After someone receives a diagnosis of chronic lymphocytic leukemia (CLL), one of the most important steps in determining treatment is having genetic tests (also known as biomarker tests) administered at the time of diagnosis (and potentially repeated during the course of treatment).

These tests can be done on a sample of blood or bone marrow, Dr. Julie Vose, chief of hematology and oncology at the University of Nebraska Medical Center’s Buffett Cancer Center, tells SurvivorNet. The specific genetic tests, she says, may include:

• A FISH panel, which identifies the specific abnormalities in the CLL cells
• A mutation test, which can identify the maturity of CLL cells

“Those two tests help us to guide the different therapies,” Dr. Vose says. If the CLL cells, for instance, “have specific genetic markers, we [might] know that chemotherapy does not work very well in those patients.”

Monitoring CLL After The Initial Diagnosis

In such cases, oncologists might decide the best course of treatment is through targeted, “pathway-directed” therapies, which work by targeting specific signals or pathways on the surface of the CLL cells.

In a small percentage of patients (about 10% to 15%), says Dr. Vose, genetic testing might show that chemotherapy could be beneficial.

Overall, however, “the use of chemotherapy in CLL is really going down because of all of these new agents that are available,” Dr. Vose says.

According to the National Comprehensive Cancer Network guidelines, the choice of the first type of therapy for CLL should be based on:

• Disease stage
• Presence/absence of del(17p) or TP53 mutation (17p deletion refers to a missing part of a chromosome. When that is missing, cells lack the P53 protein necessary to repair damaged DNA and kill off cells that can’t be repaired. Leukemia cells lacking P53 continue to grow and can resist chemotherapy.)
• IGHV mutation status  (A patient’s IGHV mutation status tells doctors the age of the cell that allowed CLL to grow.  This information helps doctors determine which type of treatment to use.)
• Patient’s age
• Patient’s health conditions (such as high blood pressure, diabetes)
• Toxicity of therapy

What To Ask Your Doctor

• Have I had the necessary genetic/biomarker tests for my CLL?
• Did the tests reveal anything specific to my CLL make-up that can help with treatment?
• What type of treatment matches my results and what can I expect from it?
• How will we monitor to see if the treatment is working?

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