Using Evolutionary Game Theory to optimize Chemotherapy for Cancer
In lecture, we talked about how evolutionary game theory works in nature to determine which species survives and which dies out. A behavior survives if it’s fit, and fitness depends on who else is out there and what their behaviors are. We also made an assumption that the players in our evolutionary game don’t make rational choices; their choices are preprogrammed instead.
The article below envisions such a game where the players are the malignant cancer cells and the oncologist treating the cancer using massive doses of cytotoxic drugs. The assumptions are a bit different than what we discussed in class. The environment is the human body, and the cancers cells have already occupied a massive portion of the environment. Also, this is an asymmetrical game where the only rational player is the oncologist; cancer cells don’t think or anticipate or plan out a strategy ahead of time, they adapt.
Currently the oncologist plays a fixed strategy of attacking the cancer with massive doses of cytotoxic drugs over a fixed period of time, and the cancer cell plays a mixed strategy of adapting to the treatment. The aim, in this case, is to wipe out the cancer cells before it can recover and start spreading again. The article points out that sometimes this fixed strategy by the oncologist works but often malignant cells that are resistant to the initial therapy survive and then repopulate; before long, these battle-hardened rebels spread to distant parts of the body. That’s called metastasis, and once the process starts, it’s very hard to stop. Cancer wins in this scenario.
The article further points out that by changing the dynamic of the game, we can change its outcome. The oncologist should use a mixed strategy instead of a fixed one: rather than try to wipe the disease out in the first move, the doctor should try to force these fast-evolving cells to reveal their treatment escape routes ahead of time—and then systematically block each one. Instead of the oncologist making the first move and the cancer cells adapting to the treatment in the first game, the opposite is true now. In this way, the oncologist will have the advantage and will be able to wipe out the cancer cells before they recover or adapt to the treatment!
http://fortune.com/2018/08/10/beating-cancer-game-theory/