How Does Cancer Cause Anemia?

Cancer or cancer treatment can lead to anemia by causing blood loss or disrupting normal red blood cell production.

• If the cancer grows in the bone marrow, there may not be enough space for red blood cell production.
• Cancer or some cancer treatments may cause your body to slow its production of red blood cells.
• Cancer or treatment may affect your ability to eat a healthy diet or to absorb nutrients from the foods you eat, contributing to iron, folate or vitamin C or B12 deficiencies (nutrients needed for red blood cell productions).
• Some cancers may keep immature red blood cells from developing into fully functioning oxygen-carrying red blood cells.
• Some cancers or cancer treatments may speed up the destruction of red blood cells.
• If the kidneys are not functioning normally (renal disease), they may not be able to secrete enough of the hormone, erythropoietin.
• Anemia may result from other diseases or problems such as hypothyroidism or malnutrition.
• Some cancers, such as colorectal cancer, can cause internal bleeding.

Read more about red blood cells in the next section.