Sentinel lymph node
The sentinel lymph node is the hypothetical first
The sentinel node procedure (also termed sentinel lymph node biopsy or SLNB) is the identification, removal and analysis of the sentinel lymph nodes of a particular tumour.[1]
Physiology
The spread of some forms of cancer usually follows an orderly progression, spreading first to regional lymph nodes, then the next echelon of lymph nodes, and so on, since the flow of lymph is directional, meaning that some cancers spread in a predictable fashion from where the cancer started. In these cases, if the cancer spreads it will spread first to lymph nodes (lymph glands) close to the tumor before it spreads to other parts of the body. The concept of sentinel lymph node surgery is to determine if the cancer has spread to the very first draining lymph node (called the "sentinel lymph node") or not. If the sentinel lymph node does not contain cancer, then there is a high likelihood that the cancer has not spread to any other area of the body.[2]
Uses
The concept of the sentinel lymph node is important because of the advent of the sentinel lymph node biopsy technique, also known as a sentinel node procedure. This technique is used in the staging of certain types of cancer to see if they have spread to any lymph nodes, since lymph node metastasis is one of the most important prognostic signs. It can also guide the surgeon to the appropriate therapy.[3]
There are various procedures entailing the sentinel node detection:
- Preoperative planar lymphoscintigraphy
- Preoperative planar lymphoscintigraphy in conjunction with
- Intraoperative visual blue dye detection
- Intraoperative fluorescence detection (fluorescence image-guided surgery)
- Intraoperative gamma probe/Geiger meter-detection
- Preoperative or intraoperative super paramagnetic iron oxide nanoparticles injection, detection by using Sentimag instrument[6][7]
- Postoperative scintigraphy of main specimen with planar acquisition
In everyday clinical activity, entailing sentinel node detection and sentinel lymph node biopsy, it is not required to include all different techniques listed above. In skilled hands and in a center with sound routines, one, two or three of the listed methods can be considered sufficient.
To perform a sentinel lymph node biopsy, the physician performs a lymphoscintigraphy, wherein a low-activity
A frozen section procedure is commonly employed (which takes less than 20 minutes), so if neoplasia is detected in the lymph node a further lymph node dissection may be performed. With malignant melanoma, many pathologists eschew frozen sections for more accurate "permanent" specimen preparation due to the increased instances of false-negative with melanocytic staining.
Clinical advantages
There are various advantages to the sentinel node procedure. First and foremost, it decreases lymph node dissections where unnecessary, thereby reducing the risk of
Research advantages
As a bridge to translational medicine, various aspects of cancer dissemination can be studied using sentinel node detection and ensuing sentinel node biopsy. Tumor biology pertaining to metastatic capacity,[19] mechanisms of dissemination, the EMT-MET-process (epithelial–mesenchymal transition) and cancer immunology[20] are some subjects which can be more distinctly investigated.
Disadvantages
However, the technique is not without drawbacks, particularly when used for melanoma patients. This technique only has therapeutic value in patients with positive nodes.[21] Failure to detect cancer cells in the sentinel node can lead to a false negative result—there may still be cancerous cells in the lymph node basin. In addition, there is no compelling evidence that patients who have a full lymph node dissection as a result of a positive sentinel lymph node result have improved survival compared to those who do not have a full dissection until later in their disease, when the lymph nodes can be felt by a physician. Such patients may be having an unnecessary full dissection, with the attendant risk of lymphedema.[22]
History
The concept of a sentinel node was first described by Gould et al. 1960 in a
patient with cancer of the parotid gland[23] and was implemented clinically on a broad scale by Cabanas in penile cancer.[24]
The technique of sentinel node radiolocalization was co-founded by James C. Alex, MD, FACS and David N. Krag MD (University of Vermont Medical Center) and they were the first ones to pioneer this method for the use of cutaneous melanoma, breast cancer, head and neck cancer and Merkel cell carcinoma. Confirmative trials followed soon after.
See also
- ALMANAC, Axillary Lymphatic Mapping Against Nodal Axillary Clearance trial
References
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- ISBN 978-1-4377-2015-0.
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- PMID 18502024.
- PMID 27117158.
- ^ "Sentimag". Endomag. Retrieved 2019-03-09.
- ^ BNMS (August 2011). "Lymphoscintigraphy Clinical Guidelines" (PDF). Retrieved 3 January 2017.
- PMID 11314938.
- PMID 11490224.
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- S2CID 61891.
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- PMID 16321468.
- ^ Wagman LD. "Principles of Surgical Oncology" in Pazdur R, Wagman LD, Camphausen KA, Hoskins WJ (Eds) Cancer Management: A Multidisciplinary Approach Archived 2013-10-04 at the Wayback Machine. 11 ed. 2008.
- S2CID 7068382.
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- PMID 837331.
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- ^ Veronesi, Umberto et al. (2006) Sentinel-lymph-node biopsy as a staging procedure in breast cancer: update of a randomised controlled study. Lancet Oncol 7:983‒990 doi:10.1016/S1470-2045(06)70947-0
- ^ Veronesi, Umberto et al. (2003) A Randomized Comparison of Sentinel-Node Biopsy with Routine Axillary Dissection in Breast Cancer. N Engl J Med 349:546-553 DOI:10.1056/NEJMoa012782
Further reading
- Alex JC, Krag DN (1993). "Gamma-probe guided localization of lymph nodes". Surgical Oncology. 2 (3): 137–43. PMID 8252203.
- Alex JC, Weaver DL, Fairbank JT, Rankin BS, Krag DN (October 1993). "Gamma-probe-guided lymph node localization in malignant melanoma". Surgical Oncology. 2 (5): 303–8. PMID 8305972.
- Krag DN, Weaver DL, Alex JC, Fairbank JT (December 1993). "Surgical resection and radiolocalization of the sentinel lymph node in breast cancer using a gamma probe". Surgical Oncology. 2 (6): 335–9, discussion 340. PMID 8130940.
- Krag DN, Meijer SJ, Weaver DL, Loggie BW, Harlow SP, Tanabe KK, Laughlin EH, Alex JC (June 1995). "Minimal-access surgery for staging of malignant melanoma". Archives of Surgery. 130 (6): 654–8, discussion 659–60. PMID 7539252.
- Alex JC, Krag DN (January 1996). "The gamma-probe-guided resection of radiolabeled primary lymph nodes". Surgical Oncology Clinics of North America. 5 (1): 33–41. PMID 8789492.
- Alex JC, Krag DN, Harlow SP, Meijer S, Loggie BW, Kuhn J, Gadd M, Weaver DL (February 1998). "Localization of regional lymph nodes in melanomas of the head and neck". Archives of Otolaryngology–Head & Neck Surgery. 124 (2): 135–40. PMID 9485103.
- Alex JC (January 2004). "The application of sentinel node radiolocalization to solid tumors of the head and neck: a 10-year experience". The Laryngoscope. 114 (1): 2–19. S2CID 32533879.
External links
- "Sentinel node biopsy using radiocolloid blue dye". You Tube.
- "Sentinel node biopsy". Cancer Management Handbook. August 11, 2011.
- "Sentinel Lymph Node". Know Your Body.
- "International Sentinel Node Society (ISNS)".