During chronic lymphocytic leukemia (CLL) treatment, specific blood tests and diagnostic measurements are examined to gauge a patient’s treatment response. Dr. Anthony Mato details the specific criteria that are assessed while monitoring a therapy.
Dr. Anthony Mato is Director of the CLL Program at Memorial Sloan Kettering Cancer Center. Learn more here.
How do you monitor to see if a treatment is working, and what if the patient doesn’t respond to any of the treatments?
Yeah, so, we response criteria, and so, they’re largely very simple measures. We perform a physical examination before and after treatment to see if the lymph nodes and spleen are decreasing in size. We measure the white blood cell count to verify that it’s going down. We look for normal parameters of normal functioning bone marrow like improvement in the hemoglobin or the platelet count.
So, those are some of the measures we use, and we put them together. And of course, just asking a patient how do they feel, do they feel better, are the symptoms that were associated with the CLL improving, and if the answer is yes, that would be considered responding disease. We also sometimes do measures like CAT scans to measure internal masses or internal lymph nodes and a bone marrow biopsy to verify that all the CLL cells are gone.
So, that’s the basics of a response assessment, and we also venture now into a new territory called MRD, or minimal residual disease, where we’ll be able to look beyond the traditional response assessment. Sometimes, it measures at a measurement of one in a million cells to verify that there’s no evidence of CLL present. If a therapy’s not working, fortunately – well, first I’ll say that with the modern therapies that we’ve already mentioned, response rates exceeded 90 percent.
So, it very, very infrequent that we have a patient where we pick the appropriate therapy where it doesn’t work for them. But if one is not working, then we do have measurements of resistance, and we can try to tell why a therapy maybe not working and switch them to an alternate class. And oftentimes, that will solve the problem.
Dr. Mato, you mentioned the term MRD. What does that mean?
It stands for minimal residual disease. That’s using technology like flow cytometry or PCR or sequencing to take a deep look in the bone marrow and the blood for the presence or absence of CLL.
So, when I perform a bone marrow biopsy, a pathologist with their eyes might count one hundred cells. With MRD testing we could look at 10,000 or 100,000 or 1,000,000 cells to see if there’s any CLL present, much more than the human eye or the human brain could process.