Uses Sentinel lymph node

1 uses

1.1 clinical advantages
1.2 research advantages
1.3 disadvantages

uses

the concept of sentinel lymph node important because of advent of sentinel lymph node biopsy technique, known sentinel node procedure. technique used in staging of types of cancer see if have spread lymph nodes, since lymph node metastasis 1 of important prognostic signs. can guide surgeon appropriate therapy.

a blue stained sentinel lymph node in axilla.



a micrograph showing adenocarcinoma of breast (dark pink) in lymph node (purple) , extending surrounding fat (white, chicken-wire appearance). h&e stain.

there various procedures entailing sentinel node detection:

preoperative planar lymphoscintigraphy
preoperative planar lymphoscintigraphy in conjunction spect/ct [single photonemission ct (spect) low-dose ct]
intraoperative visual blue dye detection
intraoperative fluorescence detection (fluorescence image-guided surgery)
intraoperative gamma probe/geiger meter-detection
postoperative scintigraphy of main specimen planar acquisition

in everyday clinical activity, entailing sentinel node detection , sentinel lymph node biopsy, not requested include different techniques listed above. in skilled hands , in center sound routines, one, 2 or 3 of listed methods can considered sufficient.

to perform sentinel lymph node biopsy, physician performs lymphoscintigraphy, wherein low-activity radioactive substance injected near tumor. injected substance, filtered sulfur colloid, tagged radionuclide technetium-99m. injection protocols differ doctor common 500 μci dose divided among 5 tuberculin syringes 1/2 inch, 24 gauge needles. in uk 20 megabecquerels of nanocolloid recommended. sulphur colloid acidic , causes minor stinging. gentle massage of injection sites spreads sulphur colloid, relieving pain , speeding lymph uptake. scintigraphic imaging started within 5 minutes of injection , node appears 5 min 1 hour. done several hours before actual biopsy. 15 minutes before biopsy physician injects blue dye in same manner. then, during biopsy, physician visually inspects lymph nodes staining , uses gamma probe or geiger counter assess lymph nodes have taken radionuclide. 1 or several nodes may take dye , radioactive tracer, , these nodes designated sentinel lymph nodes. surgeon removes these lymph nodes , sends them pathologist rapid examination under microscope presence of cancer.

a frozen section procedure commonly employed (which takes less 20 minutes), if neoplasia detected in lymph node further lymph node dissection may performed. malignant melanoma, many pathologists eschew frozen sections more accurate permanent specimen preparation due increased instances of false-negative melanocytic staining.

clinical advantages

there various advantages sentinel node procedure. first , foremost, decreases lymph node dissections unnecessary, thereby reducing risk of lymphedema, common complication of procedure. increased attention on node(s) identified contain metastasis more detect micro-metastasis , result in staging , treatment changes. main uses in breast cancer , malignant melanoma surgery, although has been used in other tumor types (colon cancer) degree of success. if undertaken prior breast reconstruction, sentinel lymph node biopsy before helps predict breast radiotherapy , avoids complications on breast reconstruction. other cancers have been investigated technique penile cancer, urinary bladder cancer, prostate cancer, testicular cancer , renal cell cancer.

research advantages

as bridge translational medicine, various aspects of cancer dissemination can studied using sentinel node detection , ensuing sentinel node biopsy. tumor biology pertaining metastatic capacity, mechanisms of dissemination, emt-met-process (epithelial–mesenchymal transition) , cancer immunology subjects can more distinctly investigated.

disadvantages

however, technique not without drawbacks, particularly when used melanoma patients. technique has therapeutic value in patients positive nodes. failure detect cancer cells in sentinel node can lead false negative result—there may still cancerous cells in lymph node basin. in addition, there no compelling evidence patients have full lymph node dissection result of positive sentinel lymph node result have improved survival compared not have full dissection until later in disease, when lymph nodes can felt physician. such patients may having unnecessary full dissection, attendant risk of lymphedema.