Should you be tested for KRAS?
Talk to your doctor about having your tumor tested for KRAS mutations:
- If you are already being treated with Erbitux® (cetuximab) or Vectibix™ (panitumumab) for colorectal cancer.
- Before beginning Erbitux or Vectibix treatment, either as single medicines or in combination with chemotherapy.
- When you are first planning a treatment strategy for advanced colon or rectal cancer.
What’s the test like?
When you had surgery, some of the tumor tissue that was removed from your body was processed into a tissue block and stored at the hospital where you had your operation. If you decide to be tested, your doctor will arrange to have part of the saved tissue block sent to a laboratory that does KRAS testing. After the test is run, the results will be sent to your doctor who will discuss them with you. The sample to be tested can come either from the original cancer in your colon or rectum or from a metastatic tumor that has spread from that primary one.
The test is made on your tumor tissue, not on your blood. Because the KRAS mutation is in the cancer tumor itself, it will not be found in other body cells like blood.
You cannot transmit this mutation to your children.
What if my tumor has a KRAS mutation?
Even if your tumor has a KRAS mutation and will not respond to Erbitux or Vectibix, you may well have good outcomes from treatment with chemotherapy or other biologic agents such as Avastin® (bevacizumab).
Discuss other treatment options with your doctor, including participating in a clinical trial.
What if my tumor does not have a KRAS mutation?
If you have no KRAS mutation, your treatment options can include Erbitux or Vectibix as well as other medicines including Avastin® (bevacizumab.
- Recent research shows that adding Erbitux to FOLFIRI or FOLFOX chemotherapy improves response rate and progression-free survival for initial treatment of colorectal cancer.
- Erbitux is also approved alone or in combination with FOLFIRI or Camptosar® (irinotecan) chemotherapy to to treat colorectal cancer that has gotten worse on other therapies.
- Vectibix is an option for you if your cancer has gotten worse on other standard treatments.
- You may also want to consider participating in a clinical trial, including trials that test Erbitux or Vectibix.
Discuss your options with your doctor.
What the experts are saying
Dr. Eric Van Cutsem, who led the CRYSTAL study of Erbitux and FOLFIRI said,
This study helps us to identify which patients are most likely to benefit from adding cetuximab to treatment. KRAS testing in all people with colorectal cancer immediately after diagnosis could help doctors find the best treatment strategies for the individual patient.
Dr. Rafael Amado, who studied the difference in response rates between patients with mutated and wild-type KRAS who were treated with panitumumab wrote in the Journal of Clinical Oncology,
KRAS status should be considered in selecting patients with metastatic colorectal cancer as candidates for panitumumab monotherapy.
Last Update: October 23, 2008
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