clinical scenario, but there are still many cases where auxiliary lymph node dissection is needed as part of the management of patients with breast cancer.

What are the risks of axillary reverse mapping?

The risks of auxiliary reverse mapping are low. It does add some time to the operative procedure, and the identification of the lymphatics is not straightforward. Sometimes they're quite small vessels, and so there have been lower rates of identification reported in some studies. There are now some studies that are looking at improving the technique by using combination of fluorescein-labeled dyes and blue dyes and other techniques of that nature that can help the surgeon identify the lymphatics and preserve them.

One of the risks in terms of the classic description of axillary reverse mapping is that if you inject the dye in the upper arm to identify the lymph nodes draining the arm, and you inject a radioactive dye in the breast to identify which lymph nodes are draining the breast, that in some cases those are the same lymph node. When you're trying to do the staging with sentinel lymph node surgery or remove involved nodes in the case of an axillary lymph node dissection, you might be leaving disease behind if you don't remove that node that is draining both the arm and the breast. That's why some people have developed these techniques of removing the nodes but preserving the lymphatics and then reconstructing the lymphatics either with other lymphatics, the afferent and efferent lymphatics – if they can be preserved, they can be reconstructed – or you can approximate the lymphatic with a branch of the axillary vein that is identified during the dissection.

How does axillary reverse mapping differ from other strategies for lymphedema prevention?

The studies seem to bear out that it does prevent lymphedema in a proportion of patients undergoing axillary lymph node dissection and those undergoing sentinel lymph node surgery as well, although the rates of lymphedema development after sentinel lymph node surgery are quite low. It's really the patients undergoing axillary lymph node dissection, especially in the setting of radiation, where the rates of lymphedema are higher. We think that preventing it is better than waiting until lymphedema develops.

Once lymphedema develops, and it depends on the stage of lymphedema in the upper arm, it can be quite difficult to manage for the patient. If the arm is sometimes 2or 3 times the size of the contralateral arm, that can obviously make it very difficult for patients to wear clothing and things of that nature. It also puts them at higher risk for getting cellulitis and infections that might require hospitalization. The techniques that have been used in the past are to do lymphovenous bypass in the extremity after the patient has developed lymphedema, and that has been shown to reduce the amount of lymphedema in the extremity. Lymphedema is not something that's completely reversible, and those techniques are not always feasible, especially when the lymphedema has gotten to very advanced stages. We feel using this auxiliary reverse mapping and doing the lymphatic bypass at the time of the initial nodal surgery can prevent lymphedema from occurring in the first place.

The other thing to consider is that there are very advanced techniques for the lymphatic reconstruction, such as doing a microvascular anastomosis with the lymphatics and branches of the auxiliary vein. That requires a microscope, it requires advanced training and technical consideration. Some of the studies are showing that just approximating the vessels together without performing that microvascular anastomosis may be similar in terms of efficacy, but we have several trials that have been completed, and we're going to be able to look at those different techniques with further follow up of the patients to see if all those techniques for the reconstruction are similar. But the first part, using the axillary reverse mapping in the first place, is the most important key because if you don't identify those lymphatics and lymph nodes, then you don't have an opportunity to preserve them because when you're dissecting in the axilla, you can't see those lymphatics without using some type of dye or material to illuminate them for the surgeon.