Myelodysplastic syndrome (MDS) is a blood disorder of hematopoietic myeloid cell lineage resulting in peripheral blood cytopenias. The bone marrow also becomes hypercellular; although, in quarter of the patients, bone marrow is hypocellular. It is more common in males and elderly population (people in their 70s). In about 80-90% of the cases myelodysplastic syndrome is de novo or primary (with unknown cause) and in the rest 10-15% cases, it is secondary to exposure to chemotherapy, radiation or toxins in the form of chemicals (benzene).(2)
The clinical course of myelodysplastic syndrome is highly variable among patients, from being an indolent course to being highly aggressive course. The revised International Prognostic Scoring System (IPSS-R) stratifies the patients into five groups; namely, very low risk, low risk, intermediate risk, high risk and very high risk. The median survival of the patients for these categories is 8.8 years, 5.3 years, 3.0 years, 1.6 years and 0.8 years respectively. IPSS-R stratifies the risk of patients based on severity of cytopenias (hemoglobin level, neutrophil and platelet count), percentage of blasts in the bone marrow and cytogenetic category.
The French-American-British (FAB) organization classifies myelodysplastic syndrome into five types; namely, Refractory Anemia (RA), Refractory Anemia with Ringed Sideroblasts (RARS), Refractory Anemia with Excess Blasts (RAEB), Refractory Anemia with Excess Blasts with transformation to AML (RAEB-T) and Chronic Myeloid Monocytic Leukemia (CMML). The rate of transformation of each subtype to AML (acute myeloid leukemia) differs with 10-20% rate for RA and RARS, 20-30% for CMML, 40-50% for RAEB and 60-75% for RAEB-T. Even if myelodysplastic syndrome does not progress to AML, it has high mortality subsequent to complications related to infections and bleeding.(2)
Treatment Of Myelodysplastic Syndrome
Myelodysplastic syndrome presents with anemia, neutropenia and thrombocytopenia. Therefore, the treatment is aimed at correcting these blood cytopenias.
The guidelines issued by National Comprehensive Cancer Network (NCCN) advocates treating lower risk myelodysplastic syndrome patients with supportive care. Supportive care includes:
- Patient monitoring, assessment of quality of life and psychosocial support
- RBC transfusion for symptomatic anemia
- Iron overload managed with deferoxamine (sc) or deferasirox (oral), excluding patients with low creatinine clearance (<40 ml/min) in patients who have received >20-30
- RBC transfusions
- Platelet transfusion for bleeding related to thrombocytopenia or aminocaproic acid for severe thrombocytopenia
- CMV negative or leukocyte depleted blood products for CMV negative transplant candidates
- Antibiotic therapy is given only in cases of recurrent infections
For lower risk patients, treatment of symptomatic anemia may also include ESAs (erythropoiesis-stimulating agents), EPO (recombinant erythropoietin) or DAR (darbepoetin) and G-CSF (granulocyte colony stimulating factor) in patients without del (5q); and lenalidomide in patients with del (5q). Azacitidine/decitabine or immunosuppressive therapy can be considered in cases of neutropenia and thrombocytopenia.
The management of higher risk myelodysplastic syndrome patients includes allogeneic hematopoietic stem cell transplant. Azacitidine or decitabine can be used in non-transplant candidates or for candidates with relapse or no response to transplantation.
HSCT (hematopoietic stem cell transplant) is considered the only potential cure for patients with myelodysplastic syndrome. It provides a 3 year survival of 65-75% in selected patients with low risk myelodysplastic syndrome having <5% marrow myeloblasts. It is only done in selected young patients <55 years and late stage myelodysplastic syndrome. HSCT carries higher post transplant relapse rate (10-40%) and high mortality with the procedure. However, the role of HSCT is limited in myelodysplastic syndrome patients as most of the patients are elderly. Therefore, recovery is rarely achieved in myelodysplastic syndrome patients. Since, most of the patients have to remain on supportive therapy for the course of the disease.
The benefit of red blood cell transfusion is temporary as it lasts only for about 2-4 weeks, which is the lifespan of transfused RBCs; therefore, repeated RBC transfusions are necessary. The benefit of platelet transfusion is also temporary and lasts only 3-7 days, which is the life span of transfused platelets. The patients may succumb to life threatening infections and severe bleeding, if not due to Myelodysplastic syndrome.(1)
- What is Myelodysplastic Syndrome: Causes, Types, Signs, Symptoms
- Myelodysplastic Syndromes: Staging, Risk Factors, Complications, Diagnosis
- Myelodysplastic Syndromes Treatments: Chemotherapy, Immunotherapy, Bone Marrow Transplant
- Myelodysplastic Syndromes or MDS: Treatment for Side Effects, Children with MDS
- Myelodysplastic Syndromes: Survival Rates, Prognosis, Recurrence, Remission, Lifestyle Changes, Prevention
- Coping with Myelodysplastic Syndromes & its Follow-Up Care