What is lymphedema?

The lymphatic system transports lymph (limf), a protein-rich clear fluid containing white blood cells, throughout the body. A key part of the body’s immune system, lymph fluid moves through lymph vessels and hundreds of lymph nodes.

Lymphedema — swelling or edema — happens when the lymphatic system isn’t working properly. It is sometimes a side effect of breast cancer treatment and is considered secondary lymphedema.

Before being diagnosed with breast cancer, I took my lymphatic system for granted. If you’d asked me anything about lymph nodes, I might have nodded, thinking of when my throat is swollen to touch.

Heck, I didn’t realize that tonsils are part of the lymphatic system! So is the appendix. My body is no longer home to either. Tonsils departed when I was about five; the appendix, in 2011 as part of another surgery.

The lymph system collects fluid, waste material, and harmful things like viruses and bacteria that exist in body tissues outside of the bloodstream. This is how it fights infection and keeps body fluids in balance. One way we know that we have an infection is by measuring our white blood cell count.

Lymph nodes and breast cancer

The lymph nodes are small bean-shaped glands that act as filters. Clusters of lymph nodes reside in the neck, axilla (underarm), chest, abdomen and groin. The lymph flows through them in only one direction, towards the chest and neck. At this end point, the filtered fluid, salts, and proteins enter the bloodstream.

lymphatic system
Illustration courtesy cancer.gov


In order for breast cancer cells to migrate out of the breast, they must pass through the axillary lymph nodes in the underarm pit. These nodes drain the lymphatic network of the upper arms,  breast, neck, and underarm area.

breast anatomy
Lymph node system in the upper body. Courtesy Memorial Sloan Kettering Cancer Center

Often lymph nodes are surgically removed (dissection) in order to determine if cancer has spread outside the breast. Removing these nodes disrupts the flow of lymph, which can lead to swelling.

Lymph nodes may be treated with radiation to kill any remaining cancer cells. Radiation treatments to the underarm lymph nodes can result in scarring and blockages.

Thus treatments for breast cancer can create an increased risk of lymphedema for the rest of our lives.

Types, incidence and risks

There are several types of lymphedema:

The National Cancer Institute  estimates that lymphedema after breast cancer treatment ranges from 6-30%, but experts agree the incidence is probably higher. Having a sentinel node biopsy elevates risk:  5-17% develop lymphedema. But having axillary lymph node dissection (removal) seriously increases the risk: from 20-53%. The more lymph nodes removed, the more risk.

A 2009 study of Philadelphia-area breast cancer patients revealed a five-year cumulative incidence of lymphedema of 42% in a cohort of 631 women.

Three studies published in 2017 identified these risk factors for breast cancer-related lymphedema:  axillary lymph node dissection, chemotherapy, radiation, more advanced disease stage, and higher body mass index (cohort of 3,136; cohort of 1,794; cohort of 964).

Although I cannot follow the logic, breast reconstruction seems to reduce the risk of lymphedema in mastectomy patients.

The National Cancer Institute  estimates that lymphedema after breast cancer treatment ranges from 6-30%, but experts agree the incidence is probably higher.

Preventing infection and injury

It’s important to protect the arm on the side of the surgery.

  • Ask that injections and blood draws to be done on the unaffected arm only.
  • Ask that all blood pressure tests to be done only on the unaffected arm.
  • Not wear clothing with elastic cuffs or tight bands.
  • Carry handbag, groceries and heavy packages with the unaffected arm.
  • Be very careful when shaving underarms.
  • Prevent sunburns and other burns to the affected arm.
  • Wear gloves when gardening and when using strong household cleaners.
  • Do approved exercises regularly to improve drainage.
  • Eat a healthy, low-sodium diet.
  • Avoid extreme hot or cold temperatures on the affected arm, such as heating pads or ice packs on your at-risk arm or shoulder.
  • Avoid vigorous, repetitive movements against resistance, such as scrubbing, pulling, or pushing with the affected arm.
  • Tell your doctor right away if you have any signs of infection, such as redness, pain, heat, increased swelling, or fever.

Learn more at the National Lymphedema Network. The Lymphedema Treatment Act seeks to improve Medicare insurance coverage of doctor-prescribed compression supplies worn daily to treat lymphedema.


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