Minimum residual disease (MRD) is a relatively new type of test used in blood cancers that can detect small numbers of cancer cells – even one malignant cell in 1 million normal cells – that may remain after leukemia treatment.^1,2 Depending on many factors, including the type of leukemia you have, your doctor may or may not order MRD testing as part of your care plan. Read more about the role of MRD in acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), chronic myeloid leukemia (CML), and chronic lymphocytic leukemia (CLL).

You may undergo MRD testing at different points depending on factors like your type of leukemia. Common testing points include:

• After a final round of combination therapy
• After stem cell transplantation (formerly known as bone marrow transplant)
• During chemotherapy or other treatment
• One year into remission and maintenance therapy
• After treatments are complete
• During or after participation in clinical trials

When it is necessary to obtain a bone marrow sample for MRD testing, a bone marrow biopsy or bone marrow aspiration is performed. A biopsy is used to obtain a sample of solid bone marrow, and an aspiration is used to obtain a fluid bone marrow sample.³ Bone marrow biopsy and aspiration are both obtained in a brief outpatient procedure using a needle. Either local or general anesthetic is usually administered before the biopsy or aspiration. In most people, bone marrow biopsy is performed in the top, rear portion of the hip, but in children may be performed in the breastbone or a lower leg bone.³

Some MyLeukemiaTeam members share concerns about undergoing bone marrow biopsy. Other members are ready with support and reassurance.

Another member who has undergone the procedure before responded, “Biopsy is only uncomfortable for a short time. Keep fighting. In 2015 no one would treat me. They said I would not survive the chemo. I am still alive three years in remission. We can fight!” Another agreed: “I just had [a bone marrow biopsy]. I was afraid, but it really wasn't that bad.”

In another conversation, a MyLeukemiaTeam member reassured another who was facing a biopsy, writing: “I hate needles and doctors, and if I can do it anyone can. It’s really only about 10 minutes, more pressure than pain, most of it was in my head! You’ve got this, stay strong and think positive.”

Members offer tips for those undergoing biopsies to ask for sedation, local anesthetic, or general anesthesia to make biopsies easier:

• “Do not hesitate to request pain medication. You deserve to be as comfortable as possible.”
• “Have them sedate you. I wouldn't do it without again.”
• “Make sure once they inject the first lidocaine [local anesthetic], they rub the area. This helps spread the lidocaine and speeds up the numbing.”
• “If they put you under [general anesthesia] there's nothing to it.😃”

There are three main types of tests that measure minimal residual disease.² Testing methods vary by type of leukemia. The main laboratory tests for MRD are:

Flow cytometry

Flow cytometry must be performed with a fresh bone marrow sample.² Flow cytometry identifies cancer cells by finding protein markers on the cell surface.² Flow cytometry can find one cancer cell in 100,000 normal cells.² Results from flow cytometry may be available in less than one day.²

Polymerase chain reaction (PCR)

PCR may be performed with a blood sample or a bone marrow sample.² PCR looks for DNA specific to leukemia cells. PCR can identify one cancer cell in 100,000 to 1 million normal cells.² It may take several weeks to find out results.

Next-generation sequencing (NGS)

Next-generation sequencing is a faster way to examine the genetic material (DNA or RNA) of cells.² NGS requires a bone marrow sample.² Results from NGS may be available within one week.² So far, the U.S. Food and Drug Administration has only approved NGS tests for use in B-cell acute lymphoblastic leukemia (ALL).²

The results of your MRD test may be:²

Positive – Leukemia cells were detected.

Negative – No leukemia cells were detected.

Negative MRD results are associated with longer remissions and may indicate longer survival rates in some types of leukemia.² MRD detection can help inform your doctor’s recommendations regarding treatment decisions.

MRD measurement is an important way for your doctor to check the effectiveness of your leukemia treatment to ensure a lasting remission.² In some types of leukemia, monitoring for MRD can also help doctors identify that a relapse is beginning and start treatment earlier.² MRD testing provides prognostic information for your doctor, allowing them to personalize your leukemia treatment and give you the best care available.¹

Read more about how MRD test results may help guide doctors’ recommendations through different steps of leukemia treatment.

Some MyLeukemiaTeam members share their MRD results with others. Negative MRD results can often bring members peace of mind.

Another wrote, “According to my last bone marrow biopsy, I am almost in remission.”

Members support each other through anxious times waiting for results, congratulate each other on good results, and encourage one another when results seem discouraging. Joining MyLeukemiaTeam means always having people who understand what you are going through because they have been there too.

If you would like to learn more about the role of minimal residual disease in leukemia, visit these external resources:

• Minimal Residual Disease (MRD) – Leukemia & Lymphoma Society
• Testing for Measurable/Minimal Residual Disease – OncoLink