When patients first meet a breast surgeon, most of their questions are about the breast: will I need a mastectomy, will there be a scar, will I need chemotherapy? What they often do not ask, until later, is about the armpit. Yet decisions about the underarm lymph nodes shape recovery, arm comfort and long-term quality of life almost as much as the breast surgery itself.
This is one of the quieter success stories of modern breast cancer surgery. A generation ago, removing most of the lymph nodes under the arm was standard for almost everyone. Today, many women need far less. This blog explains why, how, and what to do to protect your arm afterwards.
Why Do We Examine the Lymph Nodes at All?
Lymph nodes are small, bean-shaped filters that are part of the body's drainage system. The breast drains mainly towards the axillary (underarm) lymph nodes. If breast cancer cells spread beyond the breast, these nodes are usually the first place they travel to.
Knowing whether the nodes contain cancer helps us to:
- Stage the cancer accurately
- Decide whether chemotherapy, hormone therapy, targeted therapy or radiotherapy is needed, and in what form
- Plan the extent of surgery
The nodes are not removed as punishment for the cancer. They are examined because they tell us how the cancer is behaving.
The Old Approach: Axillary Lymph Node Dissection
For decades, the standard method was axillary lymph node dissection (ALND), in which a large number of lymph nodes, often 10 to 20, were removed from the armpit. It was effective at finding spread, but it came with a significant price: numbness, shoulder stiffness, pain, a pulling sensation, and above all lymphedema, a chronic swelling of the arm.
The Breakthrough: Sentinel Lymph Node Biopsy (SLNB)
The idea behind SLNB is simple and elegant. Lymph drains from the breast in an orderly way, so there is usually one or a few "first-stop" nodes. These are called sentinel nodes, like guards posted at the gate. If those first nodes are free of cancer, the remaining nodes are very likely to be clear as well, and they can be left alone.
How Is a Sentinel Node Biopsy Done?
The surgeon first locates the sentinel node(s) using one or more tracers:
- A radioactive tracer (a very small, safe dose) injected near the nipple or tumour, detected with a handheld probe
- A blue dye that stains the draining nodes
- Indocyanine green (ICG), a fluorescent dye used in some centres, detected with a special camera
The surgeon then makes a small incision, usually 2 to 4 cm, in the armpit and removes the stained or radioactive nodes. Usually only one to three nodes are removed. These are examined by a pathologist, and in some centres a rapid analysis during surgery gives an early answer. Final results are confirmed in a few days.
Two things patients commonly notice: blue dye may colour the urine green-blue for a day or two, and it can leave a temporary bluish tint on the breast skin. Both fade.
What If the Sentinel Node Contains Cancer?
This is where the science has moved forward most dramatically. In the past, one positive node meant a full armpit dissection almost automatically. Today:
- For many women having breast-conserving surgery followed by radiotherapy, who have one or two involved sentinel nodes and meet specific criteria, studies have shown that further armpit surgery can safely be avoided, without worsening survival.
- In other situations, for example when more nodes are involved, when a mastectomy is planned without radiotherapy, or when the pre-operative scans show clearly enlarged nodes, a fuller axillary operation or radiotherapy to the armpit may still be advised.
Each recommendation depends on the tumour biology, the surgery planned, the treatment to follow and the findings of the nodes. A good surgeon explains the reasoning, rather than just the decision.
What If Chemotherapy Comes Before Surgery?
Many patients now receive neoadjuvant (pre-operative) chemotherapy to shrink the tumour. In patients whose nodes were involved at diagnosis, the nodes often respond to chemotherapy as well. In such cases, surgeons may use targeted axillary dissection, in which the node known to have contained cancer is marked and removed along with the sentinel nodes, to check for response and avoid unnecessary full dissection when the nodes have cleared.
Understanding Lymphedema
Lymphedema is swelling that occurs when the lymphatic drainage of the arm is disturbed and fluid accumulates. It can involve the arm, hand, breast, or chest wall on the operated side.
How likely it is depends on the extent of treatment:
- After SLNB alone, the risk is low, commonly quoted at around 5 to 8 percent in studies.
- After full axillary dissection, the risk is considerably higher, often quoted in the region of 20 to 30 percent, and higher still when radiotherapy to the armpit is added.
- Other factors that raise the risk include obesity, infection of the arm, and radiotherapy to the lymph node areas.
Lymphedema can appear weeks, months or even years after treatment. This is why awareness and early action matter.
Early Signs of Lymphedema
- A feeling of heaviness or tightness in the arm or hand
- Rings, watch or sleeves suddenly feeling tighter
- Visible swelling, even if mild or intermittent
- Reduced flexibility in the hand, wrist or shoulder
- Skin that looks tight, shiny or thickened
If you notice any of these, tell your doctor or physiotherapist early. Early lymphedema is far easier to manage than established lymphedema.
Protecting Your Arm After Surgery
- Start movement early. After surgery, gentle arm and shoulder exercises, as guided by your surgeon or physiotherapist, prevent stiffness and frozen shoulder. Avoid heavy lifting at first, but do not keep the arm still.
- Look after the skin. Treat cuts, burns, insect bites and nail injuries on the operated side promptly, keep skin moisturised, and see a doctor early if redness, warmth, pain or fever develop, because infection (cellulitis) can trigger lymphedema.
- Be sensible, not fearful. The evidence for strict "never have a blood pressure reading or injection on that arm" rules is limited, particularly after SLNB. Many surgeons advise reasonable caution, particularly after a full dissection, rather than complete avoidance of everyday life. Ask your surgeon what applies to you.
- Maintain a healthy weight. Weight gain after treatment is linked to a higher risk of lymphedema.
- Exercise gradually. Supervised, progressive strength training is safe in women who have had breast cancer surgery and does not increase lymphedema risk when built up slowly.
- Seek a lymphedema-trained physiotherapist if swelling develops. Treatment may include manual lymphatic drainage, compression sleeves and bandaging, exercises and skin care. Compression sleeves should be professionally fitted, not self-chosen.
Today's goal in breast cancer surgery is to do everything that is needed and nothing that is not. Sentinel lymph node biopsy is the clearest example of this principle. If you are facing a breast cancer diagnosis and have questions about your armpit surgery, ask them early. The answers will help you plan not just your treatment but your recovery.
Dr. Rohan Khandelwal performs sentinel lymph node biopsy and offers complete breast cancer care at CK Birla Hospital for Women, Block J, Mayfield Garden, Sector 51, Gurugram. Call 0124 488 2200 or +91 79882 52759 to book a consultation.
This article is for general information and does not replace a personal medical consultation.
Frequently Asked Questions
There is usually mild soreness, pulling or numbness in the armpit for a few weeks. It is generally much more comfortable than full axillary surgery.
The dose is very small and is considered safe. It is far lower than that used in many routine diagnostic scans.
No technique is perfect, but SLNB is a well-established, reliable method with a low false-negative rate when performed by an experienced team.
No. Most women do not, especially after sentinel node biopsy alone.
In most invasive cancers, yes, because the node results guide further treatment. In some very low-risk situations, it may be omitted. This is a decision for your surgeon.
