Page 233 - Essential Haematology

Chapter 16 Myelodysplasia / 219

diagnosis of MDS. In a minority of cases (about problem after multiple transfusions; iron chelation
20%) the marrow is hypocellular and may resemble therapy should be started after 30 – 50 units have
aplastic anaemia; in others there is fi brosis. been transfused if the anaemia and the need for
transfusion continues to be the dominant problem.
Lenalidomide is particularly effective in MDS asso-

Cytogenetic a bnormalities
ciated with del(5q) where it can often reduce the
Cytogenetic abnormalities are more frequent in sec- size of the del(5q) clone and reduce transfusion
ondary than primary MDS and most commonly requirements. Myelosuppression is a common
constitute partial or total loss of chromosomes 5 or side - eff ect.
7 or trisomy 8 (Table 16.2 ). Several cytogenetic In selected patients standard or low - intensity
abnormalities are considered so diagnostic of MDS allogeneic stem cell transplantation (SCT) off ers a
that they allow diagnosis of MDS even in the permanent cure.
absence of morphological abnormalities within
cells. Mutations may also be found with molecular

High - r isk m yelodysplastic s yndromes
testing (e.g. of TET - 2 or N - RAS ).
Th e classification of MDS can be confusing and In these patients a variety of treatments have been

flow charts are helpful in the approach to diagnosis attempted to improve the overall prognosis, with
(Fig. 16.3 ). varying degrees of success.

Single - a gent c hemotherapy
Treatment
Hydroxyurea, clofarabine, mercaptopurine, etopo-
Treatment for MDS has improved signifi cantly in side or low - dose cytosine arabinoside may be given

recent years. A key subdivision is into patients with with some benefit to patients with refractory
low risk or high risk disease. An International anaemia with excess blasts (RAEB).
Prognostic Scoring System (IPSS) classifi es the

patients according to percentage of marrow blasts, DNA m ethyl - t ransferase i nhibitors
′
type of karyotype abnormality, and number and 5 - Azacytidine (azacitidine) and 5 - aza - 2 -
severity of cytopenias (Table 16.3 ). deoxycitidine (decitabine) improve blood counts in
a minority of high risk MDS patients. Azacitidine
is given for 7 days every month and improves sur-

Low - r isk m yelodysplastic s yndromes
vival by approximately 9 months.
Patients with less than 5% of blasts in the marrow
and only one cytopenia and favourable cytogenetics Intensive c hemotherapy
are defined as having low - grade MDS. Intensive Chemotherapy as given in AML (see p. 183 ) may

chemotherapy is rarely used for these patients. be tried in high - risk patients. Although the majority
Instead they are not treated or, if necessary, attempts of patients may obtain a remission, relapse is almost
may be made to improve marrow function with inevitable and frequently occurs within a few

haemopoietic growth factors, either singly or in months. The risks of intensive chemotherapy are
combination. Erythropoietin may improve anaemia great because prolonged pancytopenia may occur in
although the haemoglobin should not be raised some cases without normal haemopoietic regenera-
above 12 g/dL. G - CSF shows synergy with erythro- tion, presumably because normal stem cells are not
poietin and may increase the response rate. present.
Ciclosporin or antilymphocyte globulin occasion-
ally help, particularly for those with a hypocellular Stem c ell t ransplantation

bone marrow. SCT offers the prospect of complete cure for MDS
Tranfusion support with red cells and platelets and the advent of non - myeloablative conditioning
as well as appropriate use of antibiotics is often is increasing the age range of patients that may be
required. In the long term, iron overload may be a treated. SCT is usually carried out in MDS without