Sentinal lymph node biopsy

HOW SENTINAL LYMPH NODE BIOPSY HELPS A MAXILLOFACIAL SURGEON?

1. Sentinal Lymph Node Biopsy Dr Jameel Kifayatullah Khyber College of dentistry Peshawar

2. Sentinal Lymph Node Sentinel lymph node (SLN) is the first lymph node to receive drainage directly from a tumor.

3. Sentinal Lymph node biopsy SLN biopsy is based on an ordered dissemination of tumor cells from peritumoral lymphatics to the SLN, and then to more distant lymph nodes Clinical identifcation of these nodes is performed via injection of numerous types of tracers, dyes, and radioisotopes into the peritumoral site depending on the type and location of the tumor Labeled lymph nodes are surgically excised and histologically examined for the presence of disease. Identification and biopsy of the SLN can correctly indicate the status of the draining lymph node basin.

4. Sentinal node

5. ADVANATAGES OF SNB The advantages of implementing SNB instead of ND include decreased morbidity Decreased operating room time Decreased length of postoperative stay

6. Side effects OF SNB Tenderness around the area of surgery Numbness Limited range of motion Infection Lymphedema

7. T echnique The radiologist injects a harmless radioactive substance around the tumor After 30-60 seconds the area is scanned to show where the substance has travelled within the lymphatic system.

8. Technique The radioactive tracer travels within lymphatic channels and gets trapped in a lymph node. The first node to receive drainage from a tumor is called the sentinel lymph node . Sentinel node will also trap metastatic cancer cells before they spread to other lymph nodes . A special probe i.e gamma probe is used to identify the greatest concentration of radioactive tracer.

9. Gamma probe to identify tracer

10. Gamma probe display

11. technique The display shows the amount of tracer activity detected by the probe High level of tracer activity indicates location of sentinel lymph node. The sentinel node is identified again intraoperatively with the aid of a gamma probe The area with elevated radioactivity is explored to identify the sentinel lymph node

12. Technique Tissue with sentinel lymph node is identified Elevated radioactivity counts confirmed

13. T echnique The lymph node is removed and sent to pathologist if cancer cells are present If cancer is detected then more aggressive treatment such as neck dissection is carried out.

14. What is duel mapping? In dual mapping (use of a dye along with a radioisotope) cutaneous lymphoscintigraphy is used prior to sentinel node biopsy as a way to increase sensitivity and detection rate.

15. Importance of SLNB Sentinel node biopsy ( SNB) is a reliable staging test for patients with early disease and a radiologically N0 neck, can detect occult metastases with a sensitivity of 86%–94%. Patients with no sign of metastases on SNB could avoid neck dissection, and individual treatment should reduce both morbidity and cost.

16. SENTINAL LYMPH NODE BIOPSY INDICATIONS N0 neck

17. SNB Contraindications Absence of an experienced surgeon and team Clinically positive nodes Adverse or allergic reaction to radioactive dye Patient unable to give informed consent for sentinel lymph node biopsy

18. SNB USE IN ORAL CANCER controversial One of the main problem of SLNB of oral cancer is skip metastasis in which the disease bypasses level 1 and 2 nodes and goes directly to level 3-4 Ref - Jatin Shah’s Head & Neck Surgery & Oncology 4th Edition SLNB in OSCC still remains with an investigational role. This procedure is very complicated in head and neck tumors because of the great wealth of lymphatic vessels and a great variability of regional lymphatic migration

19. Future perspectives Refinements in technology including development of novel radiopharmaceutical tracers , routine incorporation of detailed anatomic perioperative imaging, emerging imaging modalities, as well as increasing surgeon experience will likely lead to improvements in use and accuracy of this technique and improved adoption of SLN procedures in the management of OSCC.