Myelodysplastic syndrome occurring after autologous bone marrow transplantation for lymphoma. Morphologic features

Therapy-related myeloid neoplasms after autologous hematopoietic stem cell transplantation in lymphoma patients

Lymphoma patients treated with autologous transplantation (ASCT) live an increasingly long life with the recent advancement in therapeutic modalities. This has resulted in an increase in the incidence of therapy-related myeloid neoplasms (t-MN), which is one of the leading causes of non-relapse mortality. Several observational studies have linked the development of t-MN after ASCT with the intensity and frequency of chemotherapy, particularly alkylating agents, use of total body irradiation (TBI), and peripheral blood progenitor cells. In addition, role of genetic factors is increasingly being identified. It is postulated that the use of chemotherapy prior to ASCT results in DNA damage of progenitor cells, mitochondrial dysfunction, and altered gene expression related to DNA repair, metabolism as well as hematopoietic regulation. Cytogenetic studies have shown the presence of abnormalities in the peripheral blood progenitor cells prior to ASCT. It is, therefore, likely that the reinfusion of peripheral blood progenitor cells, proliferative stress on infused progenitor cells during hematopoietic regeneration and associated telomere shortening ultimately result in clonal hematopoiesis and blastic transformation. Cytopenias, myelodysplasia, or cytogenetic abnormalities are common and can be transient after ASCT; therefore, only when present together, they do confirm the diagnosis of t-MN. Attempts to reduce the occurrence of t-MN should be directed toward minimizing the exposure to the identified risk factors. Although the median survival is few months to less than a year, studies have shown the promising role of allogeneic transplantation in select young t-MN patients without high-risk cytogenetics. In this review we will explain the recent findings in the field of t-MN in lymphoma patients that have implications for identifying the molecular and genetic mechanisms of leukemogenesis and discuss potential strategies to reduce the risk of t-MN in this patient population.

Therapy-related myelodysplasia and/or acute myeloid leukaemia after autologous haematopoietic progenitor cell transplantation in a prospective single centre cohort of 221 patients

To evaluate the incidence and the predictive signs of therapy-related myelodysplasia and/or acute myeloid leukaemia (tMDS/tAML), we undertook a prospective study over a 4-year period of 221 patients who underwent autologous haematopoietic progenitor cell transplantation. Only seven patients (3.1%) were identified to have tMDS/tAML. Peripheral cytopenia was the first sign; diagnosis could be achieved by cytological analysis of bone marrow smears using World Health Organization criteria. All patients presented with bi- or trilineage dysplasia. Haematopoietic reconstitution was significantly delayed in patients progressing to tMDS/tAML compared with the control group. Typical cytogenetic abnormalities were observed in five of seven patients. The mean time interval between transplantation and cytological diagnosis, or detection of cytogenetic abnormalities, was 20.0 months and 31.2 months respectively. Pantelomeric fluorescence analysis using quantitative fluorescence in situ hybridization enabled us to make two major observations: (i) the fluorescence intensity in metaphases of all autografted patients was weak, and highly variable between tMDS patients; (ii) a drastic reduction of the telomere fluorescence intensity was observed in two patients who rapidly evolved to acute leukaemia. In conclusion, early detection of tMDS/tAML could be achieved by close follow-up of the bone marrow repopulation, and confirmed by cytological bone marrow examination and cytogenetic study. Our results address the implication of several factors, such as the initial telomeric status, and the effect of cytogenetic abnormalities and clonal expansion on bone marrow repopulation.

Is there a role for reduced-intensity haematopoietic stem cell transplantation for indolent non-Hodgkin's lymphoma?

The therapeutic options for the indolent non-Hodgkin's lymphomas have evolved significantly over the years. However, at present, allogeneic haematopoietic stem cell transplantation (HSCT), despite its significant transplant associated complications, is still the only option which may be delivered with curative potential. The debut of reduced-intensity conditioning regimens has extended the applicability of allogeneic transplants to groups of patients ineligible for conventional myeloablative allografts. However, there are still substantial hurdles to overcome, namely that of relapse, graft-versus-host disease and infection. Whilst follow-up is still relatively limited for a disease group with a median survival of up to 10 years, early results are extremely encouraging and further studies are warranted.

Allogeneic hemopoietic stem cell transplantation in patients with myelodysplastic syndrome or myelofibrosis

Myelodysplastic syndrome (MDS) and myeloproliferative disorders associated with myelofibrosis (MF) are stem cell disorders, and hemopoietic stem cell transplantation (HSCT) is currently the only therapy with curative potential. Among patients with less advanced MDS, 3 year survivals of 65% to 70% are achievable with HLA-identical related and HLA-matched unrelated donors. The probability of relapse is < 5%. Among patients with advanced disease (> or = 5% marrow blasts), about 35 to approximately 45% and 25 to approximately 30%, respectively, are surviving in remission after transplantation from related or unrelated donors. The incidence of post-transplant relapse is 1035%. Criteria of the International Prognostic Scoring System (IPSS), originally developed for nontransplanted patients, also predict survival following transplantation. Patients with MF, either idiopathic or on the basis of pre-existing disorders, are also transplanted successfully with stem cells from related or unrelated donors. Transplants early in the disease, before leukemic transformation, are successful in 60 to approximately 80% of patients. Success rates are lower in patients who have developed MDS or leukemia. New conditioning regimens have permitted successful HSCT even in patients in the seventh decade of life. Results with a regimen using a combination of busulfan (targeted to predetermined plasma levels) and cyclophosphamide are particularly encouraging. Improved survival with transplants from unrelated volunteer donors may, in part, reflect selection of donors on the basis of high resolution (allele-level) HLA typing. Nevertheless, transplant-related morbidity and mortality, including graft- vs. -host disease, remain challenges that need to be addressed with innovative approaches.

Risk of therapy-related myelodysplastic syndrome/acute leukemia following high-dose therapy and autologous bone marrow transplantation for non-Hodgkin's lymphoma

BACKGROUND

Several recent reports have suggested that patients with non-Hodgkin's lymphomas (NHL) who undergo autologous stem cell transplantation (ASCT) are at increased risk of developing therapy-related myelodysplastic syndrome (tMDS) and acute myelogenous leukemia (tAML).

PATIENTS AND METHODS

We analyzed 493 patients with NHL who underwent ASCT at The University of Texas M.D. Anderson Cancer Center between January 1990 and August 1999.

RESULTS

With a median follow-up time of 21 months after HDT, 22 patients developed persistent cytopenia in at least one cell line with morphologic or cytogenetic evidence of tMDS or tAML. Univariate analysis identified prior fludarabine therapy, bone marrow involvement with lymphoma, and total body irradiation (TBI) as significant risk factors for the development of tMDS/tAML (P <0.05). Multiple logistic regression analysis showed that TBI was independently associated with an increased risk of developing tMDS/tAML (P <0.01). Further analysis of the patients who received TBI revealed that patients receiving TBI in combination with cyclophosphamide and etoposide were more likely to develop tMDS/tAML than those who received TBI with cyclophosphamide or thiotepa (P <0.01). The median survival of patients developing tMDS/tAML was 7.5 months (range 0-32 months).

CONCLUSIONS

TBI, especially when used in combination with cyclophosphamide and etoposide as the pretransplant conditioning regimen, is a significant risk factor for the development of tMDS/tAML.

Hematopoietic stem cell transplantation in patients with myelodysplastic syndrome

Myelodysplastic syndrome (MDS) is a stem cell disorder, and hematopoietic stem cell transplantation is currently the only therapeutic modality that is potentially curative. Among patients with less advanced MDS (<5% marrow blasts), 3-year survivals of 65-70% are achievable with HLA-identical related and HLA-matched unrelated donors. The overall probability of disease recurrence in these patients is <5%. Among patients with advanced disease (>/=5% marrow blasts), about 35-45% and 25-30%, respectively, are surviving in remission after transplantation from a related or from an unrelated donor; the incidence of post-transplant relapse is 10-35%. The criteria proposed by the International Prognostic Scoring System (IPSS) derived from non-transplanted patients, also predict survival following transplantation. The development of new conditioning regimens has permitted successful hematopoietic stem cell transplants even in patients more than 60 years of age. Improved survival with transplants from unrelated volunteer donors may, in part, reflect selection of donors on the basis of high resolution (allele-level) HLA typing. Autologous stem cell transplantation may be beneficial for selected patients who have obtained a complete remission with conventional chemotherapy. Treatment-related morbidity and mortality, in particular after allogeneic transplantation, remain challenges that need to be addressed with innovative approaches.

Chromosomal abnormalities in women with breast cancer after autologous stem cell transplantation are infrequent and may not predict development of therapy-related leukemia or myelodysplastic syndrome

We determined prospectively the incidence of chromosomal abnormalities in patients with high-risk breast cancer (HRBC) after high-dose chemotherapy (HDCT) and autologous stem cell transplantation (ASCT), and correlated the cytogenetic abnormalities with the development of post-transplant myelodysplastic syndrome or acute myeloid leukemia (MDS/AML). From 1990 to 1999, 229 women with HRBC underwent ASCT. Cytogenetic analysis of bone marrow (BM) cells was performed 12-59 months after ASCT in 60 consecutive women uniformly treated with six courses of FAC/FEC followed by HDCT and ASCT. With a median follow-up of 36 months after ASCT, there were no cases of MDS/AML among the 229 patients. In the selected cohort of 60 patients, three (5%) showed clonal chromosomal abnormalities (two single trisomy X and one t(1;6)), whereas two additional patients showed non-clonal reciprocal translocations. Two of the patients with clonal aberrations had blood cytopenias as well as subtle dysplastic pictures in BM which were not classifiable as MDS according to the FAB criteria. Similar dysplastic features were also observed in four patients with normal karyotypes. All cytogenetic aberrations were transient and disappeared, except a +X detected by FISH in a residual cell population in one of the patients. Retrospective cytogenetic and FISH studies of samples obtained after six cycles of FAC/FEC and before transplant demonstrated no chromosomal abnormalities in any of the five patients with post-ASCT karyotypic changes. Early changes in karyotype detected in breast cancer patients following ASCT are transient and do not correlate with or predict development of MDS/AML. As these aberrations were not present before ASCT, they may be related to the HDCT regimen or transplant procedure rather than to the prior adjuvant therapy. Our results suggest that ASCT may be less likely to cause MDS or AML in breast cancer patients as compared to other malignancies. Bone Marrow Transplantation (2000) 25, 1203-1208.

Therapy-related acute myeloid leukemia and myelodysplasia after high-dose chemotherapy and autologous stem cell transplantation

Therapy-related myelodysplasia (t-MDS) and acute myeloid leukemia (t-AML) after high-dose chemotherapy (HD-CT) and autologous stem cell transplantation (ASCT) for malignant diseases have become an important problem. The actuarial risk has varied, but has often been high if compared to the risk after conventional therapy. Prior chemotherapy with large cumulative doses of alkylating agents is the most important risk factor. In addition, patient age and previous radiotherapy, particularly the use of total body irradiation (TBI) in the preparative regimen for ASCT, have been identified as risk factors. In 3 studies, patients transplanted with CD34+ cells from peripheral blood after chemotherapy priming showed a higher risk of t-MDS or t-AML than patients transplanted with cells isolated from the bone marrow without priming. To what extent this higher risk relates to the prior therapy with a different contamination with preleukemic, hematopoietic precursors of the CD34+ cells obtained by the 2 methods, or is a direct result of chemotherapy priming, or of an increasing awareness of these complications, remains to be determined. The latent period from ASCT to t-MDS and t-AML has often been short, 12 months or less in 27% of the patients. Bone marrow pathology of early cases of t-MDS after ASCT has often been neither diagnostic nor prognostic, but most patients presented chromosome aberrations, primarily deletions or loss of the long arms of chromosomes 5 and 7. The prognosis was in general poor, although 17% with indolent t-MDS survived more than 18 months from diagnosis, and most of these presented a normal karyotype or a single chromosome aberration.

Therapy-related acute myeloid leukemia and myelodysplasia after high-dose chemotherapy and autologous stem cell transplantation

Therapy-related myelodysplasia (t-MDS) and acute myeloid leukemia (t-AML) after high-dose chemotherapy (HD-CT) and autologous stem cell transplantation (ASCT) for malignant diseases have become an important problem. The actuarial risk has varied, but has often been high if compared to the risk after conventional therapy. Prior chemotherapy with large cumulative doses of alkylating agents is the most important risk factor. In addition, patient age and previous radiotherapy, particularly the use of total body irradiation (TBI) in the preparative regimen for ASCT, have been identified as risk factors. In 3 studies, patients transplanted with CD34+ cells from peripheral blood after chemotherapy priming showed a higher risk of t-MDS or t-AML than patients transplanted with cells isolated from the bone marrow without priming. To what extent this higher risk relates to the prior therapy with a different contamination with preleukemic, hematopoietic precursors of the CD34+ cells obtained by the 2 methods, or is a direct result of chemotherapy priming, or of an increasing awareness of these complications, remains to be determined. The latent period from ASCT to t-MDS and t-AML has often been short, 12 months or less in 27% of the patients. Bone marrow pathology of early cases of t-MDS after ASCT has often been neither diagnostic nor prognostic, but most patients presented chromosome aberrations, primarily deletions or loss of the long arms of chromosomes 5 and 7. The prognosis was in general poor, although 17% with indolent t-MDS survived more than 18 months from diagnosis, and most of these presented a normal karyotype or a single chromosome aberration.

Hemopoietic stem cell transplantation for myelodysplastic syndrome

The term myelodysplastic syndrome (MDS) describes a spectrum of disorders that are characterized by dysplastic marrow cell morphology, the development of peripheral blood cytopenias, and a tendency to evolve into acute myeloid leukemia. MDS has been recognized as a stem-cell disease, and hemopoietic stem-cell transplantation is currently the only potentially curative therapy. In patients with less advanced MDS (<5% blasts in the marrow), 3-year survival rates of 70% and 65% can be achieved with HLA-identical related and HLA-matched unrelated donors, respectively. The overall probability of disease recurrence in these patients is less than 5%. Of patients with advanced disease (5% marrow blasts or more), about 40% to 45% and 25% to 30% are surviving in remission after transplantation from a related or an unrelated donor, respectively. This inferior outcome is largely due to a higher incidence of post-transplantation relapse (20% to 30%). Inclusion of the International Prognostic Scoring System criteria into outcome analyses shows an inverse correlation between overall risk category and relapse-free survival after transplantation. Future trials should explore the usefulness of different transplantation regimens for different risk categories. Among patients with less advanced disease, use of a conditioning regimen that combines cyclophosphamide and busulfan, dose adjusted to reach target plasma levels, has been associated with improved survival in recipients of transplants from related and unrelated donors. It has also permitted successful hemopoietic stem-cell transplantation in patients as old as 66 years of age. Improved survival with transplants from unrelated volunteer donors has been achieved with selection of donors based on high-resolution HLA typing. Autologous stem-cell transplantation may provide excellent consolidation for selected patients who have obtained complete remission with conventional chemotherapy. High treatment-related morbidity and mortality rates, particularly after allogeneic transplantation, remain challenges that must be addressed with innovative approaches.

Outcome in patients with myelodysplastic syndrome after autologous bone marrow transplantation for non-Hodgkin's lymphoma

PURPOSE

The absolute risk of myelodysplastic syndrome (MDS) after autologous bone marrow transplant (ABMT) for non-Hodgkin's lymphoma (NHL) exceeds 5% in several reported series. We report the outcome of a large cohort of patients who developed MDS after ABMT for NHL.

PATIENTS AND METHODS

Between December 1982 and December 1997, 552 patients underwent ABMT for NHL, with a uniform ablative regimen of cyclophosphamide and total body irradiation followed by reinfusion of obtained marrow purged with monoclonal antibodies. MDS was strictly defined, using the French-American-British classification system, as requiring bone marrow dysplasia in at least two cell lines, with associated unexplained persistent cytopenias.

RESULTS

Forty-one patients developed MDS at a median of 47 months after ABMT. The incidence of MDS was 7.4%, and actuarial incidence at 10 years is 19.8%, without evidence of a plateau. Patients who developed MDS received significantly fewer numbers of cells reinfused per kilogram at ABMT (P =.0003). Karyotypes were performed on bone marrow samples of 33 patients, and 29 patients had either del(7) or complex abnormalities. The median survival from diagnosis of MDS was 9.4 months. The International Prognostic Scoring System for MDS failed to predict outcome in these patients. Thirteen patients underwent allogeneic BMT as treatment for MDS, and all have died of BMT-related complications (11 patients) or relapse (two patients), with a median survival of only 1.8 months.

CONCLUSION

Long-term follow-up demonstrates a high incidence of MDS after ABMT for NHL. The prognosis for these patients is uniformly poor, and novel treatment strategies are needed for this fatal disorder.