Intensive treatment strategies in patients with high-risk myelodysplastic syndrome and secondary acute myeloid leukemia

[High risk of cardiac dysfunction after treatment of secondary acute myeloid leukemia following chemotherapy and radiotherapy for breast cancer]

Secondary acute myeloid leukaemia (AML) occurring after breast cancer is a rare long-term complication of the chemo- and/or radiation therapy required to treat breast cancer. The usually recognized curative option of these secondary AML includes courses of anthracycline-based chemotherapy followed by haematopoietic stem cell transplantation (HSCT). Cardiac dysfunction during AML treatment of these patients previously treated with anthracyclines for breast cancer has not been reported to date. We evaluated the evolution of cardiac function in seven patients treated with anthracyclines and/or autologous or allogeneic bone marrow transplantation for secondary AML occurring after breast cancer. All of the patients who received a cumulative anthracycline dose above the cardiac toxicity threshold developed cardiac symptoms during AML chemotherapy courses. Moreover, four of the five transplanted patients developed severe heart failure among which two were fatal. Thus, the risk of severe cardiac dysfunction after treatment of secondary AML following breast cancer must be taken in account as part of the therapeutic strategy of those patients. As discussed here, an accurate evaluation of risk factors, the use of sensitive detection tests and of cardioprotective drugs as well as that of non-cardiotoxic chemotherapy might decrease the occurrence and severity of this life-threatening complication.

The myelodysplastic syndromes: diagnosis and treatment

The myelodysplastic syndromes (MDSs) are common, acquired, clinically challenging hematologic conditions that are characterized by bone marrow failure and a risk of progression to acute leukemia. These disorders can arise de novo, especially in elderly patients or, less often, as a consequence of prior chemotherapy or radiotherapy for an unrelated disease. The MDS classification systems were revised recently and updated. These refined classification and prognostic schemes help stratify patients by their risk of leukemia progression and death; this knowledge can help clinicians select appropriate therapy. Although many treatments for MDS have been proposed and evaluated, at present, only hematopoietic stem cell transplantation offers any real hope for cure, and no available therapy beyond general supportive care offers benefit to more than a minority of patients. However, recent clinical trials enrolling patients with MDS have reported encouraging results with use of newer drugs, including lenalidomide, decitabine, and darbepoetin alfa. Other exciting treatment regimens are being tested. Here, we present a contemporary, practical clinical approach to the diagnosis and risk-stratified treatment of MDS. We review when to suspect MDS, detail how to evaluate patients who may have a form of the condition, explain key features of treatments that are currently available in the United States, and summarize a general, common-sense therapeutic approach to patients with MDS.

The effectiveness of high–resolution-comparative genomic hybridization in detecting the most common chromosomal abnormalities in pediatric myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a diverse and heterogeneous group of clonal and potentially malignant bone marrow (BM) disorders. The up-to-date used criteria are the ones proposed by the French-American-British (FAB) group in 1982, the World Health Organization (WHO) classification, and a new, recently presented classification: categories cytology cytogenetics (CCC) system or 2003 WHO classification scheme. Comparative genomic hybridization (CGH) is a technique that permits the detection of chromosomal imbalances within a "one step" analysis. In our study, we present 5 cases of MDS and 4 cases of acute myelogenous leukemia (AML). By means of high-resolution CGH (HR-CGH) analysis, we were able to detect DNA copy number alterations in 8 out of 9 samples. The changes were as follows: -7, -Y, del(5)(q33q34), del(11)(q22q24), del(5p), del(9)(q21q31), nullisomy X, and +8. In 5/9 cases the HR-CGH data were highly comparable with conventional cytogenetics and interphase/metaphase fluorescence in situ hybridization findings. Additionally, in 3 BM samples the HR-CGH revealed the presence of changes that had not been detected by conventional cytogenetics: del(5p), del(5)(q33q34), del(9)(q21q31), and nullisomy X. The high effectiveness, specificity, and sensitivity of this method are in concordance with the conventional cytogenetics and FISH findings and the ability to detect new changes.

The Hematopoietic Stem Cell in Myelodysplasia

The mechanisms underlying hematopoietic stem cell or progenitor cell abnormalities in myelodysplastic syndromes (MDSs) remain poorly characterized. Current evidence exists for multiple intrinsic and extrinsic influences upon the stem cell in these disorders. These influences are outlined in this review and include: stem cell characteristics in MDSs, as compared with those in acute myelogenous leukemia; the role of increased apoptosis; the role of signaling pathway abnormalities; the influences of immune modulation; and the effect of stromal cells and stromal cell cytokine production. Despite numerous studies that have examined these factors, how they converge to produce a situation in which accelerated proliferation and accelerated death occur simultaneously remains largely an unexplored area. It is anticipated that future studies that focus on well-characterized and purified progenitor populations in these disorders will elucidate the process by which ineffective hematopoiesis results from the influences of stem cell abnormalities versus abnormalities in the stem cell's microenvironmental and immunologic milieu.

Peripheral blood is safer than bone marrow as a source of hematopoietic progenitors in patients with myelodysplastic syndromes who receive an allogeneic transplantation. Results from the Spanish registry

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative therapy for patients with myelodysplastic syndromes (MDSs). We have analyzed the outcome of 81 patients who underwent an allogeneic transplant from an HLA-identical sibling donor. The overall survival (OS) was 31% and disease-free survival was 30% at 5.8 years. Transplant-related complications were the cause of death in 44% and disease progression in 16% of patients. Acute graft-versus-host disease (aGVHD) grades II-IV occurred in 32 cases (39%). Extensive chronic GVHD (cGVHD) was observed in 27% of patients. When the log-rank test was performed, we observed that patients transplanted more than 6 months after diagnosis, and those transplanted with bone marrow (BM) displayed a shorter survival (P=0.009 and 0.005, respectively). Patients who developed cGVHD showed a trend towards better OS (P=0.07). Patients receiving BM had a higher incidence of aGVHD (65 vs 50%) and less cGVHD (52 vs 30%), although the differences did not reach statistical significance. Moreover, patients who received PB-HSC displayed a faster engraftment (P=0.000) and showed a significantly lower early transplant-related mortality (14 vs 42%; P=0.006) and longer OS (P=0.005). In summary, our results show that hematopoietic transplantation should be performed as soon as possible in MDS patients and that PB is preferable to BM as a source of HSC.

Pathogenesis, classification, and treatment of myelodysplastic syndromes (MDS)

Myelodysplastic syndromes (MDS) comprise a heterogeneous group of clonal myeloid disorders characterized by morphologic dysplasia in one or more cell lineages. Dysplasia in MDS is associated with insufficient production of blood cells and consecutive cytopenia(s). The natural course and prognosis of MDS vary among patients and depend on genetic defects that occur during clonal evolution. In a significant group of patients (roughly 30%) progression to secondary leukemia is observed. These patients appear to have a grave prognosis. The treatment of patients with MDS has to be adjusted to the individual situation and age in each case. In many patients, control of blast cell production by palliative cytoreduction, continuous support with red blood cells, as well as other supportive measures, seem appropriate. In other patients, however, curative therapy (chemotherapy, stem cell transplantation) should be considered. The final decision to offer curative therapy must be based on many different factors including age and the overall situation of the patient. Recently established scoring systems aimed at predicting survival and evolution of leukemia in MDS may be helpful in this regard.

The myelodysplastic syndrome(s): a perspective and review highlighting current controversies

The myelodysplastic syndrome (MDS) includes a diverse group of clonal and potentially malignant bone marrow disorders characterized by ineffective and inadequate hematopoiesis. The presumed source of MDS is a genetically injured early marrow progenitor cell or pluripotential hematopoietic stem cell. The blood dyscrasias that fall under the broad diagnostic rubric of MDS appear to be quite heterogeneous, which has made it very difficult to construct a coherent, universally applicable MDS classification scheme. A recent re-classification proposal sponsored by the World Health Organization (WHO) has engendered considerable controversy. Although the precise incidence of MDS is uncertain, it has become clear that MDS is at least as common as acute myelogenous leukemia (AML). There is considerable overlap between these two conditions, and the former often segues into the latter; indeed, the distinction between AML and MDS can be murky, and some have argued that the current definitions are arbitrary. Despite the discovery of several tantalizing pathophysiological clues, the basic biology of MDS is incompletely understood. Treatment at present is generally frustrating and ineffective, and except for the small subset of patients who exhibit mild marrow dysfunction and low-risk cytogenetic lesions, the overall prognosis remains rather grim. In this narrative review, we highlight recent developments and controversies within the context of current knowledge about this mysterious and fascinating cluster of bone marrow failure states.