Chemotherapy and Low White Blood Cell Counts

Neutropenia is often a side effect of cancer treatment, such as chemotherapy and radiation therapy. It is marked by the decrease of a type of white blood cell called neutrophils. These specialized white blood cells help fight off infection in the body. When neutrophil levels are low, the body has a tougher time successfully fending off foreign invaders, like bacteria.

Chemotherapy is a common cause of neutropenia. While chemotherapy directly targets cancer cells, it also affects our blood cells in the process -- red blood cells, white blood cells, and platelets. These cells are manufactured in the bone marrow. During chemotherapy, bone marrow activity may be decreased, resulting in lowered blood cell counts within the body.

White blood cells (WBC) generally drop to their lowest count about 7 to 14 days following a chemotherapy treatment. This is called the nadir period. When WBC are at their lowest count, people are at a heightened risk of developing infections.

Diagnosing Neutropenia

Neutropenia can be a serious side effect of treatment, so your doctor will carefully monitor your blood cell counts during treatment. A complete blood count (CBC) is a blood test that measures the levels of these cells in your blood. To diagnose neutropenia, your doctor will evaluate the absolute neutrophil count (ANC) portion of the CBC. The result of the ANC dictates your risk of infection and what treatment may be necessary to prevent or treat existing infection.

When discussing your CBC results, your doctor may talk about specific numbers in relation to your results. Of course, he or she will explain them in detail, but the summary below will help you get see the "bigger picture" in relation to ANC values:

Normal ANC Values: Normal ANC values range from 2,500 to 6,000 neutrophils per cubic millimeter. Ranges vary on a number of factors, from someone just getting over being sick; the presence of infection, diseases and other conditions that may influence count; and even race.

Mild Neutropenia:Once ANC counts drop to 1,000-1,500, this is considered to be mild neutropenia. If you have mild neutropenia, you aren't at a great risk of developing an infection, but your doctor will probably instruct you to look for any signs of infections and report back any changes.

Moderate Neutropenia: Moderate Neutropenia occurs when ANC levels are between 500-1,000. If you have moderate neutropenia, then your risk of developing infection is moderate. If you develop symptoms of infection, like fever, you may still be able to monitor them at home, but some people may require hospitalization depending on other factors and test results.

Severe Neutropenia: If you have a "neutropenic fever" (a fever as well as an ANC count below 500), hospitalization is usually required. People with severely low ANC counts often do not show any signs of infection when it is present. This is due to the lack of neutrophils to elicit a biological response.

Treating Neutropenia

If your ANC reveals a low neutrophil count, treatment may be necessary to prevent infection. Mild cases of neutropenia may only require monitoring at home for signs of infection while more severe cases may need hospitalization.

In some cases, your doctor may recommend a course of antibiotics to prevent infection before it develops. This is called prophylactic antibiotic therapy.

Other medications, called growth factors or granulocyte-colony stimulating factors (G-CSF), are often used to increase white blood cell production in the bone marrow. Commonly used growth factors include:

• Leukine (sargramostim)
  
• Neulasta (pegfilgrastim)
  
• Neupogen (filgrastim)

Your doctor may also want to halt or delay treatment until your neutrophil count is stable. A lowered dosage of chemotherapy may also be necessary.

Preventing Infection During Chemotherapy

When a person has reached WBC nadir or is neutropenic, common sources of bacterial infection must be avoided. This may include avoiding:

• Fresh cut flowers
  
• Fresh fruits and vegetables
  
• Close contact with ill persons and animals (especially stray animals)
  
• Raking dead leaves or other yard work
  
• Manicures and pedicures
  
• Public pools, hot tubs, and showers
  
• Meat that has been undercooked or is raw
  
• Soft cheeses

Restrictions are based on the white blood cell count, type of cancer being treated (people with blood cancers may be more restricted), dosage of chemotherapy, and whether the person has had a bone marrow transplant.

When to Call the Doctor

If you suspect that you may have an infection, report it to your treating physician or oncology nurse immediately. Signs of infection include:

• Fever - a temperature of 100.4 or higher (can be the only sign of infection)
  
• Sore throat or problems swallowing
  
• Pain during urination
  
• Coughing or breathlessness
  
• Severe mouth sore
  
• Loose stools

Again, when levels are really low, there may be no sign of infection. When counts are this low, your body may not elicit a response to infection because there are few WBC to do so. This is one of the reasons why people with severely low blood cell counts are hospitalized, even if they do not have a fever or other signs of infection.

_Source:

American Cancer Society. How Will Chemotherapy Affect My Blood Cell Count? 09/11/2008.
hhttp://www.cancer.org/Treatment/TreatmentsandSideEffects/PhysicalSideEffects/DealingwithSymptomsatHome/caring-for-the-patient-with-cancer-at-home-blood-counts