Every person who is diagnosed with multiple myeloma hopes to achieve complete response – defined as no sign of disease – and to avoid relapses.1 With modern treatments, rates of complete response are high for many people treated for myeloma, and these rates are expected to continue to increase.2 However, relapse continues to be a serious concern for many people who achieve remission from myeloma. Even just a few cancer cells remaining after treatment could grow and eventually cause relapse.
In recent years, a new technique has emerged to accurately detect and measure even tiny numbers of cancer cells that may be missed by other types of tests.3 This measurement of remaining cancer cells is known as minimal residual disease (MRD).3 Some tests for MRD can detect even one myeloma cell among 1 million normal cells.3
Today, researchers are working to establish when MRD should be tested in people with myeloma.3
Doctors need samples of blood or bone marrow to test MRD. Tissue samples are subjected to flow cytometry, which measures cells, and next-generation genetic sequencing, which examines cells’ DNA.4 In cases of myeloma, the results of these tests are combined with imaging scans to check for signs of disease outside the bone marrow.4
Negative MRD test results indicate that no myeloma cells were detected in the tissue sample.4 Positive MRD results mean that myeloma cells were found.4 In the case of MRD testing, a negative result is a good sign.
MRD is being used within clinical trials for new myeloma treatments.5 Participants in clinical trials are tested during studies to find out whether one treatment produces more people with negative MRD test results (no remaining myeloma cells) over another treatment.5 The treatment that provides the most MRD-negative results may be more effective.5
Once guidelines are established for measuring and using MRD results in myeloma, they may provide doctors with knowledge about how well myeloma treatments are working and help them tailor your treatment plan.3
According to multiple studies, people with myeloma who achieve a negative MRD status after treatment live longer without myeloma progression.2 Someday, measuring MRD may help doctors better predict the long-term survival of many people being treated for myeloma.3
Currently, MRD testing is not routinely recommended for most people with myeloma.5 At the present time, only participants in clinical trials for myeloma treatments routinely undergo MRD testing.5 Researchers still have questions about what MRD test results mean for people with myeloma. For instance:
Without clear answers to these questions, there are not yet guidelines for how doctors should use MRD test results to help treat people with myeloma. Research is ongoing to answer these questions and determine how best to use MRD results to help make treatment decisions.
Expense is also a consideration in MRD testing. Most health insurance carriers consider MRD specialized testing.4 MRD testing may require prior authorization and may incur extra fees if samples need to be sent to an out-of-network lab.4 If your doctor has recommended you undergo MRD testing, your insurance provider can help you understand what your cost will be.
For now, MRD is valuable as a new way for researchers to better gauge the effectiveness of myeloma treatments in clinical studies.
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