1. Prefibrotisk Myelofibros
Björn Andréasson

2. Hb <13g/dL for men or <12 for women
This algorithm is able to identify the vast majority of true MF patients and true ET patients
Parameters’
thresholds N
Positives
Specificity
(includes
True MF patients)
Sensitivity
(excludes
True ET patients)
“MF suspicion”
bucket
Hb <13g/dL for men or <12 for women
536 46
92%
(422 / 457)
14%
(11 / 79)
WBC ≥13x109/L 56
91%
(417 / 457)
20%
(16 / 79)
“High likelihood
of true ET”
WBC <7x109/L
104
22%
(99/ 457)
94%
(74 / 79)
LDH < 200mU/mL
428
(101 / 457)
(72 / 79) A B
Source: Sensitivity and specificity for Hb, WBC and LDH threshold from Carobbio et al. 2012

3. Leukemic Transformation
This is key, as the patient outcomes for the two diseases are significantly different
Overall Survival
ET patients
MF patients
p value
Median Survival
21.76 years
14.44 years
0.0002
Rate at 10 years
89%
76%
Rate at 15 years
80%
59%
Leukemic Transformation
ET patients
MF patients
p value
Rate at 10 years
0.7%
5.8%
0.0012
Rate at 15 years
2.1%
11.7%
ET patients
MF patients
Source: Barbui et al. July 2011/ /JCO , Journal of clinical oncology; 1,104 patients previously diagnosed as having ET Study eligibility criteria included availability of treatment-naive BM specimens obtained within 1 year of diagnosis, all bone marrows subsequently underwent a central re-review.

4. Prefibrotic Primary Myelofibrosis (PrePMF) criteria Arber 2016
Major criteria
1. Megakaryocytic proliferation and atypia, without reticulin fibrosis >grade 1*, accompanied by increased age-adjusted bone marrow cellularity, granulocytic proliferation, and often decreased erythropoiesis
2. Not meeting the WHO criteria for BCR-ABL positive CML, PV, ET, MDS, or other myeloid neoplasms
3. Presence of JAK2, CALR, or MPL mutation or in the absence of these mutations, presence of another clonal marker,† or absence of minor reactive bone marrow reticulin fibrosis‡
Minor criteria
Presence of at least 1 of the following, confirmed in 2 consecutive determinations:
a. Anemia not attributed to a comorbid condition
b. Leukocytosis >11 x 109/L
c. Palpable splenomegaly
d. S-LDH increased to above upper normal limit of institutional reference range
Diagnosis of prePMF requires meeting all 3 major criteria, and at least 1 minor criterion

5. Diagnostic work-up in prefibrotic myelofibrosis

7. MF-0
MF-1

8. Survival according to stage of PMF% S u r v i a l
Years after diagnosis
n=178
PMF-0
n=139
n=128
n=281
PMF-3
PMF-2
PMF-1 20 40 60 80
100 2 4 6 8 10 12 14