Abstract 428

Background:

Non-CML myeloproliferative neoplasms (MPNs) include essential thrombocythemia (ET), polycythemia vera (PV), myelofibrosis (MF) and MPN not otherwise specified (MPN-NOS), and are characterized by activation of JAK2 signaling and abnormal blood cell production. Reported median overall survival (OS) for MF ranges from a few (Cervantes et al. J Clin Oncol epub 2012;42:0240) to several years (Hultcrantz et al. J Clin Oncol epub 2012;42:1925). ET and PV median OS is reported to be a decade or more, although recent findings based on the Swedish cancer registry indicate that PV and ET patients may experience shorter survival than previously understood (Hultcrantz et al. J Clin Oncol epub 2012;42:1925; Barbui et al. 2011;29:3179–3184). Survival of MPN-NOS patients is not well characterized in the literature. MPN patients experience multiple comorbidities that can increase the risk of disability and death. However, survival rates of MPN patients from a nationally representative US population have not been recently described. MPN is more prevalent in the elderly; therefore, Medicare enrollees are a highly relevant source for US-based survival estimates in these diseases.

Objective:

To compare survival rates of MPN patients (ET, PV, MF and MPN-NOS) with matched non-MPN/non-cancer controls.

Methods:

In this retrospective study, data were taken from the Survey, Epidemiology, and End Results (SEER)-Medicare linked database in the US. SEER-Medicare combines clinical information from the SEER cancer registry with medical and pharmacy claims for Medicare enrollees. Codes for reporting MPN cases to SEER have been available since 2001. In our study, Medicare enrollees with a new SEER MPN diagnosis between Jan 1, 2001 and Dec 31, 2007 were selected and evaluated for survival. Patients were classified into MPN subtypes as indicated by their SEER registry diagnosis. First MPN diagnosis was required to occur at or before Medicare enrollment to allow for continuous follow-up. Non-MPN/non-cancer control groups were selected from Medicare for each MPN subtype and matched to cases 5:1 based on year of birth, gender, race, geographic location, and reason for Medicare eligibility. Survival for both case and matching controls was determined starting from the case diagnosis date. Survival was estimated using the Kaplan-Meier method.

Results:

A total of 4,274 MPN patients (n = 1217 ET, 1625 PV, 522 MF and 910 MPN-NOS) were identified for inclusion and assigned matching controls.

Demographic results and survival findings are presented in Table 1. Kaplan-Meier survival curves are shown in Figure 1.

Table 1.

Patient Characteristics and Survival

ETPVMFMPN-NOS
 (N=1217) (N=1625) (N=522) (N=910) 
Age at MPN Diagnosis (years)         
    Mean Age 78.4 76.1 77.4 79 
    SD 8.2 10.5 7.9 8.2 
Age Group n % n % n % n % 
    <45 6 0.5 25 1.5 3 0.6 4 0.4 
    45 - 54 15 1.2 69 4.3 6 1.2 7 0.8 
    55 - 64 41 3.4 90 5.5 13 2.5 26 2.9 
    65 - 74 305 25.1 442 27.2 163 31.2 218 24 
    75 - 84 608 50.0 730 44.9 271 51.9 456 50.1 
    ≥85 242 19.9 269 16.6 66 12.6 199 21.9 
Gender         
    Male 457 37.6 808 49.7 306 58.6 457 50.2 
    Female 760 62.5 817 50.3 216 41.4 453 49.8 
Race         
    White 1059 87 1450 89.2 470 90 802 88.1 
    Black 96 7.9 92 5.7 31 5.9 80 8.8 
    Other 17 1.4 21 1.3 2 0.4 11 1.2 
    Asian 29 2.4 42 2.6 9 1.7 9 1 
    Hispanic 14 1.2 18 1.1 10 1.9 8 0.9 
North American Native 2 0.2 2 0.1 . . . . 
Patient Survival Cases Controls Cases Controls Cases Controls Cases Controls 
    Mean OS (months) 65.2 78.7 62.2 80.0 32.2 81.0 42.2 75.5 
    Median OS (months) 67.9 101.1 64.9 103.9 23.5 106.3 28.4 93.9 
ETPVMFMPN-NOS
 (N=1217) (N=1625) (N=522) (N=910) 
Age at MPN Diagnosis (years)         
    Mean Age 78.4 76.1 77.4 79 
    SD 8.2 10.5 7.9 8.2 
Age Group n % n % n % n % 
    <45 6 0.5 25 1.5 3 0.6 4 0.4 
    45 - 54 15 1.2 69 4.3 6 1.2 7 0.8 
    55 - 64 41 3.4 90 5.5 13 2.5 26 2.9 
    65 - 74 305 25.1 442 27.2 163 31.2 218 24 
    75 - 84 608 50.0 730 44.9 271 51.9 456 50.1 
    ≥85 242 19.9 269 16.6 66 12.6 199 21.9 
Gender         
    Male 457 37.6 808 49.7 306 58.6 457 50.2 
    Female 760 62.5 817 50.3 216 41.4 453 49.8 
Race         
    White 1059 87 1450 89.2 470 90 802 88.1 
    Black 96 7.9 92 5.7 31 5.9 80 8.8 
    Other 17 1.4 21 1.3 2 0.4 11 1.2 
    Asian 29 2.4 42 2.6 9 1.7 9 1 
    Hispanic 14 1.2 18 1.1 10 1.9 8 0.9 
North American Native 2 0.2 2 0.1 . . . . 
Patient Survival Cases Controls Cases Controls Cases Controls Cases Controls 
    Mean OS (months) 65.2 78.7 62.2 80.0 32.2 81.0 42.2 75.5 
    Median OS (months) 67.9 101.1 64.9 103.9 23.5 106.3 28.4 93.9 
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Conclusions:

Survival in MF and MPN-NOS patients was worse than that of patients with ET or PV and significantly worse than matched controls. Contrary to the commonly held thought that PV and ET patients experience near-normal life expectancy, survival of patients with ET or PV was substantially inferior to matched controls. These findings have implications for the clinical management of MPN patients and underscore the need for effective therapies in all MPN subtypes.

Disclosures:

Price:Eli Lilly and Company: Employment, Equity Ownership. Davis:Eli Lilly, Merck, GlaxoSmithKline, Bristol-Myers Squibb, Pfizer, Eisai, Sanof-Aventis, Gilead Sciences, MedImmune: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Karve:RTI Health Solutions: Consultancy, Research Funding. Pohl:Eli Lilly and Company: Employment, Equity Ownership. Walgren:Eli Lilly and Company: Employment, Equity Ownership.

Topics:
medicare, myeloproliferative disease, seer program, cancer, follow-up, myelofibrosis, polycythemia vera, thrombocythemia, hemorrhagic, kaplan-meier survival curve, survival curve

Author notes

*

Asterisk with author names denotes non-ASH members.

© 2012 by The American Society of Hematology
2012
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