Sentinel Lymph Node Biopsy To Check For Spread Of Breast Cancer.
Friday, 17 February 2006
Benefits to the patient
For those who do not require axillary node dissection, sentinel lymph node biopsy (SLN) is a lesser surgical technique that spares many women of the need for a more extensive operation to check for spread of breast cancer to the lymph nodes. Thus SLN greatly decreases the risk of accompanying complications resulting from the standard axillary node dissection. The standard axillary node dissection may cause numbness, seroma formation ( fluid in the armpit), sensory loss in inner arm, or decrease in shoulder function and a swelling of the arm (lymphoedema). 20-30% of patients are currently at risk of developing one or more of these problems when axillary node dissection takes place. With SLN, early breast cancer patients may only have to undergo just day surgery and thus save on hospitalisation bills.
Background: Importance of Lymph Node Examination
For someone diagnosed with breast cancer, the doctors will examine the underarm lymph nodes near the affected breast. This is in order to determine:
| 1. |
the extent of the cancer (stage) |
| 2. |
appropriate treatment (e.g. adjuvant therapy) |
| 3. |
long-term outlook (prognosis) |
Breast cancer cells that break away from the original tumor can get swept up into the lymph fluid that drains from the breast into lymph nodes. The presence of cells in the lymph nodes can mean a higher risk of the cancer spreading to another part of the body.
To find out if breast cancer cells have spread to the lymph nodes, many women with early-stage breast cancer are offered two options for lymph node removal (also called dissection):
| 1. |
Standard axillary node dissection where surgeons remove most of the lymph nodes in the armpit region. The pathologist then looks carefully at these lymph nodes to see if they contain any cancer cells. This is the current standard of care in Singapore.) |
| 2. |
(SLN) removal
Only sentinel node(s) is/are removed and examined. If these are found not to be affected by cancer, the chance of finding cancer in any of the remaining nodes is very small. Thus no other lymph nodes need to be removed.
Procedure -SLN
| 1. |
The surgeon injects a blue dye and radiocolloid (a radioactive tracer) into the area around the tumor. |
| 2. |
A lymphoscintigram is performed for the patient to help determine the location and number of sentinel lymph nodes. |
| 3. |
The blue dye and radio active colloid follows the path that tumor cells would most likely take from the tumor area to the lymph nodes. |
| 4. |
The surgeon then removes just the one lymph node ( or 2 or 3) that first takes up the dye and /or is radioactively 'hot'/enlarged.
This lymph node, the one that cancer cells are most likely to travel to, is called the "sentinel" node.
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| 5. |
The sentinel lymph node(s) is/are sent to a pathologist. |
| 6. |
If the pathologist finds cancer cells in these lymph nodes, then a surgeon usually does a standard axillary node dissection to check for additional areas of cancer. But if no cancer cells are found in the sentinel node, no more nodes are removed. |
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Eligibility
All patients presenting with and determined to have operable early breast cancer, i.e. small early breast cancers with clinically negative axillas in the outpatient clinics can be considered. Currently up to 50% of breast cancer patients with early breast cancer is likely to be eligible.
Those eligible are likely to be:
| 1. |
Patients with early breast cancer (T1 and T2) |
| 2. |
No obvious palpable axillary nodes |
| 3. |
No evidence of cancer spreading to other organs. |
Those not eligible are likely to be :
| 1. |
Locally advanced breast cancer |
| 2. |
Palpable axillary lymph nodes |
| 3. |
Previous axillary surgery |
| 4. |
Multifocal breast cancer i.e. more than 1 area of cancer in the same breast |
| 5. |
Allergic to radiocolloid/blue dye |
| 6. |
Pregnant |
Minimal Side Effects
| 1. |
The amount of radioactivity used is minimal (8-10 Mbeq or >1mCi) less than a return flight to London |
| 2. |
The side effects of the blue dye is minimal such as bluish urine and a blue tinge to the skin. Allergic reactions are rare and the reported incidence is 1.5% |
Costs
$150-200 for subsidised patients.
For more details, photos and media interviews on the above, please click [here].
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