Targeted therapy for cancer

Targeted therapy is a type of cancer treatment that uses drugs to target the specific genes, proteins and surrounding tissues that help a cancer cell grow. Targeted therapies can be used to treat many types of cancer and are often given in combination with other cancer treatments such as chemotherapy and radiation therapy.

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How does targeted therapy work?

Cells in your body rely on chemical signals from your genes to work properly. When genes mutate and change, the cells grow out of control. This turns healthy cells into cancer cells.

Targeted therapy identifies the genetic changes and mutations that are helping cancer cells grow and thrive. These changes could be found in genes, proteins within a gene, or surrounding tissue and blood vessels.

Once the genetic changes are identified, specific treatments are used to help treat cancer by:

• Stopping or blocking the chemical signals telling the cancer cell to grow
• Sending a signal to the cancer cell to destroy itself
• Changing the proteins within the cancer cell
• Stopping the growth of new blood vessels that support the cancer cell
• Sending toxins to the cancer cell

How are genetic changes in cancer cells identified?

Targeted therapy drug treatments are considered precision medicine, or personalized medicine. They are unique to you and tailored for your type of cancer.

To find the right type of targeted therapy treatment, your provider may order biomarker testing to identify the genetic changes to target and attack. This is done by taking samples from your cancer cells through a biopsy, during surgery or through a blood draw.

How does targeted therapy differ from chemotherapy?

Unlike chemotherapy, targeted therapy does not impact healthy, normal cells. Targeted therapy drugs are formulated to only attack the cancer cells.

Chemotherapy is also limited to killing off cancer cells that have already been made, where targeted therapy can stop a cancer cell from dividing and multiplying.

Types of targeted therapy

There’s a wide range of different types of targeted therapies approved to treat many different types of cancer. Monoclonal antibodies and small-molecule drugs are two of the most common types used.

• Monoclonal antibodies: Proteins produced in a lab are designed to attach to a target found on a cancer cell. Some monoclonal antibodies mark their target so your immune system knows to attack it – a treatment similar to immunotherapy for cancer. Others carry toxins or send a signal to the cancer cell to stop growing or self-destruct.
• Small-molecule drugs: These drugs are tiny enough to enter a cell. Once they find their target, they block it.

Another common type of targeted therapy involves inhibitors. These drugs block or disrupt the mutations affecting the cancer cell. Common types of inhibitors include angiogenesis inhibitors, proteasome inhibitors and signal transduction inhibitors.

• Angiogenesis inhibitors: Disrupt the growth of new blood vessels that support a cancer cell, causing the cell to die.
• Proteasome inhibitors: Disrupt normal cell functions, causing the cancer cell to die.
• Signal transduction inhibitors: Disrupt activity signals being sent to the cell, causing the cancer cell to stop growing or multiplying.

How is targeted therapy given?

Targeted therapy drugs may be taken through oral medication (small-molecule drugs) or an IV line into a vein (monoclonal antibodies).

The frequency of your targeted therapy is unique to your cancer type, stage and how your body reacts to it. Treatment may be given in cycles or given daily, weekly or monthly.

Targeted therapy examples for cancer treatment

Targeted therapy drugs are formulated to treat one or more genes found within a cancer cell. Some treatments are combined for effectiveness. A few common examples of targeted therapy drugs for cancer include:

• Breast cancer: Monoclonal antibodies and kinase inhibitors
• Ovarian cancer: Angiogenesis inhibitors and poly-ADP ribose polymerase (PARP) inhibitors
• Colon cancer: Estimated glomerular filtration rate (eGRF) inhibitors and vascular endothelial growth factor (VEGF) drugs
• Pancreatic cancer: PARP inhibitors and neurotrophic tyrosine receptor kinase (NTRK) inhibitors
• Prostate cancer: PARP inhibitors and neurotrophic tyrosine receptor kinase (NTRK) inhibitors
• Melanoma (skin cancer): Mitogen-activated protein kinase (MEK) inhibitors and V-raf murine sarcoma viral oncogene homolog B1 (BRAF) inhibitors

Targeted therapy benefits and risks

All cancer treatments have their advantages and disadvantages. While targeted therapy is an important part of cutting-edge cancer research and has many benefits, not everyone responds to it in the same way. Identifying your specific target can be a challenging process for providers as well.

Benefits of targeted therapy

• Kills cancer cells without damaging normal cells
• Blocks cancer cells from growing or multiplying
• Helps the immune system destroy cancer cells

Risks of targeted therapy

• Cancer cells may not respond to treatment
• Cancer cells may become resistant to treatment

Targeted therapy side effects

The side effects that you may experience depend on your treatment type and your health history. The most common side effects include diarrhea and liver problems. Other possible side effects include:

• Problems with blood clotting and wound healing
• Mouth sores
• Fatigue
• Heart rhythm changes
• High blood pressure (hypertension)
• Neurologic changes
• Loss of hair color
• Nail changes
• Dry skin or rashes
• Photosensitivity

Most side effects can be treated with medications and are short-term. They typically go away after you finish treatment.