Another ICG update, do we need to change anything?

A recent paper which reported on a protocol for fluoroscopy imaging of breast cancer-related arm lymphoedema provided some interesting visual data on how the body adapts to interruptions in normal lymph pathways (1). I love the way this kind of imaging can help us to understand the lymph system better, but I challenge that what has been found changes anything in our current MLD protocols for unilateral BCRL of the arm.

ICG mapping to guide a surgical procedure. Image from https://scitemed.com/article/2458/scitemed-imj-2018-00049

Currently, ICG imaging is used with great success to identify patent lymph vessels to guide micro-vascular surgery. This is within the existing TGA approval for its use in intra-operative diagnosis. Using ICG to map lymphatics is still experimental, and the paper by Suami et al (1) reports on a protocol developed to image superficial lymph pathways in post-mastectomy arms. I have written previously on this emerging technology and its limitations.

As an experimental technique, papers like this are an important contribution towards standardisation of the imaging protocol. They can also offer interesting visual data on the patterns of drainage found in the small number of people included in the study. Some therapists have interpreted this to mean that we should change our MLD protocols for everyone, but my interpretation of the results is that they support our current unilateral BCRL protocols.

The original article is available open access. Click on the image to go to the article.

Let me take you through the article and show you how I have arrived at this interpretation. Let's begin with the stated assumption that

"Conventionally, BCRL was thought to be caused by the complete obstruction of the lymphatic drainage to the ipsilateral axilla secondary to surgical and/or radiation intervention. Our results contradict this notion..."

But I have never made this assumption and as there is no reference for it in the article I don't know where it comes from either. It is certainly not what we teach in our training program which is to redirect around the axilla toward open pathways. Not because we think there is no flow through the axilla at all, rather to reduce the load going into the axilla and preserve that pathway for whatever can escape the arm that way.

So the finding that there was lymph flowing through the axilla in 67% of the arms imaged does not surprises me at all. Rather it confirms what I have told my clients for many years, which is that there will be some lymph going through your arm pit, but we'll offload whatever else cant escape that way to nearby alternate pathways. Another finding was that higher stages of lymphoedema were associated with less drainage through the axilla and more reliance on dermal movement toward adjacent open drainage areas. Again no surprises here, and a nice confirmation that there are anastomosing vessels which can transport lymph across watersheds. When no patent vessels remained in the axilla, ICG imaging showed that dermal flow also progressed toward another lymph node basin. All of these findings support using techniques to promote dermal movement towards open drainage areas and opening of anastomosing vessels at the watersheds. What the imaging confirms, is that these alternate pathways occur naturally to redirect the lymph, and my interpretation is that we are on the right track to support them.

Another finding was that

"Patients with BCRL often complain, [..] of discomfort in specific areas of their upper limb instead of uniform changes or swelling in the whole limb. In this study, we introduced a new ICG lymphography protocol for the upper limb to help to identify areas with underlying anatomical changes that occur in lymphoedema."

We already identify these underlying anatomical changes when we pay attention to what our clients tell us about the way their arm feels, and by using our palpation skills to determine what connective tissue changes have occurred. It would have been great if the researchers had added some report on how the ICG imaging matched the client's self reported symptoms, or perhaps tissues compressibility.

The confusion regarding the need to redirect has filtered into social media sources used by patients too, and I have seen worrying posts suggesting that the self-massage we were taught by our therapists is now somehow wrong.

Nothing in this paper will tell you or your client where their open drainage pathways are, which is why we must assess the multitude of individual factors applicable to each client. We want to know where the tumour was removed, where and how many lymph nodes were removed, what was the area of radiotherapy, were Taxanes were used during chemotherapy? We consider known risk factors such as BMI, level and type of usual activity, history of other surgeries, co-morbidities, medications, tight underwear etc. We palpate the tissues, note the immediate and long term responses to treatment and use all this information to design a personalised treatment protocol for each individual. One day, when ICG is approved for general use in lymphoedema, it will be a real asset in problem solving for clients who don't respond to best practice therapies. In the meantime, this paper supports our current approach to unilateral BCRL of the arm and we don't need to change our MLD protocols across the board.

The stated purpose of this paper was to show that the proposed protocol to image the superficial lymphatics with ICG is valid, and it is great that publications like this are coming out as we need a standardised method of performing this procedure. It has also increased our understanding of the lymph system and what happens when lymph drainage is inhibited, but the conclusion should be read carefully

"We developed a new ICG lymphography protocol for diagnosing BCRL focusing on identification of an individual patient’s lymphatic drainage pathway after lymph node surgery to guide MLD and to assist with selection criteria for lymphatic microsurgery. ICG imaging combined with MLD will allow a personalised approach to lymphoedema care.

1. Suami H, Heydon-White A, Mackie H, Czerniec S, Koelmeyer L, Boyages J.

A new indocyanine green fluorescence lymphography protocol for identification of the lymphatic drainage pathway for patients with breast cancer-related lymphoedema. BMC Cancer. 2019;19(1):1-7.

2.