Dear Iris,

I recently started treatment for breast cancer. I thought I was getting chemotherapy, but my doctor has also mentioned immunotherapy. Are these the same thing? What’s the difference?

L

Dear L,

Chemotherapy and immunotherapy are two different treatments that can be used to treat types of cancer. You may receive them through an infusion, a shot, or an oral pill.

Chemotherapy works by killing and/or slowing down the growth rate of cancer cells. This class of medications can attack any fast-growing cell in the body, such as hair, skin cells, and cells in the gastrointestinal tract, which is where some of the commonly known side effects such as hair loss and nausea come from. It can create a quick, meaningful shrinkage of cancer cells that can be used alone, or before surgery or radiation, depending on your treatment plan.

Immunotherapy, on the other hand, works by stimulating the body’s immune system and natural immune defenses to fight against and attack cancer cells. You may have heard your doctor mention a class of immunotherapies by name, such as monoclonal antibodies or checkpoint inhibitors.

Often immunotherapy can be used with or after traditional chemotherapy. While chemotherapy works when it’s in the body, immunotherapy can mount a sustained response against your disease and continues to work after you get the medication. It has become a common treatment choice because it’s often well-tolerated and usually produces fewer side effects.

With all of these details, it’s easy to be confused! Don’t be afraid to ask questions to your oncologist or the Iris Care Team if you’re unsure about what you are receiving or what the side effects are.

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