Who's at Risk?

If you've had an underarm lymph node dissection (with mastectomy or lumpectomy), you are at risk for developing some degree of lymphedema. Radiation treatment to underarm lymph nodes, as well as chemotherapy treatment, can add to the risk.

Researchers disagree about how big or small the risk of lymphedema actually is. Risk is usually expressed as a percentage: how many people out of 100 will develop lymphedema following treatment for breast cancer. According to some estimates, the figure is between 5% and 10% (5 or 10 people out of 100), or as high as 25% (25 people out of 100) in certain situations. But it's clear that the more treatment you've had, the higher your risk of developing lymphedema.

The risk is the same after a mastectomy with lymph node dissection as it is after a lumpectomy with lymph node dissection and radiation treatment limited to the breast.

A relatively new technique of lymph node dissection, called sentinel node dissection, aims to identify and remove only the underarm lymph nodes most likely to contain cancer cells that could have spread beyond the breast. This technique may lower the risk of developing lymphedema because fewer lymph nodes are removed, leaving more lymph fluid drainage channels in tact.

Some women may be at a higher risk for developing arm lymphedema than others. Factors that may increase your risk include:

• being very overweight; this can limit the flow of blood and lymph fluid in and around your arm
• being a heavy smoker
• having diabetes
• having any other condition that can affect the circulation of blood and lymph fluid in and around your arm
• previous surgeries in the armpit area or on your arm

What brings on lymphedema?

Lymphedema can happen just weeks after surgery, or years after initial cancer treatment. It can be brought on by trauma or infection, or it can develop without any obvious cause. Factors that can bring on lymphedema include:

• Traumas to the muscles or skin of the arm that can lead to infection. These include scratches, bug bites, sunburn, kitchen burns, garden cuts, plant rashes (poison ivy or oak), skin cracking from chronic dryness, and skin tears from nervous picking habits.
• Gaining a lot of weight after breast cancer treatment. Like being overweight to start with, gaining weight increases your risk for arm swelling.
• Heat. Because it widens blood vessels, heat allows more fluid to get into an area at risk for swelling. Very hot weather and sitting in hot tubs can bring on lymphedema.
• Blood clots. Occasionally, a blood clot in the axillary (underarm) vein will back up fluid in the arm.
• Long plane flights. Although it's rare for a long flight to bring on lymphedema for the first time, it may worsen an existing case of lymphedema because of the changes in air pressure.
• Extensive breast cancer in the lymph nodes. This uncommon cause of lymphedema can occur if the cancer blocks the free flow of lymph fluid trying to drain through the nodes.

If you are free of lymphedema, it means that your body has learned how to re-route any excess buildup of lymphatic fluid. Unfortunately, once you've developed the condition, the more lymphedema you have and the longer you have it, the harder it is to reduce the swelling in your arm.