Evaluation of prognostic scoring systems for chronic myelomonocytic leukemia in UT M.D. Anderson Cancer Center patient cohort

Priyanka Priyanka, The University of Texas School of Public Health


Introduction: Chronic myelomonocytic leukemia (CMML) is a myeloid neoplasm that belongs to the category of myelodysplastic syndrome / myeloproliferative neoplasms (MDS / MPN). Despite a number of scoring systems proposed for CMML over the years, no system has been generally accepted as the gold standard for CMML prognostication. The International Prognostic Scoring System for Myelodysplastic Syndromes (IPSS) and its revised version (IPSS-R) are currently used for newly diagnosed, untreated CMML patients. CMML-specific prognostic scoring systems proposed by Such et al (CPSS) and by the Mayo Clinic group: the Mayo prognostic scoring system (MPSS) identify four and three prognostic risk categories, respectively, for overall survival (OS) estimation and risk of acute myeloid leukemia (AML) transformation. In this study, we sought to determine the usefulness of CPSS and MPSS for CMML prognostication and to compare these scoring systems. Aim: 1) To assess the prognostic impact of each of the variables comprising the CPSS and MPSS scoring systems. (2) To evaluate and compare scores from both models to detect the highest risk patients. Patients and Methods: Two hundred and three patients (132 males / 71 females; median age: 70 years (range 27-92) diagnosed with CMML (149 CMML-1; 54 CMML-2) between 2000 and 2014 at UT MD Anderson Cancer Center (UTMDACC) were included in the study. The prognostic impact for CPSS and MPSS in terms of OS and progression to AML of each of the variables that comprise the scoring systems was studied. Patients who did not experience AML progression were censored at the time of death or last follow-up. Both scores were studied by univariate survival analysis (non-parametric tests using Kaplan-Meier; log-rank). These two prognostic indices were then assessed in a multivariate analysis using Cox proportional hazards models to determine risk categorization in patients. The strength of the CPSS and MPSS was assessed using the concordance probability estimates (CPE) for the Cox proportional hazard model. The statistical package SAS version 9.3 for Windows was used for all survival analyses. CPE were calculated with the R v3.12 statistical programming language. (R development Core 2014). Results: Two hundred and three patients with newly diagnosed, untreated CMML were identified in the clinical database. These included 132 males and 71 females; median age was 70 years (range 27-92); 149 had CMML-1 and 54 had CMML-2. A total of 107 deaths and 38 progressions to AML were observed. The median follow-up for all patients was 2.47 years (range 2 days-10 years). The variables that comprise the alternative CPSS (WHO subtype, FAB subtype, CMML-specific cytogenetic risk classification, hemoglobin) and MPSS (hemoglobin, platelet count, absolute monocyte count, and presence of immature granulocytes) as well as a description of score and risk categories are provided in Appendix-A and Appendix B. In Cox proportional hazard models, the alternative CPSS and MPSS score were found to be significantly associated with both OS and time to AML progression and clearly delineated the patient risk categories in this patient cohort (Type III p values <0.0001 respectively). Median survival times for OS were 4.07, 3.32, 2.14, and 1.23 years in the low, intermediate-1, intermediate-2, and high risk groups, respectively. Since less than half the patients progressed, the median time to AML progression could not be estimated for all groups but was 6.40 and 1.60 years in the intermediate-2 and high risk groups, respectively. Median survival times for MPSS risk categories respectively from low to high were 4.2, 4.1 and 1.8 years respectively (p < 0.0001), and chances of progression free survival for the high risk category were 44%, for intermediate 69%, and for the low risk category 86% at the end of the 2nd year approximately (p< 0.0001). Conclusions: In our patient cohort, both CPSS and MPSS were equivalent statistically in predicting OS and time to AML progression. We conclude that MPSS to be more efficient for clinical use than CPSS in CMML prognostication. These data reinforce the validity of both CPSS and MPSS and could serve as an additional validation cohort for future studies.

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Recommended Citation

Priyanka, Priyanka, "Evaluation of prognostic scoring systems for chronic myelomonocytic leukemia in UT M.D. Anderson Cancer Center patient cohort" (2014). Texas Medical Center Dissertations (via ProQuest). AAI1586904.