Anemia, a condition characterized by a reduced number of healthy red blood cells or a lower-than-normal amount of hemoglobin, affects millions of people globally. Hemoglobin, a protein in red blood cells, is responsible for carrying oxygen from the lungs to the body’s tissues. When hemoglobin levels are low, the body’s organs and tissues may not receive sufficient oxygen, leading to symptoms like fatigue and weakness. This article clarifies the relationship between anemia and cancer, explaining how cancer can lead to anemia, discussing other common causes, and advising when further medical investigation is needed.
How Anemia Can Be Linked to Cancer
Anemia can arise in individuals with cancer through several distinct mechanisms. One common way is through chronic inflammation, often referred to as anemia of chronic disease. Cancer and its treatments can induce a systemic inflammatory response, which interferes with the body’s ability to use iron effectively for red blood cell production and can also shorten the lifespan of red blood cells.
Another significant cause is blood loss, especially with certain types of cancer. Gastrointestinal cancers, such as colorectal or stomach cancer, can lead to chronic, slow bleeding that may go unnoticed, gradually depleting the body’s iron stores and resulting in iron-deficiency anemia. Gynecological cancers, like uterine and cervical cancer, can also cause blood loss.
Cancer affecting the bone marrow, where blood cells are produced, can directly impair red blood cell formation. Cancers like leukemia, lymphoma, and multiple myeloma can infiltrate the bone marrow, crowding out healthy blood-forming cells and disrupting their production. Additionally, cancer treatments such as chemotherapy and radiation therapy can suppress bone marrow activity, further reducing the production of red blood cells.
Nutritional deficiencies can also contribute to anemia in cancer patients. Cancer itself or its treatments may impact appetite, alter metabolism, or cause malabsorption of essential nutrients like iron, vitamin B12, and folate, all of which are necessary for healthy red blood cell production.
Other Common Causes of Anemia
Many cases of anemia stem from causes unrelated to malignancy. Iron deficiency anemia is the most widespread type globally, often resulting from insufficient dietary iron intake, chronic blood loss (such as heavy menstrual periods), or impaired iron absorption due to gastrointestinal issues like celiac disease.
Vitamin deficiencies, particularly of vitamin B12 and folate, are also common causes of anemia. Vitamin B12 deficiency can result from inadequate dietary intake (especially in strict vegetarian or vegan diets) or, more frequently, from conditions that hinder its absorption, such as pernicious anemia, an autoimmune condition where the body cannot absorb vitamin B12. Folate deficiency often occurs due to poor diet lacking in leafy greens, or conditions affecting absorption in the digestive system. These deficiencies lead to the production of abnormally large, dysfunctional red blood cells.
Chronic kidney disease (CKD) is another frequent cause of anemia. Damaged kidneys may not produce enough erythropoietin (EPO), a hormone that signals the bone marrow to make red blood cells. Anemia becomes more common as kidney function declines. Other chronic conditions like autoimmune diseases and inflammatory bowel disease can also cause anemia of chronic disease. Genetic conditions, such as sickle cell anemia and thalassemia, involve inherited defects in red blood cell structure or hemoglobin production, leading to anemia from birth. Certain medications can also contribute to the development of anemia.
When Anemia Warrants Further Investigation
Common indicators include persistent fatigue, unusual paleness of the skin, shortness of breath, dizziness, cold hands and feet, and headaches. While these symptoms can be subtle and develop gradually, they should prompt a discussion with a healthcare provider.
It is crucial to avoid self-diagnosing and instead seek professional medical evaluation to determine the underlying cause of anemia. A doctor will typically begin with a physical examination and a review of your medical history. Initial blood tests often include a complete blood count (CBC), which measures the number of red blood cells, hemoglobin levels, and other blood components. Further tests, such as iron studies (serum iron, ferritin), vitamin B12 and folate levels, and reticulocyte count (which assesses new red blood cell production), help pinpoint the specific type of anemia.
Depending on the initial findings and the overall clinical picture, additional investigations may be necessary. If blood loss is suspected, tests like stool samples for hidden blood, endoscopy, or colonoscopy might be performed to examine the digestive tract. In cases where bone marrow issues are a concern, a bone marrow biopsy may be recommended to assess its function and cell production. Imaging tests might also be used to evaluate potential underlying causes. Identifying the root cause is essential for effective treatment, as a thorough diagnostic process ensures proper management.