We don’t normally think of medical treatment as a component of game theory (remember A Beautiful Mind (2001)?), but someone has decided to apply it to prostate cancer treatment. NewScientist (10 March 2018) has some fascinating, if preliminary, results:
In this “game”, the oncologists are predators, and the cancer cells are prey. The oncologists’ objective is to kill the prey, or to at least keep it in check. But conventional cancer treatment shifts this balance. By giving a patient repeated strong doses of a cancer drug, the cells are pushed to evolve resistance.
When this occurs, the oncologists stop leading the game and instead have to keep up with an evolving, stronger cancer. By using the algorithm to deploy drugs more subtly, and closely monitoring what the cancer does in response, [Robert] Gatenby [of the Moffitt Cancer Center & Research Institute] says oncologists can stay ahead.
To test this approach, his team turned to people whose prostate cancer has spread to other parts of the body. They kept track of whether the cancer was growing or shrinking by measuring how much of a chemical called prostate specific antigen was shed by tumours into the blood every month. As this chemical rises and falls, the algorithm calculates how much of the drug abiraterone to administer in each treatment cycle, tailoring dosages and treatment to each individual.
And how’s this working out?
It typically takes prostate cancers 15 months to evolve resistance to standard doses of abiraterone, at which point the tumours are able to grow bigger than their initial size. But in an ongoing trial of the algorithm in the treatment of 17 men, this timescale has more than doubled to an average of 33 months – and could keep rising. Cancer has been able to progress in only three men in the trial, and some of the participants have now lived for four years without this happening, Gatenby told New Scientist. These results are so impressive that the team is beginning a larger trial, and plans to extend the treatment strategy to skin and thyroid cancer.
“This is an approach that could revolutionise cancer therapy, and it doesn’t even require the discovery and approval of a new drug,” says Carlo Maley of Arizona State University. “I want to try this on every cancer we can.”
And since this does not involve new drugs, the development costs are much lower. There are no safety tests, simply evaluation of how the administration protocol is working – and it appears to be working very well.
Coming from a family where the paternal side mostly dies of cancer, this is very encouraging. Innovative thinking seems to reign there.
