Someone in their late seventies has been tired for months. Not dramatically so, just flattened by stairs that never used to register, and short of breath hanging out washing. The GP does a full blood count, finds the haemoglobin is low, and starts iron tablets. Three months on, the tiredness has not shifted and the haemoglobin has barely moved. That moment, when the iron has not worked, is the one that matters. It is the point at which “anaemia” stops being an answer and starts being a question.
One of the answers behind that question is myelodysplastic syndrome, usually shortened to MDS. It is a blood cancer of older adults, it is reasonably common in people over 70, and most people in Ireland have never heard of it, including a fair number who are living with it.
TL;DR
- MDS is a group of bone marrow disorders in which the marrow produces faulty blood cells. The Irish Cancer Society puts Irish diagnoses at roughly 180 a year, using National Cancer Registry data.
- The classic signal is anaemia that does not respond to iron, often with a raised MCV (larger than normal red cells) and normal B12 and folate.
- Diagnosis needs a bone marrow aspirate and biopsy, not just more blood tests, so a haematology referral is the step that actually moves things forward.
- Ireland’s annual cancer statistics report prints individual rows for leukaemia, lymphoma and myeloma but none for MDS, and the HSE’s online A to Z has no entry for it.
- Lower-risk MDS is often managed for years with transfusions and injections rather than chemotherapy, and most people with MDS never go on to develop acute leukaemia.
What MDS actually is
Bone marrow is a factory. In MDS, the factory keeps running but the quality control fails: it turns out large numbers of malformed blood cells, many of which die before they ever reach the bloodstream. The Irish Cancer Society describes those faulty cells as “dysplastic”, which is where the name comes from, and notes that MDS is sometimes called bone marrow failure.
The practical consequence is a shortage of one or more of the three things marrow is supposed to make. Short of red cells, you are anaemic and exhausted. Short of neutrophils, you pick up infections that linger. Short of platelets, you bruise from nothing and bleed longer than you should. Many people start with only the first of those, which is exactly why MDS hides so well behind the phrase “a bit anaemic”.
It is a cancer, and people are often taken aback to hear that, because nothing about it looks like the cancer they have seen on television. The World Health Organization’s 2022 classification formally renamed the group “myelodysplastic neoplasms”, keeping the MDS acronym. Prior chemotherapy or radiotherapy raises the risk, so it can turn up years after someone was treated successfully for something else.
The condition Ireland collects but does not count
Here is something odd, and it has consequences.
The National Cancer Registry’s Cancer in Ireland 1994-2023 report states that it covers all invasive cancers and non-invasive neoplasms, ICD-10 codes C00 to C96 and D00 to D48. MDS sits inside that range, at D46. Yet when you work through the report’s incidence tables, there are separate lines for Hodgkin lymphoma (153 cases a year), non-Hodgkin lymphoma (860), multiple myeloma (400) and leukaemia (585), and the appendix list of D-codes runs D37, D38, D39, D40, D41, D42, D43, D44, then jumps to D47 and D48. There is no row for D46 anywhere in it.
The number exists. The Irish Cancer Society quotes around 180 Irish diagnoses a year and attributes its figures to the registry. It simply does not get published as a line of its own in the national statistical report, which means MDS is effectively invisible in the document that shapes how Ireland talks about cancer burden.
The gap repeats elsewhere. The HSE’s online health A to Z carries hundreds of conditions, including lung cancer, iron deficiency anaemia and vitamin B12 anaemia, but has no entry for MDS, and none for leukaemia, lymphoma or myeloma either. If you go looking for plain-English Irish information after a diagnosis, the state does not have a page for you. The Irish Cancer Society does, and its MDS section plus its 128-page booklet are currently the best Irish starting point there is.
What it looks like from the inside
Internationally, MDS occurs in roughly 3 to 4 people per 100,000 across the whole population, but that figure climbs to somewhere between 7 and 35 per 100,000 in people aged 60 and over. It is more common in men. In other words, the risk is heavily loaded towards exactly the age group most likely to have their fatigue filed under “well, you’re not 40 any more”.
The patterns worth noticing:
- Anaemia that iron does not fix. If the haemoglobin has not responded after a proper trial of iron, the diagnosis was probably not iron deficiency.
- A raised MCV. Red cells that are larger than normal, with normal B12 and folate levels, is a combination that deserves a second look rather than a repeat prescription.
- More than one cell line falling. A low haemoglobin alongside a low white cell count or low platelets is a different conversation from anaemia on its own.
- Infections that keep coming back, chest infections in particular, or ones that take longer to clear than they used to.
- Bruising, nosebleeds or gums that bleed when you brush.
None of these prove anything by themselves. Plenty of people have a slightly odd blood count for entirely benign reasons. The point is that the combination, and especially the failure to respond to treatment, is information rather than noise.
What to ask, and what to push for
Ireland has rapid access clinics for breast, lung and prostate cancer. There is no equivalent front door for blood cancers, so the route runs through your GP to a hospital haematology service, and persistence genuinely matters. Useful questions:
- Has the full blood count been repeated, and are the numbers going in the wrong direction over time?
- What was the MCV, and have iron, B12 and folate all been checked?
- Has a blood film been looked at by the laboratory rather than just the numbers?
- If the anaemia is unexplained, or if two or three cell lines are low, is a haematology referral warranted now?
Our guide to reading your blood test results covers what those values mean in more detail, and our piece on anaemia after 50 sets out the more common causes that come first.
How it gets diagnosed
MDS cannot be confirmed from blood tests alone. It needs a bone marrow aspirate and biopsy, usually taken from the back of the hip under local anaesthetic as a day procedure. The aspirate shows the shape and maturity of the cells and the percentage of immature blast cells; the biopsy shows how crowded or empty the marrow is. People dread it more than they need to, and it is over in well under half an hour.
Alongside that, the laboratory looks at chromosomes and at a panel of gene mutations. That is not academic detail: it decides which treatment is worth trying. The results feed into risk scores, the IPSS-R and the newer molecular IPSS-M, which sort people into lower-risk and higher-risk disease. The two scores disagree in roughly one case in ten, so if you have been told your risk category, it is reasonable to ask which system produced it.
Worth saying clearly: not every abnormal result is MDS. Older adults can have clonal changes in the marrow without disease, labelled CHIP or CCUS, and current expert practice is to monitor those rather than treat them.
What treatment looks like
For lower-risk disease, which is where most people start, the aim is not to cure but to keep you well, keep your haemoglobin up and keep you out of hospital. That usually means some combination of:
- Red cell transfusions, given on a haematology day ward, often every few weeks.
- Erythropoiesis-stimulating agents, injections that prompt the marrow to make more red cells, with response rates reported between 30 and 60 per cent.
- Luspatercept, an injection every three weeks. In the COMMANDS trial it produced a response in 60.4 per cent of people compared with 34.8 per cent on a standard erythropoietin injection.
- Imetelstat, authorised across the EU on 7 March 2025 for transfusion-dependent lower-risk MDS where erythropoietin has stopped working. In its trial, 40 per cent of people went at least eight weeks without needing a transfusion, against 15 per cent on placebo.
- Lenalidomide, for the specific subtype with a deletion on chromosome 5.
For higher-risk disease, azacitidine is the mainstay. In the AZA-001 trial it extended median survival to 24.5 months against 15 months for standard care, and the benefit held regardless of age, including in people over 75. Stem cell transplant remains the only curative option, but it is demanding and suits only a minority of older patients.
One piece of reassurance that rarely gets said out loud: although MDS can transform into acute myeloid leukaemia, most people with MDS die of its complications without ever transforming. The fear of “turning into leukaemia” dominates the first few weeks after diagnosis far more than the statistics justify.
Living with it in Ireland
If you become transfusion-dependent, iron builds up over time, and that matters. One study found median survival from the point of transfusion dependence was 5.2 years in people receiving iron chelation compared with 2.1 years in those who were not, and American guidelines suggest chelation once ferritin passes 2,500 ng/mL. Ask whether your ferritin is being tracked.
Other practical points. Keep flu, COVID-19 and pneumococcal vaccination up to date, and treat a fever during active treatment as urgent rather than something to sleep off. Tell your dentist. Hospital treatment is free in the public system, and if any of your medicines are dispensed in the community, the Drugs Payment Scheme caps a household at €80 a month. And once you have had a transfusion you are no longer eligible to donate blood yourself, which catches long-standing donors off guard.
For support, the Irish Cancer Society’s freephone Support Line on 1800 200 700 is staffed by cancer nurses Monday to Friday, 9am to 5pm, with Daffodil Centres in 13 hospitals nationwide and email at supportline@irishcancer.ie. For anyone interested in trials, Blood Cancer Network Ireland, based at University of Galway, runs early-phase blood cancer studies and a national biobank.
The thing to take away
Tiredness in your seventies is not automatically a diagnosis, and it is not automatically nothing. The useful discipline is to treat an unexplained anaemia the way you would treat an unexplained lump: as something that gets followed up until there is an actual answer. A condition that Ireland’s own statistics report never names is one that patients and families will have to name for themselves.
At Críonna Health we write about ageing as something to be navigated with good information rather than endured quietly. If a blood result has been drifting for months without explanation, that is worth a conversation, not a shrug. Our guide to fatigue after 50 is a good place to start working out which kind of tiredness you are dealing with.
This article is for general information and is not a substitute for individual medical advice. If you have symptoms that concern you, speak to your GP.
📷 Photo by ManuelTheLensman on Unsplash
