Sentinel node mapping is a procedure that is carried out pre-surgery, usually on the day of surgery, but sometimes the day before surgery.
Standard practice for breast cancer surgery is to remove all of the lymph nodes under the arm to find out if the cancer has spread beyond the breast. However, removing all the lymph nodes can result in pain, and discomfort from lymphoedema (swelling of the tissue in the arm because the lymph is no longer able to drain away properly). The fewer the lymph nodes removed, the less likely the chances of side-effects.
A sentinel lymph node is the first lymph node to which cancer cells are most likely to spread from a tumor. The position of the sentinel lymph node is mapped using a radioactive substance and a device that detects radioactivity. By removing and examining the sentinel lymph node, it is possible to determine if the cancer has spread.
The purpose of the sentinel lymph node mapping is to allow for a less invasive procedure, in which fewer lymph nodes are removed.
I had mine on the morning of surgery. It was as uncomfortable as the image above shows. It is never pleasant having a needle stabbed several times into your nipple and breast. The radiologist was gentle, but the breast and nipple are sensitive areas and it still stung.
(In the US and on US websites, they recommend using EMLA cream to numb the area, but when I asked for this, I was told that it would interfere with the drainage or density or something-or-other of the breast, so they don’t use it. Really? I find it hard to believe that the US would muddy the results of a test by the incorrect use of an analgesic.
I suspect the reluctance to use EMLA cream was something to do with the British tradition of stiff-upper-lip. My only comment to the UK medical establishment is that while some people get used to the pain of recurring medical procedures, some don’t, and especially if faced with multiple procedures, develop needle phobia – something to bear in mind the next time someone asks for pain relief.)
After the radioactive dye was injected in several positions into the breast, I was sent away into the waiting room for a couple of hours, and told to move and flap my arms, anything to get the lymph moving. Usually a longer waiting period is given, but surgery was scheduled that afternoon, and we were running out of time. So I flapped like anything, and jogged up and down and hoped for the best.
I returned to have the area scanned to see if the radioactive substance was being taken up. Unfortunately my lymph wasn’t moving that day, either that or the procedure was rushed because the sentinel lymph node was playing hide-and-seek with the radiologist. There were a few hushed and tense moments while the radiologist conferred with her assistant. I wondered if surgery might have to be delayed if the sentinel lymph node couldn’t be found.
I was warned that the radioactive dye might dye my breast or even urine blue the following day. (Well, I’m glad to say my breast didn’t turn blue.)
Finally, the radiologist thought she’d found the sentinel lymph node and marked it on her images of the breast and also on the breast itself. So surgery would go ahead after all.
OSNA stands for One Step Nucleic Acid Amplification and is a method of analysing a sentinel lymph node biopsy.
Conventional methods of analysing the sentinel lymph node biopsy are performed using frozen sections or staining. These methods are not sensitive as only a small proportion of lymph node tissue can be investigated. They can also result in false-negative results. These methods can also take up to 3 hours to perform, with part of the analysis done during surgery, and the remaining sections after surgery, which might result in a second operation for the patient.
OSNA is a kind of biopsy that examines the genetic material of the lymph node for the presence of biological markers that indicate that the cancer has spread. The test looks at the lymph node DNA to detect “gene expression” for cytokeratin-19 (CK19)
Measuring the level of gene expression shows how active the gene is. The results are available immediately, allowing surgeons to remove more tissue from the lymph nodes if the results suggest that the cancer has spread.
(the full technical bit from http://www.sysmex-lifescience.com/FAQ-189-2.html#faq10x: OSNA is a method that involves the homogenisation of lymph node tissue followed by analysis of a molecular target mRNA called CK19 by the process of reverse-transcription-loop-mediated-isothermal-amplification (RT-LAMP)
You would think that because OSNA saves time and money and prevents the need for a second operation, it would be a no brainer. Unfortunately, that wasn’t the case when I was scheduled for surgery.
A battle with the insurance company
My health insurance company refused to pay for the analysis, the portion of surgical fees for this procedure, the portion of anaesthetist’s fees for this procedure.
I sent them loads of research papers showing that OSNA would save them time and money. (see: Advantages of one step nucleic acid amplification (OSNA) whole node assay in sentinel lymph node (SLN) analysis in breast cancer).
But they were adamant. It was not approved by the National Institute for Health and Care Excellence (NICE) so they wouldn’t foot the bill. So there I was, about to have breast surgery, and getting stressed with having to negotiate with the health insurance company over a valuable procedure. Being injected in the nipple was less painful. Turns out my health insurance company had a reputation in the industry for not paying for certain procedures.
Ironically, about six months’ after surgery, NICE approved the use of OSNA for sentinel lymph node biopsies!