IN THE LITERATURE
Continued from page 7
Five Decades of Experience With MPNs:
Characterizing Survival and Outcomes
fibrotic progression, compared with PMF and ET ( TABLE ).
“Not surprisingly, patients with PMF, compared with their PV
and ET counterparts, displayed lower hemoglobin and platelet
values and more frequent cytogenetic abnormalities, transfusion
dependence, leukocyte count of at least 25x10 9 /L, and blast counts
of at least 1 percent, supporting their documented prognosti-
cally detrimental phenotype,” the authors wrote. PMF also was
associated with the highest rates of blast transformation and death
compared with the other subtypes.
However, they added, “The present data ascribed a less ‘in-
“Although they share common oncogenic pathways, the distinct
nocuous’ phenotype to ET than perhaps historically perceived.”
MPN subgroups (polycythemia vera [PV], essential thrombocythe-
This included similar incidence of blast transformation in PV and
mia [ET], and primary myelofibrosis [PMF]) have been document-
ET (4% for each), “reflecting potentially more aggressive disease
ed to differ in their survival and complication rates,” Dr. Szuber
behavior in ET regarding leukemic potential.”
and co-authors wrote. “[Our data] highlight MPN subgroup risk
Median overall survival (OS) among the disease subtypes was
categorization as key in appraising disease natural history.”
18 years for ET, 15 years for PV, and 4.4 years for PMF (p<0.05
To establish risk-stratified survival and complication rates in
for all). Survival in ET was time-dependent, with inferior survival
a large population of adult patients with MPN, the researchers re-
observed for patients diagnosed more recently (21 years for pre-
viewed medical records from 3,023 patients who were diagnosed
1990 vs. 17 years for post-1990; p<0.01). Survival in PV and PMF
with PV, ET, or PMF (according to World Health Organization
did not differ by year of diagnosis.
2016 criteria) between 1967 and 2017. All patients were followed
“This not only exposes the absence of any breakthrough
from diagnosis until death or date of last follow-up.
survival-modifying therapies in the past 30 years,” the research-
Patients had the following diagnoses: 665 with PV; 1,076 with
ers commented, “but also raises the following question: What
ET; and 1,282 with PMF.
factors are driving seemingly less favorable survival patterns
The authors confirmed that “MPNs were validated as diseases
over time in ET?”
more common in middle- or advanced-age adults,” with a median
Life expectancy differed among MPN subtypes and risk levels:
age at diagnosis of 62 years (range = 18-96 years). Patients with
The authors found “nearly indistinguishable patterns” of median
PMF presented at an older age, compared with those with either
OS between patients with low-risk PV and ET, at 28.1 and 26.7
ET or PV (median age = 65 years vs. 58 years and 62 years, re-
years, respectively (p=0.89). For each subtype, however, survival
spectively; p<0.001), and most patients (n=1,682; 56%) were older
was inferior to age- and sex-matched controls in the general pop-
than 60 years at diagnosis.
ulation (28.1 and 26.7 years vs. 39.2 and 37.5 years).
The researchers performed conventional risk stratification
Survival curves for low-risk PMF and intermediate-risk PV
on 2,925 evaluable patients using clinical and pathological
also overlapped (median = 14.3 years and 18 years; p<0.06).
variables, since many patients were seen before the discovery of
“Together, these data suggest that, from a survival standpoint,
JAK2 V617F mutations in 2005 and subsequent MPN-associated
disease nomenclature in MPNs may be superseded by disease risk
mutations. They found that nearly half of the patients with PV
level,” the authors concluded. “The fact that despite their favorable
had “high-risk” disease (n=283; 45%), while patients with ET were prognostic features … patients [with low-risk PV and ET] still
more evenly distributed among risk categories and most patients
display excess mortality relative to matched controls is somewhat
with PMF had intermediate-risk disease (n=1,075; 78%).
sobering and reiterates the need for effective disease-modifying
A review of patients’ clinical and laboratory data revealed that
agents in patients with MPNs.”
PV was associated with excess thrombotic risk and higher risk of
The study’s implications are limited by its retrospective design,
and the authors noted that “further studies explicitly
examining risk-stratified data in MPN are warranted to
TABLE. Clinical and Laboratory Characteristics at Time of Diagnosis
validate these findings.”
PV (n=665)
ET (n=1,076)
PMF (n=1,282)
The authors report relationships with Novartis and
Overall survival
18 years
15 years
4.4 years
Bristol-Myers Squibb. ●
A report based on data from more than 3,000 patients with
myeloproliferative neoplasms (MPNs) evaluated at the Mayo
Clinic in Rochester, Minnesota, over 50 years found that even
patients with low-risk disease have inferior survival compared
with the general population – despite the perception of some
MPNs as “indolent” diseases. The results, which represent “the
most mature survival and outcomes data in MPNs to date,”
according to lead author Natasha Szuber, MD, and colleagues,
were published in Mayo Clinic Proceedings.
Deaths
274 (41%) 463 (43%) 894 (70%)
26 (4%) 38 (4%) 119 (9%)
Fibrotic progression 108 (16%) 136 (13%) N/A
Post-diagnostic thrombosis 162 (24%) 224 (21%) 130 (10%)
Leukemic transformation
REFERENCE
Szuber N, Mudireddy M, Nicolosi M, et al. 3023 Mayo Clinic patients with
myeloproliferative neoplasms: risk-stratified comparison of survival and
outcomes data among disease subgroups. Mayo Clin Proc. 2019;94:599-610.
May 2019
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