Anaemia After Cancer Treatment: The Fatigue Cause That Is Often Missed

Why it lingers after treatment

Chemotherapy suppresses marrow production, surgery and gastrointestinal effects cause blood and iron loss, inflammation blocks iron use, and appetite changes reduce intake. Recovery is often slower than people expect, and nobody rechecks because the numbers were improving at discharge.

Heavy periods, gastrointestinal bleeding, and coeliac disease are ordinary causes that do not stop existing because someone has had cancer, and they still need considering.

The tests worth asking for

A full blood count, ferritin, transferrin saturation, B12 and folate, renal function, and thyroid function cover most of the ground. Ferritin rises with inflammation, so a normal ferritin with low transferrin saturation can still mean functional iron deficiency, which is why the pair is more useful than either alone.

If iron deficiency is found, the cause needs identifying rather than only correcting; unexplained iron deficiency in an adult prompts a search for a source of loss.

Why the heart cares

Anaemia increases heart rate and cardiac output to maintain oxygen delivery. In a survivor whose reserve is already reduced by anthracyclines or chest radiation, that added workload can turn a manageable limitation into breathlessness on stairs. Correcting it sometimes resolves symptoms that were being attributed to permanent cardiac damage.

What treatment looks like

Oral iron works for many people but is slow and often poorly tolerated; intravenous iron is an option where absorption is poor, losses are ongoing, or oral iron is not tolerated. Improvement in fatigue lags the blood result by weeks, so recheck rather than judging by feel alone.