Sentinel Lymph Node in Breast Cancer: What It Is and Why It Matters
The sentinel lymph node is the first lymph node in the lymphatic drainage path from the breast, and therefore the most likely site for early cancer cell metastasis in breast cancer. It is usually found in the axilla, although in some cases it may also concern other areas.
Sentinel lymph node evaluation is crucial for the disease staging, avoiding unnecessary interventions and planning appropriate complementary therapy.
What Is Sentinel Lymph Node Biopsy?
The sentinel lymph node biopsy is a targeted, minimally invasive surgical technique aimed at determining whether there is metastasis to the lymph nodes. If the sentinel lymph node is negative, then the wider one is avoided lymph node cleaning of the armpit. If it is positive, then further surgical intervention may be required or radiotherapy.
How Is the Biopsy Performed?
Before surgery, around the nipple or tumor site is injected:
- a radioisotope or paramagnetic substance,
- and a blue dye.
These help the surgeon to identify the sentinel lymph nodes with a special detector. Here's one small incision in the armpit, through which the lymph node (or lymph nodes) is removed, which is sent for rapid biopsy in the pathology laboratory.
In case mastectomy, The lymph node is usually removed through the same incision.
What If the Sentinel Lymph Node Is Positive?
In the past, every positive sentinel lymph node automatically led to axillary lymph node cleaning. Today, however, based on guidelines (ACOSOG Z0011, EORTC AMAROS), this it is not always necessary.
In selected cases, such as:
- small tumors,
- up to two positive sentinel nodes,,
- planned breast radiotherapy μαστού,
it can avoid extensive cleaning the armpit, as radiotherapy covers the area and reduces the risk of local recurrence.
Are There Complications?
Sentinel lymph node biopsy is generally safe. Possible complications include:
- hematoma or bleeding,
- infection or inflammation,
- allergic reaction o the blue dye,
- and in rare cases, lymphedema (swelling in the hand).
However, complication rates are significantly lower compared to full axillary lymph node dissection.
In summary
The sentinel lymph node biopsy is now an established and safe practice in surgical treatment of breast cancer, of enormous importance both for the forecast as well as for the maintaining quality of life of the patient.
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Bibliography:
- NCCN Clinical Practice Guidelines in Oncology: Breast Cancer. Version 4.2025.
- Giuliano AE et al. Axillary dissection vs no axillary dissection in women with invasive breast cancer and sentinel node metastasis. JAMA. 2011;305(6):569–575.
- Donker M et al. Radiotherapy or surgery of the axilla after a positive sentinel node in breast cancer (EORTC AMAROS): a phase 3 non-inferiority randomised trial. Lancet Oncol. 2014;15(12):1303–1310.
- Galimberti V et al. Axillary dissection versus no axillary dissection in patients with sentinel-node micrometastases (IBCSG 23-01): a phase 3 randomised controlled trial. Lancet Oncol. 2013;14(4):297–305.
- Lyman GH et al. Ann Surg Oncol. 2014;21(5):1222–1230.
- Caudle AS et al. Selective surgical localization of axillary lymph nodes containing metastatic carcinoma using a radioactive seed and gamma probe.
Ann Surg Oncol. 2015;22(13):4260–4266. - Galimberti V, Cole BF, Zurrida S, et al. International Breast Cancer Study Group Trials. NEJM. 2023.
- Weber WP et al. St. Gallen International Consensus Guidelines on the Primary Therapy of Early Breast Cancer 2023. Ann Oncol. 2023;34(6):472–486.
