(14) Metastatic Breast Cancer
I got several drugs before, why am I only getting one now?
Chemotherapy works by killing cancer cells. There are a number of ways to do this, and different drugs attack cancer cells in different ways. If a mugger in a dark alley attacked you, you probably would not just hit him in the stomach.
You would have a better chance of stopping him if you hit him in several vulnerable spots-stomach, head, back, and groin. When oncologists choose to use several anti-cancer drugs (combination chemotherapy) they are doing the biological equivalent of your multi-pronged attack on the mugger.
The downside of this approach is that the combined drugs have more side effects than single drugs. Breast cancer that has not metastasized is potentially curable, and oncologists throw out all the stops to do this, even if there is a chance of more toxicity. Most people are willing to accept the short-term risk of toxicity if there is a reasonable chance that the chemotherapy will cure their cancer. Unfortunately, when breast cancer has recurred or spread, it cannot be cured, and there is a need to make big changes in how it is treated. The goal of treatment is no longer cure, but to enjoy life for as long as possible.
Since you will likely be getting some form of anti-cancer treatment for the rest of your life, doctors need to balance your quality of life with the side effects that the treatment will cause. For that purpose, single agent chemotherapy is often as effective as combination chemotherapy, and less toxic.
That does not mean that oncologists never use combinations of drugs in treating metastatic breast cancer.
Sometimes two or more drugs work together to augment each other’s actions with few additional side effects. This is especially true of the newer targeted therapies, which oncologists often combine with a traditional chemotherapy drug to enhance their effect.
Combination chemotherapy - Treatment using more than one anticancer drug at a time.