myelodysplastic syndromes

what are myelodysplastic syndromes?
a heterogenous collection of clonal hematopoietic stem cell malignant disorders marked by ineffective hematopoiesis leading to anemia, thrombocytopenia, and neutropenia. 33% go on to develop acute leukemia (generally AML), and they proceed marrow failure. these used to be called *refractory anemias.
what is the most common hematologic malignancy in the elderly?
myelodysplastic syndrome – median age 60-75 *not rare – tired bone marrow, due radiotherapy etc
what is primary myelodysplasia?
idiopatic, non-comples cytogenetics, low IPSS, and responds better to therapy
what is secondary myelodysplasia?
usually due to chemo, has comples cytogenetics, high IPSS, and refractory to therapy
what defines CMML?
peripherial blood monocytosis, presents with <5% blasts in peripheral blood and up to 20% blasts in the bone marrow
what are auer rods seen in?
AML
what is refractory anemia?
erythroid dysplasia, <5% blasts, <15% ringed sideroblasts, no auer rods
what is refractory anemia w/ringed sideroblasts?
<5% blasts, <15% ringed sideroblasts, no auer rods
what is refractory cytopenia with multilineage displasia?
dysplasia in >10% of cells in 2+ cell lines
what is refractory cytopenia with multilineage displasia w/ringed sideroblasts?
dysplasia in >10% of cells in 2+ cell lines with >15% ringed sideroblasts
what is refractory anemia with excess blasts types 1 and 2?
RAEB 1: 5-9% blasts, no auer rods
RAEB 2: 10-19% blasts, +/- auer rods
(both can be uni or multilineage dysplasa)
what is 5q-?
a unilineage myelodysplasia, <5% blasts and no auer rods. lenalidamide specifically approved by FDA to treat this
how are myelodysplasic syndromes diagnosed?
blood count, if low, could be MDS due to anemia, neutropenia, thrombocytopenia, or any combo – so do bone marrow bx and look for dyplastic features. cytogenetics should also be assessed.
how doe myelodysplastic syndromes present clinically?
macrocytic anemia, low retic count (BM not working), normal to high EPO (high because body is trying to stimulate more RBCs). B12/folate deficiency needs to be ruled out esp if macrocytic
how do myelodysplastic syndromes appear in a bone marrow bx?
megaloblastic erythroid cells, ringed sideroblasts, micromegakaryocytes, and large/giant dysfunctional platelets
how are myelodysplastic syndromes treated?
there is no standard of care, supportive care: transfusions, growth factors (EPO, G-CSF, GM-CSF, IL-11), chemotherapy, (azcitidine, lenalidomide, amfostine)
how does azacitidine work?
azacitidine treats MDS by DNA hypomethylation, which restores normal function of differentiation/proliferation. it is directly cytotoxic. can double 2 yr survival.
what is lenalidamide?
a thalidomide analogue that has no sedation or neuropathy associated with it. this improved RA in 64% of pts in an 8 wk study and will also work for 5q-
what is a caution for giving pts repeated transfusions?
the body has no way of getting rid of iron, so they can get iron overload
what drug can help with sideroblast forms of RA?
high dose pyridoxine
what MDS has the lowest likelihood of leukemia? what MDS has the highest likelihood of leukemia?
lowest: RA or RARS – b/c lowest blast level. highest: RAEB II
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