Preleukaemia: a long-term prospective study of 326 patients

Two types of acquired idiopathic sideroblastic anaemia (AISA): a time-tested distinction

In 1982, acquired idiopathic sideroblastic anaemia (AISA) was included by the French-American-British (FAB) Co-operative Group in their classification of myelodysplastic syndromes (MDS). However, the malignant potentiality of AISA has always been a matter of debate. In different series, median survival and rates of transformation into acute myeloid leukaemia (AML) varied extensively. On cytomorphological grounds, AISA can be divided into pure (dyserythropoietic) sideroblastic anaemia (PSA), in which dysplasia is confined to erythropoietic cells, and a true myelodysplastic form (RARS), which is characterized by additional dysplastic features of granulopoiesis and/or megakaryopoiesis. In a previous study, based on retrospective analysis of 94 patients with AISA, we found that both types of sideroblastic anaemia differed considerably in terms of survival and risk of AML transformation. Almost identical results have now been obtained through a prospective study of 232 new patients with AISA. The difference in survival between PSA and RARS remained significant over the whole period of follow-up (survival after 3 years being 77% vs. 56%; P = 0.003), and the incidence of AML did not increase with time in the PSA group, even in the long term. This prospective study strongly supported our conclusion that cytomorphological distinction between PSA and RARS provides valuable prognostic information.

Cytogenic characterization of primary refractory anemia

Refractory anemia (RA) is the only myelodysplastic syndrome (MDS) devoid of quantitative marrow diagnostic criteria. The diagnosis rests mainly on the subjective identification of qualitative abnormalities according to the French-American-British criteria (FAB) involving one or more bone marrow hematopoietic cell lineages. The occurrence of nonrandom chromosome abnormalities remains the hallmark of the disease and the only means of investigation which confirms the disease objectively. With the purpose in mind to further characterize RA among MDS, we have undertaken a prospective high resolution banding chromosome analyses of bone marrow cells in patients with primary refractory anemia (PRA) with the aim of defining a cytogenetic phenotype and of assessing the clinical relevance of clonal abnormalities at initial diagnosis. Of 39 patients consecutively referred for chromosome analyses with a diagnosis of RA according to the FAB criteria, 27 patients had PRA and fulfilled our criteria for adequate chromosome analyses. Median age was 68 years. Fourteen of 27 patients (52%) had clonal chromosomal abnormalities at diagnosis. None of the patients showed a complex karyotype; 9/14 (64%) had a mixture of normal and abnormal cells. Interstitial or terminal deletions, involving chromosomes 5, 6, 7, 9, 11, 12, and 20, were found in 11/14 (79%) of the patients. Comparison of survival between patients with and without abnormalities showed no difference. The presence of clonal abnormalities did not predict transformation to acute myeloblastic leukemia (AML) nor was it associated with poor survival. In this study, patients with PRA were found to have a predominant pseudodiploid karyotypic pattern characterized by interstitial and/or terminal deletions as opposed to derivatives, specific and non-specific balanced translocations, or other structural and numerical abnormalities. We were unable to reveal any prognostic significance to the presence of these clonal abnormalities at initial diagnosis.

Circulating CD34+ cells: an adverse prognostic factor in the myelodysplastic syndromes

As part of an epidemiological survey of myelodysplastic syndromes (MDS) in southern Tasmania, 62 MDS patients identified over a 2 year period were tested for the presence of CD34, the human progenitor cell antigen (HPCA), in their peripheral blood. The results were correlated with transformation to acute myeloid leukemia (AML) and patient survival, and CD34+ status was compared as a prognostic indicator with Bournemouth score, cytogenetics, and CFU-GM colony growth which were also assessed. Circulating CD34+ cells were found in 23 of the 62 MDS patients; 9 of the 23 patients with circulating CD34+ cells transformed to AML, as compared with none of the 39 CD34 negative patients (P less than 0.0001); and 11 of the 23 patients with circulating CD34+ cells were dead at the end of the 2 year period, as opposed to 6 of the 39 with no CD34+ cells (P less than 0.03). The Bournemouth score was also significantly associated with transformation to AML (P less than 0.0001) and poor survival (P less than 0.04). These were the only significant associations of the possible prognostic factors studied with either transformation or survival. In summary, the presence of circulating CD34+ cells was significantly associated with both progression to AML and poor survival and was found to be a better prognostic indicator than cytogenetics or CFU-GM colony growth.

Treatment with 13-cis-retinoic acid in transfusion-dependent patients with myelodysplastic syndrome and decreased toxicity with addition of alpha-tocopherol

PURPOSE

The purpose of this study was to determine the response and tolerance to long-term treatment using 13-cis-retinoic acid (13-CRA) in transfusion-dependent patients with the myelodysplastic syndrome (MDS) and to determine the effects of therapy on the natural history of the disease.

PATIENTS AND METHODS

Sixty-six consecutive patients with transfusion-dependent MDS seen in a medical school hospital and outpatient clinic from 1981 to 1988 were studied. The first 21 patients were treated with 13-CRA alone and the next 45 patients with 13-CRA plus alpha-tocopherol (AT). We compared responses to and toxicities of therapy, rates of transformation, and survival from onset of therapy in 20 evaluable patients treated with 13-CRA alone and 43 patients treated with 13-CRA plus AT.

RESULTS

Four patients responded (20%) at 4 to 8 months to 13-CRA alone, but this response was associated with considerable toxicity and resulted in cessation of therapy. Among the responders, only one continued therapy and is currently in remission, whereas three discontinued therapy because of toxicity and have had a relapse and died. In the 13-CRA plus AT group, we observed one prolonged complete remission and 10 partial remissions (26%), with a decrease in skin and constitutional toxicities by the addition of AT, which enabled the continuation of 13-CRA indefinitely. Although the response rates were similar in both groups, fewer patients (28% versus 60%) experienced progression to acute leukemia in the 13-CRA plus AT group than in the group receiving 13-CRA alone, who terminated treatment (p = 0.018). A twofold increase in median survival of the RA/RARS and RAEB/CMML patient groups was observed with 13-CRA plus AT but was not significant (p greater than 0.5).

CONCLUSION

This study shows a 20% to 26% response rate to 13-CRA and suggests that 13-CRA, if given continuously, decreases the rate of progression or transformation to acute leukemia in patients with MDS. The addition of AT ameliorates the toxicity of 13-CRA and allows for long-term treatment with 13-CRA. Since the standard treatment for MDS is currently unsatisfactory, these findings indicate that longer treatment with a non-marrow-suppressive agent such as 13-CRA is important, and further trials to determine the role of 13-CRA plus AT in combination with new recombinant growth factors in the therapy for transfusion-dependent MDS should offer a new approach to a disease common in the elderly population.

Clonal karyotype abnormalities and clinical progress in the myelodysplastic syndrome

Clonal karyotype abnormalities in 124 patients with myelodysplastic syndrome are reviewed. 36% of patients had abnormalities at referral, the most common being 5q-, +8 and lesions of chromosomes 7 and 20. Reduced survival was associated with the presence of either single or multiple clonal abnormalities at referral, abnormalities of chromosome 7 or 8 (either alone or with other lesions) and exclusively abnormal metaphases. The presence of 5q- alone did not appear to affect survival. Sequential studies were carried out in 77 patients of whom 12 showed karyotypic evolution. Reduced survival was observed in patients with an evolving karyotype but appeared to be due almost entirely to evolution in those patients whose initial karyotype was normal. Leukaemic transformation occurred more commonly in patients with an abnormal karyotype, particularly those with multiple abnormalities, and in patients with an evolving karyotype. Although the first appearance of an abnormal karyotype or an apparent evolution are important phenomena, it is probable that in some cases they merely represent expansion of a previously existing clone that has escaped detection. The distinction between true karyotypic evolution or clonal expansion and statistical variations due to small sample size and variability of samples may be difficult but needs to be taken into account in considering clinical significance.

Bone marrow in vitro growth and cytogenetic studies in patients with FAB-classified primary myelodysplastic syndromes

Thirty-eight consecutive patients with a FAB-classified primary myelodysplastic syndrome (MDS) were investigated for in vitro growth of colony-forming units for granulocyte-macrophage precursors (CFU-GM) and cytogenetic analysis of bone marrow cells. Abnormal CFU-GM growth was found in 30 patients (79%), and clonal chromosome abnormalities were found in 13 patients (34%). The eight patients who showed normal CFU-GM growth were either cytogenetically normal (n = 5), or had a 5q-deletion (n = 3) as single or dominating karyotypic abnormality. Among the 30 patients with reduced or no colony growth, ten patients had a clonal chromosome abnormality. Leukemia developed in eight patients. None of them grew any CFU-GM colonies, and three of them were cytogenetically abnormal at the time of diagnosis of MDS. Analysis of the bone marrow in vitro growth for CFU-GM and the karyotype in patients with MDS emphasizes the close relationship between these disorders and manifest acute leukemia. Subgroups of MDS may be defined by a cytogenetic classification (e.g., the 5q-syndrome), and the CFU-GM growth pattern can be of value for predicting leukemic transformation.

Two types of acquired idiopathic sideroblastic anaemia (AISA)

On cytological bone marrow examination we distinguished between pure sideroblastic anaemia (PSA), which is confined to dyserythropoiesis, and refractory anaemia with ring sideroblasts (RARS), which is characterized by additional dysplastic features of granulopoiesis and/or megakaryopoiesis. In a follow-up study of 94 patients with AISA diagnosed according to FAB criteria for myelodysplastic syndromes we found a striking difference in the risk of leukaemic transformation between PSA and RARS (5 year cumulative rate 1.9% v. 48%). Overall survival was much better in PSA than in RARS (5 year cumulative chance 69% v. 19%). Infections and haemorrhages were frequent causes of death in RARS but not in PSA. Bone marrow culture studies (CFU-GM) were performed on 10 consecutive patients with PSA and RARS, respectively. RARS patients showed grossly impaired colony growth, typical of the myelodysplastic syndromes. Patients with PSA had persisting colony formation, even if moderately decreased in frequency, with numbers of CFU-GM being inversely correlated with the degree of erythroid hyperplasia in the bone marrow. We conclude that on cytomorphological grounds AISA can be divided into pure (dyserythropoietic) sideroblastic anaemia (PSA) and a true myelodysplastic form (RARS), with both types differing considerably in terms of survival, risk of leukaemic transformation and findings on bone marrow culture (CFU-GM).

Refractory anemia with excess of blasts in transformation hematologic and clinical study of 52 patients

This study consists of 52 patients whose blood and bone marrow findings fulfilled the French-American-British (FAB) Cooperative Group criteria for a diagnosis of refractory anemia with excess of blasts in transformation (RAEB-T). The basis for the diagnosis of RAEB-T included 37 patients (71%) meeting one criterion, 13 patients (25%) meeting two criteria, and two patients (4%) meeting three criteria; 44% met only the criterion of the detection of Auer rods. Clonal chromosome abnormalities were seen in seven of 16 cases studied and included abnormalities of chromosome 5, an extra 8, and complex abnormalities. Thirty-one patients were treated with a chemotherapeutic regimen that included an anthracycline and cytarabine; 13 of 17 patients (77%) 45 years of age or younger and six of 14 patients (43%) over 45 years of age achieved CR. The median survival for the 17 patients 45 years of age or younger is 25+ months; the median survival for the 14 patients over 45 years of age is 12.3 months. The median survival for 13 untreated patients over the age of 45 is 4.5 months. The process in 18 of the 52 patients (35%) evolved to overt acute myeloid leukemia (AML) in 1 to 38 months after diagnosis of RAEB-T, in seven of 20 patients (35%) 45 years of age or younger, and 11 of 32 patients (34%) over 45 years. Fifteen of the 18 patients received antileukemic therapy in the RAEB-T phase. There were no clinical or laboratory features that were reliably predictive of transformation to AML.

Differentiation induction therapy of myelodysplastic syndromes

Myelodysplastic syndromes are a heterogenous group of haemopoietic stem cell disorders characterized by dysplastic haematopoiesis and a defective maturation of a slowly expanding or sometimes of a stable population of haemopoietic progenitors. Defective maturation, which may involve one or more of the marrow cell lineages is regarded as the central pathophysiological feature of myelodysplastic syndromes. Patients with myelodysplastic syndromes respond poorly to conventional cytotoxic chemotherapy, frequently developing a prolonged marrow aplasia. The alternative and more appropriate form of therapy is differentiation induction therapy. The results of few preliminary clinical studies in myelodysplastic patients showed that a combination of differentiating agents is superior to single agent differentiation therapy. An extensive pre-clinical screening of the response of fresh cells from myelodysplastic patients in primary culture is needed to establish the optimal doses and conditions for significant synergies between various differentiating agents followed by large controlled randomized clinical trials based on differentiation induction therapy for patients with myelodysplastic syndromes.

Natural killer cell-mediated inhibition of bone marrow colony formation (CFU-GM) in refractory anaemia (preleukaemia): evidence for patient-specific cell populations

The role of peripheral blood mononuclear cells (PB-MNC) on the growth of bone marrow (BM) CFU-GM was investigated in refractory anaemia (RA) patients. Whereas normal donor PB-MNC were found to inhibit autologous day 7 CFU-GM, PB-MNC from RA patients exhibited little modulatory effect on autologous or allogeneic day 7 CFU-GM. In contrast, patient PB-MNC inhibited autologous CFU-GM at day 10 at a time where no significant inhibition was seen in the PB-MNC/RA CFU-GM combination. The identity of the inhibitory cells was investigated using anti-T8+ and anti-N901+ subsets purified by immune-rosette depletion with a panel of monoclonal antibodies. The activity of these subsets was tested on immature myeloid cells enriched for MY7+ cells, and it was found that cells highly enriched for NK cells were responsible for the inhibition. Further support for NK cells as the inhibitory cells was obtained in experiments where a positive correlation between the level of PB NK cytotoxicity against K562 cells and the degree of CFU-GM inhibition was demonstrated. Thus, these data suggest the presence of a specialized subset of NK cells with a capacity to inhibit autologous CFU-GM. Since RA is a potentially premalignant disease, in which a significant number of cases transform into AML, these findings also suggest a physiological role for NK cells in suppression of newly arisen clonogenic cells at least in early stages of the disease.

Chromosome study of 85 patients with myelodysplastic syndrome

We studied bone marrow chromosomes in 85 consecutive patients with myelodysplastic syndrome (MDS). Fifty-seven (67%) had a clone with an abnormal karyotype at diagnosis. Eight had secondary MDS, all with abnormal karyotypes. The frequency of abnormal karyotypes in the primary MDS was 64.9%. During subsequent follow-up, five patients acquired chromosome abnormalities; thus, at the end of the study, 72.0% of patients had an abnormal karyotype. The most frequent chromosome abnormalities were 5q-, +8, -7, -5, and -22. Forty patients (i.e., 70% of those with an abnormal karyotype and 47% of the whole group) had one of the karyotype abnormalities associated with secondary MDS or acute nonlymphocytic leukemia; in other words, 5q- or -5, or -7. Of all patients, 21.1% progressed into ANLL. Unfavorable prognostic factors associated with the risk of evolution into ANLL and with shorter overall survival were the presence of greater than 5% of bone marrow blasts, major chromosome abnormalities, and monosomy 7.

Prognostic value of clonal chromosomal abnormalities in patients with primary myelodysplastic syndromes

Chromosome analyses were carried out on bone marrow cells from 43 consecutive patients with primary myelodysplastic syndromes (MDS), classified according to the French-American-British (FAB) cooperative group criteria. The objective was to evaluate the prognostic value of clonal chromosomal abnormalities and of an excess of blasts for early death from acute nonlymphocytic leukemia (ANLL) and/or bone marrow failure (BMF). Patients were subdivided into two main groups: (1) refractory anemia without an excess of blasts (RAWEB), grouping patients with refractory anemia (RA) and refractory anemia with ringed sideroblasts (RARS), and (2) refractory anemia with an excess of blasts (RAEB), grouping patients with refractory anemia with an excess of blasts (RAEB) and refractory anemia with an excess of blasts in transformation (RAEBt). There were 29 patients with RAWEB and 14 with RAEB. The median time of observation was 26 months for RAWEB and 12 months for RAEB. Ten RAWEB patients (34%) and 11 RAEB patients (78%) had clonal chromosomal abnormalities. Among the ten RAWEB patients with clonal abnormalities, one (10%) died from ANLL, while of 19 RAWEB patients with a normal karyotype, two (10%) died from ANLL or BMF. The median survival for patients with RAWEB and an abnormal karyotype was not reached. In contrast, eight of the 11 RAEB patients with clonal chromosomal abnormalities (74%) died from ANLL or BMF. The median survival in this sub-group was 7 months. By using a Cox proportional hazard regression analysis, it was determined that a karyotype abnormality was not a significant predictory of survival once the contribution of the RAWEB/RAEB variable was taken into account. Being in the RAEB group was associated with a relative risk of 10.6 of dying from ANLL or BMF (beta = 2.36, standard error (SE) = 0.68, P = .0001). We conclude that classifying patients according to an excess of blasts will lead to a better prediction of survival than determining karyotype abnormality.

Detection of chromosomal 7 loss in myelodysplasia using an extremely polymorphic DNA probe

Chromosomal loss is a characteristic feature of the myelodysplastic syndromes (MDS). A method is described which detects chromosomal 7 loss in MDS by DNA analysis using a specific hypervariable region gene probe which has been cloned from a human DNA fingerprint. Loss of one of the chromosomal 7 homologues was demonstrated in 10/118 MDS patients; the ten patients include all the five patients which had previously been shown to have monosomy 7 by cytogenetic analysis. This technique makes it feasible to study serial samples from large numbers of patients for loss of chromosomal material and could be readily applied to the study of other human malignancies.

Mechanisms and prognostic value of cell kinetics in the myelodysplastic syndromes

Cell kinetics were studied by quantitative autoradiography in 29 patients with myelodysplastic syndromes (MDS) and in four with smouldering leukaemia (SML) in a prospective 6-year study. Cellular turnover in all FAB groups was characterized by reduced labelling index and prolonged DNA synthesis time indicating reduced proliferative activity. Two more parameters were derived from the measurements. (1) The relative cell production rate, which is increased in proerythroblasts and myeloblasts in most cases. This could be attributed to an increased number of divisions in early recognizable precursors in the absence of maturation, and (or) an increased influx from the progenitor compartments. (2) The maturation index of a cell lineage was determined by the ratio of relative cell production rate increase from the first to the last proliferative compartment over the corresponding normal value. It showed a high degree of abnormality in all FAB subgroups, indicating premature cell death in the bone marrow. None of the kinetic parameters proved to be of value in predicting the evolution of leukaemia. In contrast, an excellent correlation was found between the myeloid maturation index and survival (P less than 0.0001). No correlation, however, was found between survival and the erythroid maturation index, which was relatively normal in the worst prognostic group. These findings indicate that although in vitro cell kinetic studies can not predict the evolution of overt leukaemia, the myeloid maturation index is a useful predictor of survival in patients with MDS and SML.

A multivariate analysis of prognostic factors in chronic myelomonocytic leukaemia according to the FAB criteria

In an attempt to characterize the prognostic significance of the main initial clinical, haematological and biochemical features of chronic myelomonocytic leukaemia according to the FAB criteria, 29 such patients were analysed by means of univariate and multivariate statistical methods. At the time of the analysis 21 patients had died, with a median survival for the overall series of 8.2 months. The univariate analysis identified three parameters associated with poor prognosis: high monocyte counts, low platelet counts and splenomegaly. When all the initial features were included in a multiple regression model, only high monocyte counts and spleen enlargement retained their unfavourable prognostic influence (P = 0.002 and P = 0.02, respectively). Based on the presence or not of these prognostic factors, two populations of patients with different survival (median survival 5.6 and 16.5 months, respectively, P less than 0.005) could be identified. It seems therefore that monocytic proliferation serves not only as the diagnostic marker for chronic myelomonocytic leukaemia but also as the most important feature in the assessment of the patient's prognosis.

The myelodysplastic syndromes

The myelodysplastic syndromes constitute a fascinating model for monoclonal premalignant disorders. Haemopoiesis is 'dysplastic' with inefficient maturation of a slowly expanding or sometimes of a stable population, of blood cell precursors. About one third of the patients evolve into acute leukaemia, the result of either a progressive expansion of the original clone or a new mutation producing a more malignant subclone. The majority of patients suffer from the results of bone-marrow insufficiency, with pancytopenia and possibly immune deficiency. Characteristic karyotype anomalies involving mainly chromosomes 5, 7 and 8 are seen in half the patients. These same chromosomes are known to carry different oncogenes. The myelodysplastic syndrome occurs mainly in the aged and there is a moderate male preponderance. The incidence is still unknown but is probably similar to that of acute leukaemia. The etiology is also unknown; however, a secondary myelodysplastic syndrome precedes acute myeloid leukaemia, as a late consequence of chemo- and radio-therapy in treated Hodgkin's disease. This suggests that environmental mutagens might also be involved in primary myelodysplastic syndromes. Treatment remains highly unsatisfactory but a few recent developments improve prognosis, at least in the younger patient.

Myelodysplastic syndromes: their history, evolution and relation to acute myeloid leukaemia

The myelodysplastic syndromes (MDS) constitute a heterogeneous group of clonal disorders arising from a multipotent haemopoietic progenitor which share a leukaemic propensity, 30% of cases culminating in acute myeloid leukaemia (AML). Their pathogenesis probably entails multiple steps, phenotypic progression being determined by either expansion or evolution of the abnormal clone. The clonal origin of certain cases of de novo AML is analogous to that of MDS and evidence that they share a common pathogenesis and distinct biological characteristics is beginning to emerge.