Cancer therapy can lower your blood cell counts and chemotherapy especially can affect rapidly dividing bone marrow cells. This hinders the marrow's ability to supply new cells to the blood during treatment and for some time after. White cell counts decrease most quickly, followed by decreases in platelet counts and then red cells.
Some drugs, however, have little or no damaging effect on the marrow. The effects of other drugs can either be reversed once therapy is stopped or may last for several weeks. The severity of the drug therapy's effects depend on several factors, including:
- Whether the marrow has already been damaged by the cancer before treatment
- The type and duration of the drugs
Without treatment, low blood counts can cause the following conditions:
- Anemia, an iron deficiency caused by low numbers of red cells that can no longer supply an adequate amount of oxygen
- Thrombocytopenia, caused by low numbers of platelets, resulting in bleeding and easy bruising
- Neutropenia and monocytopenia as a result of too few neutrophils and monocytes (types of white cells), which impair the body's ability to fight infections
- Low numbers of all three blood cell counts is called pancytopenia.
Anemia and Low Red Cell Counts
Anemia is caused by a low red cell count. Its side effects include:
- Fatigue or shortness of breath, especially with physical activity
- Pale skin, gums or nails
- Light-headedness or dizziness
- A tendency to feel cold
Most people with a mild or moderate decrease in red cells don't realize they're anemic. However, anemia can become severe if you continue to produce too few red cells. Your doctor may prescribe a red cell growth factor or a blood transfusion for severe anemia to help restore your red cell count.
Erythropoiesis-stimulating agents (ESAs) are another class of drugs your doctor may use to improve your anemia. ESAs such as Epogen®, Procrit® and Aranesp® are synthetic versions of erythropoietin, a hormone produced in the kidneys that stimulates the body to produce red blood cells. ESAs are injected under your skin. Some studies suggest that ESAs may increase the risk for blood clots because they correct anemia too vigorously. Also, in some forms of cancer, the use of an ESA may be associated with a worse outcome. If your doctor prescribes an ESA, you'll be given information and guidelines from the Food and Drug Administration about the drug. Talk with your doctor about the risks and benefits of this therapy.
Your doctor may also recommend blood transfusions to raise your blood cell count and alleviate symptoms. If you're given blood transfusions, you're more susceptible to developing iron overload. See Iron Overload for more information.
Bleeding and Low Platelet Counts
A mild or moderate decrease in platelet counts usually doesn't cause bleeding. However, if you have a severely low platelet count, you may experience:
- Excessive bleeding from cuts or bruises
- Pinhead-sized bleeding points in the skin, called petechiae, especially on the lower legs and ankles
- Black-and-blue spots on the skin from minor bumps without any apparent injury
- Reddish or pinkish urine
- Black or bloody bowel movements
- Bleeding from the gums or nose
- Pain in joints and muscles
Once therapy is completed and the platelet count is restored to a sufficient level, these side effects rapidly fade. However, if you need to receive additional treatment and your platelet count remains low, you may need platelet transfusion. Certain medications can weaken the platelets and worsen bleeding problems as well.
Low Platelet Counts: 7 Ways to Avoid Problems
Follow these tips to help prevent or lessen the effects of low platelet counts:
- Ask your doctor whether it's safe to take aspirin, acetaminophen, ibuprofen or other over-the-counter or prescribed medicines.
- Don't drink alcoholic beverages without your doctor's approval.
- Use an extra soft toothbrush and follow your dentist's and doctor's advice for caring for teeth and gums or for any dental work.
- Blow gently into a soft tissue to clean the nose.
- Avoid cuts or nicks from scissors, needles, knives or tools. Use an electric shaver instead of a razor.
- Be careful not to burn yourself when ironing, cooking or baking.
- Avoid contact sports and other activities that might result in injury.
Infection and Low White Cell Counts
A severe or prolonged low white cell count puts you at an increased risk for infection, therefore your doctor may prescribe growth factors that can stimulate your marrow to make new white cells to prevent or reduce infections. The growth factors can also be used to help the marrow recover after marrow transplantation and stem cell transplantation.
Growth factors called colony-stimulating growth factors may cause mild bone pain, usually in the lower back or pelvis, about the time the white cells start to come back in the marrow. This mild pain lasts only a few days and your doctor can prescribe a painkiller. Be aware, however, that doctors are cautious when prescribing these medications for people with cancer that involves the bone marrow, because growth factors might stimulate cancer cell growth.