Anyone who has been treated for breast cancer is at risk for developing breast cancer-related lymphedema or BCRL , a side effect that causes uncomfortable swelling in arms, breast and chest. However, women who’ve had surgery and radiation therapy are at the greatest risk.

Our bodies contain a network of lymph nodes and vessels that collect watery, clear lymph fluid similar to the way veins collect and transport blood to all parts of the body. Lymph fluids are necessary to fight off infection and help the body muscles to move fluid throughout the body.

Typically during breast cancer surgery, the doctor removes at least one lymph node from the underarm to determine if the cancer has spread. Sometimes it is necessary for doctors remove more than one. When the lymph nodes are removed, the lymph vessels are also removed. Lymph vessels are responsible for carrying fluid from the arm to the rest of the body and because they are intertwined with lymph nodes it is impossible to remove one without the other.

Extraction of the nodes and vessels changes the way the lymph fluid normally moves within the upper body. The fluid can be restricted to the point where excess fluids build up in the fatty tissues just under the skin and cause swelling, known as BCRL. Radiation treatment can affect the flow of lymph fluids in the arm and breast area in the same way, further increasing the risk.

Not everyone undergoing breast cancer treatment will experience lymphedema, but many women do. It usually develops slowly over time after treatment and can take months, even years to be noticeable. However, some breast cancer patients experience it immediately after surgery or radiation treatment. Currently, there is no cure for lymphedema, but it can be controlled.

Doctors still do not fully understand why some patients are more prone to BCRL than others. As breast cancer surgery and treatments improve and become less invasive, doctors are optimistic that fewer women will develop lymphedema. Newer studies are investigating techniques that can preserve the most active lymph nodes and vessels whenever possible.

Breast cancer patients should follow their doctor’s advice to prevent short-term swelling after surgery or radiation. While current scientific studies show breast cancer patients can’t prevent lymphedema, experts generally agree that by following basic guidelines, patients can reduce the risk or slow the onset of BCRL: