The medication that Ryan took is called Xeloda (generic: Capecitabine). Before I explain what the drug does, let's talk a little bit about cancer. Cancer is basically cells gone wild. There are certain checks and balances in place that are meant to control when and how far cells divide. For example, cells are supposed to have personal bubbles. Once one cell comes in contact with its neighbor, it stops (this is called contact inhibition). But cancer cells don't play by anyone's rules.
Xeloda is one of many anti-cancer agents that stops the division process. Specifically, it is a prodrug (a "pre" drug that is metabolized in the body to become the active drug). Its active metabolite is fluorouracil, which inhibits an enzyme used to synthesize thymidine (refresher of high school biology: thymidine is one of the nucleosides used to make up DNA. T pairs with A (adenosine), remember?). Blocking this mechanism stops cell division at a specific point in the cycle. If the cells are unable to divide, they will die. Very effective. However, the drug does not differentiate between cancerous cells and normal cells. Ergo, an extensive side effects profile. For Ryan's regimen, the Xeloda will be taken twice a day, every day, until either the all-clear or until the side effects do us in. This will be combined with another powerful anti-cancer agent which we will cover a bit later.