Targeted therapy for colorectal cancer
Targeted therapy is sometimes used to treat colorectal cancer. It uses drugs to target specific molecules (such as proteins) on the surface of cancer cells. These molecules help send signals that tell cells to grow or divide. By targeting these molecules, the drugs stop the growth and spread of cancer cells while limiting harm to normal cells. Targeted therapy may also be called molecular targeted therapy.
You may have targeted therapy to:
- kill colorectal cancer cells
- slow the growth of advanced colorectal cancer
- relieve pain or control the symptoms of advanced colorectal cancer (called palliative therapy)
Your healthcare team will consider your personal needs to plan the drugs, doses and schedules of targeted therapy. You may also receive other treatments.
Targeted therapy drugs used for colorectal cancer
The following targeted therapy drugs are used for colorectal cancer.
Bevacizumab is a monoclonal antibody that targets a substance called vascular endothelial growth factor (VEGF). VEGF helps cells form new blood vessels that carry oxygen and nutrients, which cells need to grow and develop.
Many tumour cells, including colorectal cancer cells, make VEGF. Bevacizumab works by finding and attaching to VEGF and preventing cells from forming new blood vessels. This means the cells can’t get oxygen and nutrients that they need to grow. Targeted therapy drugs like bevacizumab are also called anti-angiogenesis drugs because they stop new blood vessels from forming.
Bevacizumab is given intravenously. It works best when given with chemotherapy because it may also help chemotherapy drugs get to the tumour. Bevacizumab can be combined with any of the following chemotherapy combinations:
- FOLFIRI – leucovorin (folinic acid), 5-fluorouracil (Adrucil, 5-FU) and irinotecan (Camptosar)
- FOLFOX – leucovorin, 5-fluorouracil and oxaliplatin
- irinotecan and capecitabine (Xeloda)
- oxaliplatin and capecitabine
Bevacizumab is used for advanced (unresectable), metastatic or recurrent colorectal cancer. It is given every 2–3 weeks for 6 months or until the disease progresses.
Cetuximab is a monoclonal antibody that targets the epidermal growth factor receptor (EGFR) on the surface of cells. EGFR sends signals to cells that allow them to grow and divide.
Cancer cells have a mutation that makes too many EGFRs. Cetuximab blocks EGFR from working, which stops or slows the growth of cancer cells. This drug doesn’t work on colorectal cancer cells that have KRAS gene mutations, so it is only used for tumours that don’t have the KRAS gene mutation (called KRAS wild-type tumours). Testing for the KRAS gene mutation usually happens during diagnosis.
Cetuximab is given intravenously and usually with irinotecan (Camptosar). Sometimes it is combined with FOLFIRI. It is given every 2 weeks until the disease progresses. It is most often used if the colorectal cancer stops responding to FOLFIRI. Cetuximab is usually the first targeted therapy drug used for metastatic KRAS wild-type tumours.
Panitumumab, like cetuximab (Erbitux), is a monoclonal antibody that targets the epidermal growth factor receptor (EGFR) on cells. It blocks EGFR from working, which stops or slows the growth of cancer cells. It doesn’t work on colorectal cancer cells that have KRAS gene mutations, so panitumumab is only used for tumours that don’t have the KRAS gene mutation (called KRAS wild-type tumours).
Panitumumab may be used alone to treat metastatic colorectal cancer that has not been treated previously or has stopped responding to FOLFIRI. Sometimes it is combined with FOLFIRI or FOLFOX. It is usually given every 2 weeks until the disease progresses.
Regorafenib is a kinase inhibitor. Kinases are proteins on the surface of cells that send signals to help cells grow and form new blood vessels. Regorafenib blocks many different kinases, which helps stop cancer cells from growing.
Regorafenib is given as a pill by mouth (orally). It may be used for metastatic colorectal cancer that has progressed after most other treatments. It is given until the disease progresses again.
Aflibercept is a protein that targets the vascular endothelial growth factor receptor (VEGF) on cells and prevents blood vessels from growing in the tumour. Aflibercept is only used in combination with the combination chemotherapy FOLFORI, in people with metastatic colon cancer that is no longer responding to oxaliplatin.
Information about specific cancer drugs
Details on specific drugs change quite regularly. Find out more about sources of drug information and where to get details on specific drugs.
Questions to ask about targeted therapy
A substance that can find and bind to a particular target molecule (antigen) on a cancer cell.
Monoclonal antibodies can interfere with a cell’s function or can be used to carry drugs, toxins or radioactive material directly to a tumour.
Referring to a disease or tumour that cannot be removed (resected) by surgery.
What’s the lifetime risk of getting cancer?
The latest Canadian Cancer Statistics report shows about half of Canadians are expected to be diagnosed with cancer in their lifetime.