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Is Anemia a Sign of Cancer?
Anemia, or having a low red blood cell count, can make you feel tired, weak, or short of breath. Having certain types of anemia can sometimes be a symptom of cancer, but there are many other causes of anemia. If you are experiencing fatigue or have been told you have anemia, it’s important to find out what is causing it and what you can do to help prevent and manage it.
What is anemia?
Anemia is a condition where you don’t have enough red blood cells (RBCs) circulating in your blood. RBCs have an iron-rich protein called hemoglobin (Hgb), which carries oxygen throughout your body. Cells in your body need oxygen to function and survive. When you don’t have enough RBCs carrying oxygen through your blood, it can make you feel tired, weak, short of breath, or cause other symptoms.
Anemia can be:
- Acute, coming on suddenly due to an injury, surgery, trauma, or acute illness.
- Chronic and long-lasting; some types may never go away completely.
- Mild, moderate, or severe depending on the RBC and hemoglobin levels.
There are many different types, or categories, of anemia. They are usually named for their cause or risk factor.
How do I know if I have anemia?
Anemia is found by doing a blood test called a complete blood count (CBC) to check your RBC and hemoglobin levels.
This test might be done to check for anemia because of symptoms you are having. However, you might not feel any effects of anemia until your hemoglobin level is very low.
Common signs and symptoms of anemia are:
- Extreme tiredness (fatigue)
- Fast heartbeat
- Chest pain
- Shortness of breath
- Dizziness or lightheadedness
- Swelling in the hands or feet
- Pale skin, nail beds, mouth, or gums
If anemia is found on a CBC, other tests might be needed to find out the exact cause.
How serious is anemia?
Anemia can range from mild to severe. Certain health problems such as heart or lung problems can make anemia symptoms worse.
Call 911 or go to the emergency room if you have:
- Bleeding that won't stop
- New or worse confusion
- Shortness of breath even when resting
- Chest pain or irregular heartbeat
Is anemia a symptom of cancer?
Anemia can be a symptom of cancer. Certain cancers affect the bone marrow, where blood cells are made. This can affect cause low blood counts and result in anemia. These cancers include:
- Leukemia
- Lymphoma
- Multiple myeloma
- Myelodysplastic syndromes
Other cancers can cause anemia due to chronic inflammation, blood loss, or poor nutrient absorption.
Anemia can also be a side effect of cancer treatment. For example, chemotherapy and radiation therapy can damage the bone marrow and lower RBC levels, which can lead to anemia.
Other causes of anemia
Most people with anemia do not have cancer. Anemia can be caused by many different conditions.
Nutrition problems
Inadequate nutrition or having a condition that causes nutrients not to be absorbed properly can cause anemia. This is called having a deficiency.
- Iron-deficiency anemia is caused by not enough iron in the body, leading to low hemoglobin levels and fewer RBCs. Excess blood loss from gastrointestinal (GI) bleeding and heavy menstrual periods can also cause iron-deficiency anemia.
- Vitamin deficiency anemia is due to having not enough of a specific vitamin in the body. Examples include Vitamin B12 (cobalamin) or Vitamin B9 (folate) deficiency.
Long-term health problems
Some chronic or long-term health problems can lead to anemia. Since all blood cells are produced in the bone marrow, any condition that affects the bone marrow or how nutrients are circulated can cause anemia.
- Aplastic anemia is a rare but very serious types of anemia. It’s caused by bone marrow failure leading to low RBCs (as well as white blood cells and platelets).
- Other bone marrow disorders or blood disorders.
- Chronic organ problems such as thyroid, kidney, or liver disease can affect how RBCs are circulated which can lead to anemia. Some autoimmune and immune disorders may have a similar effect.
Trauma or injury
Blood loss from an injury, major surgery, or other trauma causes anemia. This may be mild or severe, depending on the type of injury and where it’s located in the body.
Inherited or acquired blood disorders
Certain types of anemia are caused by inherited genes (genetic change or mutation) from parents. Others may develop later.
- Sickle cell anemia is a genetic disorder where RBCs are stiff and sickle-shaped, or shaped like a crescent instead of being normally round. This blocks blood flow and oxygen to parts of the body.
- Hemolytic anemia is a condition where RBCs are destroyed by the body faster than they can be replaced. Certain types are inherited, while others develop due autoimmune disorders, infections, medications, or toxins.
- Thalassemia is a genetic disorder where the body makes an abnormal form of hemoglobin, leading to excessive destruction of RBCs.
- Dyserythropoietic anemia or congenital dyserythropoietic anemia (CDA) is rare and happens when the bone marrow is not able to produce enough RBCs.
- Iron-refractory iron deficiency anemia (IRIDA) is a rare form of iron deficiency anemia that doesn’t respond well to iron supplements.
Medicines and treatments
- Certain medicines taken can have anemia as a side effect. These include aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), steroids, and antibiotics.
- Cancer treatments such as surgery, chemotherapy, and radiation therapy can cause anemia. Read more about anemia as a side effect of cancer treatment.
Can anemia be prevented?
There is no sure way to prevent anemia, but there are some things you can do that might help reduce your risk.
- Eat a healthy diet and consider supplements. Be sure you are getting enough iron, folate, vitamin B12, and other nutrients. Talk to your doctor about any supplements you might need.
- Manage any chronic conditions. Get routine care that’s recommended for managing any chronic conditions you may have, like thyroid, kidney, liver, or autoimmune disorders.
- Get regular checkups. Regular physical exams and blood tests can help find signs of anemia and other problems.
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.
American Society of Hematology (ASH).Anemia. Accessed at https://www.hematology.org/education/patients/anemia on February 24, 2025.
Drew RE. Causes of anemia in patients with cancer. UpToDate. 2023. Accessed at https://www.uptodate.com/contents/causes-of-anemia-in-patients-with-cancer on February 24, 2025.
Means RT & Brodsky RA. Diagnostic approach to anemia in adults. UpToDate. 2024. Accessed at https://www.uptodate.com/contents/diagnostic-approach-to-anemia-in-adults on February 24, 2025.
Last Revised: February 26, 2025
American Cancer Society medical information is copyrighted material. For reprint requests, please see our Content Usage Policy.
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