As one of the world's leading leukemia programs, MD Anderson's Leukemia Center brings together internationally renowned physicians with a specialized support team to customize your care. These highly experienced experts communicate and collaborate daily, ensuring you receive comprehensive leukemia treatment.
The goal of leukemia treatment is to put the disease into remission and ultimately cure the patient. For leukemia, complete remission usually means that the patient’s bone marrow has no microscopic evidence of the disease and his or her blood counts have returned to normal. For patients with acute leukemia may need additional treatment to maintain remission.
Patients who remain in continued complete remission for an extended period of time are considered cured. This means they have an extremely low chance of recurrence. The exact amount of time it takes to be considered cured differs among leukemia types, but it is typically measured in years.
If you are diagnosed with leukemia, your doctor will discuss the best options to treat it. This depends on several factors, including:
- the type of leukemia
- your age
- your general health
One or more of the following therapies may be used to treat leukemia.
Chemotherapies are powerful drugs that kill rapidly dividing cells like cancer cells. The exact chemotherapy regimen a patient receives depends on the particular type of leukemia. Chemotherapy is often used as a primary treatment for acute myelogenous leukemia (AML) and acute lymphocytic leukemia (ALL). It can also be used for chronic types of leukemia, although targeted therapies are more common. For AML and ALL patients, chemotherapy is given in different phases:
- Remission induction: This is an intense phase of treatment designed to kill leukemia cells in the blood and bone marrow and can require a hospital stay. The goal is to bring cancer into remission.
- Consolidation: This phase of chemotherapy is meant to kill any remaining cancer cells that survived the induction phase.
In addition, ALL patients undergo a third phase of chemotherapy: maintenance. During the maintenance phase, patients receive additional lower doses of chemotherapy over a longer period of time to try to wipe out any remaining cells.
Targeted therapy is designed to stop or slow the growth of cancer by interfering with, or targeting, molecules or genes in cancer cells that help the disease survive, grow and spread. By targeting these particularly vulnerable features, the leukemia cells are ultimately eliminated. There are limited and minimal associated side effects of these treatments. Read more about targeted therapy.
Cancer immunotherapy recruits the immune system to eliminate cancer. There are several types of immunotherapies, and each uses the immune system in different ways. Immunotherapies for leukemia include:
- Antibody-drug conjugates: Antibody-drug conjugates combine an immune molecule (antibody) that seeks and binds cancer cells with a cancer-killing drug. This allows for the drug to be delivered directly to the cancer cells.
- Bi-specific monoclonal antibodies: These therapies use antibodies that seek and bind to proteins on the surface of cancer cells and to activate proteins on immune cells. By doing this, these special antibodies trigger the immune cell to destroy the cancer cells.
- CAR T-cell therapy: In CAR T-cell therapy, patients are given T cells (a type of immune system cell) that have been engineered to recognize and attack cancer. For leukemia, CAR T-cell therapy is currently only FDA-approved for patients under age 25 with B-cell ALL. Only patients who have been treated unsuccessfully with at least two other cancer therapies are eligible. In addition to the FDA-approved treatments, there are a number of CAR T-cell therapy clinical trials currently underway at MD Anderson for patients with various forms of leukemia. Read more about CAR T-cell therapy.
Radiation therapy uses high-energy beams to kill cancer cells. Though it’s not a primary treatment for leukemia, it may be used when the disease has affected the brain and central nervous system or is likely to spread to these areas. Read more about radiation therapy.
A stem cell transplant (or a bone marrow transplant) may be needed for patients whose leukemia has returned or has not responded to standard treatments. It may also be recommended if the patient has a high-risk form of leukemia that would make a cure with standard treatments unlikely. This treatment can be physically challenging, so it is typically not given to patients who are older or otherwise unhealthy.
Stem cell transplantation is not a surgical procedure. It involves collecting stem cells from the blood (and sometimes the bone marrow) of a matched donor. Stem cells can also be collected from a newborn's umbilical cord and placenta.
Before the transplant, the patient receives chemotherapy (or sometimes radiation therapy) to kill off any cancerous bone marrow and to prepare the patient's bone marrow to accept the transplant.
Before the transplant, the patient receives chemotherapy (or sometimes radiation therapy) to kill off any remaining cancerous stem cells and prepare the patient’s bone marrow to accept the transplanted stem cells. The donated stem cells are then given by an intravenous infusion and travel to the bone marrow. There, they grow to produce healthy stem cells, which in turn produce red and white blood cells and platelets found in the blood. Read more about stem cell transplants.
After completing a course of treatment, there are few words that sound better to a patient than “complete remission.” It’s an indication that the treatment has worked, and there is no evidence of cancer based on scans or lab tests.
However, there is a different phrase that can be somewhat confusing to patients – minimal residual disease (MRD). This term is used often by physicians when treating patients with blood cancers, such as leukemia, lymphoma or multiple myeloma.
MRD refers to cancer cells remaining after treatment that can’t be detected by those same scans or tests. But what exactly does it mean for patients?
To learn more about minimal residual disease, we spoke with leukemia specialist Ghayas Issa, M.D., of MD Anderson’s Myelodysplastic Syndromes (MDS) and Acute Myeloid Leukemia (AML) Moon Shot® team. Here’s what he shared.
How do you explain minimal residual disease to patients?
Minimal residual disease is a small number of cancer cells left in the body after treatment. These cells have the potential to come back and cause relapse in our patients.
In leukemia, for example, we look for response after chemotherapy treatment by looking under the microscope for cancer cells present in a bone marrow biopsy. When there are no cancer cells present, and the bone marrow is making normal cells, we call that a complete response.
However, we know that if we don’t do further treatment, a portion of these patients will experience a relapse. That means there were some leukemia cells hiding that we weren’t able to detect under the microscope. That is minimal residual disease, or perhaps a better term is measurable residual disease. Typically, these cells don’t cause any symptoms, but they have the potential to lead to a relapse.
If we can’t detect minimal residual disease under the microscope, how do we test for it?
We now have much more sensitive assays available to us that allow us to quantify MRD. These could include next generation genetic sequencing, where we can analyze bone marrow samples for genetic mutations. If there are mutations present, that means there is minimal residual disease, even though we can’t see anything under the microscope.
We can also use a technique called flow cytometry, which allows us look in the same samples for abnormal proteins on the surface of cells. By determining how many cells have abnormal proteins detected, we can get a better sense of residual cancer cells. Using these new assays, we routinely try to quantify whether a patient has MRD following standard treatment.
What are the implications for a patient who has evidence of minimal residual disease after treatment?
That’s difficult to say, because it’s not the same across all types of blood cancers. Some patients with MRD will have different responses than others. In general, if a patient has MRD, we need to do additional treatments to work toward the best outcome. If we do nothing, we know that the residual cells will cause a relapse.
It also depends on the timing of the MRD test. In my leukemia patients, if there is MRD after the first cycle of chemotherapy treatment, it tells me that I probably need to give more treatment — either a different medication or a different course of treatment. If there is still MRD after many rounds of chemotherapy, that is an indication that the patient may need to have a stem cell transplant, when otherwise it might not have been appropriate.
Ultimately, MRD is a marker that we need to be more aggressive in our treatment to try and prevent the cells from coming back.
What can cancer researchers learn from the residual cancer cells?
We can learn a great deal. These cancers can adapt to treatment, meaning the cancer we start with is not the same as what we have after treatment. By studying the minimal residual disease, we can learn more about what is left after treatment.
That helps us to do several things. First, it allows us to modify our treatment, either by adding medications that target specific vulnerabilities in the cancer cells, including medications that are especially good at killing even residual cells, or doing a stem cell transplant, which is able to take care of residual cells.
Currently, I work with a wonderful team through the MDS and AML Moon Shot to study these residual cancer cells in order to find new vulnerabilities. Through our research, we’re hoping to identify new treatments that we can use in the future to specifically eliminate minimal residual disease.
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