To remove or not to remove?
So it seems that one of the major questions surgeons have to ask before removing cancerous tissue is 'What's cancerous and what isn't?' because obviously it's important to know whether you're removing the right thing or not.
Now it's understandable that it's difficult to visibly distinguish between cancerous tissue and normal tissue, especially when working with things like lymph nodes which are tiny at only half a centimetre in size which makes them difficult to distinguish from the surrounding tissue during surgery. And even when lymph nodes can be located, the fact that they are unable to distinguish between cancerous and normal tissue means more lymph nodes than necessary are removed which then results in a hindered immune system, right?
'Wait...what are Lymph Nodes??'
In short, Lymph Nodes are small nodules, located throughout the body which serve as filters that contain immune cells to fight infection and clean the blood.
When cancer cells break away from a tumor (metastasise), the cells can travel through the lymph system and hide in these Lymph Nodes.
The point of their removal is to determine if a cancer has spread.
So this is where a team of surgeons and scientists at University of California, San Diego School of Medicine come in. They have developed a new technique which will allow surgeons, during surgery, to determine which tissue is cancerous so that healthy tissue can be saved, e.g. non cancerous lymph nodes will not be removed thus preserving the effectiveness of the patient's immune system.
'So what exactly is this technique and how does it work??'
This new technique is essentially just molecular targeted imaging whereby fluorescently labelled molecules are injected and the tissues which 'take up' the fluorescent molecules and fluoresce are cancerous whereas those that don't are normal. Simple right?
This pioneering technique eliminates not only the unnecessary removal of lymph nodes, but also eliminates the need to have said removed nodes (and other tissues for that matter) sent off to the labs for pathological examination to determine whether cancer is present which makes detection of metastases and determination of the presence of cancer a lot faster and more accurate.
This technique is an improvement over traditional sentinel node mapping, which only allows the detection of the location of the lymph node but gives no information on actual cancer involvement.
Nguyen, director of the facial nerve clinic at UC San Diego Health System is quoted as saying "The range of the surgeon's visual field is greatly enhanced... so that no tumour is left behind." which goes to show just how much potential this technique has.
The technique involves the use of Ratiometric Activatable Cell-Penetrating Peptides (RACPP) which contain Cy5 (a far red fluorescent donor) and Cy7 (a near infra-red fluorescent acceptor).
The Cy5 and Cy7 work in the way that when the intervening linker between the 2 is cleaved, either by tumor-associated matrix metalloproteinases (MMP) 2 and 9 or elastases (found in cancerous tissues and tumours) the Cy5:Cy7 emission ratio is increased almost 40 fold.
This then triggers the retention of the fragment of the RACPP which contains Cy5 by the tissues thus causing the cancerous tissues to fluoresce making them easily distinguishable from normal tissues.
Seems like this technique will be extremely beneficial in terms of reducing the time in which metastases is determined as well as improving the accuracy of tissue removal, both which can only benefit patients.
I personally look forward to seeing this technique being implemented, especially as I know how stressful unnecessary surgery and testing can be on cancer patients as my mother was subjected to it on countless occasions throughout her treatment. So anything which can benefit patients and put them even at the slightest of ease and reduce the stress they're under is a win in my books!
