Mr Zenon Rayter, Consultant Surgeon from North Bristol NHS Trust, discusses his experience of implementing whole lymph node analysis using the RD-100i OSNA system into surgical practice.
This podcast is 11 minutes 50 seconds in length. It covers
- the rationale for having a diagnostic test available in theatre during breast cancer surgery
- the benefits of testing using the OSNA method compared with current methods
- how the technology works
- limitations of the procedure
- an explanation of the process required for implementing the technology into practice results and patient feedback
Transcript
Interviewer: “Hello and welcome to this NICE podcast on the diagnostics guidance “Intraoperative tests (RD-100i OSNA system and Metasin test) for detecting sentinel lymph node metastases in breast cancer.
We will be focusing on why NICE has recommended whole lymph node analysis using the OSNA system as an option for detecting sentinel lymph node metastases during breast surgery in people with early invasive breast cancer who have a sentinel lymph node biopsy and in whom axillary lymph node dissection will be considered.
I am Heather Stephens, the implementation adviser for this guidance and with me is Mr Zenon Rayter, Consultant Surgeon from the North Bristol NHS Trust. Zen is a specialist member of the Diagnostics Advisory Committee who developed the NICE recommendations.”
Interviewer: Hello Zen, could you explain the rationale for having a diagnostic test available in theatre during breast cancer surgery and why the OSNA system was recommended?
ZR: In the past, before intra operative diagnosis was employed, patients would often have to have second time round surgery to clear any further diseased lymph nodes if the sentinel lymph node was involved. The reason why the OSNA system was recommended was because there was quite a lot of data in the literature already which had shown that if you compare the results of the analyses of the lymph nodes using the OSNA system with standard routine histopathology that there was a very good correlation between the two methods. Metasin is another way of analysing whether there is tumour in the sentinel lymph node and it uses slightly different chemicals to detect the marker that is identified. The reason Metasin hasn’t been recommended by NICE is because there were no peer review publications.”
Interviewer: So what are the benefits of testing using the OSNA method compared with current methods?
ZR: Well we believe that the OSNA test is virtually a hundred per cent accurate if you employ a whole node analysis. The other methods that have been used in the past such as frozen section of lymph nodes and intra operative cytology of lymph nodes are nowhere near as accurate.
Interviewer: So in using the OSNA system, how does it actually work in practice?
ZR: The sentinel lymph node is removed at surgery and then it is given to a biomedical scientist who takes the lymph node and uses a reaction and various chemicals which extract the CK19 from the lymph node and then this is put into a machine which measures the level of expression of CK19 and compares it with a standard negative control and a positive control. The system can then work out how much CK19 is present in the lymph node by comparing it with these two controls and this tells you whether the lymph node has no CK19, whether it has just a little bit which may be indicative of isolated tumour cells, whether there are micro metastases or whether there are macro metastases and these are deposits in the lymph nodes which are two or more millimetres in diameter. And it is these macro metastases which are the important ones because if a macro metastasis is present in a lymph node, that indicates that there is something like a forty to fifty percent chance that non-sentinel lymph nodes will be involved. And that, according to current guidelines from the Association of Breast Surgery is an indication for clearing the axilla.
Interviewer: Zen, are there any clinical disadvantages to carrying out this procedure?
ZR: The main clinical disadvantage is that for patients who are under-going simple breast cancer surgery there is a little bit of a wait for the results of the sentinel lymph node that’s being harvested and some people find that a little bit frustrating that it can take forty to sixty minutes to get the result. Of course this is not a disadvantage if you are performing more complex breast surgery where the breast surgery may take as long as the waiting time.
Interviewer: So what did you have to do then, in your own hospital, to start using this new technology?
ZR: The first thing I had to do was to get the clinicians on board. The pathology colleagues were very important in particular because they had to identify the biomedical scientists who would be willing to have the training in order to be able to do the CK19 extraction test. The next thing I had to do was to get this through the New Procedures Committee to convince the trust that this test was completely safe for patients. I then went to our charitable funds to obtain the money to lease the kit and at the time we were performing the New Start programme to accredit us for performing sentinel lymph node surgery and therefore this was a golden opportunity to ensure that an ongoing audit would be in place and that the results of the OSNA tests for half the node versus the pathology test for the other half of the node was comparable and that neither test was missing a significant number of positive non-sentinel lymph nodes. The ongoing audit made us confident that we could then offer this procedure as part of our standard clinical practice. Therefore, when we started offering sentinel lymph node surgery we started to offer the OSNA test at the same time and we continued to do half and half analysis as previously described until we were confident that we could abandon doing that and use whole node analysis as is now recommended by NICE based on our experience and others experience of this test.
Interviewer: So from a practical point of view what did you have to do to start using the test within your own surgery?
ZR: The initial practical thing we had to do was to identify a room in the theatre suite where the test could be done. This had to be a room which people couldn’t walk through to make sure that the material which was going to be analysed couldn’t be contaminated by other people’s DNA. Once we’d done that, the biomedical technicians were trained on how to do the test. It’s important to realise that biomedical technicians tend to only work nine to five. The impact of this is that you have to be very careful about your theatre schedule in order to be able to fit in those patients who need a sentinel lymph node procedure and an OSNA analysis otherwise one could easily find oneself performing sentinel lymph node too late in the day for the OSNA test.
Interviewer: So what about upfront and ongoing costs then and did you have any problems accessing funding?
ZR: What we did was to lease the equipment in the first instance and we got the funding for that through our breast cancer charity. Once we had done that we then had to persuade the commissioners to fund the ongoing running costs as the trust wouldn’t fund this because there was no financial incentive for them to do this because they were missing out on second time round operations in those patients who were sentinel lymph node positive. Having then got the funding and shown our audit results to the commissioners we then went back to the charity to get funding to actually buy the kit which cost £70,000. This is actually not very expensive and is comparable in price to that of a cheap ultrasound machine. I then had to continue with my ongoing audit on a yearly basis to continue to get funding from the commissioners. We reckoned that the test would cost about £350 per patient including the cost of the technician time and this was shown to be far cheaper than re-operating on patients whose sentinel lymph nodes were positive.
Interviewer: Thanks for that Zen. So what have been the results of using the OSNA system and what do your patients think about it?
ZR: Well the results of using the OSNA system have shown concordance with routine histopathology and converting to whole node analysis has meant that we have now abolished re-do surgery to the axilla in all our breast cancer patients undergoing sentinel lymph node surgery. The patients think it’s marvellous because even if the analysis is positive, patients are very keen to have got all the procedure over in one go and not have to face second time round surgery. The other fantastic thing for the patients, especially those in whom the OSNA test is negative is they actually know before they are discharged from hospital. So all in all it’s been a win-win for the patients and for the commissioners in terms of costings as well.
Interviewer: Thank you very much Mr Rayter.
Interviewer: We hope that you will find the information in this podcast useful in helping you implement this guidance into practice.
For more information about the NICE Diagnostics Guidance on “Intraoperative tests (RD-100i OSNA system and Metasin test) for detecting sentinel lymph node metastases in breast cancer” including the NICE implementation costing tool which can be adapted for local use, please visit the NICE websitewww.nice.org.uk/DG8
Please let us know what you thought about this podcast by completing the short questionnaire accessible on the podcast page or by emailing us at implementation@nice.org.uk.
Disclaimer
This resource should be used alongside the published guidance. The information does not supersede or replace the guidance itself.
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