Risk and Relapse
If curing breast cancer was all about removing the cancer we can see, treatment would be simple. I’m a breast cancer surgeon. I’m good at cutting bad things out.
Unfortunately, we need to treat the cancer we can see (most commonly a breast lump +/- lymph node/s in the armpit)…AND the possibility of microscopic cancer spread elsewhere.
We call this micro-metastatic disease; it won’t show up on any scan or blood test. The last point is important for I’m often asked after surgery: “Isn’t there a test I can do to see if there are any cancer cells still in my body?” It’s an excellent question because no doubt, many women are actually cured by surgery itself. If we could identify this group – with a blood test for example – we could spare them further (unnecessary) treatment. Alas, the test does not exist so we always need to consider the potential for micro-metastatic disease elsewhere.
Ok, so there’s a chance breast cancer cells may have spread around the body. And for the majority of women, there’s no way of knowing this for sure. Does this mean we give every woman with breast cancer, surgery + all possible additional treatments? No! Treatments have toxicities. We don’t want to put anyone through a risk of treatment side effects and/or complications unless there is a reasonable chance the treatment will help.
So how to work out who needs further treatment and who doesn’t, and what treatments are warranted in a particular woman? Well as I touched on in my previous blog post, it comes down to working out that woman’s individual risk of relapse and looking at what treatments will reduce this.
The nature of the cancer we can see gives us a lot of information about the risk that woman is at for harbouring micro-metastatic disease. To put it simply, a 10cm breast cancer which has spread to the armpit has a higher chance of having spread elsewhere in the body as well, compared with a 1mm breast cancer which has not spread to the armpit. There’s more to it, of course … there always is … but let’s keep this simple. The more we know about the primary breast cancer, the more we can determine how risky it is and what should be the best treatment combination to combat that risk.
The way I see it, BIOLOGY x STAGE = RISK.
What do I mean by this?
BIOLOGY
Think of it as how active, angry or aggressive the cancer cells are. You can have good, or not so good tumour biology.
We look at things like:
· Grade (not to be confused with stage)
· Tumour subtype
· Estrogen and Progesterone receptors (ER/PR status)
· HER2 receptors
· Lymphovascular invasion (LVI)
· Ki67 (this one remains a bit controversial but can be useful)
STAGE
This is how advanced in its growth the primary cancer is. Think:
· Size
· Spread to lymph nodes
· (+/-) Amount of lymph node involvement
· Disease beyond the breast and armpit
I don’t want to derail the concepts here by getting more detailed than I already have. Suffice to say, women often have a combination of both good and bad tumour features. Our job as the treating team is to decipher it all, crunch the numbers and make reasonable treatment recommendations. We do this through experience, prognostic tools based on large breast cancer databases, evidence from past treatment trials and discussion within a multidisciplinary team. Recommendations take into account risk of relapse, what treatments have been shown most effective and patient features such as age and general health.
The idea is to assess a cancer correctly at the outset and implement a plan of treatment which maximises cure rate and minimises negative effects of the cancer and therapy. This is always a balance. Ultimately, choice lies in the hands of the patient - but making informed decisions is vital.