Sentinel Lymph Node Biopsy

The sentinel lymph nodes (SLNs) is a group of lymph nodes initially involved in the metastatic spread of cancer cells. SLN mapping refers to intraoperative localisation and biopsy of SLNs with specific tracers to assess lymph node metastases. It is widely used in endometrial and vulval cancer and has replaced the traditional systematic lymphadencetomy due to its minor invasiveness, few complications, and high diagnosis rate. 

Sentinel lymph node biopsy is personalised surgery. The surgery is tailored to the individual patient to target the lymph nodes most likely to harbour cancer. It helps patients get back to their everyday lives more quickly. It’s all about detecting the cancer effective and accurately in a way that helps the patients maintain their quality of life.

Sentinel lymph node for endometrial cancer

What is the goal of surgical treatment in endometrial cancer?

Hysterectomy, or surgical removal of the uterus, is the gold standard for treatment of endometrial cancer. The ovaries and fallopian tubes may be removed at the same time. This procedure is called salpingo-oophorectomy. Additionally, depending upon the histological type and grade of the tumour, imaging and intraoperative findings, removal of pelvic and, sometimes, para-aortic lymph nodes may be required to determine if the cancer has spread beyond the uterus. For, serous or clear cell histological subtypes, biopsy of the omentum (fatty apron) is also warranted to determine the spread of the disease. 

 

What is the sentinel lymph node biopsy?

Sentinel lymph nodes refer to the first group of lymph nodes that drain the primary tumour lymph, which is the first area involved when the tumour metastasis occurs, reflecting the status of lymph involvement in the entire region. Sentinel lymph node mapping helps to identify the lymph nodes that are at highest risk for containing cancer. A sentinel lymph node biopsy  is a surgical approach to identify and remove the sentinel lymph node to determine if the cancer has spread, and if so, how far. In most cases, a negative sentinel lymph node biopsy means the cancer has not spread. A positive biopsy means cancer was found in the lymph node. 

 

What happens during a sentinel lymph node biopsy?

The technique consists of the dye injection into the cervix at the beginning of the procedure.  The most commonly used dye is the indocyanine green (ICG). The ICG flows through the lymphatic system – a path or network of lymph channels and nodes. This allows the surgeon to see what lymph nodes are draining from the tumour first and identify the sentinel lymph nodes using a dedicated near-infrared optical camera. This is mainly guaranteed by robotic surgery using the DaVinciXi system because of its incorporated Firefly camera.

 

What are the benefits of sentinel lymph node biopsy?

This technique can prevent patients from needing a more invasive surgery. It can shorten post-operative recovery times and lower the risk of complications such as lymphoedema (swelling caused by the removal of more lymph nodes). Patients who have a sentinel lymph node biopsy may also experience lymphoedema, but they’re less likely to than those who have a systematic lymph node removal. 

The combination of minimally invasive surgery (robotic or laparoscopic) and performance of sentinel lymph node biopsy is associated with better recovery due to:

  • Much less blood loss
  • Lower chance of infections in the surgical wound or incisional hernia
  • Minimisation of post-operative pain
  • Lower risk of lymphoedema
  • Shorter recovery for the patients. It is typical that 24-hour hospitalisation is very often required
  • Better cosmetic outcome in the areas of incision

 

What happens after removal of sentinel lymph nodes?

After surgery, the nodes are sent to a laboratory and examined under a microscope to see if they hold cancer cells. Sentinel lymph node biopsy is  associated with higher accuracy in detecting cancer cells compared to the traditional systematic lymphadenctomy. Sentinel lymph nodes are cut into tiny pieces and stained, which allows the detection of micro-metastases and isolated tumour cells. If they show cancer cells, the remaining pelvic lymph nodes will not need to be removed with another operation, as there is no therapeutic effect of systematic lymphadenectomy. In case of a positive sentinel lymph node, you will possibly require chemotherapy and radiotherapy.

 

What are the risks of a sentinel lymph node biopsy?

The risks are very low risk, aside from the very low chance -- 2 to 4% -- that a sentinel lymph node would not be able to be identified. ICG cannot be used in patients with iodine allergy (e.g. allergies to sea food). 

Sentinel lymph node for vulval cancer

What is the goal of surgical treatment in vulval cancer?

Radical removal of the tumour with clear margins, is the gold standard for treatment of vulval cancer. Additionally, depending upon some histological parameters, removal of regional groin lymph nodes may be required to determine if the cancer has spread beyond the vulva. 

 

What is the sentinel lymph node biopsy?

Sentinel lymph nodes refer to the first group of lymph nodes that drain the primary tumour lymph, which is the first area involved when the tumour metastasis occurs, reflecting the status of lymph involvement in the entire region. Sentinel lymph node mapping helps to identify the lymph nodes that are at highest risk for containing cancer. A sentinel lymph node biopsy  is a surgical approach to identify and remove the sentinel lymph node to determine if the cancer has spread, and if so, how far. In most cases, a negative sentinel lymph node biopsy means the cancer has not spread. A positive biopsy means cancer was found in the lymph node. 

 

What happens during a sentinel lymph node biopsy?

The technique consists of the injection of a marker called a radiotracer around the site of the tumour. The most commonly used radiotracer is the technetium-99m radiocolloid (99mTc). The radiotracer flows through the lymphatic system – a path or network of lymph channels and nodes. This allows the surgeon to see what lymph nodes are draining from the tumour first and identify a sentinel lymph node using a special probe (gamma-probe). The combination of the two tracers (99mTc and blue dye or  99mTc and ICG) can be used for higher detection rates.  Then, the surgeon makes a small incision (2-3 cm) in the groin skin and identifies the lymph node for removal. 

 

Which patients are eligible for sentinel lymph node biospsy?

Women with vulval cancer are eligible for sentinel lymph node biopsy if they fulfill the following criteria:

  • Histology of squamous cell carcinoma
  • Size of the tumour less than 4 cm
  • Depth of invasion more than 1 mm
  • No suspicious groin lymph nodes

 

What are the benefits of sentinel lymph node biopsy?

This technique can prevent patients from needing a more invasive surgery. It can shorten post-operative recovery times and lower the risk of complications such as lymphoedema (swelling caused by the removal of more lymph nodes), wound infections and wound break down. Patients who have a sentinel lymph node biopsy may also experience lymphoedema, but they’re less likely to than those who have a systematic lymph node removal. 

 

What happens after removal of sentinel lymph nodes?

After surgery, the nodes are sent to a laboratory and examined under a microscope to see if they hold cancer cells. If they show cancer cells, the remaining groin lymph nodes will need to be removed with another operation or treated with radiotherapy. If the sentinel nodes do not contain cancer cells, it is unlikely that other lymph nodes are affected. You do not need to have further surgery or radiotherapy.

 

What are the risks of a sentinel lymph node biopsy?

The risks are very low risk, aside from the very low chance -- 2 to 4% -- that a sentinel lymph node would not be able to be identified. Some patients have concerns about the radiotracer used to find the sentinel lymph node. While it is radioactive, the tracer has a very low-energy emission particle. No severe adverse reactions have been reported, and the only negative reaction reported has been rare episodes of brief pain during the injection. 

Excellence in surgical care

Dr. Tranoulis is highly experienced in the treatment of gynaecological cancers and complex benign gynaecological conditions and a recognised leader in his field. International studies have demostrated that surgeons performing higher volumes of particular procedures can often offer patients better outcomes, such as shorter hospital stays and fewer complications. Dr. Tranoulis is a double board-certified Gynaecological Oncologist with subspecialisation in minimally invasive gynaecological surgery. He is also certified robotic surgeon by the Society of European Robotic Gynaecological Surgery (SERGS).

Dr. Tranoulis offers the latest surgical innovations with emphasis on minimally invasive procedures. These include: