Current descriptive epidemiological information on classic myeloproliferative neoplasms (MPNs) is incomplete. Published data among Asian population are particularly sparse.
We conducted a large population-based study to determine the incidence rates and survival patterns of MPN reported to the Singapore Cancer Registry during the period 1968–2017. Age-standardised incidence rates(ASR), overall survival, 5-/10-year relative survival ratio (RSR) were estimated. Joinpoint regression was used to evaluate quinquennial percent change (QPC) in incidence.
We identified 2557 individuals diagnosed with MPN including 1031 chronic myeloid leukaemia (CML), 424 polycythaemia vera (PV), 389 essential thrombocythaemia (ET), 134 primary myelofibrosis (PMF) and 579 MPN unclassifiable (MPN-U). The overall respective ASRs per 100,000 for CML, PV, ET, PMF and MPN-U were 1.24, 1.15, 1.07, 0.43, and 0.80 in 2013–2017. Males had higher ASR than females in all MPNs. A gradual rise in incidence trends of CML was observed between 1968 and 2017 (QPC 2.1%, 95% CI −0.9, 5.3). The overall incidence trends of non-CML MPNs including PV (QPC 62.9%, 95% CI 19.3, 122.6), ET (QPC 54.2%, 95% CI 23.5, 92.3) and PMF (QPC 103.5%, 95% CI 19.1, 247.6) increased sharply during 1993–2017. Survival was lower in MPNs compared with expected survival in general population: 5-year RSRs were 0.82 (95% CI 0.78, 0.86), 0.96 (95% CI 0.91, 1.01), 0.96 (95% CI 0.92, 1.01), 0.53 (95% CI 0.43, 0.65), and 0.74 (95% CI 0.68, 0.80) for CML, PV, ET, PMF and MPN-U respectively.
CML incidence has increased marginally, whereas non-CML MPNs incidences have sharply increased. MPN patients have a lower relative survival compared to the general population, and patients with PV and ET have the most favourable relative survival. Median survival for CML patients has increased dramatically over the last 50 years.
- • One of the few studies reporting the MPN epidemiology in multiethnic Asian population.
- • Incidence of PV, ET and PMF increased sharply whilst CML rose gradually.
- • Median survival for CML has increased dramatically over the last 50 years.
- • Survival was lower in all MPN compared with expected survival in general population.
- • Differences in disease patterns between Asian and non-Asian population appear to exist.
Myeloproliferative neoplasms (MPNs) are a group of hematological malignancies of the myeloid cell lineage occurring within the bone marrow. Previously described as myeloproliferative disorders in the 1950s, the classification of MPNs was revised in 2008 by the World Health Organization (WHO) to include chronic myeloid leukaemia (CML), non-CML MPN subtypes comprising polycythaemia vera (PV), essential thrombocythaemia (ET), primary myelofibrosis (PMF), and MPN unclassifiable (MPN-U).
MPNs are differentiated based on genetic mutations and histological features. CML is characterised by the presence of Philadelphia (Ph) chromosome following a reciprocal translocation t(9;22) (q34;q11) that involves BCR (breakpoint cluster region) gene and ABL1 (Abelson murine leukaemia) proto-oncogene. The expressed BCR-ABL1 chimeric product is an oncoprotein exhibiting tyrosine kinase activity leading to uncontrolled production of myeloid cells in the bone marrow . In 2001, imatinib mesylate, the first targeted tyrosine kinase inhibitor (TKI) was introduced and revolutionised the therapeutic paradigm of CML and dramatically improved survival . On the other hand, the majority of non-CML (or Ph-chromosome negative) MPNs are distinguished by mutations of JAK2 V617F (Janus kinase 2) and CALR (calreticulin-encoding) genes, which are oncogenes involved in the signal transduction and cytokine-independent activation of the JAK-STAT pathway .
Population-based studies of the epidemiology of MPN are sparse. Currently, most studies have been conducted in North America and European countries. The paucity of published data on the epidemiology of classic MPNs in Asia has limited an understanding of disease frequency, distribution and survival in the region.