Presence of peripheral blasts in refractory anemia and refractory cytopenia with multilineage dysplasia predicts an unfavourable outcome

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Leukemia Research 32 (2008) 33–37

Presence of peripheral blasts in refractory anemia and refractory cytopenia with multilineage dysplasia predicts an unfavourable outcome Sabine Knipp a,∗ , Corinna Strupp b , Norbert Gattermann b , Barbara Hildebrandt c , Marc Schapira a , Aristoteles Giagounidis d , Carlo Aul d , Rainer Haas b , Ulrich Germing b b

a Department of Haematology, Centre Hospitalier Universitaire Vaudois, Rue du Bugnon 44, 1011 Lausanne, Switzerland Department of Haematology, Oncology and Clinical Immunology, Heinrich-Heine-University, Moorenstr. 5, 40225 D¨usseldorf, Germany c Institute of Human Genetics, Heinrich-Heine-University, Moorenstr. 5, 40225 D¨ usseldorf, Germany d Department of Haematology, Oncology and Clinical Immunology, St. Johannes Hospital Duisburg, An der Abtei 5-7, 47166 Duisburg, Germany

Received 10 January 2007; received in revised form 15 January 2007; accepted 27 February 2007 Available online 6 April 2007

Abstract The World Health Organization (WHO) assigns myelodysplastic syndrome (MDS) to RA/RCMD/RARS/RSCM/5q− syndrome, if medullary blasts are <5% and peripheral blast (PB) count ≤1%. In 1103 patients with these diagnoses, we analysed survival and risk of AML evolution depending on the presence of PB. Median survival in the group with 1% PB (n = 74) was significantly lower as compared to those without PB (20 versus 47 months, p < 0.00005). Cumulative risk of AML was significantly higher in patients showing PB (p < 0.00005). Median survival of patients with PB was not different from that of RAEB I. We therefore propose to consider patients with PB, regardless of medullary blast, as RAEB I. © 2007 Elsevier Ltd. All rights reserved. Keywords: Myelodysplastic syndromes; Peripheral blasts; Prognosis; Risk of AML evolution; WHO classification

1. Introduction The classification of patients with myelodysplastic syndrome (MDS) according to the World Health Organization (WHO) [1], divides MDS into refractory anemia (RA), refractory anemia with ring sideroblasts (RARS), refractory anemia with multilineage dysplasia (RCMD), refractory anemia with multilineage dysplasia with ring sideroblasts (RSCMD) and 5q− syndrome depending on their morphologic features and karyotypes and MDS with elevated blasts in blood or marrow (RAEB I and RAEB II). The French American British group (FAB) [2] introduced the term “excess of blasts” to characterize patients, who present either with more than 4% medullary blasts and/or more than 1% peripheral blasts. This means, the presence of small number of circulating blast cells ∗

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not exceeding 1% was not regarded as relevant for classification and prognosis. The IPSS [3] does not rely on peripheral blasts. Based on the results of several studies, patients with low risk MDS (RA, RARS and RSCMD, RCMD or 5q− syndrome by WHO) are known to have a longer median time of survival and a lower risk of developing AML compared to patients with high risk MDS (RAEB I and RAEB II by WHO) [1,2,4]. Still, there are few patients with RA, RARS, RCMD, RSCMD or 5q− syndrome who have short survival time. Only few factors are known to identify those patients, such as poor cytogenetics and elevated LDH [5,6]. The MDS Registry at the University of D¨usseldorf now includes 1103 patients with RA, RARS, RCMD, RSCMD or 5q− syndrome, in whom a central morphologic review of peripheral blood has been performed. It is the purpose of this study to compare the risk of developing sAML and the time

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S. Knipp et al. / Leukemia Research 32 (2008) 33–37

of survival of patients with presence of 1% peripheral blasts (PB) to patients without presence of PB and with outcome of patients suffering from RAEB I.

2. Material and methods Between 1974 and 2005, 1103 patients with RA, RARS, RCMD, RSCMD or 5q− syndrome MDS and 283 patients with RAEB I, in which bone marrow slides as well as a peripheral blood smear has been reviewed centrally in our department at the time of diagnosis were included in the MDS registry. All bone marrow smears as well as peripheral blood smears were examined by the same investigator(s) (CA, UG). Morphological diagnosis was made according to the FAB classification [2] and later also according to the WHO classification [1,7]. A differential white blood count was performed on 100 cells in the peripheral blood to determine the proportion of peripheral blasts by the same investigators at the same time when bone marrow morphology was performed. Patients were followed for survival and leukemic progression through October 31, 2006. Patients were either regularly seen in our outpatient clinic or we kept in close contact with the primary care physician to gather information on the course of their disease. The product limit method (Kaplan–Meier) was used to estimate survival. Prognostic factors were determined using the Mantel–Cox test and the stepwise multivariate regression method of Cox [8]. Clinical and haematological data were

compared using the χ2 [9] and Wilcoxon rank sum test. All patients have been treated with supportive care only. In 343 patients, cytogenetic analysis was performed at the Institute of Human Genetics, Heinrich-Heine-University, D¨usseldorf. According to the criteria of the IPSS, karyotypes were separated into the three cytogenetic risk groups [3]. We compared survival and development of AML of patients suffering from RA, RARS, RCMD, RSCMD or 5q− syndrome with the presence of PB to those without the presence of PB. In addition, we compared patients with 1% PB to those with RAEB I. We, furthermore searched for a correlation between the presence of PB and the presence of cytogenetic abnormalities and other parameters in patients with low risk MDS.

3. Results We identified 1103 patients with RA, RARS, RCMD, RSCMD or 5q− syndrome. There were 552 male and 551 female with a median age of 71 years (14–94). According to WHO classification, 153 suffered from RA, 127 from RARS, 54 from 5q− syndrome, 257 from RS-RCMD and 512 from RCMD. Seventy-four patients had a peripheral blasts count of 1% at diagnosis, whereas 1029 patients were free of circulating blast cells. In a first step, we compared both groups (PB+ and PB−) with regard to clinical, haematological and morphological features (Table 1). Blasts in peripheral blood were found more often in patients with multilineage WHO types of MDS. In

Table 1 Clinical, haematological and morphological features of patients with or without PB (median and range) Variable

PB−

PB+

p-Value

Age Gender (m/f) Alive (%) AML evolution (%) Transfusion dependency (%) Hemoglobin (g/dl) Platelet count 100,000/␮l WBC × 1000/␮l ANC × 1000/␮l LDH (U/l) Chromosomal aberration (%)

72 (14–94) 520/509 39.8 6.8 60 9.2 (3.4–15.9) 175 (2–987) 4.5 (0.5–19.8) 2.6 (0.1–18.9) 181 (63–2500) 49.7

71 (21–91) 32/42 37.7 16.2 67 9.0 (4.4–16.9) 151 (9–976) 3.6 (0.9–11.9) 2.3 (0.3–7.6) 195 (120–1650) 74.1

n.s. n.s. n.s. 0.0003 n.s.

Karyotype risk (IPSS) (%) Low Intermediate High

73.7 13.0 13.3

56 26 18

n.s.

Left shift of granulopoiesis (%) Hyperplasia of granulopoiesis (%) Pseudo-pelger cell peripher (%) Degranulated cells peripher (%) Pseudo-pelger cell in marrow (%) Degranulated cells in marrow (%) Defect if myeloperoxidase (%) Mononuclear megakaryocytes (%) Micromegakaryocytes (%) Elevated lymphocytes in marrow (%)

38.8 17.6 8.6 3.3 35.8 31 15.4 28.5 17.8 12.1

49.3 33 28.8 7.8 51 48.6 9.3 30.9 18.2 17.1

0.05 0.002 0.009 0.09 0.00005 0.002 n.s. n.s. n.s. n.s.

n.s. n.s. n.s. n.s. 0.015

S. Knipp et al. / Leukemia Research 32 (2008) 33–37

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Fig. 1. (a) Cumulative survival and (b) cumulative risk of AML evolution of non-blastic MDS with or without peripheral blasts.

the group of patients with RA and RARS, there were six patients showing PB (2%). Marked differences in the risk of developing AML evolution were found. Signs of dysplasia of the granulopoiesis in blood and marrow could be seen more often in the PB+ group. Within erythropoiesis and megakaryopoiesis, there were no substantial differences. The number of cytogenetic aberrations was higher in the PB+ group as well. Age, gender distribution, clinical signs, like organomegaly or lymph node swellings and cell counts did not differ between the groups. There was no correlation between the presence of PB and LDH or IPSS category. In a next step, we analysed the impact of the presence of PB on outcome of the patients. Median survival in the group with presence of PB was 20 months, as compared to 47 months in the group without the presence of PB (p < 0.00005; Fig. 1a). The cumulative risk of AML evolution also differed significantly (p = 0.003; Fig. 1b). We then analysed the survival data of a low risk group (RA/RARS/5q− syndrome) and a high risk group (RCMD/RSCMD) (Table 2). In both the groups, as well as

within the 5q− subgroup alone, there were marked differences between those who presented with blasts and those who did not. Finally, we performed multivariate analyses in order to assess if the prognostic impact of PB is still valid when tested with other well-established parameters. When calculated together with age, hemoglobin, platelets, LDH, gender, presence of multilineage dysplasia, the presence of PB was regarded as an independent parameter for survival as well as for risk of AML evolution (Table 3a and b). Due to lack of karyotyping in many patients, this parameter was not entered into the multivariate analysis. Obviously, there is no strong correlation between cytogenetic abnormalities and presence of PB, although cytogenetic anomalies were more frequent in the PB+ group. Taking into account the worsening of the prognosis by the presence of PB, we compared the survival curves of the PB+ group with the curve of 283 patients with RAEB I. There was no difference in survival (Fig. 2a) or in cumulative risk of AML evolution (Fig. 2b).

Fig. 2. (a) Cumulative survival and (b) cumulative risk of AML evolution of non-blastic MDS with peripheral blasts compared to RAEB I.

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S. Knipp et al. / Leukemia Research 32 (2008) 33–37

Table 2 Impact of presence of blasts on survival and cumulative risk of AML evolution (univariate analysis) Variable

N

Median survival (months)

Log-rank

p

Cumulative AML evolution (%) 2 years

All patients PB− PB+

Log-rank

p

5 years

1029 74

47 20

16.53

<0.00005

6 0

10 0

17.78

<0.00005

5q− syndrome PB− 48 PB+ 6

97 16

8.25

0.0041

0 40

6 70

15.4

0.0001

RA/RARS/5q− PB− 322 PB+ 12

69 17

10.35

0.0013

2 25

4 62

25.2

<0.00005

RCMD/RSCMD PB− 706 PB+ 62

37 24

5.8

0.01

7 20

13 20

Table 3 Multivariate analyses for survival and cumulative risk of AML evolution Parameter

χ2

p

Part (a) Hemoglobin < 9 g/dl Age > 60 years Platelets < 100.000/␮l LDH elevated Multilineage dysplasia Peripheral blasts +

60.65 58.01 28.06 27.70 7.01 6.01

<0.00005 <0.00005 <0.00005 <0.00005 0.008 0.014

Part (b) Platelets <100.000/␮l Multilineage dysplasia Peripheral blasts + Hemoglobin < 9 g/dl Multilineage dysplasia LDH elevated

17.2 9.33 8.31 6.34 7.01 2.93

<0.00005 0.002 0.004 0.012 0.008 0.087

Variables entered in the model: gender, age, hemoglobin, WBC, ANC, platelets, LDH, karyotype, presence of peripheral blasts, (a) survival and (b) AML evolution.

4. Discussion In this study, we could demonstrate a significant difference with regard to prognosis between patients suffering from RA, RARS, RCMD, RSCMD or 5q− syndrome with or without presence of PB. The time of survival is significantly shorter and patients develop a AML more often, if blasts are detectable in peripheral blood. This finding is not reflected by the WHO classification, since both do not take into account a peripheral blast count of 1% [1,2,10]. Based on our observation, we propose to perform a peripheral differential white count on a large number of cells to gather sufficient information on the presence of PB. Possibly, methods like immunphenotyping of peripheral blood may be helpful to identify circulating blasts with greater accuracy. An automated differential count may not be exact enough to identify a small number of blasts. We are not aware of any other study that had addressed this topic in more detail. The presence of PB can help to identify patients at higher risk than

5.42

0.01

expected and can be especially helpful in patients for whom no data on cytogenetic aberrations are available, as is known for approximately 10% of MDS cases. We could also clearly show that patients with PB have almost the same prognosis as patients with RAEB I. Patients with RA, RARS, RCMD or RSCMD who present with PB could therefore, be allocated to the RAEB I group, regardless of their medullary blast count. This is obviously of prognostic relevance and takes the term “excess of blasts” very serious. The presence of PB is probably the reflection of a more aggressive character of the disease and may have an influence on the decision making process with regard to therapy.

Acknowledgements Contributions. S. Knipp and U. Germing provided the concept, data analysis and interpretation. C. Strupp and N. Gattermann gave critical revision of the manuscript and conducted data analysis and interpretation. B. Hildebrandt performed cytogenetic analysis. M. Schapira, A. Giagounidis, C. Aul and R. Haas gave critical revision of the manuscript. S. Knipp wrote the manuscript and conducted a review of related articles.

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