Myelodysplastic Syndromes (MDS)

What MDS is — in plain words

Think of your bone marrow as a factory producing red cells, white cells and platelets. In MDS, the factory is still running — but the assembly line is faulty. The cells produced are abnormal in shape and function (we say dysplastic), and many die before ever reaching the bloodstream. The result is low counts of one or more cell types, despite a marrow that may even look busy under the microscope.

A proportion of MDS cases — depending on the subtype and the genetics — eventually progress to acute myeloid leukemia (AML). That risk is why MDS is taken seriously, but progression is by no means inevitable; many people live with MDS as a stable, manageable condition.

Who tends to get MDS

MDS is mostly a disease of older adults — the median age at diagnosis is around 70. It's commoner in men. A small proportion of cases follow earlier chemotherapy or radiotherapy for another cancer (called therapy-related MDS). Most cases, though, have no clear cause.

How MDS tends to present

Most patients come to attention because of low blood counts found on a routine CBC, or because of symptoms from those low counts:

• Fatigue, breathlessness, palpitations, pale skin — from anaemia, by far the commonest presenting feature.
• Recurrent or prolonged infections — from low or dysfunctional white cells.
• Easy bruising, nosebleeds, gum bleeding, small red skin spots — from low platelets.
• An incidental finding on a blood test done for another reason — increasingly common.

"Most MDS patients I see have been tired for months and put it down to age. They are relieved when there's a name for what's wrong, and relieved again when we explain that for most of them, this is a condition we manage — not an emergency."

How we diagnose MDS

MDS cannot be diagnosed from blood tests alone. A proper bone marrow examination is essential.

1. Complete Blood Count with differential and reticulocyte count — confirms which cell lines are low, and rules out a simple cause (iron deficiency, B12, folate).
2. Iron studies, B12, folate, thyroid, kidney and liver function, LDH, EPO level — to exclude reversible causes and provide baseline values.
3. Peripheral blood smear — looks for dysplastic features in the circulating cells.
4. Bone marrow aspirate and biopsy — the definitive test. We look for dysplasia in at least 10% of cells in one or more lineages, count the blasts (immature cells), and assess for fibrosis. What the procedure is like →
5. Cytogenetics (chromosome analysis) and FISH — certain chromosome changes (such as isolated del(5q), or complex changes) carry very different prognoses.
6. Molecular testing (next-generation sequencing) — a panel of relevant genes (SF3B1, TP53, ASXL1, RUNX1, others) that increasingly refines both risk and treatment.

Risk stratification — the IPSS-R

Two patients can both have "MDS" and need entirely different treatments. The Revised International Prognostic Scoring System (IPSS-R) — and the newer molecular IPSS-M — assigns a risk category from very low to very high, based on:

• The percentage of blasts in the bone marrow.
• The cytogenetic findings.
• How low the haemoglobin, platelet and neutrophil counts are.

Risk category drives everything that follows. Low-risk MDS is treated mostly for symptoms; high-risk MDS is treated like a slow-motion leukemia.

Treatment — matched to risk

Lower-risk MDS

The goal is to manage symptoms and protect quality of life. Many patients do not need any anti-cancer drug at all.

Higher-risk MDS

The goal here shifts toward delaying transformation to AML and prolonging life.

• Hypomethylating agents (HMAs) — azacitidine, given as injections for seven days every four weeks, is the standard. It does not work overnight; we usually need four to six cycles before judging response. Many patients tolerate it well as outpatients.
• HMA-based combinations — venetoclax with azacitidine is now used in higher-risk MDS, particularly as a bridge to transplant.
• Allogeneic stem cell transplant — currently the only curative treatment for MDS. Reserved for fitter patients (broadly under 70 with a suitable donor and good organ function). The decision is finely balanced and made jointly with a transplant centre. Read more →
• AML-style induction chemotherapy — occasionally appropriate, particularly as a bridge to transplant.

What outcomes look like — honestly

Outlook in MDS spans a wide range. Lower-risk MDS patients often live many years with stable disease, sometimes with little more than periodic blood tests. Higher-risk MDS, untreated, behaves like a slow leukemia; treated with HMAs, many patients gain meaningful time and quality. For carefully selected fitter patients, stem cell transplant offers genuine cure. The IPSS-R score gives us a realistic prognostic range to share with you.

Daily life with MDS

Most lower-risk patients live almost normally — the main change is regular clinic visits and, for some, periodic transfusions. We'll plan transfusions around work and family. Patients on azacitidine have a week each month of injections; many take this in their stride. Throughout, we pay attention to infection prevention (vaccinations, prompt treatment of fevers), bleeding precautions (avoiding NSAIDs if platelets are low), and overall fitness — staying active really does help.

What to bring to your first visit

• All previous blood counts — even from years ago. Trends in MDS are diagnostic gold.
• Any previous bone marrow reports, with cytogenetics and molecular results.
• A list of current medications and any past chemotherapy or radiotherapy.
• A family member to listen and ask questions with you.