The sentinel node is the first lymph node that drains fluid from the area of a tumour, and so the first place cancer cells would normally lodge if they began to spread. A sentinel node biopsy finds that node, or the first two or three, with a tracer, removes them through a small incision and has them examined in detail.
If the sentinel nodes are clear, the rest of the nodes in that region are very likely to be clear too, and a full clearance with its risk of lifelong arm or leg swelling can be avoided. It is a staging test, not a treatment, and it misses disease in a small share of cases, around 5 to 10 percent.
What Sentinel Lymph Node Biopsy shows
The pathologist slices each node thinly and uses special stains to look for cancer deposits, reporting them as isolated tumour cells, micrometastases (up to 2 mm) or macrometastases. In breast cancer the result refines the stage and guides decisions on radiotherapy, further armpit treatment and sometimes drug therapy. In melanoma, a positive node upstages the disease to stage III and opens access to adjuvant immunotherapy or targeted therapy; the amount of tumour in the node also predicts outlook. The technique is used as well in vulval, penile, some head and neck, and womb cancers.
When Sentinel Lymph Node Biopsy is recommended
- Early invasive breast cancer with no abnormal armpit nodes on examination and ultrasound
- Extensive DCIS being treated by mastectomy
- Melanoma thicker than 1 mm, or 0.8 to 1 mm with ulceration or other risk features
- Merkel cell carcinoma and selected high-risk squamous skin cancers
- Early vulval, penile and oral cancers, and womb cancer staging in specialist units
- Breast cancer after chemotherapy given first, using dual tracers and removal of any clipped node
Limits and situations where another test is better:
- Nodes already proven to contain cancer by needle biopsy, where other management applies
- Inflammatory breast cancer
- Thin, low-risk melanomas under 0.8 mm without ulceration
- Frail patients whose treatment would not change whatever the result
- Earlier wide surgery in the area that has disrupted lymph drainage can make mapping unreliable
How to prepare
- An injection of radioactive tracer near the tumour or scar, a few hours before or the afternoon before, with a mapping scan (lymphoscintigraphy)
- Fast for 6 hours if the procedure is under general anaesthesia
- Tell the team about pregnancy, breastfeeding or a previous reaction to blue dye
- Blood thinners paused as instructed
What happens during the test
It is usually done in the same operation as the lumpectomy, mastectomy or wide excision of the melanoma. After you are asleep, blue dye, or a fluorescent dye such as indocyanine green, may be injected as a second tracer. The surgeon makes a 3 to 5 cm cut in the armpit, groin or neck and uses a hand-held gamma probe and the colour of the dye to pick out the hot or stained nodes, usually one to three. The biopsy itself adds 20 to 45 minutes. You normally go home the same day or after one night.
Results and next steps
Some breast units analyse the node during surgery by frozen section or a molecular assay and act on it at once. Otherwise the definitive result takes 5 to 10 working days. A clear node means no further node surgery. With one or two positive nodes in breast cancer, many patients now have radiotherapy rather than full clearance; in melanoma, positive nodes are generally followed with ultrasound surveillance plus drug treatment rather than completion dissection.
- Test time: 20 to 45 minutes added to the main operation
- Results ready: 5 to 10 working days; sometimes during surgery
- Back to everyday activity: 1 to 2 weeks, mainly from the main operation
Safety and risks
- Seroma (a fluid collection) or bruising under the wound
- Numbness or tingling on the inner upper arm or thigh
- Lymphoedema, in about 5 percent, against 20 percent or more after full clearance
- Shoulder stiffness or cording in the armpit, usually temporary
- Blue dye effects: green urine for a day, a bluish skin stain for weeks, and rarely a serious allergic reaction
- A false negative result, or wound infection
Arranging Sentinel Lymph Node Biopsy in Türkiye
Sentinel node biopsy is not done as a stand-alone reason to travel; it is part of the cancer operation. If you are having breast cancer or melanoma surgery abroad, check that the unit has nuclear medicine on site and uses dual tracers, and stay until the pathology is back, typically 7 to 10 days, because it may change the plan. Bring the complete report home for your oncology team.
Send your previous reports and the question you want answered and a Clinic-Y coordinator replies within 24 hours with suitable teams and written, all-inclusive proposals side by side. Reviewing your case is free.
Frequently Asked Questions
Is the radioactive tracer dangerous?
The dose is very small, less than many routine scans, and it is gone within a day or two. It is considered acceptable even in pregnancy, whereas blue dye is avoided.
What if the surgeon cannot find a sentinel node?
This happens in a few percent. The surgeon then decides between sampling several nodes and a limited clearance, depending on the cancer.
If the node is positive, will all my nodes be removed?
Less often than in the past. Trials have shown radiotherapy or observation with systemic therapy to be as effective for many patients, with less lymphoedema.
Can I fly after the biopsy?
Yes, once the wound is settled and any drain is out. Flying has not been shown to trigger lymphoedema; a compression sleeve is optional.