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Blood Res 2022; 57(1):

Published online March 31, 2022

https://doi.org/10.5045/br.2021.2021209

© The Korean Society of Hematology

Myelofibrotic and leukemic transformation in 2016 WHO-defined Philadelphia-negative myeloproliferative neoplasm

Ik-Chan Song1, Sang Hoon Yeon1, Myung-Won Lee1, Hyewon Ryu1, Hyo-Jin Lee1, Hwan-Jung Yun1, Seon Young Kim2, Deog-Yeon Jo1

1Division of Hematology/Oncology, Department of Internal Medicine, 2Department of Laboratory Medicine, Chungnam National University College of Medicine, Daejeon, Korea

Correspondence to : Deog-Yeon Jo, M.D., Ph.D.
Division of Hematology/Oncology, Department of Internal Medicine, Chungnam National University Hospital, 282 Munhwa-ro, Jung-gu, Daejeon 35015, Korea
E-mail: deogyeon@cnu.ac.kr
*This study was supported by Chungnam National University Hospital Research Fund (2021).

Received: November 14, 2021; Revised: February 5, 2022; Accepted: February 7, 2022

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background
Information on myelofibrotic and leukemic transformations in Korean Philadelphia chromosome- negative myeloproliferative neoplasms (Ph MPNs) is limited.
Methods
This study retrospectively analyzed transformations in patients diagnosed with essential thrombocythemia (ET), polycythemia vera (PV) prefibrotic/early primary myelofibrosis (pre-PMF), or overt primary myelofibrosis (PMF) based on the 2016 World Health Organization criteria between January 1996 and December 2020 at Chungam National University Hospital, Daejeon, Korea.
Results
A total of 351 patients (144 with ET, 131 with PV, 45 with pre-PMF, and 31 with PMF; 204 men and 147 women) with a median age of 64 years (range, 15‒91 years) were followed for a median of 4.6 years (range, 0.2‒24.8 years). The 10-year incidence of overt myelofibrosis was higher in pre-PMF than in ET (31.3% and 13.7%, respectively; P =0.031) and PV (12.2%; P =0.003). The 10-year incidence of leukemic transformation was significantly higher in PMF than in ET (40.0% and 7.9%, respectively; P =0.046), pre-PMF (4.7%; P =0.048), and PV (3.2%; P =0.031). The 5-year incidence of leukemic transformation was higher in patients with secondary myelofibrosis (SMF) than in those with PMF (19.0% and 11.4%, respectively; P =0.040). The 5-year overall survival of patients with SMF was significantly worse than that of patients with pre-PMF (74% and 93%, respectively; P=0.027) but did not differ from that of patients with PMF (57%; P=0.744).
Conclusion
The rates and clinical courses of myelofibrotic and leukemic transformations in Korean patients with Ph MPN did not differ from those in Western populations.

Keywords Myeloproliferative neoplasm, Essential thrombocythemia, Polycythemia vera, Primary myelofibrosis, Secondary myelofibrosis, Leukemia

Article

Original Article

Blood Res 2022; 57(1): 59-68

Published online March 31, 2022 https://doi.org/10.5045/br.2021.2021209

Copyright © The Korean Society of Hematology.

Myelofibrotic and leukemic transformation in 2016 WHO-defined Philadelphia-negative myeloproliferative neoplasm

Ik-Chan Song1, Sang Hoon Yeon1, Myung-Won Lee1, Hyewon Ryu1, Hyo-Jin Lee1, Hwan-Jung Yun1, Seon Young Kim2, Deog-Yeon Jo1

1Division of Hematology/Oncology, Department of Internal Medicine, 2Department of Laboratory Medicine, Chungnam National University College of Medicine, Daejeon, Korea

Correspondence to:Deog-Yeon Jo, M.D., Ph.D.
Division of Hematology/Oncology, Department of Internal Medicine, Chungnam National University Hospital, 282 Munhwa-ro, Jung-gu, Daejeon 35015, Korea
E-mail: deogyeon@cnu.ac.kr
*This study was supported by Chungnam National University Hospital Research Fund (2021).

Received: November 14, 2021; Revised: February 5, 2022; Accepted: February 7, 2022

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background
Information on myelofibrotic and leukemic transformations in Korean Philadelphia chromosome- negative myeloproliferative neoplasms (Ph MPNs) is limited.
Methods
This study retrospectively analyzed transformations in patients diagnosed with essential thrombocythemia (ET), polycythemia vera (PV) prefibrotic/early primary myelofibrosis (pre-PMF), or overt primary myelofibrosis (PMF) based on the 2016 World Health Organization criteria between January 1996 and December 2020 at Chungam National University Hospital, Daejeon, Korea.
Results
A total of 351 patients (144 with ET, 131 with PV, 45 with pre-PMF, and 31 with PMF; 204 men and 147 women) with a median age of 64 years (range, 15‒91 years) were followed for a median of 4.6 years (range, 0.2‒24.8 years). The 10-year incidence of overt myelofibrosis was higher in pre-PMF than in ET (31.3% and 13.7%, respectively; P =0.031) and PV (12.2%; P =0.003). The 10-year incidence of leukemic transformation was significantly higher in PMF than in ET (40.0% and 7.9%, respectively; P =0.046), pre-PMF (4.7%; P =0.048), and PV (3.2%; P =0.031). The 5-year incidence of leukemic transformation was higher in patients with secondary myelofibrosis (SMF) than in those with PMF (19.0% and 11.4%, respectively; P =0.040). The 5-year overall survival of patients with SMF was significantly worse than that of patients with pre-PMF (74% and 93%, respectively; P=0.027) but did not differ from that of patients with PMF (57%; P=0.744).
Conclusion
The rates and clinical courses of myelofibrotic and leukemic transformations in Korean patients with Ph MPN did not differ from those in Western populations.

Keywords: Myeloproliferative neoplasm, Essential thrombocythemia, Polycythemia vera, Primary myelofibrosis, Secondary myelofibrosis, Leukemia

Fig 1.

Figure 1.Myelofibrotic and leukemic transformations in patients with myeloproliferative neoplasm.
Abbreviations: AML, acute myeloid leukemia; ET, essential thrombo-cythemia; PMF, overt primary myelofibrosis; pre-PMF, prefibrotic/early primary myelofibrosis; PV, polycythemia vera.
Blood Research 2022; 57: 59-68https://doi.org/10.5045/br.2021.2021209

Fig 2.

Figure 2.Cumulative incidence of myelofibrotic transformation in myeloproliferative neoplasms.
Abbreviations: ET, essential thrombocythemia; pre-PMF, prefibrotic/early primary myelofibrosis; PV, polycythemia vera.
Blood Research 2022; 57: 59-68https://doi.org/10.5045/br.2021.2021209

Fig 3.

Figure 3.Cumulative incidence of leukemic transformation in myelo-proliferative neoplasms.
Abbreviations: ET, essential thrombocythemia; PMF, overt primary myelofibrosis; pre-PMF, prefibrotic/early primary myelofibrosis; PV, polycythemia vera; SMF, secondary myelofibrosis.
Blood Research 2022; 57: 59-68https://doi.org/10.5045/br.2021.2021209

Fig 4.

Figure 4.Overall survival of secondary myelofibrosis, prefibrotic/early primary myelofibrosis, and overt primary myelofibrosis.
Abbreviations: OS, overall survival; PMF, overt primary myelofibrosis; pre-PMF, prefibrotic/early primary myelofibrosis; SMF, secondary myelofibrosis.
Blood Research 2022; 57: 59-68https://doi.org/10.5045/br.2021.2021209

Table 1 . Patient characteristics (N=351)..

ET (N=144)PV (N=131)Pre-PMF (N=45)PMF (N=31)
Age (yr), median (range)62 (15–88) 64 (18–91)63.5 (22–88)68.5 (40–88)
Female, N (%)70 (48.6) 48 (36.6)19 (42.2)10 (32.3)
Palpable splenomegaly, N (%) 0 (0.0) 11 (8.4)4 (8.9)16 (51.6)
Laboratory findings
WBC, ×109/L11.0±4.514.7±6.214.5±10.2a)13.7±11.0
Monocyte, ×109/L0.6±0.40.7±0.40.8±0.4a)1.0±0.8
Hemoglobin, g/dL13.6±2.218.3±2.513.0±2.810.3±2.5
Platelet, ×109/L946.5±244.9510.9±288.41,093.9±461.1a)424.8±327.5
LDH, ×UNL1.1±0.41.3±0.51.6±0.7a)2.0±1.5
Abnormal cytogenetics, N (%)0 (0.0) 3 (2.3)3 (6.7)3 (9.7)
Driver gene mutation, N (%)b)
JAK2V617F83/122 (68.0)100/114 (87.7)24/38 (63.2)15/23 (65.3)
CALR14/122 (11.5)-5/38 (13.2)5/23 (21.7)
MPL0/12 (0.0)-0/3 (0.0)0/3 (0.0)
JAK2 exon 12-6/114 (5.3)--
IPSET, N (%)
Low46 (31.9)---
Intermediate42 (29.2)---
High56 (38.9)---
IPSS, N (%)
Low--24 (53.3)5 (16.1)
Intermediate-1--17 (37.8)8 (25.8)
Intermediate-2--3 (6.7)12 (38.7)
High--1 (2.2)6 (19.4)
Comorbidity, N (%)
Hypertension51 (35.4) 78 (59.5)23 (51.1)11 (35.5)
Diabetes mellitus19 (13.2) 33 (25.2)9 (20.0)7 (22.6)
Chronic kidney disease21 (14.6) 29 (22.1)10 (22.2)4 (12.9)
Smoking29 (20.1) 53 (40.5)14 (31.1)4 (12.9)
Treatments, N (%)
Cytoreductive treatment109 (75.7)108 (82.4)34 (75.6)17 (29.0)
Hydroxyurea93 (64.6)107 (81.7)28 (62.2)8 (25.8)
Anagrelide13 (9.0) 0 (0.0)4 (8.9)1 (3.2)
Both 3 (2.1) 1 (0.7)2 (4.4)0 (0.0)
Ruxolitinib 0 (0.0) 0 (0.0)0 (0.0)8 (25.8)
Aspirin128 (88.9)123 (93.9)38 (84.4)12 (38.7)
Thrombosis, N (%)c)37 (25.7) 39 (29.8)13 (28.9)1 (3.2)
FU (yr), median (range)6.5 (0.6–24.8) 6.2 (0.6–20.3)4.0 (0.5–16.4)3.2 (0.2–14.7)

a)P<0.05 compared to ET. b)A subpopulation of the patients enrolledunderwent gene mutation tests. c)Thrombosis before and at the time of diagnosis..

Abbreviations: FU, follow-up; ET, essential thrombocythemia; IPSET, International Prognostic Score for Essential Thrombocythemia; IPSS, International Prognostic Scoring System; LDH, lactate dehydrogenase; pre-PMF, prefibrotic/early primary myelofibrosis; PV, polycythemia vera; UNL, upper normal limit..


Table 2 . Clinical features of patients with essential thrombocythemia and polycythemia vera who developed myelofibrosis..

ET (N=10)PV (N=11)
At ET diagnosisAt SMF diagnosisPa)At PV diagnosisAt SMF diagnosisPa)
Age (yr), median (range)62 (51–75)70 (63–83)61 (36–75)73 (52–85)
Palpable splenomegaly, N (%)0 (0.0)6 (60.0)<0.0014 (36.4)5 (45.5)1.000
Laboratory findings
WBC, ×109/L7.0±6.08.6±6.10.10115.1±7.720.9±21.70.384
Monocyte, ×109/L0.8±0.40.4±0.50.1181.1±0.61.6±2.30.598
Hemoglobin, g/dL12.9±2.58.9±1.50.00117.3±3.110.6±1.40.001
Platelet, ×109/L667.0±845.7527.8±486.80.033626.7±426.3399.3±401.20.154
Leukoerythroblastosis, N (%)0 (0.0)8 (80.0)<0.0010 (0.0)10 (90.9)<0.001
LDH, ×UNL1.3±0.62.8±1.20.0041.1±1.12.2±0.60.037
Abnormal karyotype, N (%)0 (0.0)3 (30.0)<0.0012 (18.2)6 (54.5)0.076

a)Data presented as mean±SD were analyzed using Student’s t-test for paired samples; data presented as percentages were analyzed using the chi-square test..

Abbreviations: ET, essential thrombocythemia; LDH, lactate dehydrogenase; SMF, secondary myelofibrosis; UNL, upper normal limit..


Table 3 . Clinical features of patients with prefibrotic/early myelofibrosis who progressed to overt myelofibrosis (N=10)..

At pre-PMF diagnosisAt overt PMF diagnosisPa)
Age (yr), median (range)62 (16–72)69.5 (34–79)
Palpable splenomegaly, N (%)2 (20.0)7 (70.0)0.025
Laboratory findings
WBC, ×109/L12.6±5.312.6±10.90.987
Monocyte, ×109/L 0.8±0.30.5±0.40.119
Hemoglobin, g/dL13.2±2.49.2±2.50.004
Platelet, ×109/L1,186.3±567.7450.7±196.50.003
LDH, ×UNL 1.5±0.42.8±0.50.005
Leukoerythrolastosis, N (%)2 (20.0)9 (90.0)0.002
Abnormal karyotype, N (%)1 (10.0)7 (70.0)0.006
IPSS, N (%)0.004
Low7 (70.0)1 (10.0)
Intermediate-13 (30.0)1 (10.0)
Intermediate-20 (0.0)3 (30.0)
High0 (0.0)5 (50.0)

a)Data presented as mean±SD were analyzed using Student’s t-test for paired samples; data presented as percentages were analyzed using the chi-square test..

Abbreviations: LDH, lactate dehydrogenase; IPSS, International Prognostic Scoring System; pre-PMF, prefibrotic/early primary myelofibrosis; UNL, upper normal limit..


Table 4 . Clinical features of patients with secondary and overt primary myelofibrosis..

SMF (N=21)PMF (N=31)P
Age (yr), median (range)70.5 (52–85)68 (32–86)0.118
Male, N (%)11 (52.4)21 (67.7)0.358
Palpable splenomegaly, N (%)11 (52.4)14 (45.2)0.382
Laboratory findings
WBC, ×109/L14.9±14.613.7±10.10.741
Monocyte, ×109/L0.8±1.31.0±0.80.488
Hemoglobin, g/dL9.6±1.710.3±2.60.282
Platelet, ×109/L458.1±408.0424.8±327.50.749
LDH, ×UNL2.6±1.02.1±1.60.252
Bone marrow fibrosis, N (%)
MF-10 (0.0)0 (0.0)1.000
MF-2/321 (100.0)31 (100.0)1.000
Abnormal karyotype, N (%)9 (42.9)3 (9.7)0.002
Diver gene mutation, N (%)
JAK2V617F12/17 (70.6)15/23 (65.2)0.615
CALR3/17 (17.6)5/23 (21.7)0.604
JAK2 exon 121/17 (5.9)--
IPSS, N (%)
Low0 (0.0)5 (16.1)0.038
Intermediate-12 (9.5)8 (25.8)
Intermediate-29 (42.9)12 (38.7)
High10 (47.6)6 (19.4)
Treatment, N (%)
Hydroxyurea12 (57.1)9 (29.0)0.028
Ruxolitinib8 (38.1)9 (29.0)0.417
Leukemic transformation, N (%)3 (14.3)2 (6.5)0.316
FU (yr), median (range)1.5 (0.1–5.9)2.5 (0.1–14.7)0.145

Abbreviations: FU, follow-up; IPSS, International Prognostic Scoring System; LDH, lactate dehydrogenase; PMF, overt primary myelofibrosis; SMF, secondary myelofibrosis; UNL, upper normal limit..


Table 5 . Fine and Gray regression analysis to determine risk factors for developing myelofibrosis in patients with essential thrombocythemia (N=144)..

Univariate analysisMultivariate analysis
HR95% CIPHR95% CIP
Factors at diagnosis
Age >60 yr1.890.59–6.050.286---
Male1.820.49–6.740.367---
IPSET high0.830.24–2.830.768---
WBC >11.0×109/L0.820.27–2.490.721---
Monocyte >1.0×109/L2.791.23–9.120.0453.571.17–10.910.026
Platelet >1,000×109/L0.920.30–2.850.890---
LDH >1.5×UNL0.580.15–2.270.432---
Positive JAK2V617F0.720.21–2.500.602---
Positive CALR mutation3.261.01–10.470.0484.421.20–16.370.026
Thrombosis before or at diagnosis1.860.52–6.660.342---
Hydroxyurea treatment1.270.27–5.940.766---

Abbreviations: CI, confidence interval; HR, hazard ratio; IPSET, International prognostic scoring for essential thrombocythemia; LDH, lactate dehydrogenase; UNL, upper normal limit..


Table 6 . Fine and Gray regression analysis to determine risk factors for developing myelofibrosis in patients with polycythemia vera (N=131)..

Univariate analysisMultivariate analysis
HR95% CIPHR95% CIP
Factors at diagnosis
Age >60 yr0.840.27–2.630.765---
Female2.920.99–8.570.051---
Palpable splenomegaly3.190.97–10.440.056---
WBC >11.0×109/L1.440.38–5.440.588--
Monocyte >1.0×109/L3.170.89–11.350.076---
Platelet >1,000×109/L2.010.30–13.680.473---
LDH >1.5×UNL4.011.04–15.590.0442.390.31–18.600.405
Positive JAK2V617F2.720.30–24.400.386---
Positive JAK2 exon 12 mutation2.670.35–20.160.341---
Abnormal karyotype21.445.71–80.91<0.00118.202.0–165.950.010
Thrombosis before or at diagnosis0.310.04–2.630.284---
Hydroxyurea treatment2.200.27–17.740.458---

Abbreviations: CI, confidence interval; HR, hazard ratio; LDH, lactate dehydrogenase; UNL, upper normal limit..


Table 7 . Fine and Gray regression analysis to determine risk factors for leukemic transformation in patients with myeloproliferative neoplasm (N=351)..

Univariate analysisMultivariate analysis
HR95% CIPHR95% CIP
Factors at diagnosis
Age >60 yr2.900.75–11.300.125---
Female1.980.62–6.340.247---
Palpable splenomegaly2.790.80–9.870.140---
WBC >11.0×109/L1.860.57–6.060.304---
Monocyte >1.0×109/L4.051.23–13.390.0223.220.69–14.680.135
Platelet >1,000×109/L2.440.77–7.730.128---
LDH >1.5×UNL2.740.81–9.260.105---
Positive JAK2V617F3.400.41–28.400.258---
Positive CALR mutation0.990.26–2.110.579---
PMF3.510.80–15.440.096---
Abnormal karyotype5.601.10–28.590.0383.620.41–31.140.241
Thrombosis before or at diagnosis1.260.34–4.660.730---
Hydroxyurea treatment1.980.43–9.110.381---

Abbreviations: CI, confidence interval; HR, hazard ratio; LDH, lactate dehydrogenase; PMF, overt primary myelofibrosis; UNL, upper normal limit..


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