Neutropenia is a condition caused by lower-than-normal amounts of neutrophils, a type of white blood cell. Neutrophils fight infection in the body by killing harmful bacteria and other blood-borne pathogens.
The most common cause of neutropenia during breast cancer treatment is chemotherapy, though other types of cancer medicine can also cause it. Chemotherapy can cause neutropenia because it kills rapidly dividing cells, such as cancer cells. It can also affect other quickly dividing cells in our bodies, including white blood cells, red blood cells, and platelets. When chemotherapy destroys too many white blood cells, neutropenia occurs. This can put you at a higher risk of infections, which is one of the most serious complications of chemotherapy. If you have other health problems besides cancer, such as an autoimmune disease like HIV, you are also at a higher risk.
Not everyone who has chemotherapy develops neutropenia, and the symptoms and how severe they are can vary, so talk with your health care team about your treatment plan and the risk of developing neutropenia.
Neutropenia doesn’t always cause symptoms you can see or feel. You may first learn you have it from the results of blood tests that you get before each chemotherapy treatment. These tests check on important features of your blood, including your white blood cell count. Your white blood cell count shows the number of infection-fighting neutrophils in your blood.
While neutropenia occurs due to low counts of neutrophils, febrile neutropenia occurs when an individual gets a fever during a period of neutropenia. The primary symptom of febrile neutropenia is a fever of more than 38 degrees centigrade, along with a low white blood cell count. Fever is often the first sign of infection and if the neutrophil count is very low, there is a greater chance of serious infection compared to having a fever with a normal or near-normal neutrophil count. Neutrophil counts usually start to decrease about a week after each round of chemotherapy. They reach their lowest point about one to two weeks after your treatment day. You’re most likely to get an infection at that point in time.
Noticeable symptoms of infection can include:
- Fever
- Pain when you urinate
- Lower back pain
- Sinus pain
- Chills
- Redness, swelling, pain, or warmth of the skin at the site of an injury, or around a central line catheter or port
- Diarrhea
- Breathlessness or coughing
- Unusual vaginal itching or discharge
- Sore throat
- Fatigue
It is important to be monitored by your healthcare team when receiving chemotherapy to watch for signs of febrile neutropenia. During the course of treatment, you should expect to have routine blood tests to measure levels of white blood cells. If you present with a fever accompanied by symptoms of febrile neutropenia, healthcare professionals should take your medical history, administer a physical examination, take blood to measure your level of white blood cells, and perform a chest x-ray and urine analysis to determine the site of infection.
Other cancer treatments that may cause neutropenia include:
- Radiation therapy
- Some targeted therapies such as:
- Olaparib (Lynparza)
- Talazoparib (Talzenna)
- Ado-trastuzumab emtansine (Kadcyla)
- Pertuzumab (Perjeta)
- Trastuzumab (Herceptin)
Metastatic breast cancer treatments can also cause neutropenia because continuous treatment increases the risk of cumulative effects on the bone marrow, and this can increase the risk of lowering your white blood cell count. If you develop neutropenia, the ongoing nature of metastatic breast cancer treatment does put you at higher risk of developing a serious infection. And while rare, neutropenia can also happen if breast cancer that has traveled to the bones, called bone metastasis, becomes very advanced. If the cancer is in bones that have a lot of bone marrow, such as the pelvis or femur, it can crowd out healthy bone marrow cells. And because bone marrow is an important source of white blood cells, crowding out marrow cells can cause neutropenia.
Febrile neutropenia can delay treatments to allow the white blood cell count to recover. If you develop a complication or a serious infection due to febrile neutropenia, your cancer treatment may have to be changed or stopped altogether. Usually, results from treatment are the best when chemotherapy can be given at the original dose and on schedule. If you are at high-risk of developing febrile neutropenia or develops it during treatment, your doctor will prescribe medicines to reduce the risk of infection, such as a G-CSF (a type of growth factor that makes the bone marrow produce more white blood cells) or antibiotics. Growth factors are only used when necessary and they are not given to all patients. Your health care team will talk with you about what is best for you.
Growth factors have side effects, and these will be different for each person. The most common side effect is bone pain. This may be a dull ache or discomfort in the bones of your back, arms, legs, or hips. This pain is usually mild and goes away once you have stopped treatment with growth factors. Sometimes the skin around the injection site can get red or itchy. You might get fever or chills when you get growth factors.
When diagnosed with a low white blood cell count, you are more susceptible to bacteria and infection. It is important to report any signs of infection to your healthcare team. Below are a few tips to stay healthy during treatment.
- Wash your hands often.
- Practice good oral hygiene.
- Avoid contact with people who are ill, or people who live with a person who was recently sick.
- Try not to clean up after pets (cats or dogs) when they have a bowel movement. Also, do not clean fish tanks.
- Clean any cuts and cover them with a bandage.
- 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.
- Get enough rest, eat a well-balanced diet, drink plenty of fluids and get regular exercise.
- Cook vegetables and wash and peel fruit to get rid of any surface bacteria. Avoid uncooked eggs, raw or undercooked meats, poultry, fish, and seafood.
- Talk to your health care team about intimacy. You may need more lubrication than usual. If you have sex, have a warm shower right afterward and clean yourself well. If you have a very low white blood cell count, you should not be having sex at all.
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