# Myelodysplastic Syndrome

Evaluate persistent unexplained cytopenias with marrow morphology, conventional cytogenetics, and molecular testing; then use IPSS-R or IPSS-M risk, transfusion burden, erythropoietin level, and transplant fitness to select supportive, anemia-directed, disease-modifying, or curative therapy.

**Clinical question:** How should clinicians confirm, risk-stratify, and select treatment for myelodysplastic syndrome?

Updated: 2026-08-24T17:35:09.830118+00:00

## What matters in practice
- Establish MDS with integrated peripheral-blood and marrow morphology, marrow karyotype, and molecular testing; flow cytometry is most useful when morphology and cytogenetics remain indeterminate. [11][12][14]
- Risk assignment should incorporate marrow blast percentage, cytopenias, cytogenetics, and somatic mutations through IPSS-R or IPSS-M rather than cytopenia severity alone. [4][13][14]
- For symptomatic lower-risk anemia, select erythropoiesis-stimulating therapy, lenalidomide when del(5q) is present, or other phenotype-directed therapy; continue transfusion and infection support as needed. [2][7]
- Refer medically fit higher-risk patients for allogeneic hematopoietic stem-cell transplantation early; it is the only potentially curative treatment, and hypomethylating therapy can serve as a bridge. [7][23]
- For higher-risk patients not proceeding to transplant, initiate azacitidine or decitabine and continue treatment if tolerated until disease progression. [7]

## Confirm clonal myeloid disease before assigning MDS therapy

Persistent cytopenia requires a marrow-centered assessment that also identifies AML, overlap neoplasms, and therapy-related disease.

Obtain a peripheral smear, bone marrow aspirate and trephine biopsy, marrow blast assessment, conventional chromosome banding analysis, and myeloid molecular testing when MDS is suspected. Cytomorphologic abnormalities in blood and marrow and histologic findings in the core biopsy remain central to diagnosis, while clonal cytogenetic or molecular abnormalities refine classification and prognosis. [11][14]

Request marrow conventional karyotype at the initial diagnostic sampling; chromosome banding analysis is considered mandatory for WHO-HAEM5 or ICC classification and for IPSS-R/IPSS-M scoring. Clonal chromosomal abnormalities occur in approximately 40% to 45% of de novo MDS and up to 80% of therapy-related MDS, making therapy exposure history clinically consequential at presentation. [14]

Use multiparameter flow cytometry as an adjunct rather than a replacement for morphology and cytogenetics. It can demonstrate quantitative and qualitative hematopoietic abnormalities and may establish an immunophenotypic abnormality when combined morphology and cytogenetics are nondiagnostic; interpret results in the full clinicopathologic context. [12][15]
- Document prior cytotoxic chemotherapy or radiation because therapy-related MDS has a substantially higher frequency of chromosomal abnormalities than de novo disease. [14]
- If marrow blasts reach 20%, redirect evaluation and treatment planning to acute myeloid leukemia rather than MDS risk models. [4]
- When thrombocytosis accompanies ring sideroblasts, distinguish MDS/MPN with ring sideroblasts and thrombocytosis from MDS with isolated del(5q); del(5q) favors the latter pattern, whereas JAK2, MPL, and CALR testing informs the former differential. [8]

*Diagnostic components and their management role in suspected MDS. [11][12][14]*

| Test or specimen | Decision supported | Interpretation that changes next step |
| --- | --- | --- |
| Peripheral smear and marrow aspirate | Establish dysplasia and quantify blasts | Morphologic dysplasia supports MDS; blast percentage is required for classification and prognostic assessment. [10][11][13] |
| Trephine marrow biopsy | Corroborate marrow pathology | Histologic findings complement aspirate morphology when diagnosing a myeloid neoplasm. [11] |
| Conventional marrow karyotype | Classify disease and calculate risk | Required for WHO-HAEM5/ICC disease typing and IPSS-R/IPSS-M scoring; identifies abnormalities with independent prognostic importance. [14] |
| Myeloid next-generation sequencing | Refine molecular subtype and prognosis | Integrate mutations with blood counts, blasts, and cytogenetics for IPSS-M; SF3B1 supports an MDS-SF3B1 phenotype, whereas TP53 is associated with adverse risk. [7][13][21] |
| Multiparameter flow cytometry | Resolve equivocal cases | Abnormal immunophenotypic patterns can support MDS when morphology and cytogenetics are indeterminate. [12] |

## Use blast, cytogenetic, and molecular risk to determine treatment urgency

Risk stratification separates patients needing cytopenia-directed care from those needing disease-modifying therapy or transplant evaluation.

Calculate IPSS-R at diagnosis using marrow blasts, cytogenetic abnormalities, and the degree of cytopenias. IPSS-M extends this framework by incorporating blood counts, marrow blasts, the five IPSS-R cytogenetic categories, 16 main-effect genes, and 15 residual genes; it was developed and validated in 3,711 patients. [13]

Do not regard “lower-risk” as clinically uniform. Lower-risk disease often has lower immediate risk of death or AML evolution, but anemia, transfusion requirements, thrombocytopenia, neutropenia, and inflammatory complications may drive morbidity and mortality and should determine the intervention target. [9]

Recognize molecularly defined patterns that alter counseling and management emphasis. SF3B1 mutation is strongly associated with ring sideroblasts, normal cytogenetics, and favorable disease characteristics, whereas TP53 mutations add adverse prognostic information beyond clinicopathologic variables. [7][21]
- Use IPSS-R or IPSS-M alongside performance status, comorbidity, age, transfusion dependence, and transplant eligibility; a prognostic score does not by itself determine treatment intensity. [2][7][9]
- Reassess disease status with new or worsening cytopenias, rising marrow blasts, evolving cytogenetic abnormalities, or loss of response to prior therapy, because these findings can alter risk and transplant timing. [7][14]
- Interpret the 2022 WHO and ICC classifications with awareness that their MDS/AML and increased-blast terminology differs, while IPSS, IPSS-R, and IPSS-M remain commonly used for prognostic guidance. [9]

*Actionable MDS phenotypes that influence treatment selection and urgency. [2][7][9][21][23]*

| Clinical pattern | Key discriminator | Management implication |
| --- | --- | --- |
| Symptomatic lower-risk anemia | Anemia burden, transfusion needs, erythropoietin level, and disease genotype | Use anemia-directed therapy such as an erythropoiesis-stimulating agent; consider lenalidomide particularly with del(5q). [2][7] |
| MDS with isolated del(5q) | del(5q) on marrow cytogenetics | Lenalidomide is a key lower-risk anemia-directed option. [7][9] |
| SF3B1-associated/ring sideroblast phenotype | SF3B1 mutation with ring sideroblast association | Classify as a favorable molecular phenotype and consider anemia-directed options that include luspatercept in appropriate patients. [2][21] |
| Higher-risk MDS | Adverse risk assignment, excess blasts, or aggressive clinical trajectory | Evaluate promptly for allogeneic hematopoietic stem-cell transplantation; use hypomethylating therapy as a bridge when appropriate. [7][23] |
| Higher-risk MDS without transplant option | Not medically fit for or not proceeding to allogeneic transplant | Start azacitidine or decitabine and continue if tolerated until progression. [7] |

## Treat the dominant cytopenia and molecular phenotype

For lower-risk disease, prioritize symptom relief, transfusion reduction, and prevention of cytopenia-related complications.

For symptomatic anemia, treatment selection should account for symptoms and severity of cytopenias, disease characteristics, and erythropoietin levels. Erythropoiesis-stimulating agents are a principal initial option; lenalidomide is particularly relevant in patients with deletion 5q. [2][7]

For lower-risk anemia not adequately addressed by initial erythroid support, phenotype-directed options include luspatercept and imetelstat; the treatment sequence should also account for ring sideroblast/SF3B1 features, transfusion burden, prior therapies, and ongoing cytopenias. [2][9][21]

Consider immunosuppressive therapy with antithymocyte globulin, thrombopoiesis-stimulating agents, or a hypomethylating agent in selected lower-risk patients rather than treating all lower-risk disease identically. Use transfusions and antimicrobial therapy when clinically needed across risk categories. [2][7]
- Use lenalidomide preferentially when cytogenetics demonstrate del(5q), rather than treating the cytogenetic finding as prognostic information alone. [7][9]
- Use SF3B1 and ring sideroblast findings to identify a phenotype generally associated with favorable disease characteristics; the percentage of ring sideroblasts itself is not predictive of survival. [21]
- Escalate from cytopenia-directed care when progressive marrow blasts, worsening cytopenias, clonal evolution, or failure of serial lower-risk therapies indicates a higher-risk trajectory. [7][14]

### Supportive care remains active treatment

Provide red-cell or platelet transfusions for clinically significant cytopenias and use antimicrobial therapy when infection risk or infection is present. Infection is a major cause of death in MDS and can occur before AML transformation, so neutropenia and infectious complications warrant active surveillance rather than deferral until disease-modifying therapy begins. [2][7]

*Lower-risk treatment selection by dominant clinical problem. [2][7][9]*

| Dominant problem | Preferred treatment direction | Selection modifier |
| --- | --- | --- |
| Symptomatic anemia | Erythropoiesis-stimulating agent | Use symptoms, anemia severity, and erythropoietin level to guide selection. [2] |
| Anemia with del(5q) | Lenalidomide | Cytogenetically confirmed del(5q) makes lenalidomide particularly relevant. [7][9] |
| Anemia with ring sideroblast/SF3B1 phenotype | Consider luspatercept among anemia-directed options | SF3B1 is strongly associated with ring sideroblasts and favorable disease features. [2][21] |
| Selected immune-responsive lower-risk disease | Antithymocyte globulin-based immunosuppression | Reserve for selected patients rather than routine lower-risk use. [2][7] |
| Persistent cytopenia with progression or inadequate response | Hypomethylating agent or reassessment for higher-risk strategy | Reevaluate blasts, cytogenetics, and molecular risk before continuing a lower-risk pathway. [7][14] |

## Refer for transplant early and use hypomethylating therapy when transplant is delayed or unsuitable

Allogeneic transplantation is the only potentially curative approach; candidacy and timing should be addressed when higher-risk disease is identified.

Refer transplant-eligible patients with higher-risk MDS for allogeneic hematopoietic stem-cell transplantation as soon as possible. Allogeneic transplantation remains the best curative option for higher-risk MDS, while nontransplant therapies are not curative. [7][22][23]

Use azacitidine or decitabine as disease-modifying therapy for higher-risk patients who are not transplant candidates and continue treatment if tolerated until disease progression. For a transplant candidate, hypomethylating therapy can be used as a bridge while donor identification, pretransplant assessment, and conditioning planning proceed. [7]

Discuss prognosis in quantitative terms when counseling higher-risk patients. In a 2,045-patient higher-risk MDS cohort, median overall survival from diagnosis was 15.1 months; 2-year and 5-year overall survival were 32% and 15%, and cumulative AML transformation was 24% at 2 years and 29% at 5 years. These cohort-level estimates should not replace individualized IPSS-R/IPSS-M assessment. [22]
- Assess transplant fitness in parallel with risk scoring; delaying referral until hypomethylating-agent failure may forfeit the window for a curative strategy. [7][23]
- Monitor marrow blasts, blood counts, transfusion requirement, treatment tolerance, and cytogenetic or molecular evolution during hypomethylating therapy. [7][14]
- Reclassify as AML-directed disease when marrow blasts meet the 20% threshold. [4]

*Higher-risk MDS treatment pathway. [7][22][23]*

| Clinical decision | Action | Rationale |
| --- | --- | --- |
| Fit candidate for allogeneic transplant | Initiate early transplant evaluation and proceed as soon as feasible | Allogeneic hematopoietic stem-cell transplantation is the only potentially curative MDS therapy. [7][23] |
| Transplant candidate requiring disease control or awaiting transplant | Use azacitidine or decitabine as a bridge | Hypomethylating agents are used as a bridge to transplant in higher-risk disease. [7] |
| Not a transplant candidate | Start azacitidine or decitabine | Continue if tolerated until disease progression. [7] |
| Progression to 20% marrow blasts | Transition to AML evaluation and treatment planning | The 20% blast threshold separates AML from MDS in the cited IPSS-M study population. [4] |

## Monitor for cytopenia complications, loss of response, and clonal progression

Follow-up should detect actionable progression before infection, bleeding, or AML evolution dictates the next intervention.

At each treatment interval, track complete blood counts, transfusion requirement, infectious events, bleeding, and therapy tolerance. Cytopenia complications—including infection—account for substantial morbidity and mortality before AML transformation, so supportive measures should be adjusted as clinical events emerge. [2][7]

Repeat marrow assessment with cytogenetics and molecular reassessment when there is an unexplained change in counts, suspected progression, loss of hematologic response, or concern for AML transformation. Karyotype abnormalities have independent prognostic importance and are required for IPSS-R/IPSS-M calculation, making clonal evolution clinically actionable. [13][14]

Use disease reassessment to revisit transplant eligibility rather than reserving transplant discussion for diagnosis alone. In higher-risk disease, transplant is the curative option; in lower-risk disease, escalating marrow blasts, progressive cytopenias, or unfavorable molecular evolution may change the risk-benefit balance toward disease-modifying therapy or transplant consultation. [7][23]
- Investigate fever or other suspected infection promptly in neutropenic patients and use antimicrobial treatment when clinically indicated. [2][7]
- Recalculate prognostic risk when updated marrow blasts, cytogenetics, or molecular findings are available. [13][14]
- Continue hypomethylating therapy in higher-risk nontransplant candidates while it is tolerated and disease has not progressed. [7]

*Triggers for management reassessment in MDS. [2][7][13][14]*

| Trigger | Reassessment | Potential action |
| --- | --- | --- |
| Worsening anemia, thrombocytopenia, or neutropenia | CBC trend, transfusion burden, clinical complications, and marrow evaluation when unexplained | Adjust supportive care and determine whether risk or disease biology has changed. [2][7] |
| Loss of response to anemia-directed treatment | Reassess disease phenotype, cytogenetics, and molecular risk | Select another lower-risk option or transition to disease-modifying management when progression is evident. [2][7][14] |
| Rising marrow blasts | Repeat marrow morphology and calculate updated prognostic risk | Accelerate transplant evaluation or transition to AML-directed planning at 20% blasts. [4][7] |
| New cytogenetic abnormality | Repeat conventional karyotype and integrate with IPSS-R/IPSS-M | Revise prognosis and treatment urgency. [13][14] |

## References
1. Cellular, Tissue, and Gene Therapies Advisory Committee ... — www.fda.gov — https://www.fda.gov/media/159009/download
2. Myelodysplastic syndrome - Symptoms, diagnosis and treatment | BMJ Best Practice US — bestpractice.bmj.com — https://bestpractice.bmj.com/topics/en-us/377
3. Society for Immunotherapy of Cancer (SITC) clinical practice guideline on immune effector cell-related adverse events | Journal for ImmunoTherapy of Cancer — jitc.bmj.com — https://jitc.bmj.com/content/8/2/e001511
4. A Refined Prognostic Scoring System for Myelodysplastic Syndromes: The IPSS-M | NEJM Clinician — clinician.nejm.org — https://clinician.nejm.org/refined-prognostic-scoring-system-myelodysplastic-syndromes-ipss-m-nejm-jw.NA55056
5. Genome Sequencing as an Alternative to Cytogenetic ... — www.nejm.org — https://www.nejm.org/doi/full/10.1056/NEJMoa2024534
6. Which lower risk myelodysplastic syndromes should be ... — www.nature.com — https://www.nature.com/articles/s41375-020-0967-x
7. Myelodysplastic syndromes current treatment algorithm 2018 | Blood Cancer Journal — www.nature.com — https://www.nature.com/articles/s41408-018-0085-4
8. Hematopathology (1387–1604) — www.nature.com — https://www.nature.com/articles/modpathol201813.pdf
9. Management of patients with lower-risk myelodysplastic syndromes | Blood Cancer Journal — www.nature.com — https://www.nature.com/articles/s41408-022-00765-8
10. Association between phenotypic features of blasts and the blast percentage in bone marrow of patients with myelodysplastic syndromes - ScienceDirect — www.sciencedirect.com — https://www.sciencedirect.com/science/article/abs/pii/S0145212604001201
11. Morphology, cytogenetics and classification of MDS - ScienceDirect — www.sciencedirect.com — https://www.sciencedirect.com/science/article/abs/pii/S1521692613000522
12. Diagnostic utility of flow cytometric immunophenotyping in myelodysplastic syndrome - ScienceDirect — www.sciencedirect.com — https://www.sciencedirect.com/science/article/pii/S000649712063110X
13. Evaluation of new IPSS-Molecular model and... : Blood Science — journals.lww.com — https://journals.lww.com/bls/fulltext/2023/07000/evaluation_of_new_ipss_molecular_model_and.6.aspx
14. Cytogenetics in the management of myelodysplastic neoplasms (myelodysplastic syndromes, MDS): Guidelines from the groupe francophone de cytogénétique hématologique (GFCH) - ScienceDirect — www.sciencedirect.com — https://www.sciencedirect.com/science/article/pii/S2452318623000338
15. Diagnostic flow cytometry for low‐grade myelodysplastic syndromes - Ogata - 2008 - Hematological Oncology - Wiley Online Library — onlinelibrary.wiley.com — http://onlinelibrary.wiley.com/doi/10.1002/hon.857/abstract
16. Guadecitabine vs treatment choice in newly diagnosed ... — ashpublications.org — https://ashpublications.org/bloodadvances/article-pdf/doi/10.1182/bloodadvances.2023010179/2056056/bloodadvances.2023010179.pdf
17. Prognostic models in myelodysplastic syndromes — ashpublications.org — https://ashpublications.org/hematology/article/2013/1/504/20752/Prognostic-models-in-myelodysplastic-syndromes
18. Frontline treatment options for higher-risk MDS: can we move ... — ashpublications.org — https://ashpublications.org/hematology/article/2023/1/65/506420/Frontline-treatment-options-for-higher-risk-MDS
19. The conundrum of drug development in higher-risk MDS — ashpublications.org — https://ashpublications.org/blood/article/147/8/811/548015/The-conundrum-of-drug-development-in-higher-risk
20. Myelodysplastic Syndrome and Acute Myeloid Leukemia ... — stacks.cdc.gov — https://stacks.cdc.gov/view/cdc/76951/cdc_76951_DS1.pdf
21. Diagnostic algorithm for lower-risk myelodysplastic syndromes | Leukemia — www.nature.com — https://www.nature.com/articles/s41375-018-0173-2
22. Impact of allogeneic stem cell transplantation in patients with higher risk myelodysplastic syndromes | Blood Cancer Journal — www.nature.com — https://www.nature.com/articles/s41408-026-01479-x
23. Outcome after allogeneic stem cell transplantation with ... — www.nature.com — https://www.nature.com/articles/s41409-023-01931-7
24. U2AF1 pathogenic variants in myeloid neoplasms and ... — www.nature.com — https://www.nature.com/articles/s41408-023-00922-7

## Editorial note

Prepared from cited clinical literature using Astra's research workflow. Verify recommendations against current guidance and patient-specific factors.