What is cancer? Part 2

And here you can see - this is actually the biopsy of the first lady I showed you, so here is someone who has breast cancer tissue.

So question one - what is it? - is always a tissue sample of some sort. Examine it under the microscope, it tells us what it is.

The second question in sorting out the dimensions of the problem is to know ‘Where is it?' And this, in doctor-speak, is called the stage.

You might recall seeing these images that showed the spread of breast cancer to the liver, to the lung, to the pleural cavity where the fluid is sitting and to the bone. This represents advanced stage of cancer.

So clearly here, if we were to treat this patient, which we did, we would need to use a treatment that works in many parts of the body.

Staging is complex, and again it can be very bewildering. There's a new system (and when I say new, it's about 10 years old) called TNM. The T describes the Tumour, the N describes the original lymph glands, such as the armpit glands in the case of breast cancer, and M the presence of absence of metastases.

You may hear your doctors talk about stage and they may talk about T numbers, N numbers and M numbers, and it's a sort of shorthand that allows us to communicate accurately and fairly quickly, the extent of the cancer. It's the answer to the question ‘Where is it?'

So rational treatment requires knowledge of ‘What is it?' - via a biopsy. ‘Where is it?' That's always answered by investigations like X-rays and CT scans, MRIs - all of those sorts of things. That then must be blended with knowledge. What works with this particular type of cancer, at this particular stage? And there have been systematic studies done over the last century to work out what works best.

This little graph here shows you that if you were in this particular study, you would have rather been on the yellow treatment than the red treatment because the lines are declining because treatment was failing. So that sort of information gets integrated into that prediction about which sorts of treatment are best to use.

Now that system that I've put up there sounds all well and good, but it's not enough. There are very many other important factors about individualising treatment. Who is this patient? What's their age? Do they have other illnesses? Do they have personal preferences?

And finally there needs to be wisdom. And in the year 2007 it's not very common to find that one individual contains within them enough wisdom to make decisions for a patient. That's why often care is by a team - a multidisciplinary team - and there can be conferences about what is the best way to proceed with treatment for patients.

So understanding and treating cancer is a bit like this diagram here. Clinicians - we're simple folks. We'd much prefer to have something like this with a single switch where when it comes to treatment it's easy to flick the switch and everything's done.

But the complexity of cancer means it's much more like the bottom part of the diagram. There are many things to tweak, there are many things to understand, there are many settings to adjust. And the other thing that's very important to understand is that because we're constantly generating new knowledge, we are actually on a bit of a moving carpet of knowledge so decision we make this year, will not be current decisions in two years time. Just as decisions that I made for patients 5 years ago would now be modified with new data that we've learnt in the last 5 years from research.

This very complicated diagram is actually now quite old. It was published in the year 2000 and even then was a simplification of the wiring diagram of what controls cell growth. So if you want to interfere with cell growth - either because you're a cancer cell and you want to have unrestrained growth - or if you're a cancer doctor and you want to stop unrestrained growth, there are many, many options in this wiring diagram where you may interfere.

I'm going to talk about a little bit of research that concerns just this tiny corner of the diagram, just to give you an idea of the complexity.

There is a picture from the light microscope. That is all that we had back in the 19th century. By the 1980s we had immuno-histo-chemistry - brown stains that told us about the presence or absence of specific molecules in cancer that helped us with prediction. By the year 2000 we were able to look at the actual DNA, which gives us information about specific genes being present - being increased or being deleted.

And now we're able to look at vast arrays of genetic material or a protein within cancer cells and we have multi gene predictors of how a particular cancer is going to behave and how it's going to respond to treatment. This now is the cutting edge of research at this time.