Please can you outline the current method for carrying out a sentinel lymph node biopsy for early breast cancer?
Our current method, which is recommended by the Association of Breast Surgeons in the UK, involves the use of injections of blue dye and radioisotope to identify the first node(s) under the arm (axilla) called the sentinel nodes.
How did your research into an alternative method originate?
Radioisotope is expensive, involves radiation exposure for patients and staff, and is increasingly difficult to obtain due to international shortages.
There was therefore a requirement to identify new tracers for sentinel node biopsy that were cheap, safe and as effective as current agents.
Indocyanine green (ICG) is a fluorescent dye that has been used in various areas of medicine for many years and seemed an ideal choice to investigate.
Could you please describe the new sentinel lymph node biopsy method that you developed and explain how it differs from current practices?
The new method involves injection of blue dye and ICG in the skin of the nipple at the start of breast cancer surgery. By using a near infrared PhotoDynamic Eye (PDE) camera, the ICG can be seen highlighting the lymphatic channels as the traverse towards the axilla allowing selection if the optimal site for a small incision in the axilla.
Once the axillary dissection commences, the blue dye can be seen in the lymphatic channels and traced to the first node or nodes. The sentinel nodes can be seen as blue with the naked eye and intensely fluorescent with the PDE camera.
Is the new method as safe and as effective as the method currently in use?
Our recent publication (Wishart et al, Eur J Surg Oncol 2012; 38(8): 651-6) showed that the use of ICG for sentinel node biopsy in early breast cancer is safe and extremely effective. The optimal combination of tracer agents was with blue dye and ICG with a node detection rate of 95%.
Why is it important to keep the number of false-negative biopsies to a minimum in early breast cancer?
A false negative biopsy means that lymph nodes containing tumour are left in the axilla and can give rise to recurrence in the axilla or other regional lymph nodes.
In addition, it will lead to under staging of patients who will be undertreated by adjuvant therapies following surgery.
Are there plans in place for this new sentinel lymph node biopsy method to be adopted?
The use of ICG is already underway in many parts of Europe and Japan and following recent presentations is attracting interest from breast units in the UK.
How easy is this technique to teach surgical trainees?
One of the benefits of using blue dye and ICG is that it allows a didactic step by step dissection of the axillary lymph nodes and we have found that in all node positive cases, the first sentinel node removed was always positive.
This type of stepwise dissection is much easier to learn for surgical trainees and the technology is also easy to use and understand.
What impact do you think this new method will have on sentinel lymph node detection?
In my opinion the use of ICG has the potential to replace the use of radioisotope for sentinel node biopsy in breast and other cancers. Studies are already underway in sentinel node biopsy in melanoma skin cancer and anal cancer.
What research plans do you have for the future?
We are currently exploring use of ICG injections to look at tissue flap viability during breast reconstruction and a number of centres in the UK are now using ICG and the PDE camera to identify lymphatic channels in the arm during microvascular surgery for lymphoedema of the arm.
Where can readers find more information?
Readers can view an abstract of the paper online at PubMed and find out more information about the PDE technology by clicking here.
About Prof. Gordon Wishart
Professor Gordon Wishart studied at Edinburgh University Medical School and trained in general, breast & endocrine surgery in the West of Scotland deanery.
He completed a Cancer Research Campaign Research Fellowship at the CRC Beatson Laboratories in Glasgow in 1989 leading to award of a MD entitled “Aspects of multidrug resistance in breast cancer” in 1992.
Following his initial appointment as a consultant breast & endocrine surgeon in Sussex in 1995, he moved to Cambridge in 1998 to develop the breast unit at Addenbrooke’s Hospital, now known as the Cambridge Breast Unit.
As clinical director of the Cambridge Breast Unit (CBU) from 2005-2010 he played a significant role in developing the CBU as a breast centre with a national and international reputation for research and clinical excellence.
He was appointed as visiting Professor of Cancer Surgery at Anglia Ruskin University in 2008 and has an international reputation in the field of clinical breast cancer research and is a medico-legal expert in delay in breast cancer diagnosis and impact on survival.
He recently led a team that developed the new PREDICT breast cancer survival and treatment benefit model (www.predict.nhs.uk).