The information on this website is not intended for diagnosis or treatment. Please consult your physician for health concerns.

Skip to main content

Sentinel lymph node biopsy

Sentinel lymph node biopsy — targeted staging surgery that investigates lymph node spread of disease in breast cancer and melanoma.

A staging procedure in which the first lymph node receiving lymphatic drainage from the tumor (the sentinel node) is surgically removed and examined to determine whether the cancer has spread to the lymph nodes, helping avoid unnecessary extensive lymph node dissection.

Indication

  • Early-stage breast cancer with clinically non-suspicious axillary lymph nodes
  • Thick cutaneous melanoma (Breslow > 0.8 mm) and selected thin melanomas
  • Vulvar, penile and head-and-neck melanoma with clinically negative lymph nodes
  • Selected cases of certain early-stage head-and-neck and cutaneous squamous cell carcinomas
  • Situations in which post-surgical staging will determine the treatment plan (chemotherapy, radiotherapy)

Preparation

  • Review of preoperative imaging findings such as mammography, ultrasound or PET-CT
  • Injection of radioactive tracer (Tc-99m) or indocyanine green (ICG) on the day of or before the procedure
  • Inquiry into allergy history if blue dye injection will be used in some protocols
  • Fasting for 6-8 hours before anesthesia, physician approval for medications and blood thinners
  • Signed informed consent and an anesthesia consultation when needed

How it's performed

  1. Performed under general anesthesia (most often) or local anesthesia + sedation
  2. A marker (radiocolloid and/or blue dye) is injected at or around the tumor site
  3. The sentinel lymph node(s) are localized using a gamma probe or an ICG fluorescence camera
  4. The sentinel node(s) are removed through a small 2-4 cm skin incision
  5. The removed lymph node(s) are sent to pathology; frozen section may be performed when needed
  6. If the sentinel is positive, axillary dissection is considered in the same session or at a later session

Post-procedure

  • Several hours of observation after the procedure; most patients are discharged the same day or the following day
  • Transient sensory changes or mild swelling in the axilla resolve within 1-2 weeks
  • If blue dye was used, urine, sweat and skin may appear greenish-blue for 24-48 hours
  • Pathology results are usually evaluated within 5-10 days, and treatment is planned at the multidisciplinary tumor board
  • Wound care, suture care and further staging imaging are arranged

Risks

  • Mild lymphedema in the arm or surgical area (markedly lower than after full axillary dissection)
  • Seroma, infection or hematoma at the surgical site
  • Transient nerve sensitivity or sensory changes at the marker site
  • Rare allergic reaction to blue dye
  • Failure to identify the sentinel node or false-negative result (rare)

FAQ

What is a sentinel lymph node?

It is the first lymph node receiving lymphatic drainage from the tumor area, where cancer cells are most likely to spread. If this node is clear, the remaining nodes are usually considered clear as well, and extensive lymph node dissection is avoided.

Does the procedure require removing all lymph nodes in my axilla?

No. The aim of sentinel biopsy is precisely to prevent that. Only 1-3 sentinel nodes are removed. Whether additional surgery is needed is decided based on the pathology result and the multidisciplinary board's decision.

Is the radioactive tracer harmful?

It is used in a very low dose and its effect dissipates quickly. There is no known general health hazard; however, the team should be informed for special precautions in pregnancy or while caring for a child.

When can I return to my normal activities after the procedure?

Most patients return to daily activities within 1-2 weeks. Heavy lifting and prolonged overhead activities should be avoided for 2-3 weeks. A detailed plan is created together with the surgical team.