What Type Of Cancer Causes Low Hemoglobin

A number of medical conditions, such as chronic kidney disease can result in anemia in which red blood cells are not small (as in iron deficiency anemia) nor large (as in pernicious anemia). This is known as anemia of chronic disease.

The Link Between Anemia and Cancer

Julie Wilkinson is a registered nurse and book author who has worked in both palliative care and critical care.

Updated on July 27, 2022

Oliver Eng, MD, is a double board-certified surgeon and surgical oncologist and an Assistant Professor of Surgery at the University of Chicago.

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Table of Contents

Anemia—low red blood cell count or low hemoglobin—is common in people with cancer. Cancer itself can affect production, and chemotherapy can have both direct and indirect impact on your levels as well.

Having cancer doesn’t mean you’re not at risk for other potential causes of anemia too. Having cancer when one of these is at play only heightens your risk for anemia.

That’s why your healthcare team will monitor your blood carefully over the course of your illness. It’s also why a healthcare provider may pursue the possibility of a cancer diagnosis if you have anemia without an established cause.

Let’s look at the ways these two conditions are intertwined, and what you need to know to be able to identify symptoms and advocate in your health.

anemia symptoms

Cancer and Anemia Link

Anemia is caused by lower than normal levels of hemoglobin. Hemoglobin is a protein in red blood cells that carries oxygen to your cells.

The types of cancer most often associated with low hemoglobin include:

  • Blood cancers such as leukemia and lymphoma
  • Cancers that are associated with blood loss, such as colon cancer and cervical cancer

Cancer and anemia are linked in a number of ways. For those with cancer, especially colon cancer or blood-related cancer such as leukemia or lymphoma, anemia may be one of the first signs of the disease.

If you have anemia without a known cause (such as heavy menstrual bleeding), your healthcare provider may talk to you about screening for colon cancer, or other tests.

For people living with cancer, there are a number of possible causes of anemia, both those related to cancer, and those which can affect anyone with or without cancer.

What Causes Anemia?

Anemia can result from conditions that affect red blood cells directly, or may instead be caused by iron deficiency. The hemoglobin molecules in your red blood cells contain iron, which serves to attach and transport oxygen to your tissues.

Anemia is not a diagnosis, but rather a symptom with many possible causes.

When you have anemia, you have a reduced capacity for delivering oxygen to the tissues in your body. This can lead to symptoms such as fatigue, shortness of breath, and even unconsciousness if your anemia is severe.

Causes of Anemia Related to Cancer

Causes of anemia that are related to cancer (either due to cancer itself or due to treatments for cancer) include:

  • Bone marrow replacement: Some cancers, such as lymphomas or metastases from breast cancer can invade the bone marrow and replace the bone marrow cells which make red blood cells.
  • Chemotherapy: Chemotherapy can induce anemia.
  • Cytokines: High levels of cytokines related to some cancers can slow the production of red blood cells by the bone marrow.
  • Change in diet: Cancer itself can cause a poor appetite which can result in nutritional deficiencies leading to anemia. In addition to affecting the bone marrow, chemotherapy can cause symptoms such as mouth sores, taste changes, and loss of appetite that can lead to anemia.
  • Hemolytic anemia: This can occur in people without cancer but is particularly common in people with lymphomas.

Anemia Due to Chemotherapy

Chemotherapy attacks all rapidly growing cells, not just cancer cells, and the cells in the bone marrow that are used to replace white blood cells, red blood cells, and platelets are some of the most rapidly dividing cells in the body.

Chemotherapy is a common cause of anemia in people with cancer, and this occurs with many of the drugs commonly used.

Blood counts are usually done before each chemotherapy infusion, and if the red blood cell count is too low, chemotherapy may need to be delayed. Some people with cancer are treated with medications that stimulate the production of red blood cells so that chemotherapy can continue to be given.

In a 2016 study, 90% of people receiving chemotherapy for solid tumors were noted to have anemia. 

Anemia and Colon Cancer

Iron deficiency can be one of the first symptoms of colon cancer. Because the right side of your colon is distant to your rectum, blood in the stool has time to degrade and probably will not be recognizable by the time you pass it in a bowel movement.

Large tumors in this portion of the colon can continue to bleed slowly, and over time, this will be reflected in a low blood count.

In one study, 6% of people referred to a clinic due to iron deficiency anemia were found to have colon cancer.   Of these people, the majority of cancers were in the right colon.

Anemia at the time of diagnosis with colon cancer was linked with a poor prognosis in the past, but this does not appear to be the case in more recent studies.

Other Causes of Anemia

Some of the other possible causes of anemia include:

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Blood Loss

Blood loss leading to anemia can occur with certain cancers, but it can also happen for other reasons. Large amounts of blood can be lost during surgery, menstruation, or accident. The chronic loss of microscopic amounts of blood (such as from polyps in the digestive tract, ulcers, or even hemorrhoids) can also cause anemia.

Blood loss may also be moderate but greater than your body’s ability to keep up with the loss as is often seen among women with heavy menstrual periods.

Nutritional Deficits

A diet deficient in iron-rich foods may result in iron deficiency anemia, especially in women that have regular menstrual periods. A diet deficient in vitamin B12 can result in anemia characterized by large red blood cells (pernicious anemia). Folate deficiency can also lead to anemia.

Chronic Disease

A number of medical conditions, such as chronic kidney disease can result in anemia in which red blood cells are not small (as in iron deficiency anemia) nor large (as in pernicious anemia). This is known as anemia of chronic disease.


You may have difficulty absorbing iron from what you eat. Malabsorption can be the result of chronic intestinal diseases, such as Crohn’s disease, or a result of chronic diarrhea (your body cannot absorb the iron fast enough).

Destruction of Red Blood Cells

Conditions such as autoimmune hemolytic anemia can lead to the destruction of red blood cells. There are several drugs that can result in drug-induced hemolytic anemia including some antibiotics.

Anemia Symptoms to Lookout For

Anemia might be accompanied by symptoms that reflect your body’s deficit of red blood cells, including:

  • Feeling weak or tired all of the time
  • Shortness of breath (not related to a history of asthma or a cardiac condition)
  • Increased susceptibility to infection
  • Cold hands or feet
  • Pallor (most easy to see in the mucous membranes)
  • Pica (feeling the need to eat items that are not meant as food, such as dirt)

It’s important to note, however, that not everyone who is anemic has symptoms.

If you have one or more symptoms of anemia, especially if you have cancer or a known family history of colon cancer, do not delay talking to your healthcare provider.


Anemia is diagnosed on a complete blood count in which a low red blood cell count or low hemoglobin levels are noted.

  • Red blood cell count: A normal red blood cell count is 4.32 to 5.72 trillion cells/L in men and 3,90 t0 5.03 trillion cells/L in women.
  • Hemoglobin: A hemoglobin level less than 13.5 grams/100 ml in men or 12.0 grams/100 ml in women is considered low.
  • Hematocrit: A normal hematocrit is 42% to 54% in men and 38% to 46% in women.

In addition to the levels, healthcare providers look at other lab tests to learn more about the potential causes of anemia. Some of these include:

  • Mean corpuscular volume (MCV): MCV gives information about the size of red blood cells, whether normal, small (such as in iron deficiency) or large (such as in folate and B12 deficiency).
  • Red cell distribution width (RDW): RDW gives further information on the size of red blood cells and whether there are two different populations, which can point toward different causes.
  • Mean corpuscular hemoglobin concentration (MCHC): MCHC gives further information about the shape of red blood cells.


As noted, when the cause of anemia is not known in someone without cancer, tests to rule out cancer, especially colon cancer and blood-related cancers may be considered, depending on factors including a person’s age and more.

The treatment of anemia in people with cancer includes two primary steps. The first is the treatment of the underlying cause of the anemia, which can sometimes eliminate the cause. Treatment is also aimed at treating the anemia itself, especially if it is causing symptoms or has developed rapidly. 

Treatment of the Underlying Cause

The treatment of anemia will depend on the underlying cause, which as noted, can be a number of different things. For chemotherapy-induced anemia, your next infusion may need to be canceled or delayed until your counts have increased.

If your cancer has invaded your bone marrow, treatment addressing cancer in your bone marrow will be the first step.

Treatments for Anemia

Specific treatments for anemia may include:

  • Diet: If your anemia is mild, simply eating iron-rich foods may suffice. It takes some time (on the order of months) to restore your red blood cell count through this method alone. Iron-rich foods that may make good choices include liver (chicken or beef), red meat, iron-fortified cereals, and legumes.
  • Iron supplements: Iron supplements may be prescribed, but only take these under the advice of your healthcare provider. Studies suggest intravenous iron can be very helpful for some people with anemia due to cancer. These can be constipating, so your healthcare provider may recommend a stool softener as well.
  • Blood transfusion: A blood transfusion is a way to rapidly increase your red blood cell count and is usually used if your anemia is causing significant symptoms.
  • Medications: These stimulate the production of red blood cells in your bone marrow. The drugs Procrit or Epogen (epoetin alfa) or Aranesp (darbepoetin alfa) are similar to compounds made by our own bodies to stimulate red blood cell production.
  • Steroids: Steroids are sometimes used for the treatment of hemolytic anemia with lymphomas.


Anemia can be difficult to cope with, especially the resultant fatigue. While fatigue is not dangerous on its own, many people find cancer fatigue to be one of the most annoying symptoms of cancer and cancer treatments.

Some simple measures can help as your anemia is being evaluated and treated. Standing up or sitting up slowly can help to avoid orthostatic hypotension or the decrease in blood pressure which can lead to lightheadedness or “blacking out” when going from a lying down to a standing position too rapidly. 

Pacing yourself throughout the day and prioritizing activities is also helpful, as is learning to ask for help. Eating well and making sure you are hydrated is important both for anemia as well as coping with cancer itself.

Frequently Asked Questions

What are the risk factors for anemia?

Some risk factors for developing anemia include poor diet, family history of anemia, being over age 65, cancer, cancer treatment, intestinal disorders, alcohol use disorder.

Can anemia lead to complications for people with cancer?

Untreated and severe anemia can lead to further complications, including depression, heart problems such as arrhythmia and enlarged heart, and increased risk of infection.

10 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

  1. Alexiusdottir KK, Möller PH, Snaebjornsson P, et al. Association of symptoms of colon cancer patients with tumor location and TNM tumor stage. Scand J Gastroenterol. 2012;47(7):795-801. doi:10.3109/00365521.2012.672589
  2. Turner J, Badireddy M. Anemia. StatPearls.
  3. Spivak JL. Cancer-related anemia: its causes and characteristics. Semin Oncol. 1994;21(2 Suppl 3):3-8.
  4. Calabrich A, Katz A. Management of anemia in cancer patients. Future Oncol. 2011;7(4):507-17. doi:10.2217/fon.11.24
  5. Xu H, Xu L, Page JH, et al. Incidence of anemia in patients diagnosed with solid tumors receiving chemotherapy, 2010-2013. Clin Epidemiol. 2016;8:61-71. doi:10.2147/CLEP.S89480
  6. Raje D, Mukhtar H, Oshowo A, Ingham clark C. What proportion of patients referred to secondary care with iron deficiency anemia have colon cancer? Dis Colon Rectum. 2007;50(8):1211-4. doi:10.1007/s10350-007-0249-y
  7. Jimenez K, Kulnigg-dabsch S, Gasche C. Management of Iron Deficiency Anemia. Gastroenterol Hepatol (N Y). 2015;11(4):241-50.
  8. Lebrun F, Klastersky J, Levacq D, Wissam Y, Paesmanns M. Intravenous iron therapy for anemic cancer patients: A review of recently published studies. Supportive Care in Cancer. 2017;25(7):2313-2319. doi:10.1007/s00520-017-3672-1
  9. Figueroa JJ, Basford JR, Low PA. Preventing and treating orthostatic hypotension: As easy as A, B, C. Cleve Clin J Med. 2010;77(5):298-306. doi:10.3949/ccjm.77a.09118
  10. National Heart, Lung, and Blood Institute. Iron-deficiency anemia.
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Additional Reading

  • DeLoughery T. Iron deficiency anemia. Medical Clinics of North America. 2017;101(2):319-332. doi:10.1016/j.mcna.2016.09.004
  • Kasper DL, Fauci AS, Hauser SL. Harrison’s Principles of Internal Medicine. New York: Mc Graw Hill education, 2015. Print.

By Julie Wilkinson, BSN, RN
Julie Wilkinson is a registered nurse and book author who has worked in both palliative care and critical care.

What Type Of Cancer Causes Low Hemoglobin?

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Cancer and anemia are linked in a number of ways. For those with cancer, especially colon cancer or blood-related cancer such as leukemia or lymphoma, anemia may be one of the first signs of the disease.

Does colon cancer cause low hemoglobin?

A new study shows that most patients with colon cancer have a history of consistently declining hemoglobin levels up to four years before being diagnosed with the disease. Anemia, a common blood disorder characterized by low hemoglobin levels, has long been associated with those suffering from colorectal cancer.

What was your first colon cancer symptom?

A persistent change in your bowel habits, including diarrhea or constipation or a change in the consistency of your stool. Rectal bleeding or blood in your stool. Persistent abdominal discomfort, such as cramps, gas or pain. A feeling that your bowel doesn’t empty completely.

Does being anemic mean you have colon cancer?

Some common symptoms of anemia are fatigue, shortness of breath, racing heart and paleness. One of the many symptoms and warning signs of colon cancer is anemia. Tumors can bleed because they have their own fragile network of blood vessels, and you may feel fatigued and weak because the tumor is bleeding internally.

How do I know if I have anemia or cancer?

If you have cancer, it’s especially important to see your doctor and get tested for anemia if you experience symptoms like fatigue, a fast heartbeat, shortness of breath or trouble breathing during physical activity, dizziness, chest pain, swelling in your hands or feet, or paleness of your skin, nail beds, mouth, or …

What happens if low hemoglobin is not treated?

Anemia if not treated for a long period can lead to serious complications. These include heart failure, severe weakness and poor immunity. Anemia is a medical condition in which the person does not have enough red blood cells or RBCs. The RBCs in the blood carry iron a specialized protein called hemoglobin.

What is the main cause of low hemoglobin?

A lack of iron in the body is the most common cause of anemia. This is called iron-deficiency anemia. If you don’t get enough iron, your body cannot make hemoglobin.

Is hemoglobin 9.5 Low?

A normal hemoglobin level is 11 to 18 grams per deciliter (g/dL), depending on your age and gender. But 7 to 8 g/dL is a safe level. Your doctor should use just enough blood to get to this level. Often, one unit of blood is enough.

What are the symptoms of low Haemoglobin?

Typical symptoms of low hemoglobin include:

  • weakness.
  • shortness of breath.
  • dizziness.
  • fast, irregular heartbeat.
  • pounding in the ears.
  • headache.
  • cold hands and feet.
  • pale or yellow skin.

How do I raise my hemoglobin?

How to increase hemoglobin

  1. meat and fish.
  2. soy products, including tofu and edamame.
  3. eggs.
  4. dried fruits, such as dates and figs.
  5. broccoli.
  6. green leafy vegetables, such as kale and spinach.
  7. green beans.
  8. nuts and seeds.

Should I be worried about low hemoglobin?

If you have signs and symptoms of a low hemoglobin count, make an appointment with your doctor. Signs and symptoms can include: Fatigue. Weakness.

What is a critical low hemoglobin level?

Hemoglobin (Hb or Hgb) is a protein in red blood cells that carries oxygen throughout the body. A low hemoglobin count is generally defined as less than 13.5 grams of hemoglobin per deciliter (135 grams per liter) of blood for men and less than 12 grams per deciliter (120 grams per liter) for women.


How long does it take to raise hemoglobin levels?

In general, patients with iron deficient anemia should manifest a response to iron with reticulocytosis in three to seven days, followed by an increase in hemoglobin in 2-4 weeks.

Can low Haemoglobin cause death?

It results in anemia in person, and symptoms such as tiredness, headaches, and weakness occur. As the condition worsens, the person has chest pain and even shortness of breath, causing severe health issues. If heart conditions worsen, it can cause death.

What hemoglobin level requires a blood transfusion?

The American Society of Anesthesiologists uses hemoglobin levels of 6 g/dL as the trigger for required transfusion, although more recent data suggest decreased mortality with preanesthetic hemoglobin concentrations of greater than 8 g/dL, particularly in renal transplant patients.

What drink is high in iron?

Prune juice is made from dried plums, or prunes, which contain many nutrients that can contribute to good health. Prunes are a good source of energy, and they don’t cause a rapid hike in blood sugar levels. Half cup of prune juice contains 3 mg or 17 per cent iron.

How low can hemoglobin go before death occurs?

People also sometimes want to know how low can hemoglobin go before causing death. In general, a hemoglobin less than 6.5 gm/dL is considered life-threatening.

Will a full blood count detect cancer?

Complete blood count (CBC).

This common blood test measures the amount of various types of blood cells in a sample of your blood. Blood cancers may be detected using this test if too many or too few of a type of blood cell or abnormal cells are found. A bone marrow biopsy may help confirm a diagnosis of a blood cancer.

What is considered severe anemia?

Mild anemia corresponds to a level of hemoglobin concentration of 10.0-10.9 g/dl for pregnant women and children under age 5 and 10.0-11.9 g/dl for nonpregnant women. For all of the tested groups, moderate anemia corresponds to a level of 7.0-9.9 g/dl, while severe anemia corresponds to a level less than 7.0 g/dl.

Why do I need a colonoscopy if im anemic?

Conclusion: Colonoscopy is an effective modality to evaluate iron deficiency anemia, and use of ferritin as a predictor of colorectal neoplams can be effective in identifying those patients at higher risk for neoplasms.

What is a critical hemoglobin level?

An Hb value less than 5.0 g/dL (50 g/L) can lead to heart failure and death. A value greater than 20 g/dL (200 g/L) can lead to obstruction of the capillaries as a result of hemoconcentration.

What happens if your hemoglobin is too low?

If you have anemia, your hemoglobin level will be low too. If it is low enough, your tissues or organs may not get enough oxygen. Symptoms of anemia — like fatigue or shortness of breath — happen because your organs aren’t getting what they need to work the way they should.

Is 126 hemoglobin normal?

Normal hemoglobin levels are different in women and in men. Normal levels for females are between 120 g/L to 160 g/L. Normal levels for males are between 140 g/L to 180 g/L.

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Alex Koliada, PhD, is a well-known doctor. He is famous for his studies of ageing, genetics and other medical conditions. He works at the Institute of Food Biotechnology and Genomics NAS of Ukraine. His scientific researches are printed by the most reputable international magazines. Some of his works are: Differences in the gut Firmicutes to Bacteroidetes ratio across age groups in healthy Ukrainian population [BiomedCentral.com]; Mating status affects Drosophila lifespan, metabolism and antioxidant system [Science Direct]; Anise Hyssop Agastache foeniculum Increases Lifespan, Stress Resistance, and Metabolism by Affecting Free Radical Processes in Drosophila [Frontiersin].
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