The Link Between Cancer and Anemia

If you have cancer and feel short of breath, tired, and lightheaded, you may be anemic. Anemia is a common side effect of cancer treatments, and in some instances, the cancer itself is the cause of anemia.

Anemia is a condition in which your body does not have enough red blood cells, the cells that carry oxygen to body tissues. Mild anemia may not bother you much, but moderate anemia causes fatigue and headache, among other symptoms, and severe anemia can be life threatening.

If you are being treated for cancer, your doctor will probably check to see if your red blood cell count or hemoglobin (an iron-rich protein) levels are low, especially if you are showing signs of anemia. A normal level in women is 12 grams per deciliter of blood (g/DL), in men it’s 15g/DL. If you show below-normal hemoglobin, your doctor may perform other blood tests to determine what’s causing the problem.

Possible anemia causes include an underlying iron or vitamin deficiency that may be unrelated to your cancer. Your doctor will find out why you are deficient and may recommend iron or vitamin supplements. The anemia also could be related to another chronic illness you have, such as an autoimmune disease like lupus.

Anemia and Cancer Treatments

Almost all cancer patients receiving chemotherapy drugs are mildly anemic and some 80 percent develop a more serious problem, according to the National Anemia Action Council. The type of chemotherapy you’re receiving, the stage of your cancer, and your overall health play a role in whether you will develop anemia.

Chemotherapy drugs target and kill fast-dividing cells in the body, whether they are cancer or not, says Zora R. Rogers, MD, a pediatric hematologist-oncologist at The University of Texas Southwestern Medical Center in Dallas. Cells in the bone marrow, where your blood cells are made, are particularly sensitive to chemo.

Chemotherapy temporarily decreases the bone marrow’s ability to make new blood cells, Dr. Rogers says. When red blood cell production drops, you become anemic. If hemoglobin levels fall to 8 g/DL or below in adults, it’s usually time for a transfusion of red blood cells, Rogers says.

People who develop anemia because of chemotherapy are at times given erythropoiesis-stimulating agents (ESAs) in hopes of increasing red blood cell production and decreasing the need for blood transfusions. Erythropoietin is a hormone in your kidneys that signals your bone marrow to make more red blood cells when needed.

But recent studies have questioned the safety and effectiveness of ESAs, such as epoetin alfa (Procrit, Epogen) and darbepoetin alfa (Aranesp). One study linked ESAs to the formation of potentially fatal blood clots. Talk to your doctor about the potential risks and benefits of taking ESAs.

Aside from chemo, radiation therapy to large areas of the body or to bones in the pelvis, chest, legs, or abdomen can damage the bone marrow and cause anemia.

When Cancer Causes Anemia

Sometimes the cause of anemia is the cancer itself or one of its complications. In general, cancer patients’ red blood cells wear out faster than normal and are not replaced as quickly as they are needed. Cancer can slow down your body’s ability to make red blood cells or interfere with your body’s ability to used stored iron.

The cancer you have may make you more prone to becoming anemic. The cancers most closely associated with anemia are:

  • Cancers that involve the bone marrow. Blood cancers like leukemia, lymphoma, and myeloma interfere with or destroy the marrow’s ability to make healthy blood cells. Other cancers that spread to the bone marrow can also cause anemia.
  • Cancers that cause blood loss. Gastrointestinal, urinary tract, male genital, head and neck, and cervical and vaginal cancers can cause bleeding and lead to anemia.

While cancer can cause anemia, anemia alone does not cause cancer, says Rogers. However, certain types of inherited bone-marrow failure syndromes, like Fanconi anemia, Diamond

Blackfan anemia, and Shwachman-Diamond syndrome, predispose a person to cancer. Still, it’s not the anemia that causes the cancer — underlyinsg defective cells are at fault, Rogers explains, adding that if cancer develops in these patients, it’s usually leukemia or squamous cell carcinomas.

Whatever the cause, it’s very important to treat your anemia. Severely anemic patients may not be able to get their cancer treatments on schedule or may have to get lower doses. Also, people with certain cancers and anemia may not respond to radiation therapy as expected.

Even if your anemia doesn’t interfere with cancer treatment, getting it under control will help restore your energy and improve your quality of life.

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