Targeted therapy is a treatment that targets the cancer’s specific genes, proteins, or the tissue environment that contributes to cancer growth and survival. This type of treatment blocks the growth and spread of cancer cells while limiting damage to healthy cells.
Not all tumors have the same targets. To find the most effective treatment, your doctor may run tests to identify the genes, proteins, and other factors in your tumor. This helps doctors better match each patient with the most effective treatment whenever possible. In addition, research studies continue to find out more about specific molecular targets and new treatments directed at them. These drugs are becoming more important in the treatment of colorectal cancer. Learn more about the basics of targeted treatments.
Studies have shown that older patients are able to benefit from targeted therapies, similar to younger patients. In addition, the expected side effects are usually manageable in both older and younger patients.
For colorectal cancer, the following targeted therapies may be options.
Anti-angiogenesis therapy. Anti-angiogenesis therapy is focused on stopping angiogenesis, which is the process of making new blood vessels. Because a tumor needs the nutrients delivered by blood vessels to grow and spread, the goal of anti-angiogenesis therapies is to “starve” the tumor.
Epidermal growth factor receptor (EGFR) inhibitors. Researchers have found that drugs that block EGFR may be effective for stopping or slowing the growth of colorectal cancer.
Recent studies show that cetuximab and panitumumab do not work as well for tumors that have specific mutations, or changes, to a gene called RAS. ASCO recommends that all patients with metastatic colorectal cancer who may receive an EFGR inhibitor have their tumors tested for RAS gene mutations. If a tumor has a mutated form of the RAS gene, ASCO recommends that patients do not receive EFGR inhibitors. Furthermore, the FDA now recommends that both cetuximab and panitumumab only be given to people with a tumor with non-mutated, sometimes called wild-type, RAS genes.
Tumor-agnostic treatment. Larotrectinib (Vitrakvi) is a type of targeted therapy that is not specific to a certain type of cancer but focuses on a specific genetic change called an NTRK fusion. This type of genetic change is found in a range of cancers, including colorectal cancer. It is approved as a treatment for colorectal cancer that is metastatic or cannot be removed with surgery and has worsened with other treatments.
The tumor may also be tested for other molecular markers, including BRAF, HER2 overexpression, and others. These markers do not have FDA-approved targeted therapies yet, but there may be opportunities in clinical trials that are studying these molecular changes.
Side effects of targeted therapies
Talk with your doctor about possible side effects for a specific medication and how they can be managed. The side effects of targeted treatments can include a rash to the face and upper body, which can be prevented or reduced with various treatments. Find out more about skin reactions to targeted therapies.