Many chemotherapy treatments cause low white blood cell (WBC) counts, or neutropenia. This means you have lower than the normal amounts of neutrophils, a type of white blood cell that fights infection by killing harmful bacteria in the blood. A normal neutrophil count, also known as the Absolute Neutrophil Count, or ANC, is between 2,500 and 5,000. A low neutrophil count of less than 1,000 is known as neutropenia.
Neutropenia puts you at an increased risk of infection, which is one of the most serious complications of chemotherapy.
Neutropenia doesn’t usually cause any symptoms you can see. You may only learn you have neutropenia based on the results of a blood test that reports your WBC and ANC. These blood tests are normally done before each chemotherapy treatment, or if you get an infection.
Symptoms of Infection May Include:
- Pain when you urinate or new lower back pain
- Stuffed nose
- Shaking chills
- Redness, swelling, pain, or warmth at the site of an injury, around a central line catheter, or of the skin
- Diarrhea or change in the odor of your stool
- Breathlessness or cough
- Unusual vaginal itching or discharge
- Sore throat
An infection in a person with neutropenia is an emergency and considered life-threatening. If you have neutropenia, even a minor infection can quickly become serious. Seek immediate help from your doctor if your fever is over 100.4 degrees Fahrenheit or you have any other signs of infection.
Chemotherapy targets cells that divide quickly, such as cancer cells. Chemotherapy can also affect quickly dividing normal cells, such as those made in our bone marrow, including white blood cells, red blood cells and platelets. When white blood cells are destroyed, neutropenia occurs. But not everyone who has chemotherapy develops neutropenia, and the symptoms and how severe they are can vary among those who do.
Neutropenia Can Also Be Caused By
- radiation therapy
- some targeted therapies
- exposure to other medicines or chemicals
- vitamin deficiencies, such as B12, folate, or copper
- a virus
- other diseases caused by infection or a parasite
Your doctor can also lower your risk of chemotherapy-induced neutropenia with medicines called growth factors, which help increase blood counts. These are injections given under the skin. Your providers are more likely to recommend using growth factors with chemotherapies that have the highest chance of causing neutropenia.
Neutrophil counts usually start to go down about a week after each round of chemotherapy. They reach their lowest point about 7 to 14 days after treatment. This is when you are most likely to get an infection. Your neutrophil level should go back to normal between 3 and 4 weeks after treatment ends.
Your doctor may prescribe a growth factor such as filgrastim (Neupogen) or pegfilgrastim (Neulasta) to help raise your white blood cell counts. Or, you may receive one of their biosimilars filgrastim-sndz (Zarxio), a biosimilar of filgrastim, or pegfilgrastim-jmdb (Fulphila), a biosimilar of pegfilgrastim. Some medicines, like filgrastim, are made of living cells. This makes it impossible to create a generic version of the medicine that is exactly alike. But medicines can be created that are very similar. These are called biosimilars. They are designed to work as well and be as safe as the original medicine, but may be significantly less expensive.
Sometimes growth factors are not enough to get your white blood cell counts back up. If white blood counts stay very low between chemotherapy cycles, your doctor may adjust your treatment dose or schedule.
If you have neutropenia, here are some steps you can take to help reduce your risk of an infection:
- Your best line of defense is to wash your hands often! Keep your hands clean, and encourage those who come into contact with you to do the same
- Brush your teeth regularly
- Avoid contact with sick people (with a cold, the flu, etc.) or with people who have someone at home who was recently sick
- Clean all wounds and cover them with a bandage
- Avoid raw foods, including fruits with thin peels (such as grapes, peaches, nectarines) and uncooked vegetables; undercooked meat, fish, and eggs; unpasteurized milk, yogurt, cheese, and dairy products; and well water
- Avoid large crowds where there is a greater chance of contacting germs, such as shopping malls, houses of worship, or other large gatherings
- Avoid swimming or wading in hot tubs, ponds, lakes, and rivers