Myelosuppression as a Side Effect of Chemotherapy

Myelosuppression, sometimes called bone marrow suppression, is a common side effect of chemotherapy that is characterized by a decrease in blood cell production.

Three different kinds of blood cells are produced in the body's bone marrow – red blood cells, white blood cells and platelets. Myelosuppression can result in the decrease in one, two or all three types of blood cells. A decrease in red blood cells is the most common type of myelosuppression experienced by chemotherapy patients. This type of bone marrow suppression is referred to as anemia.

Lowered production of white blood cells is also fairly common among cancer patients. When the chemotherapy results in the reduction of neutrophils, a specific type of white blood cell, the myelosuppression is subcategorized as neutropenia.

A drop in platelet numbers is called thrombocytopenia. This type of bone marrow suppression is fairly rare, and only negatively affects less than 10 percent of all cancer patients. When an individual experiences a drop in all three types of blood cells, the condition is called pancytopenia.

Causes of Myelosuppression

The majority of chemotherapy drugs have been associated with myelosuppression. However, different chemo agents affect blood cell production in different ways. A list of the most common cancer drugs and their myelosuppression characteristics are listed below:

  • Fluorouracil: all forms of myelosuppression
  • Oxaliplatin: neutropenia and thrombocytopenia
  • Irinotecan: neutropenia
  • Capecitabine: all forms of myelosuppression

Typically, when the applicable drugs above are administered with bolus rather than continuous infusion, myelosuppression is more common. Cancer drugs such as bevacizumab and cetuximab are not commonly linked to reduced blood cell counts. However, when taken in combination with other drugs, the probability for bone marrow suppression increases.

Other causes of myelosuppression include nutritional deficiencies, viruses, therapeutic x-rays performed on cancer patients and cancer cells themselves. Sometimes, cancer cells attack the bone marrow, reducing their numbers. Other times, the cancer prevents bone marrow activity without invasion.

Symptoms of Myelosuppression

Myelosuppression does not hurt in and of itself. However, a number of side effects that result from low blood cell counts can have significant effects on an individual's health. While the majority of side effects are not life threatening, they can dramatically affect the patient's short-term quality of life.

Symptoms associated with myelosuppression vary depending on the specific type. The most common side effects of anemia include fatigue, dizziness and shortness of breath. Depending on the severity, anemic patients may also exhibit pale skin, especially at the lips and nail beds. Increased heart rate is another common symptom of anemia.

Neutropenia results in a reduction in the body's ability to fight off disease. As a result, fever and chills are the most common side effect of reduced white blood cells. Signs of infection may also be present, including swelling, redness or an area that is warm to the touch. Other common neutropenia side effects include diarrhea and rash.

Thrombocytopenia is most commonly characterized by easy bruising and bleeding from the nose, gums or mouth. Blood may also show up in urine or bowel movements. Small red spots on the skin, called petechiae, may also manifest.

Treatment of Myelosuppression

Blood cell numbers typically begin to drop seven to 10 days after chemotherapy begins. Once chemotherapy is completed, blood counts should return to normal after a few weeks. In mild cases, no treatment may be necessary. However, in rare cases chemotherapy can cause irreparable damage. If early signs of such damage are identified, or blood counts dip dangerously low, then chemotherapy may be stalled, reduced or stopped altogether to allow the bone marrow to recover.

Transfusions can be effective in replenishing red blood cells and platelets. However, relief is typically short-term and requires repeated treatments.

An alternative to transfusions is growth factor injections. These growth factors are natural chemicals that boost bone marrow performance. Different kinds of growth factors can be used to target the reproduction of red blood cells, white blood cells or platelets.

In rare cases where bone marrow is damaged beyond repair, a bone marrow transplant may be a required form of treatment.

Minimizing Myelosuppression Symptoms

For mild cases of myelosuppression that do not require additional medical treatment, there are several simple ways to reduce visible symptoms. These include:

  • Avoiding strenuous activities such as contact sports
  • Engaging in low-impact exercise
  • Avoiding foods with sharp edges that may promote bleeding
  • Abstaining from alcohol
  • Washing hands frequently to avoid infection
  • Eating a high-protein diet
  • Staying hydrated
  • Stop shaving the arms, legs and face

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