In the past, chemotherapy was really one of the only treatment options available for cancer, but science and research have come a long way.
For example, there are increasingly targeted breast cancer therapies and targeted therapies for other types of cancer as well. These treatments can mean less anxiety, fewer treatment-related side effects, and better outcomes.
Below, we compare targeted therapy and chemo to provide an overview of each.
What is Targeted Therapy For Cancer?
The majority of targeted therapies that are used as cancer treatments will interfere with particular proteins that help tumors grow and spread through the body.
Targeted therapy is part of what’s called precision medicine. Targeted therapies are either small-molecule drugs or monoclonal antibodies.
A small-molecule drug is one that’s tiny enough to enter cells, so they target what’s inside a cell. Monoclonal antibodies are proteins made in a lab. These proteins attach to certain targets that are on cancer cells. Sometimes, monoclonal antibodies can mark cancerous cells, allowing the immune system to better see and destroy them. There are also monoclonal antibodies that can directly stop the growth of cancer cells or cause them to self-destruct. A third type of monoclonal antibody can carry toxins to cells that are cancerous to destroy them.
There are some types of cancer where most people will have a target for a particular drug so they can be treated with it universally. More commonly, though, a tumor has to be tested. The testing is done to see if there are targets that a drug exists for.
If your cancer is being tested for targets, it’s known as biomarker testing. This may require a biopsy.
How Does Targeted Therapy Work?
These were touched on above, but below is more detail about how these targeted therapies work:
- Targeted therapy can help your immune system destroy cancer cells. Cancer cells are often able to thrive because they can hide from your immune system, but with targeted therapy, the cells are marked, making it easier for your immune system to find and kill them. There are also immunotherapies, which are targeted therapies, and that help your immune system function better against cancer.
- Some therapies will interrupt the signals that lead cancerous cells to grow and divide in an out-of-control and out-of-order way.
- A tumor needs to form new blood vessels to grow. This process is called angiogenesis. Some targeted therapies will prevent these signals so that a blood supply can’t form. When there’s no blood supply, a tumor can stay small, or if the tumor already has a blood supply, targeted therapy may kill the blood vessels, leading to tumor shrinkage.
- Monoclonal antibodies can be combined with radiation, chemotherapy drugs, or toxins to deliver them directly to cancer cells. Cells without a particular target aren’t killed or harmed.
- Cancer cells can avoid the cellular dying process, but targeted therapies can cause cancer cells to go through cell death, in a process known as apoptosis.
- Certain types of prostate and breast cancers need hormones to grow. Hormone therapies are targeted therapies that can prevent your body from making certain hormones, or they can prevent hormones from acting on cells.
How Chemo Is Different
Our cells go through cell cycles as they form new cells. Cancerous cells form new cells faster than normal ones. Chemotherapy drugs are designed to affect cells at certain stages of their cycle but don’t differentiate between the cells that are cancerous and the ones that are healthy.
There are a lot of healthy cells that can also have a rapid cell cycle, such as hair follicles and cells in the GI tract. That means they’re going to be susceptible to the effects of chemotherapy like the cancerous cells, which is why there are side effects like nausea and hair loss.
Chemotherapy is different from targeted therapy because targeted therapy drugs affect how the cell works, with a focus on the part of a cancer cell that makes it different from a healthy cell. Targeted drugs leave healthy cells alone, reducing the side effects.
While targeted therapy can be generally less toxic than chemo, it’s not without side effects.
Liver and diarrhea problems may occur, as can mouth sores, the loss of hair color, fatigue, and problems with wound healing and blood clotting.
Finally, cancer cells can also become resistant to targeted therapy, and in these cases, multiple types of treatment approaches may need to be used together. For example, targeted therapy might be used along with chemotherapy to prevent treatment resistance.