Targeted therapies are drugs or other substances that block the growth and spread of cancer by interfering with specific molecules involved in tumor growth and progression. Because scientists often call these molecules “molecular targets," targeted cancer therapies are sometimes called “molecularly targeted drugs,” “molecularly targeted therapies,” or other similar names. By focusing on molecular and cellular changes that are specific to cancer, targeted cancer therapies may be less harmful to normal cells and more effective than other types of treatment.
Targeted therapies are considered a chemotherapy drug, but they work differently than traditional chemotherapy drugs. They are able to identify the cancerous cells and attack them, while leaving the normal, healthy cells alone.
Types of Targeted Therapy
Targeted therapies include oral agents called tyrosine kinase inhibitors and intravenous agents called monoclonal antibodies, which are administered in our offices at Medical Oncology Hematology Consultants. Most targeted therapies are either small-molecule drugs or monoclonal antibodies.
- Small-molecule drugs are small enough to enter cells easily, so they are used for targets that are inside cells.
- Monoclonal antibodies are drugs that are not able to enter cells easily. Instead, they attach to specific targets on the outer surface of cancer cells.
Who Receives Targeted Therapy
For some types of cancer, most patients with that cancer will have a target for a certain drug, so they can be treated with that drug. But, most of the time, your tumor will need to be tested to see if it contains targets for which we have drugs.
Many times this type of treatment is safer and has fewer side effects than traditional chemotherapy drugs. Our physicians will determine if a patient is a candidate for a targeted therapy treatment and will explain all that is involved in the treatment process.
How Targeted Therapy Works Against Cancer
Most targeted therapies help treat cancer by interfering with specific proteins that help tumors grow and spread throughout the body. They treat cancer in many different ways. They can:
- Help the immune system destroy cancer cells. One reason that cancer cells thrive is because they are able to hide from your immune system. Certain targeted therapies can mark cancer cells so it is easier for the immune system to find and destroy them. Other targeted therapies help boost your immune system to work better against cancer.
- Stop cancer cells from growing. Healthy cells in your body usually divide to make new cells only when they receive strong signals to do so. These signals bind to proteins on the cell surface, telling the cells to divide. This process helps new cells form only as your body needs them. But, some cancer cells have changes in the proteins on their surface that tell them to divide whether or not signals are present. Some targeted therapies interfere with these proteins, preventing them from telling the cells to divide. This process helps slow cancer’s uncontrolled growth.
- Stop signals that help form blood vessels. Tumors need to form new blood vessels to grow beyond a certain size. These new blood vessels form in response to signals from the tumor. Some targeted therapies are designed to interfere with these signals to prevent a blood supply from forming. Without a blood supply, tumors stay small. Or, if a tumor already has a blood supply, these targeted therapy treatments can cause blood vessels to die, which causes the tumor to shrink.
- Deliver cell-killing substances to cancer cells. Some monoclonal antibodies are combined with toxins, chemotherapy drugs, and radiation. Once these monoclonal antibodies attach to targets on the surface of cancer cells, the cells take up the cell-killing substances, causing them to die. Cells that don’t have the target will not be harmed.
- Cause cancer cell death. Healthy cells die in an orderly manner when they become damaged or are no longer needed. But, cancer cells have ways of avoiding this dying process. Some targeted therapies can cause cancer cells to go through this process of cell death.
- Starve cancer of the hormones it needs to grow. Some breast cancers and prostate cancers require certain hormones to grow. Hormone therapies are a type of targeted therapy that can work in two ways. Some hormone therapies prevent your body from making specific hormones. Others prevent the hormones from acting on your cells, including cancer cells.