Researchers in London have found a new way to gauge how likely breast cancer is to spread, by examining patients' lymph nodes in far closer detail than before. The findings, from teams at King's College London and University College London, were set out to Sky News by Dr Simon Vincent, chief scientific officer at the charity Breast Cancer Now, who said the work could eventually lead to gentler and more precisely targeted treatment.
Lymph nodes are part of the body's immune system, working as channels that let immune cells move to different areas of the body, with a large concentration of them sitting under the armpit. Because so many lie close to the breast, they have become a key focus for doctors trying to work out whether a cancer is staying put or starting to move beyond the original tumour.
For the women, and the smaller number of men, who develop breast cancer, the disease can spread through the body, and it frequently does so first by travelling through these nodes. That is why they are checked so carefully once a tumour has been found, and why the precise changes that take place inside them have become so important to understand.
At the moment the nodes are often removed during surgery and then tested to see whether the cancer has already spread. Dr Vincent warned that the operation can bring serious side effects, among them a difficult condition known as lymphoedema, in which the arm swells up and becomes very hard to live with.
The new work looked instead at how the lymph nodes themselves change when cancer is present, and how they respond to chemotherapy. The aim was to find out whether the state of the nodes can show how likely the disease is to spread further through the rest of the body, giving a clearer read on how it is likely to behave.
A sharper understanding of the nodes could help doctors choose treatments with more confidence and steer towards options that are less damaging and have less impact on the patient. The better the nodes can be read, the greater the chance that people are spared the harshest therapies while still receiving the care they need.
Even so, the approach is unlikely to become a routine screening test, and is instead expected to improve what can be learned from the surgery and testing already carried out. The nodes act as a two way channel: when a cancer cell breaks away from the tumour, they are often its route into the rest of the body, which is why surgeons examine those closest to the cancer first. Finding cancer cells there points to a strong chance the disease has spread, while their absence suggests it probably has not.