Prognosis of myelodysplastic syndromes/neoplasms (MDS) in adults

INTRODUCTION — 

Myelodysplastic syndromes/neoplasms (MDS) refer to a diverse group of hematologic malignancies with variable clinical courses and outcomes. These disorders are characterized by ineffective hematopoiesis, cytopenias (ie, anemia, neutropenia, and/or thrombocytopenia), dysplastic features, and a variable risk of progression to acute myeloid leukemia (AML) [1]. Outcomes for patients with MDS are associated with certain clinical, pathologic, and molecular features. Assessment of prognosis is key to the selection of a management strategy and serves as a default staging system for MDS.

This topic discusses risk factors and prognostic models for MDS.

Clinical presentation, evaluation, diagnosis, classification, management, and pathogenesis of MDS are discussed separately:

●(See "Clinical manifestations, diagnosis, and classification of myelodysplastic syndromes (MDS)".)

●(See "Myelodysplastic syndromes/neoplasms (MDS): Overview of diagnosis and management".)

●(See "Cytogenetics, molecular genetics, and pathophysiology of myelodysplastic syndromes/neoplasms (MDS)".)

PROGNOSTIC FACTORS — 

Outcomes in myelodysplastic syndromes/neoplasms (MDS) are associated with clinical, pathologic, and molecular features.

Clinical — Clinical factors that are associated with adverse outcomes in MDS include [2-5]:

●Age – Increased patient age

●Fitness – Impaired performance status (table 1), frailty, and comorbid conditions

●Cytopenias – Number of affected lineages and the severity of cytopenias

Therapy-related MDS is discussed separately. (See "Therapy-related myeloid neoplasms: Epidemiology, causes, evaluation, and diagnosis".)

Pathology — Pathologic features that are closely associated with outcomes in patients with MDS include:

●Bone marrow blasts – The percentage of blasts (detected by microscopy or CD34 expression, using immunohistochemistry) correlates with prognosis and is a criterion for diagnosis and classification of MDS [1]. (See "Clinical manifestations, diagnosis, and classification of myelodysplastic syndromes (MDS)", section on 'Diagnosis'.)

●Cytogenetic abnormalities – Recurrent cytogenetic abnormalities are found in approximately half of cases of primary (de novo) MDS and in a higher percentage of therapy-related/secondary MDS. The Comprehensive Cytogenetic Scoring System for MDS stratifies cytogenetic findings into very good, good, intermediate, poor, and very poor categories [6].

Recurrent cytogenetic abnormalities in MDS are associated with certain clinical syndromes, natural history, and/or response to therapy, as discussed separately. (See "Cytogenetics, molecular genetics, and pathophysiology of myelodysplastic syndromes/neoplasms (MDS)".)

●Dysplasia – Morphologic dysplasia in one or more cellular lineages is seen in many cases of MDS, but it is not clearly associated with prognosis.

Dysplasia is a component of MDS classification in the International Consensus Classification system [7], but it is not a consideration for disease classification in the World Health Organization (WHO) 5^th edition [8]. (See "Clinical manifestations, diagnosis, and classification of myelodysplastic syndromes (MDS)".)

Genetic mutations — Acquired somatic mutations are detected in nearly all cases of MDS [9,10]. Most individual cases have two to four driver mutations among the >50 distinct mutations associated with MDS [1].

No individual mutation is pathognomonic for MDS and many of the more common mutations are also associated with acute myeloid leukemia (AML), myeloproliferative neoplasms (MPNs), and clonal hematopoiesis of indeterminate potential (CHIP). However, certain mutations (eg, involving rearrangements of RUNX1, CBFB, PML::RAR) exclude a diagnosis of MDS.

Among the most common mutations in MDS (>5 percent of cases), the following prognostic associations have been reported [11-16]:

●Adverse – ASXL1, SRSF2, DNMT3A, RUNX1, U2AF1, TP53, EZH2, STAG2, CBL, NRAS, BCOR

●Favorable – SF3B1

●Neutral or uncertain – TET2, ZRSR2, IDH1, IDH2

A study of nearly 3000 patients detected at least one molecular abnormality in 94 percent of patients and reported a median of four mutations per patient [9]. In this study, mutations alone (ie, without a cytogenetic abnormality) were found in 53 percent of patients, 37 percent had both a mutation and a cytogenetic abnormality, while only 4 percent had a cytogenetic abnormality alone (ie, no mutation).

In addition to their prognostic significance, the following should be noted regarding mutations in the diagnosis and management of MDS:

●Gene alterations that exclude MDS – Certain findings, namely RUNX1::RUNX1T1, associated with t(8;21)(q22;q22); CBFB::MYH11, associated with inv(16)(p13.1q22); PML::RARA, associated with t(15;17)(q22;q21.1), and translocations involving KMT2A and MECOM are diagnostic of AML and exclude the diagnosis of MDS. (See "Cytogenetics, molecular genetics, and pathophysiology of myelodysplastic syndromes/neoplasms (MDS)".)

●Impact on treatment choices – In a small percentage of cases of MDS, the presence of particular mutations may affect the choice of treatment, as discussed separately. (See "Treatment of lower-risk myelodysplastic syndromes/neoplasms (MDS)".)

Germline (ie, inherited) mutations are thought to contribute to 4 to 15 percent of cases of MDS [17] and are discussed separately. (See "Familial disorders of acute leukemia and myelodysplastic syndromes".)

CHOICE OF PROGNOSTIC MODEL — 

Prognostic scoring systems are useful for assessing patient outcomes and serve as a default staging system for MDS.

We favor the International Prognostic Scoring System-Revised (IPSS-R) or a validated, mutation-based prognostic model. Compared with other models, IPSS-R and mutation-based models provide superior risk stratification and more accurate prediction of survival and transformation to acute myeloid leukemia (AML).

●IPSS-R – This prognostic model includes clinical, pathologic, and cytogenetic findings, but it does not incorporate mutational data. (See 'International Prognostic Scoring System-Revised' below.)

●Mutation-based models – Validated models that incorporate mutational features are described below. (See 'Mutation-based models' below.)

We no longer endorse the use of IPSS (original) to make treatment decisions for patients with MDS. IPSS lacks the prognostic accuracy of other models, is based on outmoded diagnostic criteria, and incorporates only limited clinical and cytogenetic findings (table 2), as described below. (See 'IPSS (Original IPSS)' below.)

International Prognostic Scoring System-Revised — 

IPSS-R incorporates clinical and pathologic features but does not include molecular findings. We consider IPSS-R acceptable for treatment decisions, but it may be phased out over time, in favor of more precise mutation-based models. (See 'Comparisons with IPSS-R' below.)

IPSS-R was generated from a study of 2902 patients with primary MDS, and it was validated in an independent cohort of 1632 patients [6]. IPSS-R has also been validated in other, independent patient cohorts [18-22]. Beyond the absence of mutational data, IPSS-R has other significant limitations. IPSS-R included patients who would now be considered to have AML (ie, ≥20 marrow blasts), it is not dynamic (ie, it can only be used at diagnosis), and outcomes data were derived from patients who primarily received supportive care [6,18]. IPSS-R should be used judiciously in patients who are treated with disease-modifying agents, as there are conflicting data regarding its validity in such settings [19,23-26].

●Calculation – To calculate the IPSS-R, a value from 0 to 4 is determined for each of five variables (table 3) (calculator 1) [18]:

•Bone marrow blasts – (0 points) ≤2 percent; (1 point) >2 to <5 percent; (2 points) 5 to 10 percent; (3 points) >10 percent

•Karyotype

-Very good karyotype – (0 points) includes -Y or del(11q)

-Good karyotype – (1 point) includes normal karyotype, del(5q), del(12p), del(20q), or a double abnormality including del(5q)

-Intermediate karyotype – (2 points) includes del(7q), +8, +19, i(17q) and any other single or double independent clones

-Poor karyotype – (3 points) includes -7, inv(3)/t(3q)/del(3q), double abnormalities including -7/del(7q), or three abnormalities

-Very poor karyotype – (4 points) includes complex karyotype (>3 abnormalities)

•Hemoglobin (g/dL) – (0 points) ≥10; (1 point) 8 to <10; (1.5 points) <8

•Platelets (cells/microL) – (0 points) ≥100,000; (0.5 points) 50,000 to 100,000; (1 point) <50,000

•Absolute neutrophil count (ANC; cells/microL) – (0 points) ≥800; (0.5 points) <800

The IPSS-R score equals the sum of the points from the five parameters described above.

●Risk categories – There are five IPSS-R prognostic categories: very low, low, intermediate-1, intermediate-2, and high risk (table 3).

IPSS-R was applied to 7012 patients with primary MDS, who had at least two months of stable blood counts, ≤30 percent bone marrow blasts, and ≤19 percent peripheral blood blasts, and who were observed until progression to AML transformation or death [18]. Patients received primarily supportive care, rather than disease-modifying therapies. After a median follow-up of nearly four years, the median OS and time for 25 percent of patients to progress to AML (AML-t25) were:

•Very low risk (≤1.5 points) – OS 8.8 years; AML-t25 >14.5 years

•Low risk (>1.5 to 3 points) – OS 5.3 years; AML-t25 >10.8 years

•Intermediate risk (>3 to 4.5 points) – OS 3.0 years; AML-t25 3.2 years

•High risk (>4.5 to 6 points) – OS 1.6 years; AML-t25 1.4 years

•Very high risk (>6 points) – OS 0.8 years; AML-t25 0.7 years

●Comparison of IPSS-R with original IPSS – IPSS-R is more effective than the original IPSS for predicting prognosis.

Compared with the original IPSS (described below), IPSS-R incorporates more cytogenetic abnormalities, better accounts for the severity of cytopenias, establishes a lower cutoff for ANC, and assigns greater weight to cytogenetic abnormalities than to blast percentage [18]. IPSS-R was more effective for predicting the prognosis of 7012 patients with primary MDS than the analysis of 816 patients using the original IPSS. (See 'IPSS (Original IPSS)' below.)

For treatment purposes, patients with IPSS-R score of ≤3.5 are considered to have lower-risk disease, while those with a score >3.5 have higher-risk disease [27]. (See "Myelodysplastic syndromes/neoplasms (MDS): Overview of diagnosis and management", section on 'Overview of management'.)

MUTATION-BASED MODELS

IPSS-Molecular (IPSS-M) — IPSS-M is readily accessible with an online calculator, personalized (ie, provides an individualized risk score), easily interpretable (ie, a one-unit increase in score is associated with doubled risk), and it provides a flexible/transparent strategy to account for missing data [9]. Compared with nonmutation-based models, IPSS-M provides improved discrimination across all key endpoints, including survival and transformation to acute myeloid leukemia (AML).

IPSS-M was developed by the International Working Group for Prognosis in MDS (IWG-PM) using clinical, cytogenetic, and molecular data from nearly 3000 patients, including 234 patients with treatment-related/secondary (t-MDS) and 370 with MDS/myeloproliferative neoplasm overlap syndromes (MDS-MPN) [9]. IPSS-M was validated with an independent cohort of 754 patients.

Online calculator — An online calculator (https://mds-risk-model.com) [28] offers a personalized risk score; assigns the patient to a prognostic category; and provides estimates of overall survival (OS), leukemia-free survival (LFS), and transformation to AML. In addition to calculating the IPSS-M score, the online calculator also calculates prognosis according to the IPSS-Revised (IPSS-R) model, a widely used model that does not incorporate mutational findings. (See 'International Prognostic Scoring System-Revised' above.)

Risk categories — IPSS-M risk categories and associated median OS, median LFS, and four-year risk for transformation to AML (AML-t) in IPSS-M are:

●Very low – OS 10.6 years, LFS 9.7 years, AML-t 2.8 percent

●Low – OS 6.0 years, LFS 5.9 years, AML-t 5.1 percent

●Moderate-low – OS 4.6 years, LFS 4.5 years, AML-t 11.4 percent

●Moderate-high – OS 2.8 years, LFS 2.3 years, AML-t 18.9 percent

●High – OS 1.7 years, LFS 1.5 years, AML-t 29.2 percent

●Very high – OS 1.0 years, LFS 0.8 years, AML-t 42.8 percent

IPSS-M outperformed IPSS-R in untreated patients, reclassified some patients into lower- or higher-risk groups, and improved prognostic discrimination across all clinical endpoints. We await validation of its prognostic accuracy in treated patients. (See 'Comparisons with IPSS-R' below.)

For treatment purposes, we stratify IPSS-M risk categories as follows (see "Myelodysplastic syndromes/neoplasms (MDS): Overview of diagnosis and management", section on 'Overview of management'):

●Lower-risk MDS – Lower-risk comprises very low, low, and moderate-low categories.

●Higher-risk MDS – Higher-risk includes patients classified as moderate-high, high, and very high in IPSS-M.

Other mutation-based models — Other mutation-based MDS prognostic models are acceptable and may be favored by some experts or institutions:

●Personalized Prediction Model for MDS (PPM-MDS) – This model applied machine-learning techniques to clinical and molecular data from 1471 patients in a training cohort and validated the findings with various independent external cohorts [29]. The algorithm identified age, platelet count, hemoglobin level, marrow blast percentage, karyotypic findings, total number of mutations, and mutations of seven specific genes as having prognostic impact on OS and LFS. Findings were validated in a variety of different clinical settings, including an external cohort of 465 patients, patients with MDS treated in a prospective clinical trial, patients with paired samples at different time points during the disease course, and patients who underwent HCT.

PPM-MDS outperformed IPSS-R, is dynamic, and reported that one-fifth of patients were upstaged, while one-third were downstaged [29].

●EuroMDS – This model retrospectively analyzed data from 2043 patients in an international database and identified eight prognostic groups by combining 63 clinical and genomic variables (using Bayesian networks and Dirichlet processes with random-effects Cox proportional hazards multistate modeling) [30]. The EuroMDS model was validated with an independent external cohort of 318 patients.

Prediction of OS by EuroMDS was superior to age-adjusted IPSS-R [30].

Comparisons with IPSS-R — Each of the validated mutation-based models (described above) outperformed IPSS-R and reclassified substantial percentages of patients, which has potentially important prognostic and therapeutic implications for individual patients. (See "Myelodysplastic syndromes/neoplasms (MDS): Overview of diagnosis and management", section on 'Overview of management'.)

IPSS-R is discussed below. (See 'International Prognostic Scoring System-Revised' above.)

●IPSS-M versus IPSS-R – IPSS-M improved prognostic discrimination across all clinical endpoints and reclassified many patients [9].

•Reclassification – Mapping of corresponding categories between IPSS-M and IPSS-R reclassified 46 percent of patients; three-quarters of reclassified patients were upstaged, while one-quarter were downstaged [9]. However, reclassification reflects, at least in part, the different number of categories in the two systems (six in IPSS-M and five in IPSS-R). More than one-half of patients classified as IPSS-R intermediate shifted, including one-fifth who were upstaged to IPSS-M very high. Notably, 7 percent were reclassified by more than one stratum; most such patients were from IPSS-R very low, low, or intermediate categories.

•Importance of specific mutations in reclassification – The total number of mutations and presence of particular mutations influenced the estimation of risk and assignment to a prognostic category in IPSS-M. Nearly two-thirds of patients who were reclassified by IPSS-M had two or more mutations, while one-quarter of reclassified patients had one mutated gene [9].

Mutated genes associated with adverse prognosis include multi-hit mutations of TP53 (but not monoallelic TP53 mutation), FLT3 tyrosine kinase domain (TKD) and internal tandem duplication (ITD) mutations, and partial tandem duplication (PTD) of KMT2A (formerly called MLL). Conversely, SF3B1 mutations were associated with favorable outcomes, but the size of the effect was modulated by co-mutated genes.

Nearly all patients (95 percent) who were upstaged from very low/low to very high/high and most (82 percent) patients who were upstaged from intermediate to very high/high had ≥2 adverse prognosis genes.

•Prognostic implications – The discovery cohort for IPSS-M included 234 patients with treatment-related MDS (t-MDS), a group of patients who are generally considered to have adverse outcomes [9]. As expected, half of patients with t-MDS were classified as either IPSS-M high or very high, but, unexpectedly, 39 percent of patients with t-MDS were classified as IPSS-M very low, low, or moderate-low.

To illustrate the prognostic implications of reclassification, for a patient with IPSS-R intermediate who is reclassified as IPSS-M very high, the median OS is one year, whereas a patient reclassified from IPSS-R intermediate to IPSS-M low has an estimated median OS of six years.

•Therapeutic implications – Reclassification has important therapeutic implications for individual patients.

More than half of patients classified as IPSS-R intermediate were reclassified, including 21 percent who were upstaged to IPSS-M very high; such a shift might change management from observation to lower-intensity or even higher-intensity treatment. Conversely, down-staging might affect management in the opposite direction. (See "Myelodysplastic syndromes/neoplasms (MDS): Overview of diagnosis and management", section on 'Overview of management'.)

Mutation analysis also provided insight into the likelihood of a treatment response. Multi-hit TP53 mutation was the strongest predictor of worse outcomes across all treatment modalities (ie, hypomethylating agent [eg, azacitidine, decitabine], lenalidomide, or HCT).

●Other mutation-based models versus IPSS-R – Both PPM-MDS and EuroMDS reclassified and/or refined prognosis compared with IPSS-R, as described above. (See 'Other mutation-based models' above.)

OTHER PROGNOSTIC MODELS — 

Other MDS prognostic models have been created, but only the original International Prognostic Scoring System (IPSS) was widely used. Presently, these models are less accurate than mutation-based models and IPSS-Revised (IPSS-R) and have significant limitations. We expect their use to wane as providers adopt mutation-based models. We describe them to facilitate the interpretation of earlier clinical studies.

IPSS (Original IPSS) — We suggest not using the original IPSS model because it does not incorporate molecular findings, it considers very limited clinical and cytogenetic findings (table 2), is based on outmoded diagnostic criteria, is not dynamic, and lacks the prognostic accuracy of subsequent models (including mutation-based models and IPSS-R). A calculator for IPSS (calculator 2) is presented here to aid analysis of earlier clinical trials of MDS.

IPSS classified patients in four risk categories (low, intermediate-1, intermediate-2, high) that were associated with different outcomes. Accuracy of survival data was improved by stratifying for age; for each IPSS category, median overall survival (OS) declined with increasing age (table 4) [31].

For treatment purposes, patients who were classified as IPSS low or intermediate-1 are considered to have lower-risk MDS, while those classified as IPSS intermediate-2 or high are considered to have higher-risk MDS. (See "Myelodysplastic syndromes/neoplasms (MDS): Overview of diagnosis and management", section on 'Overview of management'.)

Approval of some drugs by the European Medicines Agency (eg, azacitidine, lenalidomide, epoetin alfa) is based on IPSS classification.

MDACC model — The MD Anderson Cancer Center (MDACC) was derived from the IPSS model for use with patients in lower-risk or higher-risk IPSS categories [2]. The MDACC MDS model is complicated and has not been widely adopted for clinical practice, but a calculator is available (calculator 3).

The MDACC model was created from analyses of 958 patients with de novo or secondary MDS, validated with a group of 957 patients, and subsequently validated in a retrospective study of 775 patients with MDS treated from another institution [2,32].

INFORMATION FOR PATIENTS — 

UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient education" and the keyword(s) of interest.)

●Basics topics (see "Patient education: Myelodysplastic syndromes (MDS) (The Basics)" and "Patient education: Allogeneic bone marrow transplant (The Basics)")

●Beyond the Basics topics (see "Patient education: Myelodysplastic syndromes (MDS) in adults (Beyond the Basics)" and "Patient education: Hematopoietic cell transplantation (bone marrow transplantation) (Beyond the Basics)")

SUMMARY

●Description – Myelodysplastic syndromes/neoplasms (MDS) are hematologic malignancies characterized by clonal hematopoiesis, cytopenias, morphologic dysplasia, and variable progression to acute myeloid leukemia (AML). Assessment of prognosis is a key aspect of management because this diverse group of malignancies has variable natural history, prognosis, and need for treatment.

●Prognostic factors – Factors associated with outcomes in patients with MDS include:

•Clinical – Increased age, frailty, comorbid conditions, impaired performance status, cytopenias, and transfusion dependence are associated with adverse prognosis. (See 'Clinical' above.)

•Pathology – Bone marrow blasts and cytogenetic abnormalities are associated with outcomes in MDS. (See 'Pathology' above.)

•Molecular – Acquired somatic mutations are detected in nearly all cases of MDS. Some mutations (eg, biallelic TP53 mutations, FLT3, KMT2A, others) are associated with adverse prognosis, while mutation of SF3B1 is associated with more favorable outcomes. (See 'Genetic mutations' above.)

●Choice of a prognostic model – We favor the International Prognostic Scoring System-Revised (IPSS-R) or a validated mutation-based model. Compared with other prognostic models, IPSS-R and mutation-based models provide superior risk stratification and a more accurate prediction of survival and transformation to AML. (See 'Choice of prognostic model' above.)

●IPSS-Revised (IPSS-R) – IPSS-R is based on clinical and cytogenetic data but not mutation status (calculator 1) (table 3). (See 'International Prognostic Scoring System-Revised' above.)

●Mutation-based models – Validated mutation-based MDS prognostic models include (see 'Mutation-based models' above):

•IPSS-Molecular – Online calculator (https://mds-risk-model.com)

•Personalized Prediction Model for MDS (PPM-MDS)

•EuroMDS

●Other models – We do not favor use of the original IPSS (calculator 2) (table 2) or the MD Anderson Cancer Center model. (See 'Other prognostic models' above.)

ACKNOWLEDGMENTS

The UpToDate editorial staff acknowledges the late Elihu H Estey, MD, who contributed as an author for this topic.

The editors of UpToDate acknowledge the contributions of Stanley L Schrier, MD as author on this topic, his tenure as the founding Editor-in-Chief for UpToDate in Hematology, and his dedicated and longstanding involvement with the UpToDate program.