The myelodysplastic syndromes (MDS) are a group of bone marrow failure disorders. The bone marrow is the factory for the production of blood cells including red blood cells (energy), white blood cells (immune system), and platelets (clotting). In MDS, the bone marrow is damaged and fails to produce enough blood cells (cytopenias).
The cause of MDS is unknown in more than 80% of patients. MDS is more common in men and is more common in older individuals. Exposure to chemicals such as benzene and other solvents and tobacco are known to increase the risk of developing MDS. Patients who receive certain types of chemotherapy or radiation treatment for other cancers may also be at increased risk of developing MDS.
MDS is typically a disease of older individuals, but MDS can occur in younger patients and even children. Up to 10% of cases, mostly diagnosed in children and young adults, have a genetic predisposition. Many of these are linked with the inherited genetic conditions such as Fanconi anemia, Familial MDS/AML (GATA2, DDX41), Thrombocytopenia 2 (ANKRD26), Thrombocytopenia 5 (ETV6), Familial aplastic anemia (SRP72), Shwachman-Diamond syndrome, Diamond Blackfan anemia, Congenital neutropenia, Familial platelet disorder, and Myeloid neoplasms with germline predisposition (ATG2B, GSKIP). Since inherited forms of MDS are diagnosed at an early age it is not recommended that older individuals who develop MDS have their families screened. Younger individuals who develop MDS may wish to be evaluated by a genetics specialist to determine if an inherited syndrome exists.
MDS is a rare disease with only 10-15,000 new patients diagnosed each year. However, the incidence may be increasing as the population ages and more individuals are exposed to toxic chemicals and/or prior chemotherapy treatments.
The main symptoms of MDS are a consequence of the low blood counts (cytopenias):
a) Fatigue, shortness of breath, palpitations (common anemia symptoms from low red blood cells)
b) Fever, recurrent or prolonged infections (common neutropenia symptoms from low white blood cells)
c) Bruising, petechiae, or bleeding (common thrombocytopenia symptoms from low platelet counts)
Routine complete blood counts (CBC) often indicate decreased levels of blood cells and prompt referral to a blood specialist (hematologist or oncologist). After excluding vitamin deficiencies (such as low iron or vitamin B12), a bone marrow evaluation is performed. This involves inserting a needle into the hip bone and removing a small specimen for examination under the microscope. A diagnosis of MDS requires abnormal changes (dysplasia) observed in at least one blood cell factory. The sample may also be examined for changes (mutations) of chromosomes or genes, which determine prognosis and may influence treatment decisions.
The diagnosis of MDS requires the bone marrow to look abnormal (“dysplasia”) under the microscope, have leukemia blasts, or have characteristic chromosomal changes. But sometimes individuals have suspicious blood problems that don’t fit into the diagnostic categories. Three new classifications have recently been defined. Patients with Idiopathic Cytopenia of Undetermined Significance (ICUS) have persistently low blood counts but do not have the required changes of MDS in the bone marrow. Patients with Clonal Hematopoiesis of Indeterminate Potential (CHIP) have abnormal gene mutations commonly associated with MDS but no abnormal blood counts or other findings. Finally, patients with Clonal Cytopenia of Undetermined Significance (CCUS) have both genetic mutations and low blood counts but do not have the MDS required abnormal appearing bone marrow cells in 10% or more of the cells. ICUS, CHIP, and CCUS may evolve over time into MDS or other blood diseases. Individuals with these pre-MDS conditions should be monitored every few months with blood counts to watch for progression.
About one-third of people with MDS will develop Acute Myelogenous Leukemia, a disease in which blasts fill up the bone marrow inhibiting blood production. These patients may need more aggressive chemotherapy treatments to restore blood count recovery. MDS patients who have the excess blast subtypes (RAEB-1 and RAEB-2) are at increased risk of converting to leukemia. However, overall, the majority of MDS never develop leukemia.
The International Prognostic Scoring System (IPSS) is the most commonly utilized tool to estimate prognosis and guide treatment planning. This simple system uses the number of cytopenias, types of cytogenetic abnormalities and percentage of leukemia blasts to place patients into prognostic groupings. The scoring system has been recently revised and other systems are available. A scoring calculator is available on-line on the MDS Foundation website.
Many patients with MDS will have genetic abnormalities found within the abnormal blood or bone marrow cells (somatic mutations). This is not the same as having a genetic abnormality in the “germline” which can be passed onto the next generation (inheritable). These somatic genetic changes are a part of the cancer and drive the aggressiveness of MDS.
An important part of MDS diagnosis is to look for chromosomal changes within the bone marrow aspirate/biopsy sample. A “cytogenetic analysis” or “karyotyping” is a detailed examination of approximately 20 bone marrow cells for large breaks or changes in the DNA. Chromosomal changes are associated with varying prognosis. This information is used as part of the revised IPSS (International Prognostic Scoring System). It is important that MDS patients know their cytogenetic pattern to determine their prognosis (the R-IPSS calculator can be found on the MDS Foundation website). Certain chromosomal changes also suggest specific treatments – for example patients with a deletion of the long arm of chromosome 5 (known as 5q minus) are more likely to respond to treatment with lenalidomide.
A new part of MDS prognosis is an examination for specific gene mutations (smaller than cytogenetic changes). Next-generation-sequencing (or NGS) can identify changes in individual genes found in blood in addition to marrow samples. Over 80% of patients will have at least one mutation using NGS. We are still learning how these mutations effect prognosis or may change treatments. For example mutations of TP53, EZH2, ETV6, RUNX1, and ASXL1 have all been associated with higher risk disease. The hope is that these mutations will also open new opportunities for drug development, such as new treatments being directed against IDH1/IDH2 or TP53.
Treatment selection for MDS is highly individualized based on the subtype of MDS and the prognostic score (R-IPSS). In patients with lower risk disease attention towards improving quality of life issues becomes paramount. Transfusional support reduce fatigue and shortness of breath is common. Blood growth factors (such as erythropoietin) and low dose chemotherapy options may also be appropriate. For patients with higher risk disease treatments are often geared towards extending life. Outpatient chemotherapy options have been proven to be beneficial and are usually well tolerated even in older individuals. Bone marrow transplants may be considered as a curative treatment in healthier younger patients.
Some of the most common treatment options are:
Anemia, or low red blood, is common in MDS and may lead to symptoms of fatigue, shortness of breath and chest pain. A transfusion of red blood cells may help reduce these symptoms. Normal hemoglobin levels are 14-16 gm/dl for men and 12-14 gm/dl for women. Most patients will feel pretty normal if the hemoglobin is above 10 gm/dl. Many doctors will offer transfusions to MDS patients who have hemoglobin levels below 7 gm/dl or any patient who is symptomatic (transfusion triggers vary from center to center). A transfusion of one unit of red blood cells may raise the hemoglobin by just shy of 1 gm/dl. However with repeated transfusions, the hemoglobin may not rise as much as the patient’s immune system starts to destroy the foreign blood. Your blood type determines what type of blood you can receive. During the infusion some individuals with MDS may develop fevers or itching which typically goes away quickly. Shortness of breath from the fluid of the transfusion may occur but can be treated with diuretics (medications that cause increased urination to rid the excess fluids). All blood is screened for HIV (AIDS) and hepatitis and thus the risk is very, very, small for these viruses. Bacterial infections from the transfusions have also occurred, but again the risk is small. Since blood contains iron, patients who receive more than 20 transfusions may develop iron overload. Screening for iron overload (ferritin test) may be performed as medications for iron overload may be helpful in some patients.
Thrombocytopenia, or low platelets, may cause an increased risk of bleeding. Transfusions of platelets are possible and have similarly low risks of infusion reactions or infections to red blood cell transfusions. Normal platelets are >150,00/uL but bleeding is rare unless platelet counts are very low (<20,000/uL).
Growth factors are proteins that help stimulate the body to produce blood cells. In MDS patients with low red blood cells (anemia) injections with erythropoietin may slowly help raise blood counts and reduce the need for transfusions. These injections are initially given on a weekly basis for up to 8-12 weeks, but then may be spaced out as needed to maintain adequate blood counts. Erythropoietin injections are a common early treatments for “low grade” MDS and are most effective for individuals who are not yet receiving frequent transfusions or for those patients who have low natural levels of erythropoietin (<500, as the kidneys make erythropoietin). A new red blood cell growth factor, luspatercept, is completing experimental testing and may be available shortly. White blood cell growth actors, including filgrastim, sargramostim and pegfilgrastim, quickly raise white blood cells to fight infections. They are used mostly during times of infection, rather than routinely during low blood counts, as their effect is limited. Platelet growth factors are available, but rarely used in MDS, as they may increase the risk of conversion to leukemia.
The most common chemotherapy treatments for higher grade MDS are injections with the hypomethylating agents azacytadine or decitabine. They are administered for one week (5-7 days) each month in the outpatient cancer center. They are well tolerated, with most patients having minimal side-effects, although nausea, diarrhea or constipation, bruising or low grade fevers may occur. They work slowly to improve blood counts over 4-6 months, but may make the blood counts worse for the first 1-2 months. They may also slow the progression to leukemia. Large clinical studies performed for than a decade ago demonstrated that MDS patients with IPSS intermediate-2 and high risk disease obtained improved blood counts, less leukemia, better quality of life, and longer lifespan compared to transfusions alone. These studies support routine use of the hypomethylating agents for most higher risk disease, even in older or frail patients, especially since they improved quality of life compared to no treatment. Newer studies have suggested that shorter courses (3-5 days per month) may improve blood counts in IPSS lower risk disease. Patients who are improving (or stable) on the hypomethylating agents may continue these treatments indefinitely. There are many experimental treatments under investigation that seek to combine new drugs with the hypomethylating agents.
Lenalidomide is a chemotherapy pill used to improve red blood cells in MDS. It is commonly used for patients a specific low grade subtype of MDS (5q minus chromosome deletion) but occasionally used in patients with other low grade subtypes (“off label” non-approved). The medication may take 2-3 months to improve blood counts. Common side-effects include rash, itching, diarrhea and fatigue. Blood clots in the legs have been seen in patients with multiple myeloma (a different blood cancer) but are rarely noted in MDS as the dose and disease is different. Lenalidomide is a derivative of thalidomide, a medication that caused birth defects, and thus young women (caregivers) should not touch the pills.
Rarely, MDS may be caused by an altered immune system. Many of these patients may have an “empty” or “hypocellular” bone marrow biopsy which is opposite to the more common “packed” or “hypercellular” bone marrow seen in MDS. These patients may benefit from treatments that temporarily suppress the immune system. Horse or rabbit serum (anti-thymocyte globulin, ATG), or alemtuzumab have been used in immune mediated MDS. These are specialized medications, often given in the hospital, and patients must be watched for infections carefully.
Hematopoietic stem cell transplantation is an aggressive treatment that may cure MDS. However transplants also contain very real risks including death. The decision to proceed to transplant must therefore be considered very carefully, and the procedure should only be performed in experienced centers.
The first step of the transplant is the identification of a bone marrow donor whose white blood cells are similar to the recipient (HLA matching). The donor may give the stem cells in the operating room (multiple bone marrow aspirations) or via an outpatient leukapheresis procedure (similar to dialysis). These procedures are safe for the donor.
The patient with MDS is typically admitted to the hospital for one month to undergo the transplant. During the first week chemotherapy (and/or radiation) is used to destroy the damaged MDS bone marrow. The transplant is next and is merely a transfusion of the donor cells. Patients then wait several weeks for this new marrow to grow. Fevers, infection, and bleeding may occur while the old marrow is gone until the new marrow “engrafts.” Once the blood counts rise patients may be discharged from the hospital but must maintain close contact with the transplant center (often weekly or more visits) for the next several months as they are observed for the important immunologic complication of graft-vs-host disease. GVHD occurs when the donor cells attack their new home, causing rashes, diarrhea, nausea and liver disease. Medications are used to prevent and treat GVHD but this complication can be fatal.
The chance at cure and the risk of serious complications vary widely depending on the type of MDS, the availability of the donor, and the overall health status of the patient (heart, lung, kidney function, etc). Age is an important factor as a many older MDS patients are frail and might not tolerate this aggressive treatment. But older “healthy” patients can be considered. Typically transplant is offered to “higher grade” MDS patients (IPSS-2/high) who are medically “fit”. A discussion however of the risks and benefits of transplantation is always appropriate.
Non-live vaccinations (including flu, pneumonia, and the new shingles vaccine) are safe in MDS patients. Live vaccines should generally be avoided. If you are traveling to an exotic location consultation with an infectious disease expert might be an appropriate.
New therapies requiring testing before they become part of the standard treatment options for patients with MDS. A clinical trial is a research study designed to learn if a new treatment is beneficial. Clinical trials may be offered both as part of the first treatment options or later in the treatment course. Enrollment in a clinical trial requires your informed consent and typically will require additional discussions with research personnel. Studies are monitored by local and federal rules to maximize patient safety. New medications often go through 3 steps towards approval: Phase I studies involve the newest medications with the goals of establishing dose and safety – they entail the most unknown risk. Phase II studies focus on establishing whether the medication works. Phase III studies are often the last step, comparing the new treatment with the current standard treatment to determine which is better. Until everyone is cured, clinical trials are important in advancing care.
In 2020, Reblozyl (luspatercept-aamt) was FDA approved for the treatment of anemia in adult patients with very low-to-intermediate-risk myelodysplastic/myeloproliferative neoplasm with ring sideroblasts (MDS-RS) or myelodysplastic/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis (MDS/MPN-RS/T). To be eligible for this therapy, patients must have proven lack of repsonse to an erythropoiesis stimulating agent and require at least two units of packed red blood cells over an eight-week period. Reblozyl is administered via a subcutaneous injection once every three weeks. The dose is adjusted based on hemoglobin values, transfusion needs, and side effects. Patients should know that it can take up to seven cycles to see maximum benefit.
A lot of focus on the development of new therapies for MDS has been on oral medications. Patients on all-oral therapy regimens may experience benefits such as improved quality of life due to increased flexibility in scheduling and decreased invasive administrations (IV, injection, etc.) Decitabine was initially approved for the treatment of MDS in 2006. Per the IV regimen, patients receive up to five daily infusions every four weeks; the dose is adjusted based on recovery of blood counts. In July of 2020, Inqovi (an oral combination of decitabine and cedazuridine) was FDA approved for the treatment of adults with myelodysplastic syndrome to include chronic myelomonocytic leukemia (CMML). The cedazuridine allows the body to absorb the decitabine when taken orally. Patients take Inqovi on the same schedule as they would receive the IV medication, five daily doses every twenty-eight days. An advantage of this is a reduction in clinic visits days from five to one on treatment weeks unless extra appointments are needed for side effect management. Clinical trials exploring other oral regimens are still ongoing.
Clinical trials are how we move closer towards a cure in MDS. And research is not just for patients who have failed everything else. Many trials are for newly diagnosed or minimally treated patients. Studies have shown the patients who participate in clinical research receive better care, more attention, and may have better outcomes. The MDS Foundation encourages clinical research and lists several high priority studies on its website. The MDS Foundation also uses some of the donated money it receives to support young investigators who are pushing the forefront of MDS research.
Most active clinical studies are listed on a government website: WWW.CLINICALTRIALS.GOV. It is helpful if you know your MDS subtype and IPSS prognostic score as you search for appropriate trials. The MDS Foundation may also be able to suggest potential trials and/or refer patients to their local MDS Foundation Center of Excellence (described below) for additional information.
MDS is a blood cancer and is best treated by either a hematologist (blood disease specialist) or oncologist (cancer specialist). “Board certification” indicates that the doctor has passed national tests demonstrating knowledge of blood cancers including MDS. However not all hematologist-oncologists are familiar with MDS and it is important to choose a doctor who keeps abreast of the newer treatments of MDS. Major medical centers often have physicians who sub-specialize in MDS, leukemia, and/or transplantation. Some centers also conduct basic research (laboratory or animal) and/or clinical research (human studies) on MDS. These centers may offer treatments otherwise not available. Location may also be important, as MDS therapy may require frequent clinic visits for transfusions, growth factors or chemotherapy. If the major MDS center is a distance from your home, inquire whether the local physician works in concert with the expert team (joint management) or will refer for second opinions to help with major decisions. Never be fearful about offending your doctor by asking for a second opinion. And don’t hide the results of the opinion — modern doctors welcome help. Finally, the MDS-Foundation maintains a list of “Centers of Excellence” and they are listed on the website. These centers have dedicated clinical and research expertise in the treatment of MDS.
The MDS Foundation is the leading patient advocacy organization for patients with myelodysplastic syndromes and bone marrow failure disorders. You can support our mission by becoming a member. Applications are on the website. Attending an MDS Foundation seminar and learning more about the disease will help you and your loved ones face the disease better. Each year approximately 10 seminars are held at rotating sites across the United States. Spreading the word about MDS on social media such as Facebook and Twitter helps increase awareness. And of course, financial donations are always welcomed.
Under the microscope the bone marrow appears abnormal (dysplasia) and may have changes at a genetic-molecular level. Therefore, MDS meets the formal definition of cancer. However, from a clinical standpoint, MDS acts more like a marrow failure disease. MDS may turn into leukemia which can be very aggressive.
Being open and asking questions is an important part of MDS care. Talk to the doctors, nurses and other health professionals. Inquire about social and financial support if needed. Chat with other patients and consider support groups. The more you tell your team, the better they can help you. The MDS Foundation is also available to guide you through the journey.
