Indications
Breast cancer – patients having either breast-conserving surgery or a mastectomy are candidates for sentinel lymph node dissection (SLND) if there
is no palpable lymph node disease or clinical evidence of axillary lymph node disease. The presence of breast cancer in axillary lymph nodes changes the staging of the disease, contributes to the prognosis of recurrence and survival, and impacts the decision regarding chemotherapy, radiation, and hormonal therapy.
The correlation of standard axillary lymph node dissection and sentinel lymph node dissection is around 95% in the hands of an experienced surgeon. It must be noted however that sentinel lymph nodes are found in only 90% – 95% of dissections – that is some patients do not have a dominant node in the lymphatic drainage basin of the axilla. In addition, there is a false negative rate of 5% – 10% in sentinel lymph node dissection. This means that a correctly identified sentinel lymph node does not contain cancer but there is cancer present in higher level nodes.
Contraindications
Breast reduction – alters normal lymphatic flow.
Palpable axillary lymph adenopathy.
Multiple primary breast cancers.
Prior axillary surgery.
Locally advanced primary breast cancers – > 5 cm.
Surgical Details of Procedure.
1. Approximately 90 minutes before the start of the procedure injects a radionuclide solution into the breast.
2. This is most commonly done by using four separate syringes containing a sulfur colloid solution using a technetium-99 tag.
3. Each syringe is loaded with 1 mL of solution (each syringe contains approximately 100 muC of radioactivity).
4. The breast is prepped and draped with sterile drapes.
5. The four injection sites above, below, and on each end of the biopsy site are injected intradermally with a local anesthetic.
6. The injections at the end of the biopsy incision are typically oriented toward the center of the scar with a deviation of 45 degrees.
7. The injections above and below the biopsy scar are directed at 90 degrees from each other and away from the incision.
8. Care must be taken to not inject into the biopsy cavity.
9. The patient is then transported to the operating room where anesthesia is induced and the breast and axilla are prepped and draped in the normal sterile fashion.
10. Approximately 5 mL of 1% isosulfan blue is injected in the same manner as the previously injected radionuclide.
11. The area of injection of the blue dye is massaged for several minutes.
12. Often the drainage of dye toward the axilla is seen as a faint blue blush in the dermis.
13. A hand-held gamma detector with a sterile cover is then used to scan the axilla to locate the area with the highest radiation count.
14. Locating one spot that has a clearly increased radiation count can be difficult if the area injected was in the upper/outer quadrant of the breast.
15. When the area with the highest count is localized a 4-5 cm transverse incision is made with dissection through the subcutaneous fat performed with the knife or Bovie cautery.
16. The proble is then placed in a sterile bag and then placed into the open incision and used to further direct the dissection.
17. A blue blush or blue lymph node should be used to guide dissection and lymph node removal.
18. All lymph nodes that are “hot” should be removed – this defined as a node that has a radiation count greater than ten percent of the sentinel node or that has a count 2-3 times higher than the background of the axillary tissue.
19. After the above nodes are removed, a manual palpation of the area of dissection should be performed to find any nodes that appear to be hard or firm.
20. The nodal tissue is now examined on the back table and the nodes are dissected free of their surrounding tissue.
21. The blue stained node is labelled as the principal sentinel node and any other nodes that have the above described count are labelled as secondary sentinel nodes.
22. The wound is then irrigated with meticulous hemostasis obtained.
23. The Scarpa’s fascia is closed using a fine Vicryl stitch and the skin is closed using a running subcuticular stitch such as 4-0 Monocryl.
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