Autologous stem cell transplantation for therapy-related acute myeloid leukemia and myelodysplastic syndrome

Outcomes of children, adolescents, and young adults following allogeneic stem cell transplantation for secondary acute myeloid leukemia and myelodysplastic syndromes-The MD Anderson Cancer Center experience

We conducted a retrospective analysis of outcomes for children and young adults with sAML/sMDS who underwent HSCT at our institution. Thirty-two patients (median age 20 years) with sAML (n=24) and sMDS (n=8) received HSCT between 1990 and 2013. The median time from sAML/sMDS diagnosis to HSCT was 4.1 months (range: 1.2-27.2 months). The transplant regimens were primarily busulfan based (n=19). BM was the primary donor source (n=15). Eleven recipients were transplanted with residual disease. At a median follow-up of 62.3 months (range: 0.4-250.9 months), 14 patients had disease recurrence. Acute GVHD, grade III/IV, occurred in three patients. Causes of death were as follows: disease relapse (n=12), infection (n=2), pneumonia (n=1), pulmonary hemorrhage (n=1), acute GVHD (n=1), and graft failure (n=1). A PS of ≥90% at the time of HSCT had a significant impact on PFS (P=.02). Patients achieving pretransplant primary CR (n=8) and those with sMDS and RA (n=6) had prolonged PFS (P=.04). On multivariate analysis, shorter time to transplantation (≤6 months from diagnosis of sAML/sMDS) was associated with superior OS (P=.0018) and PFS (P=.0005).

Myelodysplastic syndrome and acute myeloid leukemia following adjuvant chemotherapy with and without granulocyte colony-stimulating factors for breast cancer

Risk of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) post-breast cancer treatment with adjuvant chemotherapy and granulocyte colony-stimulating factors (G-CSF) is not fully characterized. Our objective was to estimate MDS/AML risk associated with specific breast cancer treatments. We conducted a retrospective cohort study of women aged ≥66 years with stage I-III breast cancer between 2001 and 2009 using the Surveillance, Epidemiology, and End Results-Medicare database. Women were classified as receiving treatment with radiation, chemotherapy, and/or G-CSF. We used multivariable Cox proportional hazards models to estimate adjusted hazard ratios (HR) and 95 % confidence intervals (CI) for MDS/AML risk. Among 56,251 breast cancer cases, 1.2 % developed MDS/AML during median follow-up of 3.2 years. 47.1 % of women received radiation and 14.3 % received chemotherapy. Compared to breast cancer cases treated with surgery alone, those treated with chemotherapy (HR = 1.38, 95 %-CI 0.98-1.93) and chemotherapy/radiation (HR = 1.77, 95 %-CI 1.25-2.51) had increased risk of MDS/AML, but not radiation alone (HR = 1.08, 95 % CI 0.86-1.36). Among chemotherapy regimens and G-CSF, MDS/AML risk was differentially associated with anthracycline/cyclophosphamide-containing regimens (HR = 1.86, 95 %-CI 1.33-2.61) and filgrastim (HR = 1.47, 95 %-CI 1.05-2.06), but not pegfilgrastim (HR = 1.10, 95 %-CI 0.73-1.66). We observed increased MDS/AML risk among older breast cancer survivors treated with anthracycline/cyclophosphamide chemotherapy that was enhanced by G-CSF. Although small, this risk warrants consideration when determining adjuvant chemotherapy and neutropenia prophylaxis for breast cancer patients.

SHIP1 regulates MSC numbers and their osteolineage commitment by limiting induction of the PI3K/Akt/β-catenin/Id2 axis

Here, we show that Src homology 2-domain-containing inositol 5'-phosphatase 1 (SHIP1) is required for the efficient development of osteoblasts from mesenchymal stem cells (MSCs) such that bone growth and density are reduced in mice that lack SHIP1 expression in MSCs. We find that SHIP1 promotes the osteogenic output of MSCs by limiting activation of the PI3K/Akt/β-catenin pathway required for induction of the MSC stemness factor Id2. In parallel, we demonstrate that mice with myeloid-restricted ablation of SHIP1, including osteoclasts (OCs), show no reduction in bone mass or density. Hence, diminished bone mass and density in the SHIP1-deficient mice results from SHIP deficiency in MSC and osteolineage progenitors. Intriguingly, mice with a SHIP-deficient MSC compartment also exhibit decreased OC numbers. In agreement with our genetic findings we also show that treatment of mice with an SHIP1 inhibitor (SHIPi) significantly reduces bone mass. These findings demonstrate a novel role for SHIP1 in MSC fate determination and bone growth. Further, SHIPi may represent a novel therapeutic approach to limit bone development in osteopetrotic and sclerotic bone diseases.

Predictive factors for latency period and a prognostic model for survival in patients with therapy-related acute myeloid leukemia

Therapy-related acute myeloid leukemia (t-AML) is an increasingly recognized sequela in patients receiving chemotherapy or radiotherapy for a primary malignancy or autoimmune disease. This study assessed factors related to the latency period (LP) between the antecedent disorder (AD) and t-AML diagnosis and developed a comprehensive prognostic model to predict overall survival (OS). We evaluated a cohort of newly diagnosed t-AML patients treated with cytarabine-based induction therapy from 2001 to 2011. Multivariable linear and proportional hazards models were used to assess the impact of different classes of chemotherapy on the LP and to identify independent prognostic factors for OS. Of 730 treated AML patients, 58 (7.9%) had t-AML. Median LP to t-AML was 5.6 years (range, 0.5-38.4). 64% of patients achieved CR and median OS was 10.7 months. Independent prognostic factors of short LP were age at AD (P < 0.0001) and prior treatment with mitotic inhibitors (P = 0.05). Unfavorable cytogenetics (P = 0.004), antecedent hematologic or autoimmune disease (P = 0.01), age >60 (P = 0.03), and platelet count <30,000 μL (P = 0.04) at the time of t-AML diagnosis were prognostic for inferior OS. A prognostic model using these factors was developed that risk stratified t-AML patients into two groups: favorable and unfavorable. Patients in the favorable group had a median OS of 37.6 months compared with 6.4 months in patients comprising the unfavorable group (P < 0.0001). Multicomponent prognostic models integrating disease or treatment-related covariates can help better understand how t-AML evolves; and can be clinically useful in risk stratifying t-AML patients undergoing induction therapy.

Impact of polymorphisms in drug pathway genes on disease-free survival in adults with acute myeloid leukemia

Acute myeloid leukemia (AML) is a clinically heterogeneous disease, with 5-year disease-free survival (DFS) ranging from under 10% to over 70% for distinct groups of patients. At our institution, cytarabine, etoposide and busulfan are used in first or second remission patients treated with a 2-step approach to autologous stem cell transplantation (ASCT). In this study, we tested the hypothesis that polymorphisms in the pharmacokinetic and pharmacodynamic pathway genes of these drugs are associated with DFS in AML patients. A total of 1659 variants in 42 genes were analyzed for their association with DFS using a Cox proportional hazards model. 154 genetically European patients were used for the primary analysis. An intronic SNP in ABCC3 (rs4148405) was associated with a significantly shorter DFS (HR=3.2, p=5.6 x 10(-6)) in our primary cohort. In addition a SNP in the GSTM1-GSTM5 locus, rs3754446, was significantly associated with a shorter DFS in all patients (HR=1.8, p=0.001 for 154 European ancestry; HR=1.7, p=0.028 for 125 non-European patients). Thus for the first time, genetic variants in drug pathway genes are shown to be associated with DFS in AML patients treated with chemotherapy-based autologous ASCT.

Hematopoietic stem cell transplantation for myelodysplastic syndrome: a review

Allogeneic hematopoietic stem cell transplantation (HSCT) continues to be the only curative option for myelodysplastic syndrome (MDS). Since the majority of the patients with this disease are often older and frail, treatment-related mortality and morbidity remain major obstacles to be overcome. Reduced-intensity conditioning and continued lines of investigation in the field of allogeneic transplantation are expected to ultimately improve the overall therapeutic approach to MDS. In this review we summarize current recommendations and controversies surrounding HSCT for MDS, as well as the use of novel therapeutics in the peri-transplant period.

Therapy-related myeloid neoplasms: pathobiology and clinical characteristics

Therapy-related myeloid neoplasms (t-MNs) are serious long-term consequences of cytotoxic treatments for an antecedent disorder. t-MNs are observed after ionizing radiation as well as conventional chemotherapy including alkylating agents, topoisomerase-II-inhibitors and antimetabolites. In addition, adjuvant use of recombinant human granulocyte-colony stimulating factor may also increase the risk of t-MNs. There is clinical and biological overlap between t-MNs and high-risk de novo myelodysplastic syndromes and acute myeloid leukaemia suggesting similar mechanisms of leukaemogenesis. Human studies and animal models point to a prominent role of genetic susceptibilty in the pathogenesis of t-MNs. Common genetic variants have been identified that modulate t-MN risk, and t-MNs have been observed in some cancer predisposition syndromes. In either case, establishing a leukaemic phenotype requires acquisition of somatic mutations - most likely induced by the cytotoxic treatment. Knowledge of the specific nature of the initiating exposure has allowed the identification of crucial pathogenetic mechanisms and for these to be modelled in vitro and in vivo. Prognosis of patients with t-MNs is dismal and at present, the only curative approach for the majority of these individuals is haematopoietic stem cell transplantation, which is characterized by high transplant-related mortality rates. Novel transplantation strategies using reduced intensity conditioning regimens as well as novel drugs - demethylating agents and targeted therapies - await clinical testing and may improve outcome. Ultimately, individual assessment of genetic risk factors may translate into tailored therapies and establish a strategy for reducing t-MN incidences without jeopardizing therapeutic success rates for the primary disorders.

Treatment of therapy-related myeloid neoplasms with high-dose cytarabine/mitoxantrone followed by hematopoietic stem cell transplant

Few clinical protocols have focused on patients with therapy-related myeloid neoplasms (t-MN). Therefore, we enrolled 32 patients with previously untreated t-MN on a clinical trial testing the effectiveness of a unified induction regimen of high-dose cytarabine and mitoxantrone. The complete remission (CR) rate was 66% (95% CI 47-81%) and the partial remission (PR) rate was 16% (95% CI 5-33%), for an overall response rate of 82%. Day 30 treatment mortality was 9% (3/32), and the most serious induction toxicity was cardiac dysfunction. Among the patients with CR, 13 (62%) received consolidation therapy using an allogeneic hematopoietic cell transplant (HCT), four (21%) received an autologous HCT, and three (16%) received further chemotherapy. We observed long-term disease-free survival in patients who received all three types of consolidation therapy. The remission induction of high-dose cytarabine and mitoxantrone for t-MN is a well-tolerated efficacious combination, which allows aggressive consolidation and long-term disease-free survival.

Value of allogeneic versus autologous stem cell transplantation and chemotherapy in patients with myelodysplastic syndromes and secondary acute myeloid leukemia. Final results of a prospective randomized European Intergroup Trial

BACKGROUND

Allogeneic stem cell transplantation is usually considered the only curative treatment option for patients with advanced or transformed myelodysplastic syndromes in complete remission, but post-remission chemotherapy and autologous stem cell transplantation are potential alternatives, especially in patients over 45 years old.

DESIGN AND METHODS

We evaluated, after intensive anti-leukemic remission-induction chemotherapy, the impact of the availability of an HLA-identical sibling donor on an intention-to treat basis. Additionally, all patients without a sibling donor in complete remission after the first consolidation course were randomized to either autologous peripheral blood stem cell transplantation or a second consolidation course consisting of high-dose cytarabine.

RESULTS

The 4-year survival of the 341 evaluable patients was 28%. After achieving complete remission, the 4-year survival rates of patients under 55 years old with or without a donor were 54% and 41%, respectively, with an adjusted hazard ratio of 0.81 (95% confidence interval [95% CI], 0.49-1.35) for survival and of 0.67 (95% CI, 0.42-1.06) for disease-free survival. In patients with intermediate/high risk cytogenetic abnormalities the hazard ratio in multivariate analysis was 0.58 (99% CI, 0.22-1.50) (P=0.14) for survival and 0.46 (99% CI, 0.22-1.50) for disease-free survival (P=0.03). In contrast, in patients with low risk cytogenetic characteristics the hazard ratio for survival was 1.17 (99% CI, 0.40-3.42) and that for disease-free survival was 1.02 (99% CI, 0.40-2.56). The 4-year survival of the 65 patients randomized to autologous peripheral blood stem cell transplantation or a second consolidation course of high-dose cytarabine was 37% and 27%, respectively. The hazard ratio in multivariate analysis was 1.22 (95% CI, 0.65-2.27) for survival and 1.02 (95% CI, 0.56-1.85) for disease-free survival.

CONCLUSIONS

Patients with a donor and candidates for allogeneic stem cell transplantation in first complete remission may have a better disease-free survival than those without a donor in case of myelodysplastic syndromes with intermediate/high-risk cytogenetics. Autologous peripheral blood stem cell transplantation does not provide longer survival than intensive chemotherapy.

Acute leukemia in women

The treatment and survival outcome of acute leukemia in women is generally similar to that of men. However, acute leukemia in women poses additional challenges in clinical practice. In addition to important precautions during therapy, such as prevention of abnormal uterine bleeding in premenopausal women and therapy during pregnancy, women who are survivors of acute leukemia face unique and potentially long-term health-related problems. In this review, we address the aforementioned issues, as well as the various health and psychosocial challenges faced by women who survive childhood leukemia during their path to adulthood. Finally, we address the issue of therapy-related acute leukemia in the category of women who are survivors of breast and ovarian cancer.

[Special issues related to the treatment of acute leukemias in women]

The treatment of acute leukemia is usually similar in women and men. The outcome is also generally the same. However, diagnosis in women poses additional challenges in clinical practice such as leukemia following breast or ovarian cancers, prevention of abnormal uterine bleeding in premenopausal females, treatment during pregnancy related-problems in long-term survivors. All these special issues are addressed in this review of the literature.

Diagnosis and management of acute myeloid leukemia in adults: recommendations from an international expert panel, on behalf of the European LeukemiaNet

In 2003, an international working group last reported on recommendations for diagnosis, response assessment, and treatment outcomes in acute myeloid leukemia (AML). Since that time, considerable progress has been made in elucidating the molecular pathogenesis of the disease that has resulted in the identification of new diagnostic and prognostic markers. Furthermore, therapies are now being developed that target disease-associated molecular defects. Recent developments prompted an international expert panel to provide updated evidence- and expert opinion–based recommendations for the diagnosis and management of AML, that contain both minimal requirements for general practice as well as standards for clinical trials. A new standardized reporting system for correlation of cytogenetic and molecular genetic data with clinical data is proposed.

Allogeneic transplantation for therapy-related myelodysplastic syndrome and acute myeloid leukemia

Therapy-related myelodysplastic syndromes (t-MDSs) and acute myeloid leukemia (t-AML) have a poor prognosis with conventional therapy. Encouraging results are reported after allogeneic transplantation. We analyzed outcomes in 868 persons with t-AML (n = 545) or t-MDS (n = 323) receiving allogeneic transplants from 1990 to 2004. A myeloablative regimen was used for conditioning in 77%. Treatment-related mortality (TRM) and relapse were 41% (95% confidence interval [CI], 38-44) and 27% (24-30) at 1 year and 48% (44-51) and 31% (28-34) at 5 years, respectively. Disease-free (DFS) and overall survival (OS) were 32% (95% CI, 29-36) and 37% (34-41) at 1 year and 21% (18-24) and 22% (19-26) at 5 years, respectively. In multivariate analysis, 4 risk factors had adverse impacts on DFS and OS: (1) age older than 35 years; (2) poor-risk cytogenetics; (3) t-AML not in remission or advanced t-MDS; and (4) donor other than an HLA-identical sibling or a partially or well-matched unrelated donor. Five-year survival for subjects with none, 1, 2, 3, or 4 of these risk factors was 50% (95% CI, 38-61), 26% (20-31), 21% (16-26), 10% (5-15), and 4% (0-16), respectively (P < .001). These data permit a more precise prediction of outcome and identify subjects most likely to benefit from allogeneic transplantation.

Risk factors for therapy-related myelodysplastic syndrome and acute myeloid leukemia treated with allogeneic stem cell transplantation

BACKGROUND

After successful treatment of malignant diseases, therapy-related myelodysplastic syndrome and acute myeloid leukemia have emerged as significant problems.

DESIGN AND METHODS

The aim of this study was to investigate outcome and risk factors in patients with therapy-related myelodysplastic syndrome or acute myeloid leukemia who underwent allogeneic stem cell transplantation. Between 1981 and 2006, 461 patients with therapy-related myelodysplastic syndrome or acute myeloid, a median age of 40 years and a history of solid tumor (n=163), malignant lymphoma (n=133), or other hematologic diseases (n=57) underwent stem cell transplantation and their data were reported to the European Group for Blood and Marrow Transplantation.

RESULTS

The cumulative incidence of non-relapse mortality and relapse at 3 years was 37% and 31%, respectively. In a multivariate analysis significant factors for relapse were not being in complete remission at the time of transplantation (p=0.002), abnormal cytogenetics (p=0.005), higher patients' age (p=0.03) and therapy-related myelodysplastic syndrome (p=0.04), while higher non-relapse mortality was influenced by higher patients' age. Furthermore, there was a marked reduction in non-relapse mortality per calendar year during the study period (p<0.001). The 3-year relapse-free and overall survival rates were 33% and 35%, respectively. In a multivariate analysis significant higher overall survival rates were seen per calendar year (p<0.001), for younger age (<40 years) and normal cytogenetics (p=0.05). Using age (<40 years), abnormal cytogenetics and not being in complete remission at the time of transplantation as risk factors, three different risk groups with overall survival rates of 62%, 33% and 24% could be easily distinguished.

CONCLUSIONS

Allogeneic stem cell transplantation can cure patients with therapy-related myelodysplastic syndrome and acute myeloid leukemia and has markedly improved over time. Non-complete remission, abnormal cytogenetics and higher patients' age are the most significant factors predicting survival.

Therapy-related myeloid leukemia

Therapy-related myelodysplastic syndrome and acute myeloid leukemia (t-MDS/t-AML) are thought to be the direct consequence of mutational events induced by chemotherapy, radiation therapy, immunosuppressive therapy, or a combination of these modalities, given for a pre-existing condition. The outcomes for these patients have been poor historically compared to people who develop de novo AML. The spectrum of cytogenetic abnormalities in t-AML is similar to de novo AML, but the frequency of unfavorable cytogenetics, such as a complex karyotype or deletion or loss of chromosomes 5 and/or 7, is considerably higher in t-AML. Survival varies according to cytogenetic risk group in t-AML patients, with better outcomes being observed in those with favorable-risk karyotypes. Treatment recommendations should be based on performance status and karyotype. A deeper understanding of the factors that predispose patients to the development of therapy-related myeloid leukemia would help clinicians monitor patients more carefully after treatment for a primary condition. Ultimately, this knowledge could influence initial treatment strategies with the goal of decreasing the incidence of this serious complication.

Predictors of outcome following myeloablative allo-SCT for therapy-related myelodysplastic syndrome and AML

Administration of alkylating agents (Alk), topoisomerase II inhibitors (Topo II) and radiotherapy (RT) can result in therapy-related myelodysplastic syndrome or acute myelogenous leukaemia (t-MDS/t-AML), the optimal treatment for which is allo-SCT. A retrospective review was performed of 24 patients who underwent related- or unrelated-donor SCT for t-MDS/t-AML at our institution. Eight patients remain alive and in continuous remission (median follow-up 54 months (range, 12-161)) with estimated 5-year EFS being 30% (95% confidence intervals 16-58%). Corresponding actuarial risks of relapse and non-relapse mortality (NRM) are 39% (19-60%) and 30% (13-50%), respectively. EFS was 40% in Alk/RT-related t-MDS/t-AML and 11% in Topo II-related t-MDS/t-AML (P=0.05), with an increased risk of relapse in the latter (56 vs 29%, respectively (P=0.05)). In multivariate analysis, development of acute GVHD (P=0.009) and Topo II-related t-MDS/t-AML (P=0.018) were associated with inferior EFS. Patients with acute GVHD had an increased risk of NRM (P=0.03) whereas risk of relapse was higher for patients of advanced age (P=0.046) and for patients who underwent bone marrow (vs blood) SCT (P=0.032). Allo-SCT can result in long-term survival for individuals with t-MDS/t-AML although outcome in Topo II-related t-MDS/t-AML patients remains suboptimal.

The role of cytotoxic therapy with hematopoietic stem cell transplantation in the therapy of acute myelogenous leukemia in adults: an evidence-based review

Clinical research examining the role of hematopoietic stem cell transplantation (HSCT) in the therapy of acute myelogenous leukemia (AML) in adults is presented and critically evaluated in this systematic evidence-based review. Specific criteria were used for searching the published literature and for grading the quality and strength of the evidence and the strength of the treatment recommendations. Treatment recommendations based on the evidence are presented in Table 3, entitled Summary of Treatment Recommendations Made by the Expert Panel for Adult Acute Myelogenous Leukemia, and were reached unanimously by a panel of AML experts. The identified priority areas of needed future research in adult AML include: (1) What is the role of HSCT in treating patients with specific molecular markers (eg, FLT3, NPM1, CEBPA, BAALC, MLL, NRAS, etc.) especially in patients with normal cytogenetics? (2) What is the benefit of using HSCT to treat different cytogenetic subgroups? (3) What is the impact on survival outcomes of reduced intensity or nonmyeloablative versus conventional conditioning in older (>60 years) and intermediate (40-60 years) aged adults? (4) What is the impact on survival outcomes of unrelated donor HSCT vesus chemotherapy in younger (<40 years) adults with high risk disease?

Second cancers in patients with the Ewing sarcoma family of tumours

BACKGROUND

Patients are at risk of second malignancies (SM) after treatment for Ewing sarcoma family of tumours (ESFT).

METHODS

We performed a retrospective review of 237 patients with ESFT treated at our institution from September 1979 through to February 2004. Cumulative incidence (CI) of SM by the type of malignancy and treatment was estimated.

RESULTS

Twelve patients with SM were identified. Secondary leukaemia (SL) developed in 8 patients (2 ALL, 6 MDS/AML), a median 2.6 years (range 1.4-19.6 years) after diagnosis of ESFT. Four patients had secondary solid tumours, a median 8.0 years (range 7.4-9.4 years) after the ESFT diagnosis. Five- and 10-year estimates of the CI of SM were 3.0+/-1.1% and 4.7+/-1.5%, respectively. Patients treated on recent protocols with higher cumulative doses or an increased dose intensity of alkylators and epipodophyllotoxins and the use of G-CSF had a higher estimated CI of SL than those in earlier studies (5-year CI 6.4+/-2.4% versus 0.0+/-0.0%, respectively, P=0.004).

CONCLUSIONS

Patients with ESFT are at risk for SM after treatment. The cumulative incidence of SM is higher with the current treatment protocols and may be related to the intensification of chemotherapeutic agents.

Myelodysplastic syndrome after autologous peripheral blood stem cell transplantation for multiple myeloma

Long-term survivors after autologous peripheral blood stem cell transplantation (APBSCT) for lymphoma or Hodgkin's disease are known to have a high risk of developing myelodysplastic syndrome (MDS), but the risk of MDS is not clear for patients transplanted for myeloma. We reviewed the outcomes for 82 myeloma patients who underwent APBSCT at our center. The group included 47 men and 35 women of median age 56 years (range: 37-74 years). Median time from diagnosis to APBSCT was 8.2 months (range: 2.6-86.1 months). Before coming to transplantation, 28% had received oral melphalan (MEL), 98% received other chemotherapy and 34% received radiation. A single APBSCT was provided for 68, and 32% underwent APBSCT more than once. High-dose MEL alone was used as the preparative regimen for 83%, and the remainder received at least one APBSCT with a more intensive preparative regimen. Ten patients (12%) developed MDS. The 5-year cumulative incidence is 18% (95% confidence interval, 9-30%). There were no demographic factors associated with an increased risk of developing MDS. Median survival after the diagnosis of MDS was 18 months. There is a relatively high risk of MDS after APBSCT for myeloma, and optimal therapy has not been established for these patients.

An antecedent diagnosis of refractory anemia with excess blasts has no influence on mobilization of peripheral blood stem cells and hematopoietic recovery after autologous stem cell transplantation in acute myeloid leukemia

Several studies have reported data on factors influencing mobilization of peripheral blood stem cells (PBSC) in non-myeloid malignancies. On the contrary, data from patients with acute myeloid leukemia (AML) are very limited, in particular, as the impact of an antecedent diagnosis of refractory anemia with excess blasts (RAEB) on mobilization of PBSCs as well as hematopoietic recovery after autologous stem cell transplantation (ASCT) is concerned. We retrospectively analyzed a cohort of 150 consecutive AML patients in first complete remission in order to make a comparison between patients with de novo AML and secondary AML (s-AML) in terms of CD34 positive (CD34+) cells mobilization and number of leukapheresis needed to collect at least one single stem cell graft. Data concerning hematopoietic recovery after ASCT were also compared. The successful mobilization rate (>2 x 10(6) CD34+ cells/kg) was comparable between de novo AML patients (87%) and those with s-AML (76%), P:0.21. No statistically significant difference was found in terms of either median number of CD34+ cells collected (P:0.44) or CD34+ cells peak in peripheral blood (P:0.28). Both groups of patients needed a median of two apheresis (P:0.45) and no difference was found on the median number of CD34+ cells collected per single apheresis (P:0.59). Finally, neutrophil and platelet recovery after ASCT were comparable between the two groups. An antecedent diagnosis of RAEB has no impact on mobilization and collection of PBSCs in AML as well as on hematopoietic recovery after ASCT.

Etiology and management of therapy-related myeloid leukemia

The diagnosis of therapy-related myeloid leukemia (t-MDS/t-AML) identifies a group of high-risk patients with multiple and varied poor prognostic features. These neoplasms are thought to be the direct consequence of mutational events induced by cytotoxic therapy. Their outcomes have historically been poor compared with those of people who develop acute myeloid leukemia (AML) de novo. The question arises whether a diagnosis of t-AML per se indicates a poor prognosis, or whether their bad outcomes result from other clinical and biologic characteristics. Because of lingering damage from prior cytotoxic therapy and, in some cases, the persistence of their primary disorder, patients with t-AML are often poor candidates for intensive AML therapy. The spectrum of cytogenetic abnormalities in t-AML is similar to de novo AML, but the frequency of unfavorable cytogenetics, such as a complex karyotype or deletion or loss of chromosomes 5 and/or 7, is higher in t-AML. Survival varies according to cytogenetic risk group, with better outcomes observed in patients with t-AML with favorable-risk karyotypes. Treatment recommendations should be based on performance status and karyotype. Patients with t-AML should be enrolled on front-line chemotherapy trials, appropriate for de novo AML patients with similar disease characteristics. Allogeneic hematopoietic cell transplantation can cure some patients with t-AML. Most important , the molecular and genetic differences that appear to determine the phenotype and the outcome of these patients need to be investigated further.