Skip to main content


The risk of developing lymphoedema after a sentinel lymph node biopsy (SLNB) is lower than after an axillary lymph node dissection (ALND). 

What is a sentinel lymph node biopsy?

A sentinel lymph node (SLN) is defined as the first lymph node to which cancer cells are most likely to spread from a primary tumour. Sometimes, there can be more than one sentinel lymph node.

A sentinel lymph node biopsy is surgery used to diagnose the severity of cancer. When the SLN is tumour-free, greater lymph node removal can be omitted leading to a significant reduction in surgery-related morbidity.

To read more about the procedure, you can visit this published article: The Basics of Sentinel Lymph Node Biopsy: Anatomical and Pathophysiological Considerations and Clinical Aspects by Dogan and colleagues.

How many lymph nodes are usually removed in a sentinel lymph node biopsy?

In a study of  777 patients who had at least 1 SLN that was positive for cancer, researchers found that, “In general, the removal of a maximum of 5 SLNs at surgery allowed for the recovery of >99% of positive SLNs in patients with breast cancer.” You can read more in this published paper: How Many Sentinel Lymph Nodes Are Enough During Sentinel Lymph Node Dissection for Breast Cancer? by Yi and colleagues. 

Removing more than 5 lymph nodes is generally classes as an axillary lymph node dissection.

What are the risks of lymphoedema following a sentinel lymph node biopsy?

Studies have shown that there is a risk of lymphoedema following SLNB.

The risk is MUCH lower than after an ALND.

“When compared with SLNB vs ALND, SLNB alone results in a significantly lower rate of lymphoedema 5 years postoperatively. However, even after SLNB alone, there remains a clinically relevant risk of lymphoedema. Higher body weight, infection, and injury are significant risk factors for developing lymphoedema.” Prevalence of Lymphedema in Women With Breast Cancer 5 Years After Sentinel Lymph Node Biopsy or Axillary Dissection: Objective Measurements by McLaughlin and colleagues.

Prevalence of lymphoedema abstract


A 2022 paper confirmed that patients have a higher likelihood of developing lymphoedema when >5 lymph nodes are excised. Lymphedema After Sentinel Lymph Node Biopsy: Who Is at Risk? by Isik and colleagues. 

What are other factors to consider?

A study from researchers at Harvard Medical School looked at who gets lymphoedema and when. This paper highlighted the impact of other cancer treatments, namely lymph node radiation. Those receiving a sentinel lymph node biopsy with regional lymph node radiation (RLNR) had a 12.2% incidence of lymphoedema.

The lymphoedema risk peaked between 6 and 12 months in the ALND-without-RLNR group, between 18 and 24 months in the ALND-with-RLNR group, and between 36 and 48 months in the group receiving sentinel lymph node biopsy with RLNR.

Timing of lymphoedema abstract

What are the clinical implications for lymphoedema therapists?

CANCER TREATMENT + INDIVIDUAL risk factors need to be considered when talking to patients about the risk of lymphoedema. Cancer-treatment related risk factors include factors such as the type of breast cancer surgery (mastectomy vs breast conserving surgery), lymph node removal (such as SLND VS ALND), radiation (chest wall vs regional lymph node radiation) and chemotherapy type (Taxane-based vs other types). Individual risk factors include factors such as higher body weight, infection, and injury as well as post-op seromas and cording.

Patients therefore benefit from individualised consultations where you can discuss your patients medical history. You can then help them create an individualised treatment and lymphoedema monitoring plan.

To learn more you can undertake our CANpractice course.