Lymphedema risk: sentinel node biopsy vs axillary dissection

Lymphedema is long-lasting swelling that happens when lymph fluid cannot drain properly from the arm, hand, breast or chest wall. After breast cancer, the main cause is surgery or radiotherapy to the armpit lymph nodes, which are the drainage route for fluid from the arm. The more nodes and lymph channels that are removed or treated, the higher the risk. A sentinel node biopsy removes only the first few nodes, so its risk is low. Studies often report lymphedema in roughly one in twenty people or fewer after sentinel node biopsy alone. An axillary lymph node dissection, also called axillary clearance, removes many more nodes, and studies commonly report lymphedema in around one in five people, sometimes more. Radiotherapy to the armpit or nearby nodes adds to the risk, and combining a clearance with nodal radiotherapy carries the highest risk. Other factors also matter, including a higher body weight, infection in the arm, wound problems after surgery and having had many nodes involved. Lymphedema can appear within weeks, but it can also start months or even years later. The good news is that sentinel node biopsy has spared many people a clearance, early swelling can often be managed well, and staying at a healthy weight, keeping active and caring for the skin of the arm can help lower your risk.

Fewer nodes, lower risk

Sentinel node biopsy carries a much lower risk than a full clearance.

Radiotherapy adds to it

Treating the armpit nodes with radiotherapy raises the risk further.

It can start late

Swelling may appear months or years after treatment.

Risk figures help with decisions, but they cannot tell you exactly what will happen to you.

Figures vary between studies

Research uses different ways to measure swelling and follows people for different lengths of time, so reported rates differ.

Low risk is not no risk

Lymphedema can still happen after sentinel node biopsy, so it is worth knowing the early signs.

Cancer control comes first

Sometimes a clearance or nodal radiotherapy is needed to treat the cancer properly, even though it adds risk.

What this page cannot tell you

It cannot give your personal risk. Your surgeon and oncologist can estimate that from your treatment plan and health.

Lymphedema usually starts gently. Noticing it early gives you the best chance of keeping it under control.

Heaviness or tightness

A full, heavy or tight feeling in the arm, hand or chest can come before visible swelling.

Rings, bangles or sleeves feel tighter

Jewellery or blouse sleeves that suddenly feel snug on one side can be an early clue.

Visible changes

Look for puffiness, less visible veins or knuckles, or a pitting mark after pressing the skin.