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 cancer cells or inside them. 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 and limit harm to normal cells. Targeted therapy may also be called molecular targeted therapy.

You may have targeted therapy to:

• 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.

The following targeted therapy drugs may be given for advanced or recurrent colorectal cancer.

Bevacizumab (Avastin, Mvasi) is given through a needle in a vein (intravenously) every 2 to 3 weeks. It is usually 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 (Eloxatin)
• CAPOX (also called XELOX) – capecitabine (Xeloda) and oxaliplatin

Cetuximab (Erbitux) is given intravenously, usually alone or combined with irinotecan for some colorectal cancers. Sometimes it is combined with FOLFIRI. It is given every 1 to 2 weeks.

Panitumumab (Vectibix) 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 given intravenously every 1 to 2 weeks.

Encorafenib (Braftovi) is given as a pill by mouth. It is combined with cetuximab to treat metastatic colorectal cancer with a BRAF V600E mutation. It may also sometimes be combined with panitumumab.

Regorafenib (Stivarga) is given as a pill by mouth (orally). It may be used for metastatic colorectal cancer that has progressed after other treatments have been tried.

Side effects can happen with any type of treatment for colorectal cancer, but everyone’s experience is different. Some people have many side effects. Other people have only a few side effects.

Targeted therapy attacks cancer cells but doesn’t usually damage healthy cells, so there are usually fewer and less severe side effects than with chemotherapy or radiation therapy. Chemotherapy and radiation therapy can damage healthy cells along with cancer cells.

If you develop side effects, they can happen any time during, immediately after or a few days or weeks after targeted therapy. Sometimes late side effects develop months or years after targeted therapy. Most side effects go away on their own or can be treated, but some side effects may last a long time or become permanent.

Side effects of targeted therapy will depend mainly on the type of drug or combination of drugs, the dose, how it’s given and your overall health. Some common side effects of targeted therapy for colorectal cancer are:

• fatigue
• skin problems
• headache
• fever
• bleeding
• blood clots
• mouth sores
• loss of appetite
• diarrhea
• low white blood cell counts

Less common but serious side effects include:

• holes (perforations) in the stomach or intestines
• heavy bleeding

Tell your healthcare team if you have these side effects or others you think might be from targeted therapy. The sooner you tell them of any problems, the sooner they can suggest ways to help you deal with them.

Details on specific drugs change regularly. Find out more about sources of drug information and where to get details on specific drugs.

Find out more about targeted therapy. To make the decisions that are right for you, ask your healthcare team questions about targeted therapy.