Dr. Kerry Courneya

So these cells have to go on an arduous journey through the vasculature.

So they can spread through the lymph system but also through blood vessels.

And there's some really interesting research suggesting that if you exercise while the tumors are shedding these circulating tumor cells, those circulating tumor cells are less likely to survive because of the increased shear stress.

So when blood's flowing through the vasculature, it's under a certain amount of pressure, but of course that's dramatically increased when you exercise.

And these circulating tumor cells are far more likely to die and not survive that journey if you're exercising.

So this is another really interesting mechanism for how exercise might be able to prevent the spread of a primary tumor.

And once those cells are circulating or they've kind of disseminated elsewhere in the body, this is where some of these other mechanisms can be important.

The metabolic effects of exercise such as reducing insulin and IGF, these are all things that help cancer cells grow and divide more rapidly.

the anti-inflammatory effects of exercise can be very important.

And probably one of the key ones is the immune system, tracking down and killing these cancer cells, right?

This is why we have the whole new treatment now, immunotherapy.

We've realized how important it is to call on the immune system to be able to track down and kill these cancer cells.

So exercise in some ways was the original immunotherapy.

You know, this was stimulating the immune system, uh,

and improving natural killer cell cytotoxicity, the number of natural killer cells, the number of T cells and B cells that were all doing immunosurveillance of these cancer cells.

So lots of good biological mechanisms for how exercise might improve these cancer outcomes.

Yeah, so that's been demonstrated in those preclinical mouse models.

So they've shown that the mice that exercise will have higher numbers of T cells, natural killer cells within the tumor itself.

So that improved blood flow allows everything to get into the tumor in order to be able to kill it.

So yeah, the improved immunity.